The BKG Ntrip Client (BNC) is a program for simultaneously retrieving, decoding, converting and processing real-time GNSS data streams. It has been developed within the framework of the IAG sub-commission for Europe (EUREF) and the International GNSS Service (IGS). Although meant as a real-time tool, it comes with some Post Processing functionality. You may like to use it for data coming from NTRIP Broadcasters like
BNC has been written under GNU General Public License (GPL). Source code is available from Subversion software archive http://software.rtcm-ntrip.org/svn/trunk/BNC. Binaries for BNC are available for Windows, Linux, and Mac OS X systems. We used the MinGW Version 4.4.0 compiler to create the Windows binaries. It is likely that BNC can be compiled on other systems where a GNU compiler and Qt Version 4.8.4 or any later version are installed. Please ensure that you always use the latest precompiled version of BNC available from http://igs.bkg.bund.de/ntrip/download. Note that static and shared builds of BNC are made available. A static build would be sufficient in case you don't want BNC to trace PPP results using Google Map (GM) or Open StreetMap (OSM). However, GM/OSM usage requires the QtWebKit library which can only be part of BNC builds from shared libraries. Using a shared library BNC build requires that you first install your own shared Qt library. The 'README.txt' file which comes with the BNC source code describes how to install Qt on Windows, Linux and Mac systems.
Feel free to send us comments, suggestions or bug reports. Your contribution would be appreciated.
Contents
1. Purpose
2. Handling
3. Settings
4. Limitations
5. Annex
Authors
The BKG Ntrip Client (BNC) and its Qt Graphical User Interface (GUI) has been developed for
Federal Agency for Cartography and Geodesy (BKG)
c/o Dr. Georg Weber
Department of Geodesy
Frankfurt, Germany
[euref-ip@bkg.bund.de] or [igs-ip@bkg.bund.de]
BNC was written by
Prof. Dr. Leos Mervart
Czech Technical University (CTU)
Department of Geodesy
Prague, Czech Republic
While work on BNC startet in June 2005, Prof. Mervart's sole responsibility for the progam code and concept lasted till February 2015. Since March 2015 the expert in charge for further develoments is
Dipl.-Ing. Andrea Stürze
Federal Agency for Cartography and Geodesy (BKG)
Department of Geodesy
Section Navigation
Frankfurt, Germany
[andrea.stuerze@bkg.bund.de]
BNC includes the following GNU GPL software components:
Note that some figures presented in this documentation show screenshots from earlier versions of BNC. If so then there is either no relevant change compared to the current appearance of the program or no change at all.
Acknowledgements
The purpose of BNC is to
BNC supports the following GNSS stream formats and message types:
Note that BNC allows to by-pass its decoding and conversion algorithms for incoming streams, leave whatever is received untouched to save it in files or output it through local TCP/IP port.
BNC is permanently completed to finally support all existing GNSS systems throughout all features of the program. The table below shows in detail which GNSS systems are so far supported by particular applications when using the latest BNC version. Application areas named here are:
Table: Status of RTCM Version 3 message implementations in BNC supporting various GNSS systems
| Message Type # | Description | GNSS System | RTCM Proposal | Decoding | RINEX/ SP3 | Encoding | Upload | PPP | Combin. |
General | |||||||||
| 1005,1006 | Station | x | |||||||
| 1007,1008 | Antenna | x | |||||||
| 1033 | Receiver, Antenna | x | |||||||
| 1013 | System Parameters | x | |||||||
Navigation | |||||||||
| 1019 | Ephemeris | GPS | x | x | x | x | x | x | |
| 1020 | Ephemeris | GLONASS | x | x | x | x | x | x | |
| 1045 | Ephemeris | Galileo F/Nav | x | x | x | x | x | ||
| 1046 | Ephemeris | Galileo I/Nav | x | x | x | x | x | x | |
| 1043 | Ephemeris | SBAS | x | x | x | x | x | ||
| 1044 | Ephemeris | QZSS | x | x | x | x | |||
| 63 | Ephemeris | BDS | x | x | x | x | x | ||
Observation | |||||||||
| 1001-4 | Conventional Messages | GPS | x | x | x | ||||
| 1009-12 | Conventional Messages | GLONASS | x | x | x | ||||
Observation | |||||||||
| 1071-77 | Multiple Signal Message | GPS | x | x | x | ||||
| 1081-87 | Multiple Signal Message | GLONASS | x | x | x | ||||
| 1091-97 | Multiple Signal Message | Galileo | x | x | x | ||||
| 1101-07 | Multiple Signal Message | SBAS | x | x | x | ||||
| 1111-17 | Multiple Signal Message | QZSS | x | x | |||||
| 1121-27 | Multiple Signal Message | BDS | x | x | x | ||||
SSR I | |||||||||
| 1057 | Orbit Corrections | GPS | x | x | x | x | x | x | |
| 1063 | Orbit Corrections | GLONASS | x | x | x | x | x | x | |
| 1240 | Orbit Corrections | Galileo | x | x | x | x | x | x | |
| 1246 | Orbit Corrections | SBAS | x | x | x | x | x | ||
| 1252 | Orbit Corrections | QZSS | x | x | x | x | x | ||
| 1258 | Orbit Corrections | BDS | x | x | x | x | x | ||
| 1058 | Clock Corrections | GPS | x | x | x | x | x | x | |
| 1064 | Clock Corrections | GLONASS | x | x | x | x | x | x | |
| 1241 | Clock Corrections | Galileo | x | x | x | x | x | x | |
| 1247 | Clock Corrections | SBAS | x | x | x | x | x | ||
| 1253 | Clock Corrections | QZSS | x | x | x | x | x | ||
| 1259 | Clock Corrections | BDS | x | x | x | x | x | ||
| 1059 | Code Biases | GPS | x | x | x | x | x | ||
| 1065 | Code Biases | GLONASS | x | x | x | x | x | ||
| 1242 | Code Biases | Galileo | x | x | x | x | x | x | |
| 1248 | Code Biases | SBAS | x | x | x | x | x | ||
| 1254 | Code Biases | QZSS | x | x | x | x | x | ||
| 1260 | Code Biases | BDS | x | x | x | x | x | ||
| 1061, 1062 | User Range Accuracy, HR | GPS | x | ||||||
| 1067, 1068 | User Range Accuracy, HR | GLONASS | x | ||||||
| 1244, 1245 | User Range Accuracy, HR | Galileo | x | x | |||||
| 1250, 1251 | User Range Accuracy, HR | SBAS | x | x | |||||
| 1256, 1257 | User Range Accuracy, HR | QZSS | x | x | |||||
| 1262, 1263 | User Range Accuracy, HR | BDS | x | x | |||||
| 1060 | Comb. Orbits & Clocks | GPS | x | x | x | x | x | x | |
| 1066 | Comb. Orbits & Clocks | GLONASS | x | x | x | x | x | x | |
| 1243 | Comb. Orbits & Clocks | Galileo | x | x | x | x | x | x | |
| 1249 | Comb. Orbits & Clocks | SBAS | x | x | x | x | x | ||
| 1255 | Comb. Orbits & Clocks | QZSS | x | x | x | x | x | ||
| 1261 | Comb. Orbits & Clocks | BDS | x | x | x | x | x | ||
SSR II | |||||||||
| 1264 | VTEC | GNSS | x | x | x | x | x | ||
| 1265 | Phase Biases | GPS | x | x | x | x | x | ||
| 1266 | Phase Biases | GLONASS | x | x | x | x | x | ||
| 1267 | Phase Biases | Galileo | x | x | x | x | x | ||
| 1268 | Phase Biases | SBAS | x | x | x | x | x | ||
| 1269 | Phase Biases | QZSS | x | x | x | x | x | ||
| 1270 | Phase Biases | BDS | x | x | x | x | x |
BNC can be used in different contexts with varying data flows. Typical real-time communication follows the Ntrip protocol over TCP/IP (probably via SSL), RTSP/RTP or UDP, plain TCP/IP protocol, or serial communication links. Stream contents could be observations, ephemeris, satellite orbit/clock products or NMEA sentences.
The first of the following figures shows a flow chart of BNC connected to a GNSS receiver providing observations via serial or TCP communication link for the purpose of Precise Point Positioning. The second figure shows the conversion of RTCM streams to RINEX files. The third figure shows a flow chart of BNC feeding a real-time GNSS engine which estimates precise orbits and clocks. BNC is used in this scenario to encode correctors to RTCM Version 3 and upload them to an NTRIP Broadcaster. The fourth figure shows BNC combining several Broadcast Correction streams to disseminate the combination product while saving results in SP3 and Clock RINEX files.
Figure 1: Flowchart, BNC connected to a GNSS rover for Precise Point Positioning.
Figure 2: Flowchart, BNC converting RTCM streams to RINEX batches.
Figure 3: Flowchart, BNC feeding a real-time GNSS engine and uploading encoded Broadcast Corrections.
Figure 4: Flowchart, BNC combining Broadcast Correction streams.
Although BNC is mainly a real-time tool to be operated online, it can be run offline
Unless it runs offline, BNC
The main window of BNC shows a 'Top menu bar' section, a 'Settings' sections with panels to set processing options, a 'Streams' section, a section for 'Log' tabs, and a 'Bottom menu bar' section, see figure below.
Figure 5: Sections on BNC's main window.
Running BNC in interactive mode requires graphics support. This is also required in batch mode when producing plots. Windows and Mac OS X systems always support graphics. However, when using BNC in batch mode on Linux systems for producing plots, you need to make sure that at least a virtual X-Server like 'Xvfb' is installed and the '-display' command-line option is used.
The usual handling of BNC is that you first select a number of streams ('Add Stream'). Any stream configured to BNC shows up on the 'Streams' canvas in the middle of BNC's main window. You then go through BNC's various configuration panels to select a combination of input, processing and output options before you start the program ('Start'). Most configuration panels are dedicated to a certain functionality of BNC. If the first option field on such a configuration panel is empty, the affected functionality is - apart from a few exceptions - deactivated.
Records of BNC's activities are shown in the 'Log' tab. The bandwidth consumption per stream, the latency of incoming observations and a PPP time series for coordinates are shown in the 'Throughput', 'Latency' and 'PPP Plot' tabs.As a default, configuration files for running BNC on Unix/Linux/Mac OS X systems are saved in directory '${HOME}/.config/BKG'. On Windows systems, they are typically saved in directory 'C:/Documents and Settings/Username/.config/BKG'. The default configuration file name is 'BNC.bnc'.
The default file name 'BNC.bnc' can be changed and the file contents can easily be edited. On graphical user interfaces it is possible to Drag & Drop a configuration file icon to start BNC (not on Mac OS X systems). Some configuration options can be changed on-the-fly. See annexed 'Configuration Examples' for a complete set of configuration options. It is also possible to start and configure BNC via command line.
BNC maintains configuration options at three different levels:
Figure 6: Management of configuration options in BNC:
Left: BNC in graphics mode where active configuration options are introduced through
GUI input fields and finally saved on disk.
Middle: BNC in 'no window' mode where active configuration options are read from disk.
Right: BNC in 'no window' mode without configuration file where default configuration
options can be replaced via command line options.
Configuration options are usually specified using GUI input fields (1) after launching BNC. When hitting the 'Start' button, configuration options are transferred one level down to become BNC's active configuration (2) allowing the program to begin its operation. Pushing the 'Stop' button ends data processing so that the user can finally terminate BNC through 'File'->'Quit'->'Save Options' which saves processing options in a configuration file to disk (3). It is important to understand that:
This chapter describes how to set the BNC program options. It explains the 'Top Menu Bar', the 'Settings Canvas' with the processing options, the 'Streams Canvas' and 'Log Canvas', and the 'Bottom Menu Bar'.
Top Menu Bar
3.1. Top Menu Bar
3.1.1 File
3.1.2 Help
Settings Canvas
3.2. Network
3.2.1 Proxy
3.2.2 SSL
3.3. General
3.3.1. Logfile
3.3.2. Append Files
3.3.3. Reread Configuration
3.3.4. Auto Start
3.3.5. Raw Output File
3.4. RINEX Observations
3.4.1. File Names
3.4.2. Directory
3.4.3. File Interval
3.4.4. Sampling
3.4.5. Skeleton Extension
3.4.6. Skeleton Mandatory
3.4.7. Script
3.4.8. Version 2
3.4.9. Version 3
3.5. RINEX Ephemeris
3.5.1. Directory
3.5.2. Interval
3.5.3. Port
3.5.4. Version
3.6. RINEX Editing & QC
3.6.1 Action
3.6.2 Input Files
3.6.3 Output Files
3.6.4 Logfiles
3.6.5 Plots for Signals
3.6.6 Directory for Plots
3.6.7 Set Edit Options
3.6.8 Command Line, No Window
3.7. SP3 Comparison
3.7.1 Input SP3 Files
3.7.2 Exclude Satellites
3.7.3 Logfile
3.8. Broadcast Corrections
3.8.1. Directory, ASCII
3.8.2. Interval
3.8.3. Port
3.8.4. Wait for Full Corr Epoch
3.9. Feed Engine
3.9.1. Port
3.9.2. Wait for Full Obs Epoch
3.9.3. Sampling
3.9.4. File
3.9.5. Port (unsynchronized)
3.10. Serial Output
3.10.1. Mountpoint
3.10.2. Port Name
3.10.3. Baud Rate
3.10.4. Flow Control
3.10.5. Parity
3.10.6. Data Bits
3.10.7. Stop Bits
3.10.8. NMEA
3.10.9. File
3.10.10. Height
3.10.11. Sampling
3.11. Outages
3.11.1. Observation Rate
3.11.2. Failure Threshold
3.11.3. Recovery Threshold
3.11.4. Script
3.12. Miscellaneous
3.12.1. Mountpoint
3.12.2. Log Latency
3.12.3. Scan RTCM
3.12.4. Port
3.13. PPP Client
3.13.1 PPP (1): Input and Output
3.13.1.1 Data Source
3.13.1.2 RINEX Observation File
3.13.1.3 RINEX Navigation File
3.13.1.4 Correction File
3.13.1.5 Corrections Stream
3.13.1.6 Coordinates
3.13.1.7 Logfile
3.13.1.8 ANTEX File
3.13.1.9 NMEA File
3.13.1.10 SNX TRO File
3.13.2 PPP (2): Processed Stations
3.13.2.1 Sigma North/East/Height
3.13.2.2 Noise North/East/Height
3.13.2.3 Tropo Sigma
3.13.2.4 Tropo Noise
3.13.2.5 NMEA Port
3.13.3 PPP (3): Processing Options
3.13.3.1 Linear Combinations
3.13.3.2 Code Observations
3.13.3.3 Phase Observations
3.13.3.4 Elevation Depending Weighting
3.13.3.5 Minimum Number of Observations
3.13.3.6 Minimum Elevation
3.13.3.7 Wait for Clock Corrections
3.13.3.8 Seeding
3.13.4 PPP (4): Plots
3.13.4.1 PPP Plot
3.13.4.2 Audio Response
3.13.4.3 Track Map
3.13.4.3.1 Google/OSM
3.13.4.4 Dot-properties
3.13.4.4.1 Size
3.13.4.4.2 Color
3.13.4.5 Post Processing Speed
3.14. Combine Corrections
3.14.1 Combine Corrections Table
3.14.1.1 Add Row, Delete
3.14.1.2 Method
3.14.1.3 Maximal Residuum
3.14.1.4 Sampling
3.14.1.5 Use GLONASS
3.15. Upload Corrections
3.15.1 Add, Delete Row
3.15.2 Host, Port, Mountpoint, Password
3.15.3 System
3.15.4 Center of Mass
3.15.5 SP3 File
3.15.6 RNX File
3.15.7 Interval
3.15.8 Sampling
3.15.8.1 orbits
3.15.8.2 SP3
3.15.8.3 RINEX
3.15.9 Custom Trafo
3.15.10 ANTEX File
3.16. Upload Ephemeris
3.16.1 Host & Port
3.16.2 Mountpoint & Password
3.16.3 Sampling
Streams Canvas
3.17. Streams
3.17.1 Edit Streams
3.17.2 Delete Stream
3.17.3 Reconfigure Stream Selection On-the-fly
Logging Canvas
3.18. Logging
3.18.1 Log
3.18.2 Throughput
3.18.3 Latency
3.18.4 PPP Plot
Bottom Menu Bar
3.19. Bottom Menu Bar
3.19.1. Add Stream
3.19.1.1 Add Stream - Coming from Caster
3.19.1.1.1 Caster Host and Port
3.19.1.1.2 Casters Table
3.19.1.1.3 User and Password
3.19.1.1.4 Get Table
3.19.1.1.5 NTRIP Version
3.19.1.1.6 Map
3.19.1.2 Add Stream - Coming from TCP/IP Port
3.19.1.3 Add Stream - Coming from UDP Port
3.19.1.4 Add Stream - Coming from Serial Port
3.19.2. Delete Stream
3.19.3. Map
3.19.4 Start
3.19.5 Stop
Command Line
3.20. Command Line Options
3.20.1. No Window Mode
3.20.2. File Mode
3.20.3. Configuration File
3.20.4. Configuration Options
The top menu bar allows selecting a font for the BNC windows, save configured options, or quit the program execution. It also provides access to program documentation.
The 'File' button lets you
The 'Help' button provides access to
BNC comes with a help system providing online information about its functionality and usage. Short descriptions are available for any widget. Focus to the relevant widget and press Shift+F1 to request help information. A help text appears immediately; it disappears as soon as the user does something else. The dialogs on some operating systems may provide a "?" button that users can click; click the relevant widget to pop up the help text.
You may need to specify a proxy when running BNC in a protected network. You may also like to use the Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL) cryptographic protocols for secure NTRIP communication over the Internet.
3.2.1 Proxy - Usage in a protected LAN
If you are running BNC within a protected Local Area Network (LAN), you might need to use a proxy server to access the Internet. Enter your proxy server IP and port number in case one is operated in front of BNC. If you don't know the IP and port of your proxy server, check the proxy server settings in your Internet browser or ask your network administrator.
Note that IP streaming is often not allowed in a LAN. In this case you need to ask your network administrator for an appropriate modification of the local security policy or for the installation of a TCP relay to the NTRIP Broadcasters. If these are not possible, you might need to run BNC outside your LAN on a host that has unobstructed connection to the Internet.
3.2.2 SSL - Transport Layer Security
Communication with an NTRIP Broadcaster over SSL requires the exchange of client and/or server certificates. Specify the path to a directory where you save certificates on your system. You may like to check out http://software.rtcm-ntrip.org/wiki/Certificates for a list of known NTRIP Server certificates. You may also just try communication via SSL to check out whether this is supported by the involved NTRIP Broadcaster.
SSL communication may involve queries coming from the NTRIP Broadcaster. Tick 'Ignore SSL authorization errors' if you don't want to be bothered with this. Note that SSL communication is usually done over port 443.
The following defines general settings for BNC's logfile, file handling, reconfiguration on-the-fly, and auto-start.
Records of BNC's activities are shown in the 'Log' tab on the bottom of the main window. These logs can be saved into a file when a valid path is specified in the 'Logfile (full path)' field. The logfile name will automatically be extended by a string '_YYMMDD' carrying the current date. This leads to series of daily logfiles when running BNC continuously for extended. Message logs cover the communication status between BNC and the NTRIP Broadcaster as well as problems that may occur in the communication link, stream availability, stream delay, stream conversion etc. All times are given in UTC. The default value for 'Logfile (full path)' is an empty option field, meaning that BNC logs will not be saved into a file.
The following is an example for the contents of a logfile written by BNC when operated in Single Point Positioning (SPP) mode:
15-06-30 11:40:17 ========== Start BNC v2.12 (MAC) ========== 15-06-30 11:40:17 Panel 'PPP' active 15-06-30 11:40:17 CUT07: Get data in RTCM 3.x format 15-06-30 11:40:17 RTCM3EPH: Get data in RTCM 3.x format 15-06-30 11:40:17 Configuration read: PPP.conf, 2 stream(s) 15-06-30 11:40:21 2015-06-30_11:40:19.000 CUT07 X = -2364337.6814 Y = 4870283.8110 Z = -3360808.3085 NEU: -0.0000 -0.0000 -0.0000 TRP: +2.4026 -0.0001 15-06-30 11:40:22 2015-06-30_11:40:20.000 CUT07 X = -2364337.6853 Y = 4870283.8130 Z = -3360808.3082 NEU: +1.1639 +0.6988 -2.1178 TRP: +2.4018 +0.0003 15-06-30 11:40:23 2015-06-30_11:40:21.000 CUT07 X = -2364337.6862 Y = 4870283.8155 Z = -3360808.3107 NEU: +0.1317 -0.4655 -4.4614 TRP: +2.4009 +0.0009 15-06-30 11:40:24 2015-06-30_11:40:22.000 CUT07 X = -2364337.6864 Y = 4870283.8106 Z = -3360808.3099 NEU: +0.1543 +0.2121 -1.0190 TRP: +2.4022 +0.0009 15-06-30 11:40:25 2015-06-30_11:40:23.000 CUT07 X = -2364337.6861 Y = 4870283.8111 Z = -3360808.3105 NEU: -0.9782 +0.0916 -2.3544 TRP: +2.4017 +0.0013 15-06-30 11:40:26 2015-06-30_11:40:24.000 CUT07 X = -2364337.6884 Y = 4870283.8123 Z = -3360808.3103 NEU: -0.5606 -0.0938 -1.9498 TRP: +2.4018 +0.0016 15-06-30 11:40:27 2015-06-30_11:40:25.000 CUT07 X = -2364337.6913 Y = 4870283.8133 Z = -3360808.3122 NEU: -0.1799 -0.1525 -4.8142 TRP: +2.4007 +0.0025 15-06-30 11:40:28 2015-06-30_11:40:26.000 CUT07 X = -2364337.6919 Y = 4870283.8171 Z = -3360808.3184 NEU: +0.7497 +0.7994 -2.0363 TRP: +2.4018 +0.0032 15-06-30 11:40:29 2015-06-30_11:40:27.000 CUT07 X = -2364337.6923 Y = 4870283.8196 Z = -3360808.3230 NEU: +0.8099 +0.5592 -2.8552 TRP: +2.4015 +0.0039 15-06-30 11:40:30 2015-06-30_11:40:28.000 CUT07 X = -2364337.6960 Y = 4870283.8219 Z = -3360808.3222 NEU: -0.2952 +1.9737 -4.5565 TRP: +2.4008 +0.0047 15-06-30 11:40:31 2015-06-30_11:40:29.000 CUT07 X = -2364337.6982 Y = 4870283.8209 Z = -3360808.3209 NEU: +0.3563 +2.1067 -5.5327 TRP: +2.4005 +0.0057 ...
When BNC is started, new files are created by default and any existing files with the same name will be overwritten. However, users might want to append existing files following a restart of BNC, a system crash or when BNC crashed. Tick 'Append files' to continue with existing files and keep what has been recorded so far. Note that option 'Append files' affects all types of files created by BNC.
3.3.3 Reread Configuration - optional
When operating BNC online in 'no window' mode (command line option -nw), some configuration options can nevertheless be changed on-the-fly without interrupting the running process. For that you force the program to reread parts of its configuration in pre-defined intervals from the disk. Select '1 min', '1 hour', or '1 day' to let BNC reread on-the-fly changeable configuration options every full minute, hour, or day. This lets in between edited options become effective without interrupting uninvolved threads. See annexed section 'Configuration Examples' for a configuration file example and a list of on-the-fly changeable options.
You may like to auto-start BNC at startup time in window mode with pre-assigned configuration options. This may be required i.e. immediately after booting your system. Tick 'Auto start' to supersede the usage of the 'Start' button. Make sure that you maintain a link to BNC for that in your Autostart directory (Windows systems) or call BNC in a script below directory /etc/init.d (Unix/Linux/Mac OS X systems).
See BNC's command line option -nw for an auto-start of BNC in 'no window' mode.
3.3.5 Raw Output File - optional
BNC can save all data coming in through various streams in one daily file. The information is recorded in the specified 'Raw output file' in the received order and format. This feature allows a BNC user to run the PPP option offline with observations, Broadcast Corrections, and Broadcast Ephemeris being read from a previously saved file. It supports the offline repetition of a real-time situation for debugging purposes and it is not meant for Post Processing.
Data will be saved in blocks in the received format separated by ASCII time stamps like (example):
2010-08-03T18:05:28 RTCM3EPH RTCM_3 67
This example block header tells you that 67 bytes were saved in the data block following this time stamp. The information in this block is encoded in RTCM Version 3 format, comes from mountpoint RTCM3EPH and was received at 18:05:29 UTC on 2010-08-03. BNC adds its own time stamps in order to allow the reconstruction of a recorded real-time situation.
The default value for 'Raw output file' is an empty option field, meaning that BNC will not save all raw data into one single daily file.
Observations will be converted to RINEX if they come in either RTCM Version 2 or RTCM Version 3 format. Depending on the RINEX version and incoming RTCM message types, files generated by BNC may contain data from GPS, GLONASS, Galileo, SBAS, QZSS and/or BDS(BeiDou). In case an observation type is listed in the RINEX header but the corresponding observation is unavailable, its value is set to zero '0.000'. Note that the 'RINEX TYPE' field in the RINEX Version 3 Observation file header is always set to 'M(MIXED)' or 'Mixed' even if the file only contains data from one system.
It is important to understand that converting RTCM streams to RINEX files requires a-priori information on observation types for specifying a complete RINEX header. Regarding the RINEX Version 2 file header, BNC simply introduces all observation types defined in the Version 2 standard and later reports "0.000" for all observations which are not received. However, following this approach is not possible for RINEX Version 3 files from RTCM Version 3 MSM streams because of the huge number of observation types which might in principle show up. The solution implemented in BNC is to start with RINEX Version 3 observation type records from skeleton files (see section 'Skeleton Extension' and 'Skeleton Mandatory') and switch to a default selection of observation types when such skeleton file is not available or does not contain the required information. The following is a default selection of observation types specified for a RINEX Version 3 file:
C 9 C2I L2I S2I C6I L6I S6I C7I L7I S7I SYS / # / OBS TYPES
E 12 C1X L1X SX1 C5X L5X SX5 C7X L7X SX7 C8X L8X SX8 SYS / # / OBS TYPES
G 15 C1C L1C S1C C1W L1W S1W C2X L2X S2X C2W L2W S2W C5X SYS / # / OBS TYPES
L5X S5X SYS / # / OBS TYPES
J 15 C1C L1C S1C C1W L1W S1W C2X L2X S2X C2W L2W S2W C5X SYS / # / OBS TYPES
L5X S5X SYS / # / OBS TYPES
R 6 C1C L1C S1C C2P L2P S2P SYS / # / OBS TYPES
S 9 C1C L1C S1C C5I L5I S5I C5Q L5Q S5Q SYS / # / OBS TYPES
Please note that RTCM Version 3 messages 1084 for GLONASS observations don't contain the channel numbers. However, these messages can only be converted to RINEX when you add messages which include the channel numbers. This could be done though an additional stream carrying 1087 GLONASS observation messages or an additional stream carrying 1020 GLONASS ephemeris messages. You could also consider setting up a streams which contains both, the 1084 and the 1020 messages.
The screenshot below shows an example setup of BNC when converting streams to RINEX. Streams are coming from various NTRIP Broadcasters as well as from a serial communication link. Specifying a decoder string 'ZERO' means to not convert the affected stream but save its contents as received.
Figure 7: BNC translating incoming streams to 15 min RINEX Version 3 files.
RINEX file names in BNC follow the convention of RINEX Version 2.11. So far BNC does not support extended file names as defined in RINEX Version 3.02. File names are derived by BNC from the first 4 characters of the corresponding stream's mountpoint (4Char Station ID). For example, data from mountpoints FRANKFURT and WETTZELL will have hourly RINEX Observation files named
FRAN{ddd}{h}.{yy}O
WETT{ddd}{h}.{yy}O
where 'ddd' is the day of year, 'h' is a letter which corresponds to an hour long UTC time block and 'yy' is the year.
If there is more than one stream with identical 4Char Station ID (same first 4 characters for their mountpoints), the mountpoint strings are split into two sub-strings and both become part of the RINEX file name. For example, when simultaneously retrieving data from mountpoints FRANKFURT and FRANCE, their hourly RINEX Observation files are named as
FRAN{ddd}{h}_KFURT.{yy}O
FRAN{ddd}{h}_CE.{yy}O.
If several streams show exactly the same mountpoint name (example: BRUS0 from www.euref-ip.net and BRUS0 from www.igs-ip.net), BNC adds an integer number to the file name leading i.e. to hourly RINEX Observation files like
BRUS{ddd}{h}_0.{yy}O
BRUS{ddd}{h}_1.{yy}O.
Note that RINEX file names for all intervals less than 1 hour follow the file name convention for 15 minutes RINEX Observation files i.e.
FRAN{ddd}{h}{mm}.{yy}O
where 'mm' is the starting minute within the hour.
Here you can specify the path to where the RINEX Observation files will be stored. If the specified directory does not exist, BNC will not create RINEX Observation files. Default value for 'Directory' is an empty option field, meaning that no RINEX Observation files will be written.
3.4.3 File Interval - mandatory if 'Directory' is set
Select the length of the RINEX Observation file generated. The default value is 15 minutes.
3.4.4 Sampling - mandatory if 'Directory' is set
Select the RINEX Observation sampling interval in seconds. A value of zero '0' tells BNC to store all received epochs into RINEX. This is the default value.
3.4.5 Skeleton Extension - optional
Whenever BNC starts generating RINEX Observation files (and then once every day at midnight), it first tries to retrieve information needed for RINEX headers from so-called public RINEX header skeleton files which are derived from sitelogs. A HTTP or HTTPS link to a directory containing these skeleton files may be available through data field number 7 of the affected NET record in the source-table. See http://www.epncb.oma.be:80/stations/log/skl/brus.skl for an example of a public RINEX header skeleton file for the Brussels EPN station.
However, sometimes public RINEX header skeleton files are not available, their contents is not up to date, or you need to put additional/optional records in the RINEX header. For that BNC allows using personal skeleton files that contain the header records you would like to include. You can derive a personal RINEX header skeleton file from the information given in an up to date sitelog. A file in the RINEX Observations 'Directory' with a 'Skeleton extension' suffix is interpreted by BNC as a personal RINEX header skeleton file for the corresponding stream.
Examples for personal skeleton file name convention: RINEX Observation files for mountpoints WETTZELL, FRANKFURT and FRANCE (same 4Char Station ID), BRUS0 from www.euref-ip.net and BRUS0 from www.igs-ip.net (same 4Char Station ID, identical mountpoint stings) would accept personal skeleton files named
WETT.skl
FRAN_KFURT.skl
FRAN_CE.skl
BRUS_0.skl
BRUS_1.skl
if 'Skeleton extension' is set to 'skl'.
Note the following regulations regarding personal RINEX header skeleton files:
If neither a public nor a personal RINEX header skeleton file is available for BNC, a default header will be used.
The following is a skeleton example for a RINEX file:
OBSERVATION DATA M (MIXED) RINEX VERSION / TYPE
CUT0 MARKER NAME
59945M001 MARKER NUMBER
5023K67889 TRIMBLE NETR9 5.01 REC # / TYPE / VERS
4928353386 TRM59800.00 SCIS ANT # / TYPE
-2364337.2699 4870285.5624 -3360809.8398 APPROX POSITION XYZ
0.0000 0.0000 0.0000 ANTENNA: DELTA H/E/N
gnss@curtin.edu.au CUT OBSERVER / AGENCY
C 10 C1I L1I D1I S1I C6I L6I S6I C7I L7I S7I SYS / # / OBS TYPES
E 13 C1X L1X D1X S1X C5X L5X S5X C7X L7X S7X C8X L8X S8X SYS / # / OBS TYPES
G 13 C1C L1C D1C S1C C2W L2W S2W C2X L2X S2X C5X L5X S5X SYS / # / OBS TYPES
J 19 C1C L1C D1C S1C C1X L1X S1X C1Z L1Z S1Z C2X L2X S2X SYS / # / OBS TYPES
C5X L5X S5X C6L L6L S6L SYS / # / OBS TYPES
R 13 C1C L1C D1C S1C C1P L1P S1P C2C L2C S2C C2P L2P S2P SYS / # / OBS TYPES
S 7 C1C L1C D1C S1C C5I L5I S5I SYS / # / OBS TYPES
PORTIONS OF THIS HEADER GENERATED BY THE IGS CB FROM COMMENT
SITELOG cut0_20150507.log COMMENT
END OF HEADER
3.4.6 Skeleton Mandatory - optional
Tick check box 'Skeleton mandatory' in case you want that RINEX files are only produced if skeleton files are available for BNC. If no skeleton file is available for a particular source then no RINEX observation file will be produced from the affected stream.
Note that a skeleton file contains RINEX header information such as receiver and antenna types. In case of stream conversion to RINEX Version 3 a skeleton file should also contain information on potentially available observation types. A missing skeleton file will therefore enforce BNC to only save a default set of RINEX 3 observation types.
Whenever a RINEX Observation file is saved, you might want to compress, copy or upload it immediately via FTP. BNC allows you to execute a script/batch file to carry out these operations. To do that, specify the full path of the script/batch file here. BNC will pass the RINEX Observation file path to the script as a command line parameter (%1 on Windows systems, $1 on Unix/Linux/Mac OS X systems).
The triggering event for calling the script or batch file is the end of a RINEX Observation file 'Interval'. If that is overridden by a stream outage, the triggering event is the stream reconnection.
As an alternative to initiating file uploads through BNC, you may like to call an upload script or batch file through your crontable or Task Scheduler (independent from BNC) once every one or two minutes after the end of each RINEX file 'Interval'.
GNSS observation data are generally hold available within BNC according to attributes as defined in RINEX Version 3. These attributes describe the tracking mode or channel when generating the observation signals. Capital letters specifying signal generation attributes are A, B, C, D, I, L, M, N, P, Q, S, W, X, Y, and Z, see RINEX Version 3 documentation. Although RINEX Version 3 with its signal generation attributes is the internal default processing format for BNC, there are two applications where the program is explicitly required to produce data in RINEX Version 2 format:
The default 'Signal priority' list is an empty option string meaning a priority sequence of 'CWPX_?' attributes when mapping RINEX 3 to RINEX 2. The meaning of this sequence of characters - take it as an example - is as follows:
You may like to specify you own 'Signal priority' string for producing RINEX Version 2 files. If you neither convert observation streams to RINEX Version 2 nor concatenate RINEX Version 3 to Version 2 files then the 'Version 2' option is meaningless.
The default format for RINEX Observation files is RINEX Version 2.11. Select RINEX 'Version 3' if you would like to save RTCM Version 3 observation streams in RINEX Version 3 format.
Note that it is possible to force a RTCM Version 2 stream to be saved in RINEX Version 3 file format. However, this is not recommended because such stream can not be precisely mapped to RINEX Version 3 as the required information on tracking modes (observation attributes) is not part of RTCM Version 2.
Broadcast Ephemeris can be saved as RINEX Navigation files when received via RTCM Version 3 e.g. as message types 1019 (GPS) or 1020 (GLONASS) or 1044 (QZSS) or 1043 (SBAS) or 1045 and 1046 (Galileo) or 63 (tentative, BDS/BeiDou). The file name convention follows the details given in section 'RINEX File Names' except that the first four characters are 'BRDC' and the last character is
Note that streams dedicated to carry Broadcast Ephemeris messages in RTCM Version 3 format in high repetition rates are listed on http://igs.bkg.bund.de/ntrip/ephemeris.
Specify a path for saving Broadcast Ephemeris data as RINEX Navigation files. If the specified directory does not exist, BNC will not create RINEX Navigation files. Default value for Ephemeris 'Directory' is an empty option field, meaning that no RINEX Navigation files will be created.
3.5.2 Interval - mandatory if 'Directory' is set
Select the length of RINEX Navigation files. The default value is '1 day'.
BNC can output Broadcast Ephemeris in RINEX Version 3 format on your local host (IP 127.0.0.1) through an IP 'Port'. Specify an IP port number to activate this function. The default is an empty option field, meaning that no ASCII ephemeris output via IP port is generated.
The source code for BNC comes with an example perl script 'test_tcpip_client.pl' that allows you to read BNC's ASCII ephemeris output from the IP port.
Default format for RINEX Navigation files containing Broadcast Ephemeris is RINEX Version 2.11. Select 'Version 3' if you want to save the ephemeris data in RINEX Version 3 format.
Note that this does not concern the Broadcast Ephemeris output through IP port which is always in RINEX Version 3 format.
Besides stream conversion from RTCM to RINEX, BNC allows editing RINEX files or concatenate their contents. RINEX Observation and Navigation files can be handled. BNC can also carry out a RINEX file Quality Check. In summary and besides Stream Translation this functionality in BNC covers
Select an action. Options are 'Edit/Concatenate' and 'Analyze'.
Specify full path to input RINEX Observation file(s), and
specify full path to input RINEX Navigation file(s).
When specifying several input files BNC will concatenate their contents. In case of RINEX Observation input files with different observation type header records, BNC will output only one specific set of adjustet observation type records in the RINEX header which fits to the whole file contents.
Note that you may specify several RINEX Version 2 Navigation files for GPS and GLONASS.
3.6.3 Output Files - optional if 'Action' is set to 'Edit/Concatenate'
If 'Edit/Concatenate' is selected, specifying the full path to output RINEX Observation file(s) and specifying the full path to output RINEX Navigation file(s) is optional. Default are empty option fields, meaning that no RINEX files will be saved on disk.
Specify the name of a logfile to save information on RINEX file Editing/Concatenation or Analysis. Default is an empty option fieled, meaning that no logfile will be saved.
Note that logfiles from analyzing RINEX files may become quite large. Hence BNC provides an option 'Summary only' to limit this logfile contents to some essential information in case 'Action' is set to 'Analyze'. The following is an example for a RINEX quality check analysis logfile:
QC Format Version : 1.0
Navigation File(s): brdm1660.15p
Ephemeris : 6421 OK 4 BAD
Bad Ephemeris : brdm1660.15p S27 2015 06 15 05 04 00
Bad Ephemeris : brdm1660.15p S27 2015 06 15 05 46 40
Bad Ephemeris : brdm1660.15p S27 2015 06 15 05 59 28
Bad Ephemeris : brdm1660.15p C08 2015 06 15 08 00 00-
Observation File : cut01660.15o
RINEX Version : 3.02
Marker Name : CUT0
Marker Number : 59945M001
Receiver : TRIMBLE NETR9
Antenna : TRM59800.00 SCIS
Position XYZ : -2364337.2971 4870285.5843 -3360809.8188
Antenna dH/dE/dN : 0.0000 0.0000 0.0000
Start Time : 2015-06-15 00.00.00.0
End Time : 2015-06-15 23.59.30.0
Interval : 30
Navigation Systems: 6 C E G J R S
C: Satellites: 13
C: Signals : 3 2I 6I 7I
C: 2I: Observations : 29094
C: 2I: Slips (file+found): 183 + 2
C: 2I: Gaps : 31
C: 2I: Mean SNR : 42.2
C: 2I: Mean Multipath : 0.40
C: 6I: Observations : 29048
C: 6I: Slips (file+found): 191 + 0
C: 6I: Gaps : 57
C: 6I: Mean SNR : 44.8
C: 6I: Mean Multipath : 0.00
C: 7I: Observations : 29048
C: 7I: Slips (file+found): 191 + 2
C: 7I: Gaps : 57
C: 7I: Mean SNR : 44.4
C: 7I: Mean Multipath : 0.30
E: Satellites: 7
E: Signals : 4 1X 5X 7X 8X
E: 1X: Observations : 7440
E: 1X: Slips (file+found): 332 + 1
E: 1X: Gaps : 11
E: 1X: Mean SNR : 44.3
E: 1X: Mean Multipath : 0.36
...
G: Satellites: 31
G: Signals : 4 1C 2W 2X 5X
G: 1C: Observations : 31331
G: 1C: Slips (file+found): 959 + 20
G: 1C: Gaps : 81
G: 1C: Mean SNR : 44.2
G: 1C: Mean Multipath : 0.69
...
J: Satellites: 1
J: Signals : 6 1C 1X 1Z 2X 5X 6X
J: 1C: Observations : 2880
J: 1C: Slips (file+found): 43 + 0
J: 1C: Gaps : 0
J: 1C: Mean SNR : 44.0
J: 1C: Mean Multipath : 0.60
...
R: Satellites: 24
R: Signals : 4 1C 1P 2C 2P
R: 1C: Observations : 24500
R: 1C: Slips (file+found): 194 + 36
R: 1C: Gaps : 76
R: 1C: Mean SNR : 45.2
R: 1C: Mean Multipath : 0.81
...
S: Satellites: 4
S: Signals : 2 1C 5I
S: 1C: Observations : 11520
S: 1C: Slips (file+found): 5 + 145
S: 1C: Gaps : 0
S: 1C: Mean SNR : 41.1
S: 1C: Mean Multipath : 0.91
...
> 2015 06 15 00 00 0.0000000 39 0.6
G14 1.50 14.90 2 L1C s. 32.4 C1C . 0.76
G15 11.79 117.66 6 L1C .. 39.1 C1C . 0.86 L2W .. 20.9 C2W . 1.10 L2X .. 37.1 C2X . 1.11
G16 53.56 -107.67 4 L1C .. 48.8 C1C . 0.31 L2W .. 39.9 C2W . 0.26
G18 72.61 84.24 4 L1C .. 50.0 C1C . 0.29 L2W .. 43.1 C2W . 0.26
G19 6.07 -124.61 4 L1C .. 36.1 C1C . 0.91 L2W .. 18.6 C2W . 0.43
G20 4.75 138.88 4 L1C s. 35.5 C1C . 0.00 L2W s. 15.6 C2W . 0.00
G21 40.44 132.24 4 L1C .. 45.7 C1C . 0.59 L2W .. 33.3 C2W . 0.24
G22 55.62 -12.81 4 L1C .. 51.6 C1C . 0.44 L2W .. 41.7 C2W . 0.26
G26 56.96 -45.95 8 L1C .. 50.8 C1C . 0.56 L2W .. 42.7 C2W . 0.23 L2X .. 50.7 C2X . 0.30 L5X .. 55.7 C5X . 0.00
G27 33.71 -136.99 8 L1C .. 46.9 C1C . 0.51 L2W .. 35.5 C2W . 0.34 L2X .. 45.9 C2X . 0.36 L5X .. 52.0 C5X . 0.00
G29 15.74 68.66 6 L1C .. 41.3 C1C . 0.93 L2W .. 22.8 C2W . 0.44 L2X .. 38.1 C2X . 0.37
R01 52.20 117.58 8 L1C .. 52.5 C1C . 0.42 L1P .. 50.5 C1P . 0.39 L2C .. 43.8 C2C . 0.49 L2P .. 43.5 C2P . 0.39
R02 47.13 19.13 8 L1C .. 53.3 C1C . 0.31 L1P .. 52.0 C1P . 0.45 L2C .. 47.9 C2C . 0.39 L2P .. 47.6 C2P . 0.39
R03 3.03 -10.43 8 L1C .. 36.0 C1C . 2.06 L1P .. 34.4 C1P . 1.03 L2C .. 36.6 C2C . 0.69 L2P .. 37.0 C2P . 0.65
R08 9.52 152.59 8 L1C .. 41.3 C1C . 1.11 L1P .. 39.9 C1P . 0.76 L2C .. 38.3 C2C . 0.89 L2P .. 38.1 C2P . 0.63
R14 15.31 -50.83 8 L1C .. 39.0 C1C . 1.16 L1P .. 37.4 C1P . 0.78 L2C .. 34.3 C2C . 0.63 L2P .. 34.0 C2P . 0.57
R15 22.97 -99.16 8 L1C .. 43.7 C1C . 0.72 L1P .. 42.2 C1P . 0.47 L2C .. 42.0 C2C . 0.46 L2P .. 42.2 C2P . 0.39
R16 4.62 -152.37 8 L1C .. 40.4 C1C . 1.24 L1P .. 39.1 C1P . 0.89 L2C .. 35.3 C2C . 0.73 L2P .. 33.9 C2P . 0.57
R17 42.68 -161.68 8 L1C .. 50.6 C1C . 0.56 L1P .. 48.6 C1P . 0.43 L2C .. 39.1 C2C . 0.56 L2P .. 38.4 C2P . 0.32
R23 14.50 88.21 8 L1C .. 43.8 C1C . 1.25 L1P .. 42.5 C1P . 0.61 L2C .. 35.2 C2C . 0.88 L2P .. 34.3 C2P . 0.59
R24 47.18 133.41 8 L1C .. 47.0 C1C . 0.48 L1P .. 46.0 C1P . 0.45 L2C .. 42.9 C2C . 0.40 L2P .. 43.1 C2P . 0.32
E18 0.00 0.00 8 L1X .. 45.0 C1X . 0.58 L5X .. 47.2 C5X . 0.26 L7X .. 46.1 C7X . 0.00 L8X .. 51.1 C8X . 0.00
J01 79.88 57.76 12 L1C .. 49.9 C1C . 0.18 L1X .. 53.8 C1X . 0.25 L1Z .. 51.3 C1Z . 0.26 L2X .. 51.3 C2X . 0.23 L5X .. 55.9 C5X . 0.00 L6X .. 46.5 C6X . 0.00
S27 16.07 -73.59 4 L1C .. 36.8 C1C . 0.92 L5I .. 41.7 C5I . 0.75
S28 38.67 -50.73 4 L1C s. 44.9 C1C . 0.00 L5I s. 45.0 C5I . 0.00
S29 41.34 46.37 2 L1C .. 39.2 C1C . 0.00
S37 41.34 46.37 2 L1C .. 39.9 C1C . 0.00
C01 -14.73 163.85 6 L2I .. 42.5 C2I . 0.47 L7I .. 46.6 C7I . 0.23 L6I .. 45.5 C6I . 0.00
C02 33.21 145.93 6 L2I .. 37.9 C2I . 0.29 L7I .. 43.0 C7I . 0.18 L6I .. 43.3 C6I . 0.00
C03 -37.46 -58.16 6 L2I .. 44.1 C2I . 0.21 L7I .. 46.6 C7I . 0.21 L6I .. 47.3 C6I . 0.00
C04 64.99 -5.73 6 L2I .. 37.7 C2I . 0.37 L7I .. 41.8 C7I . 0.25 L6I .. 42.9 C6I . 0.00
C05 -42.36 -80.31 6 L2I .. 35.9 C2I . 0.27 L7I .. 38.7 C7I . 0.21 L6I .. 39.6 C6I . 0.00
C06 -15.26 -74.59 6 L2I .. 47.0 C2I . 0.60 L7I .. 47.1 C7I . 0.24 L6I .. 48.0 C6I . 0.00
C07 34.21 14.11 6 L2I .. 32.8 C2I . 0.87 L7I .. 36.4 C7I . 0.40 L6I .. 35.2 C6I . 0.00
C08 -0.07 -107.77 6 L2I .. 49.7 C2I . 0.17 L7I .. 49.1 C7I . 0.21 L6I .. 50.2 C6I . 0.00
C09 -10.42 107.30 6 L2I .. 41.6 C2I . 0.54 L7I .. 42.6 C7I . 0.37 L6I .. 42.3 C6I . 0.00
C10 32.77 7.17 6 L2I .. 36.9 C2I . 0.87 L7I .. 36.7 C7I . 0.58 L6I .. 36.0 C6I . 0.00
C11 33.14 61.19 6 L2I .. 43.1 C2I . 0.57 L7I .. 44.0 C7I . 0.52 L6I .. 43.6 C6I . 0.00
C14 -22.42 106.32 6 L2I .. 49.6 C2I . 0.35 L7I .. 50.7 C7I . 0.26 L6I .. 52.3 C6I . 0.00
> 2015 06 15 00 00 30.0000000 39 0.6
...
Note that in addition to cycle slips recorded in the RINEX 'file', cycle slips identified by BNC are reported as 'found'.
3.6.5 Plots for Signals - mandatory if 'Action' is set to 'Analyze'
Multipath and signal-to-noise sky plots as well as plots for satellite availability, elevation and PDOP are produced per GNSS system and frequency with the multipath analysis based on CnC observation types (n = band / frequency). The 'Plots for signals' option lets you exactly specify the observation signals to be used for that and also enables the plot production. You can specify the navigation system (C = BDS, E = Galileo, G = GPS, J = QZSS, R = GLONASS, S = SBAS), the frequency, and the tracking mode or channel as defined in RINEX Version 3. Specifications for fequency and tracking mode or channel must be seperated by ampersand character '&'. Specifications for each navigation systems must be seperated by blank character ' '. The following string is an example for option field for 'Plots of signals':
ts for signals' option lets you exactly specify the observation signals to be used for that and also enables the plot production. You can specify the navigation system, the frequency, and the tracking mode or channel as defined in RINEX Version 3. Specifications for fequency and tracking mode or channel must be seperated by ampersand character '&'. Specifications for each navigation systems must be seperated by blank character ' '.
C:2&7 E:1&5 G:1&2 J:1&2 R:1&2 S:1&5This default configuration will present;
3.6.6 Directory for Plots - optional if 'Action' is set to 'Analyze'
If 'Analyze' is selected, specifying the path to a directory where plot files will be saved is optional. File names will be composed from the RINEX input file name(s) plus suffix 'PNG' to indicate the plot file format in use. Default is an empty option field, meaning that plots will not be saved on disk.
3.6.7 Set Edit Options - mandatory if 'Action' is set to 'Edit/Concatenate'
Once the 'Edit/Concatenate' action is selected, you have to 'Set Edit Options'. BNC lets you specify the RINEX version, a signal priority list when mapping RINEX Version 3 to Version 2, the sampling interval, begin and end of file, operator, observation types, comment lines, and marker, antenna, receiver details. Note that some of the specifications for editing and concatenation are only meaningful for RINEX Observation files but not for RINEX Navigation files.
A note on converting RINEX Version 3 to RINEX Version 2 and vice versa:
Optionally you may specify a 'RUN BY' string to be included in the emerging new RINEX file header. Default is an empty option field, meaning the operator's ID is automatically used as 'RUN BY' string.
You can specify a list of observation codes in field 'Use Obs. Types' to limit the output file contents to specific observation codes. GNSS system characters in that list are followed by a colon and a two or three characters observation code. A two characters observation code would mean that all available tracking modes of the affected observation type and frequency will be accepted as part of the RINEX output file. Observation codes are separated by a blank character. Default is an empty option field, meaning that any input observation code will become part of the RINEX output file.
Specifying comment line text to be added to the emerging new RINEX file header is another option. Any introduction of a newline through '\n' in this enforces the beginning of a further comment line. Comment line(s) will be added to the header immediately after the 'PGM / RUN BY / DATE' record. Default is an empty option field, meaning that no additional comment line will be added to the RINEX header.
If you specify a 'New' but no 'Old' marker/antenna/receiver name, the corresponding data field in the emerging new RINEX Observation file will be filled accordingly. If you in addition specify an 'Old' marker/antenna/receiver name, the corresponding data field in the emerging new RINEX Observation file will only be filled accordingly where 'Old' specifications match existing file contents.
Figure 8: Example for 'RINEX Editing Options' window.
Figure 9: Example for RINEX file concatenation with BNC.
Figure 10: Example for creating RINEX quality check analysis graphics output with BNC.
Figure 11: Example for satellite availability, elevation and PDOP plots as a result of a RINEX quality check analysis with BNC.
Figure 12: Sky plot examples for multipath, part of RINEX quality check analysis with BNC..
Figure 13: Sky plot examples for signal-to-noise ratio, part of RINEX quality check analysis with BNC..
3.6.8 Command Line, No Window - optional
BNC applies options from the configuration file but allows updating every one of them on the command line while the contents of the configuration file remains unchanged, see section on 'Command Line Options'. The syntax for that looks as follows
--key <keyName> <keyValue>
where <keyName> stands for the name of an option contained in the configuration file and <keyValue> stands for the value you want to assign to it. This functionality may be helpful in the 'RINEX Editing & QC' context when running BNC on a routine basis for maintaining a RINEX file archive.
The following example for a Linux platform calls BNC in 'no window' mode with a local configuration file 'rnx.conf' for concatenating four 15min RINEX files from station TLSE residing in the local directory to produce an hourly RINEX Version 3 file with 30 seconds sampling interval:./bnc --nw --conf rnx.conf --key reqcAction Edit/Concatenate --key reqcObsFile "tlse119b00.12o,tlse119b15.12o,tlse119b30.12o,tlse119b45.12o" --key reqcOutObsFile tlse119b.12o --key reqcRnxVersion 3 --key reqcSampling 30
You may use asterisk '*' and/or question mark '?' wildcard characters as shown with the following globbing command line option to specify a selection of files in a local directory:
--key reqcObsFile "tlse*"
or:
--key reqcObsFile tlse\*
The following Linux command line produces RINEX QC plots (see Estey and Meertens 1999) offline in 'no window' mode and saves them in directory '/home/user'. Introducing a dummy configuration file /dev/null makes sure that no configuration options previously saved on disc are used:
/home/user/bnc --conf /dev/null --key reqcAction Analyze --key reqcObsFile CUT02070.12O --key reqcNavFile BRDC2070.12P --key reqcOutLogFile CUT0.txt --key reqcPlotDir /home/user --nw
The following Linux command line produces the same RINEX QC plots in interactive autoStart mode:
/home/user/bnc --conf /dev/null --key reqcAction Analyze --key reqcObsFile CUT02070.12O --key reqcNavFile BRDC2070.12P --key reqcOutLogFile CUT0.txt --key --key startTab 4 --key autoStart 2
The following is a list of available key names for 'RINEX Editing & QC' (short: REQC, pronounced 'rek') options and their meaning, cf. section 'Configuration Examples':
| Keyname | Meaning |
| reqcAction | RINEX Editing & QC action |
| reqcObsFile | RINEX Observation input file(s) |
| reqcNavFile | RINEX Navigation input files(s) |
| reqcOutObsFile | RINEX Observation output file |
| reqcOutNavFile | RINEX Navigation output file |
| reqcOutLogFile | Logfile |
| reqcLogSummaryOnly | Summary of Logfile |
| reqcSkyPlotSignals | Plots for signals |
| reqcPlotDir | RINEX QC plot directory |
| reqcRnxVersion | RINEX version of emerging new file |
| reqcSampling | Sampling interval of emerging new RINEX file |
| reqcV2Priority | Version 2 Signal Priority |
| reqcStartDateTime | Begin of emerging new RINEX file |
| reqcEndDateTime | End of emerging new RINEX file |
| reqcRunBy | Operator name |
| reqcUseObsTypes | GNSS systems and observation types |
| reqcComment | Additional comment lines |
| reqcOldMarkerName | Old marker name |
| reqcNewMarkerName | New marker name |
| reqcOldAntennaName | Old antenna name |
| reqcNewAntennaName | New antenna name |
| reqcOldAntennaNumber | Old antenna number |
| reqcNewAntennaNumber | New antenna number |
| reqcOldAntennadN | Old component of north excentricity |
| reqcOldAntennadE | Old component of east excentricity |
| reqcOldAntennadU | Old component of up excentricity |
| reqcNewAntennadN | New component of north excentricity |
| reqcNewAntennadE | New component of east excentricity |
| reqcNewAntennadU | New component of up excentricity |
| reqcOldReceiverName | Old receiver name |
| reqcNewReceiverName | New receiver name |
| reqcOldReceiverNumber | Old receiver number |
| reqcNewReceiverNumber | New receiver number |
BNC allows to compare the contents of two files containing GNSS orbit and clock data in SP3 format. SP3 ASCII files basically contain a list of records over a certain period of time. Each record carries a time tag, the X,Y,Z position of the satellite's Center of Mass at that time and the corresponding satellite clock value. Both SP3 files may contain some records for different epochs. If so then BNC only compares records for identical epochs. BNC accepts that a specific GNSS system or a specific satellite is only available from one of the SP3 files. Note that BNC does not interpolate orbits when comparing SP3 files.
To compare satellite clocks provided by the two files BNC first converts coordinate differences dX,dY,dZ into along track, out-of-plane and radial compoments. It then corrects the clock differences for the radial components of coordinate differences. RMS values of clock differences are finally calculated after introducing at first one offset 'per epoch for all satellites' and secondly one offset 'per satellite for all epochs'.
3.7.1 Input SP3 Files - optional
Specify the full path of two SP3 files separated by a comma.
3.7.2 Exclude Satellites - optional
You may want to exclude one or more satellites in your SP3 files from the comparison. Or you may like to exclude all satellites of a specific GNSS system from the comparison. The following are example strings to be entered for excluding satellites from the comparison.
Default is an empty option field, meaning that no satellite will be excluded from the comparison.
3.7.3 Logfile - mandatory if 'Input SP3 Files' is set
Specify a logfile name to save results of the SP3 file comparison.
The following is an example for a SP3 Comparsion logfile:
! SP3 File 1: esr18283.sp3 ! SP3 File 2: rt218283.sp3 ! ! MJD PRN radial along out clk clkRed iPRN ! ---------------------------------------------------------------- 57043.000000 G01 -0.0001 -0.0318 -0.0354 0.0266 0.0267 1 57043.000000 G02 -0.0062 -0.0198 0.0111 0.0082 0.0143 2 57043.000000 G03 0.0052 0.0060 0.0032 0.0386 0.0334 3 57043.000000 G04 -0.0049 -0.0193 -0.0071 -0.1696 -0.1648 4 57043.000000 G05 0.0027 0.0154 0.0275 0.0345 0.0318 5 57043.000000 G06 0.0247 -0.0398 -0.0111 0.0483 0.0236 6 57043.000000 G07 -0.0052 0.2854 -0.0975 -0.0940 -0.0888 7 57043.000000 G08 -0.0247 0.0937 -0.0184 -0.1563 -0.1316 8 57043.000000 G09 0.0152 0.0583 0.0086 -0.0144 -0.0296 9 ... ... ... ! ! RMS[m] ! ! PRN radial along out nOrb clk clkRed nClk Offset ! --------------------------------------------------------------------- ! G01 0.0151 0.0377 0.0196 96 0.0157 0.0154 96 0.0152 ! G02 0.0083 0.0278 0.0228 96 0.0097 0.0124 96 -0.0626 ! G03 0.0105 0.0311 0.0307 96 0.0352 0.0309 96 0.0898 ! G04 0.0113 0.0334 0.0154 94 0.0725 0.0707 94 -0.5087 ! G05 0.0103 0.0319 0.0299 96 0.0417 0.0403 96 0.1185 ! G06 0.0182 0.0509 0.0302 96 0.0218 0.0166 96 0.0040 ! G07 0.0337 0.1632 0.0463 96 0.0483 0.0435 96 0.3031 ! G08 0.0228 0.0741 0.0321 88 0.0616 0.0561 88 -0.2232 ... ... ... ! R20 0.0637 0.2115 0.1131 96 0.1580 0.1345 96 0.7371 ! R21 0.0475 0.1657 0.0880 96 0.1123 0.0840 96 -0.4133 ! R22 0.0125 0.1249 0.0646 96 0.0414 0.0444 96 -0.7375 ! R23 0.0435 0.1503 0.0573 96 0.0987 0.1099 96 0.6620 ! R24 0.0278 0.2026 0.1186 96 0.1446 0.1303 96 -1.1470 ! ! Total 0.0262 0.0938 0.0492 5268 0.0620 0.0561 5268
The first part int this uses the following abbreviations:
| 'MJD' | Modified Julian Date |
| 'PRN' | Satellit specification |
| 'radial' | Radial component of orbit coordinate difference [m] |
| 'along' | Along track component of orbit coordinate difference [m] |
| 'out' | Out-of-plane component of orbit coordinate difference [m] |
| 'clk' | Clock difference [m] |
| 'clkRed' | Clock difference reduced by radial component of orbit coordinate difference [m] |
| 'iPRN' | BNC internal sequence number |
The second part following string 'RMS' provides a summary of the comparison using the following abbreviations:
| 'PRN' | Satellite specification |
| 'radial' | RMS of radial component of orbit coordinate differences [m] |
| 'along' | RMS of along track component of orbit coordinate differences [m] |
| 'out' | RMS of out-of-plane component of orbit coordinate differences [m] |
| 'nOrb' | Number of epochs used in in orbit comparision |
| 'clk' | RMS of clock differences [m] |
| 'clkRed' | RMS of clock differences after reduction of radial orbit differences [m] |
| 'nClk' | Number of epochs use in clock comparisons |
| 'Offset' | Clock offset [m] |
Figure 14: BNC configuration example for comparing two SP3 files with satellite orbit and clock data.
Differential GNSS and RTK operation using RTCM streams is currently based on corrections and/or raw measurements from single or multiple reference stations. This approach to differential positioning is using 'observation space' information. The representation with the RTCM standard can be called 'Observation Space Representation' (OSR).
An alternative to the observation space approach is the so called 'sate space' approach. The principle here is to provide information on individual error sources. It can be called 'State Space Representation' (SSR). For a rover position, state space information concerning precise satellite clocks, orbits, ionosphere, troposphere et cetera can be converted into observation space and used to correct the rover observables for more accurate positioning. Alternatively the state information can directly be used in the rover's processing or adjustment model.
RTCM has developed Version 3 messages to transport satellite orbit and clock corrections in real-time. Note that corrections refer to satellite Antenna Phase Centers (APC). The current set of SSR messages concerns:
RTCM Version 3 streams carrying these messages may be used i.e. to support real-time Precise Point Positioning (PPP) applications.
When using clocks from Broadcast Ephemeris (with or without applied corrections) or clocks from SP3 files, it may be important to understand that they are not corrected for the conventional periodic relativistic effect. Chapter 10 of the IERS Conventions 2003 mentions that the conventional periodic relativistic correction to the satellite clock (to be added to the broadcast clock) is computed as dt = -2 (R * V) / c^2 where R * V is the scalar product of the satellite position and velocity and c is the speed of light. This can also be found in the GPS Interface Specification, IS-GPS-200, Revision D, 7 March 2006.
Orbit corrections are provided in along-track, cross-track and radial components. These components are defined in the Earth-centered, Earth-fixed reference frame of the broadcast ephemerides. For an observer in this frame, the along-track component is aligned in both direction and sign with the velocity vector, the cross-track component is perpendicular to the plane defined by the satellite position and velocity vectors, and the radial direction is perpendicular to the along track and cross-track ones. The three components form a right-handed orthogonal system.
After applying corrections, the satellite position and clock is referred to the 'ionospheric free' phase center of the antenna which is compatible with the broadcast orbit reference.
The orbit and clock corrections do not include local effects like Ocean Loading, Solid Earth Tides or tropospheric delays. However, accurate single frequency applications can be correct for global ionospheric effects using so-call VTEC messages for global ionospheric state parameters.
While we have a plain ASCII standard for saving broadcast ephemeris in RINEX Navigation files, we don't have an equivalent standard for corrections to broadcast ephemeris. Hence BNC saves Broadcast Correction files following its own format definition. The file name convention for Broadcast Correction files follows the convention for RINEX Version 2 files except for the last character of the file name suffix which is set to 'C'.
BNC's Broadcast Correction files contain blocks of records in plain ASCII format. Each block covers information about one sprecific topic and starts with an 'Epoch Record'.
The 'Epoch Record' of a Broadcast Corrections block
The leading 'Epoch Record' of each block in a Broadcast Corrections file contains 11 parameters. Example:
> ORBIT 2015 06 17 11 43 35.0 2 53 CLK93
Their meaning is as follows:
Example for block 'ORBIT' carrying orbit corrections
> ORBIT 2015 06 17 11 43 35.0 2 53 CLK93 G01 9 0.5134 0.3692 0.6784 0.0000 -0.0000 -0.0000 G02 25 57.6817 139.0492 -91.3456 0.5436 -0.6931 1.0173 G03 79 -32.1768 191.8368 -121.6540 0.2695 0.2296 0.4879 ... G32 82 1.8174 1.1704 0.2200 -0.0002 -0.0000 -0.0001 R01 59 0.7819 -0.6968 0.7388 -0.0001 0.0004 0.0004 R02 59 0.5816 -0.5800 -0.2004 0.0001 -0.0006 0.0001 R03 59 0.4635 -0.9104 -0.3832 0.0001 0.0001 0.0005 ... R24 59 0.5935 2.0732 -0.6884 -0.0000 0.0004 0.0003
Records in this block provide the following satellite specific information:
Example for block 'CLOCK' carrying clock corrections
> CLOCK 2015 06 17 11 43 35.0 2 53 CLK93 G01 9 0.5412 0.0000 0.0000 G02 25 11.1811 0.0000 0.0000 G03 79 45.0228 0.0000 0.0000 ... G32 82 -1.5324 0.0000 0.0000 R01 59 4.2194 0.0000 0.0000 R02 59 2.0535 0.0000 0.0000 R03 59 1.8130 0.0000 0.0000 ... R24 59 2.7409 0.0000 0.0000
Records in this block provide the following satellite specific information:
Example for block 'CODE_BIAS' carrying code biases
> CODE_BIAS 2015 06 17 11 43 35.0 2 53 CLK93 G01 5 1C -3.3100 1W -3.7500 2W -6.1900 2X -5.7800 5I -5.4200 G02 5 1C 3.6000 1W 3.9300 2W 6.4800 2X 0.0000 5I 0.0000 G03 5 1C -2.1600 1W -2.6500 2W -4.3600 2X -4.4800 5I -5.3400 ... G32 5 1C -1.5800 1W -1.1000 2W -1.8200 2X 0.0000 5I 0.0000 R01 4 1C -2.4900 1P -2.4900 2C -3.1500 2P -4.1200 R02 4 1C 0.3900 1P 0.2100 2C 0.4000 2P 0.3400 R03 4 1C 2.4800 1P 2.2800 2C 3.7800 2P 3.7700 ... R24 4 1C 2.7000 1P 2.7800 2C 3.9800 2P 4.6000
Records in this block provide the following satellite specific information:
Example for block 'PHASE_BIAS' carrying phase biases
> PHASE_BIAS 2015 06 17 11 43 35.0 2 31 CLK93 0 1 G01 245.39062500 0.00000000 3 1C 3.9518 1 2 6 2W 6.3177 1 2 6 5I 6.8059 1 2 6 G02 250.31250000 0.00000000 3 1C -4.0900 1 2 5 2W -6.7044 1 2 5 5I 0.0000 1 2 5 G03 281.95312500 0.00000000 3 1C 2.9327 1 2 4 2W 4.6382 1 2 4 5I 5.4120 1 2 4 ... G32 290.39062500 0.00000000 3 1C 1.2520 1 2 5 2W 2.0554 1 2 5 5I 0.0000 1 2 5
The second record in this block provides the following consistency information:
Example for block 'VTEC' carrying ionospheric corrections
> VTEC 2015 06 17 11 43 35.0 6 1 CLK93
1 6 6 450000.0
17.6800 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
4.5200 8.8700 0.0000 0.0000 0.0000 0.0000 0.0000
-4.6850 -0.3050 1.1700 0.0000 0.0000 0.0000 0.0000
-2.2250 -1.3900 -1.0250 -0.1300 0.0000 0.0000 0.0000
0.8750 -0.3800 0.2700 -0.1300 0.0400 0.0000 0.0000
1.2150 0.9050 -1.0100 0.3700 -0.1450 -0.2450 0.0000
-0.8200 0.4850 0.2300 -0.1750 0.3400 -0.0900 -0.0400
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 -0.0700 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.5800 -1.4150 0.0000 0.0000 0.0000 0.0000
0.0000 -0.6200 -0.1500 0.2600 0.0000 0.0000 0.0000
0.0000 0.0700 -0.0900 -0.0550 0.1700 0.0000 0.0000
0.0000 0.5000 0.3050 -0.5700 -0.5250 -0.2750 0.0000
0.0000 0.0850 -0.4700 0.0600 0.0700 0.1600 0.0400
The second record in this block provides four parameters:
3.8.1 Directory, ASCII - optional
Specify a directory for saving Broadcast Corrections in files. If the specified directory does not exist, BNC will not create Broadcast Correction files. Default value for Broadcast Corrections 'Directory' is an empty option field, meaning that no Broadcast Correction files will be created.
3.8.2 Interval - mandatory if 'Directory, ASCII' is set
Select the length of the Broadcast Correction files. The default value is 1 day.
BNC can output epoch by epoch synchronized Broadcast Corrections in ASCII format on your local host (IP 127.0.0.1) through an IP 'Port'. Specify an IP port number to activate this function. The default is an empty option field, meaning that no Broadcast Correction output via IP port is generated.
The output format is similar to the format used for saving Broadcast Corrections in a file.
The following is an example output for the stream from mountpoint CLK93:
> ORBIT 2015 06 19 16 41 00.0 2 53 CLK93
G01 85 0.5891 -0.5124 -0.0216 -0.0001 -0.0002 0.0000
G02 25 -150.1820 11.4676 84.5216 0.4130 -0.6932 1.0159
G03 79 15.1999 141.9932 -156.4244 0.6782 -0.8607 -0.8211
...
G32 39 1.8454 0.4888 -0.3876 -0.0001 -0.0001 0.0001
R01 79 -0.0506 1.9024 -0.0120 0.0004 0.0002 -0.0000
R02 79 0.1623 0.9012 0.3984 0.0001 0.0001 0.0002
R03 79 0.3247 -2.6704 -0.0240 0.0005 -0.0002 0.0002
...
R24 79 0.7046 -0.5088 -0.0160 -0.0000 0.0000 -0.0002
> CLOCK 2015 06 19 16 41 00.0 2 53 CLK93
G01 85 -116.9441 0.0000 0.0000
G02 25 -110.4472 0.0000 0.0000
G03 79 -96.8299 0.0000 0.0000
...
G32 39 -119.2757 0.0000 0.0000
R01 79 1.5703 0.0000 0.0000
R02 79 -1.4181 0.0000 0.0000
R03 79 0.2072 0.0000 0.0000
...
R24 79 1.1292 0.0000 0.0000
> CODE_BIAS 2015 06 19 16 41 00.0 0 56 CLK93
E11 3 1B 1.3800 5Q 2.4800 7Q 2.5000
E12 3 1B 0.3900 5Q 0.6900 7Q 0.5300
E19 3 1B -1.7800 5Q -3.1900 7Q -3.0700
G01 5 1C -3.3100 1W -3.7500 2W -6.1900 2X -5.7800 5I -5.4200
G02 5 1C 3.6000 1W 3.9300 2W 6.4800 2X 0.0000 5I 0.0000
G03 5 1C -2.1600 1W -2.6500 2W -4.3600 2X -4.4800 5I -5.3400
...
G32 5 1C -1.5800 1W -1.1000 2W -1.8200 2X 0.0000 5I 0.0000
R01 4 1C -2.4900 1P -2.4900 2C -3.1500 2P -4.1200
R02 4 1C 0.3900 1P 0.2100 2C 0.4000 2P 0.3400
R03 4 1C 2.4800 1P 2.2800 2C 3.7800 2P 3.7700
...
R24 4 1C 2.7000 1P 2.7800 2C 3.9800 2P 4.6000
> PHASE_BIAS 2015 06 19 16 41 00.0 2 31 CLK93
0 1
G01 309.37500000 0.00000000 3 1C 3.9922 1 2 6 2W 6.3568 1 2 6 5I 6.8726 1 2 6
G02 263.67187500 0.00000000 3 1C -4.0317 1 2 7 2W -6.6295 1 2 7 5I 0.0000 1 2 7
G03 267.89062500 0.00000000 3 1C 3.1267 1 2 4 2W 4.9126 1 2 4 5I 5.6478 1 2 4
...
G32 255.93750000 0.00000000 3 1C 1.3194 1 2 5 2W 2.1448 1 2 5 5I 0.0000 1 2 5
> VTEC 2015 06 19 16 41 00.0 6 1 CLK93
1 6 6 450000.0
16.7450 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
4.9300 8.1600 0.0000 0.0000 0.0000 0.0000 0.0000
-4.4900 0.2550 1.0950 0.0000 0.0000 0.0000 0.0000
-2.2450 -1.9500 -0.7950 -0.4700 0.0000 0.0000 0.0000
1.0250 -0.9000 -0.0900 0.1050 0.1450 0.0000 0.0000
1.5500 0.9750 -0.8150 0.3600 0.0350 -0.0900 0.0000
-0.4050 0.8300 0.0800 -0.0650 0.2200 0.0150 -0.1600
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 -0.1250 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 1.0050 -0.7750 0.0000 0.0000 0.0000 0.0000
0.0000 -0.2300 0.7150 0.7550 0.0000 0.0000 0.0000
0.0000 -0.4100 -0.1250 0.2400 0.2700 0.0000 0.0000
0.0000 0.0850 -0.3400 -0.0500 -0.2200 -0.0750 0.0000
0.0000 0.2000 -0.2850 -0.0150 -0.0250 0.0900 0.0650
The source code for BNC comes with an example perl script 'test_tcpip_client.pl' that allows you to read BNC's Broadcast Corrections from the IP port.
Figure 15: BNC configuration example for pulling, saving and output of Broadcast Corrections.
BNC can generate synchronized or unsynchronized observations epoch by epoch from all stations and satellites to feed a real-time GNSS network engine. Observations can be streamed out through an IP port and/or saved in a local file. The output is always in plain ASCII format and sorted per incoming stream.
Any epoch in the output begins with a line containing the GPS week number and the seconds within the GPS week. Following lines begin with the mountpoint string of the stream which provides the observations followed by a satellite ID. Observation types are specified by the three character observation code defined in RINEX Version 3. In case of phase observations a Slip Count is added which is put to "-1" if it is not set. The end of an epoch in indicated by an empty line.
Note on 'Slip Count':
It is the current understanding of BNC's authors that different Slip Counts could be referred to different phase measurements (i.e. L1C and L1P). The 'loss-of-lock' flags in RINEX are an example for making such kind of information available per phase measurement. However, it looks like we do have only one Slip Count in RTCM Version 3 for all phase measurements. As it could be that a receiver generates different Slip Counts for different phase measurements, we output one Slip Count per phase measurement to a listening real-time GNSS network engine.
The following is an example for file and IP port output which presents observations from GPS, GLONASS, Galileo, BDS (BeiDou), QZSS, and SBAS satellites as collected through streams WTZR0, CUT07, and COCO0:
> 1850 120556.0000000 WTZR0 G01 C1C 25394034.112 L1C 133446552.870 127 S1C 43.000 C2W 25394040.832 L2W 103984354.397 127 S2W 34.750 WTZR0 G12 C1C 21452585.278 L1C 112734165.968 127 S1C 50.500 C2W 21452584.578 L2W 87844835.675 127 S2W 46.250 WTZR0 G13 C1C 24061255.720 L1C 126442693.941 127 S1C 45.750 C2W 24061259.860 L2W 98526745.844 127 S2W 35.500 ... WTZR0 G28 C1C 25200320.952 L1C 132428507.619 127 S1C 43.500 C2W 25200323.952 L2W 103191035.510 127 S2W 35.000 WTZR0 R01 C1C 21380903.420 L1C 114293200.377 127 S1C 48.750 C2P 21380907.340 L2P 88894741.570 127 S2P 41.500 WTZR0 R02 C1C 22644814.432 L1C 120837082.440 127 S1C 46.500 C2P 22644817.592 L2P 93984421.793 127 S2P 42.500 WTZR0 R08 C1C 23068202.108 L1C 123529160.309 127 S1C 46.500 C2P 23068204.988 L2P 96078225.806 127 S2P 41.750 ... WTZR0 R21 C1C 23024132.668 L1C 123206823.917 127 S1C 47.250 C2P 23024137.748 L2P 95827547.481 127 S2P 42.000 CUT07 G02 C1C 23272399.734 L1C 122297070.388 597 D1C -87.977 S1C 42.312 C2W 23272400.234 L2W 95297219.119 597 S2W 26.688 CUT07 G03 C1C 24110497.680 L1C 126701879.242 659 D1C -3056.984 S1C 37.875 C2W 24110505.621 L2W 98728694.271 659 S2W 21.688 C2X 24110505.926 L2X 98728386.267 659 S2X 40.312 C5X 24110510.094 L5X 94614774.123 659 S5X 45.312 CUT07 G05 C1C 24944957.625 L1C 131087212.915 520 D1C 3895.703 S1C 37.625 C2W 24944962.168 L2W 102145324.192 520 S2W 20.875 C2X 24944962.004 L2X 102145177.172 520 S2X 36.125 ... CUT07 G30 C1C 20928146.555 L1C 109978415.517 606 D1C 2025.395 S1C 54.000 C2W 20928151.566 L2W 85697602.266 606 S2W 43.188 C2X 20928151.930 L2X 85697012.264 606 S2X 49.875 C5X 20928155.511 L5X 82126237.098 606 S5X 55.812 CUT07 R04 C1C 22160327.953 L1C 118666825.671 652 D1C -2522.773 S1C 46.375 C1P 22160327.797 L1P 118667617.662 652 S1P 45.188 C2C 22160332.254 L2C 92297583.036 652 S2C 43.625 C2P 22160332.567 L2P 92297422.037 652 S2P 42.312 CUT07 R05 C1C 19447023.836 L1C 103954847.683 632 D1C 379.031 S1C 48.500 C1P 19447023.914 L1P 103954847.676 632 S1P 47.000 C2C 19447027.547 L2C 80853787.461 632 S2C 50.500 C2P 19447028.449 L2P 80853787.472 632 S2P 49.875 CUT07 R06 C1C 21207223.649 L1C 113165770.921 587 D1C 3560.348 S1C 50.875 C1P 21207223.375 L1P 113166378.915 587 S1P 49.125 C2C 21207227.008 L2C 88017617.177 587 S2C 46.000 C2P 21207228.262 L2P 88017377.180 587 S2P 45.500 ... CUT07 R16 C1C 19585043.860 L1C 104620582.766 598 D1C 2187.578 S1C 53.312 C1P 19585044.758 L1P 104620582.776 598 S1P 51.375 C2C 19585048.981 L2C 81371454.856 598 S2C 49.375 C2P 19585049.879 L2P 81371454.858 598 S2P 48.812 CUT07 E20 C1X 27365616.429 L1X 143807095.898 527 D1X 2876.149 S1X 35.000 CUT07 S27 C1C 39931452.594 L1C 209841056.112 679 D1C 406.422 S1C 39.000 C5I 39931443.285 L5I 156699444.322 679 S5I 42.375 CUT07 S28 C1C 37844752.406 L1C 198874711.984 683 D1C 407.059 S1C 46.625 C5I 37844741.785 L5I 148510882.534 704 S5I 45.000 CUT07 S29 C1C 37651158.016 L1C 197858052.600 683 D1C 403.512 S1C 43.000 CUT07 S37 C1C 37651147.828 L1C 197858448.618 683 D1C 403.531 S1C 41.625 CUT07 J01 C1C 40048292.047 L1C 210455903.893 704 D1C -1583.379 S1C 41.812 C1Z 40048289.996 L1Z 210455441.428 704 S1Z 40.875 C6L 40048292.316 L6L 170824217.096 704 S6L 37.000 C2X 40048298.183 L2X 163991247.082 704 S2X 40.688 C5X 40048303.817 L5X 157158277.377 704 S5X 46.375 C1X 40048292.351 L1X 210455442.883 704 S1X 44.000 CUT07 C01 C2I 37324042.141 L2I 194356552.952 704 D2I 440.996 S2I 42.688 C6I 37324028.519 L6I 157929660.388 704 S6I 45.875 C7I 37324033.363 L7I 150287901.788 704 S7I 46.312 CUT07 C02 C2I 38275575.024 L2I 199310999.358 704 D2I 404.117 S2I 37.875 C6I 38275566.211 L6I 161956457.229 704 S6I 43.000 C7I 38275569.942 L7I 154119870.634 704 S7I 42.312 CUT07 C03 C2I 37135200.797 L2I 193371988.170 692 D2I 431.973 S2I 43.312 C6I 37135190.051 L6I 157131416.391 692 S6I 48.000 C7I 37135194.422 L7I 149528282.423 692 S7I 46.812 ... CUT07 C10 C2I 36760375.289 L2I 191420952.281 640 D2I 1025.387 S2I 45.688 C6I 36760364.426 L6I 155545258.984 640 S6I 46.688 C7I 36760373.723 L7I 148018880.533 640 S7I 46.312 COCO0 G02 C1C 22476261.427 L1C 118113589.570 586 D1C 1412.187 S1C 44.938 C2W 22476260.826 L2W 92036575.260 586 D2W 1100.406 S2W 35.312 COCO0 G03 C1C 24341919.159 L1C 127917554.810 663 D1C -2074.090 S1C 38.688 C2W 24341930.673 L2W 99676015.236 663 D2W -1616.167 S2W 24.438 C2L 24341930.723 L2L 99676013.201 662 D2L -1616.219 S2L 38.750 C5Q 24341933.159 L5Q 95522839.465 662 D5Q -1548.741 S5Q 42.875 COCO0 G05 C1C 25474658.679 L1C 133870244.277 493 D1C 3159.081 S1C 39.438 C2W 25474663.398 L2W 104314491.669 491 D2W 2461.609 S2W 24.562 ... COCO0 G30 C1C 20331006.470 L1C 106840352.867 617 D1C -212.495 S1C 52.188 C2W 20331010.207 L2W 83252324.005 617 D2W -165.585 S2W 49.500 C2L 20331010.394 L2L 83252323.011 613 D2L -165.567 S2L 50.250 COCO0 R04 C1C 23325683.508 L1C 124907994.343 660 D1C -873.812 S1C 41.125 C2C 23325691.864 L2C 97150681.177 660 D2C -679.608 S2C 42.312 C2P 23325691.726 L2P 97150688.171 660 D2P -679.605 S2P 43.188 COCO0 R05 C1C 21328759.151 L1C 114014512.115 644 D1C 1069.493 S1C 42.812 C2C 21328765.687 L2C 88678051.219 647 D2C 831.814 S2C 47.812 C2P 21328765.883 L2P 88678030.225 645 D2P 831.850 S2P 47.438 COCO0 R09 C1C 21027128.207 L1C 112283840.462 555 D1C 3490.368 S1C 45.188 ... COCO0 R21 C1C 23445025.787 L1C 125459055.095 555 D1C -765.275 S1C 42.688 C2C 23445033.733 L2C 97579294.654 555 D2C -595.265 S2C 40.188 C2P 23445033.487 L2P 97579294.651 537 D2P -595.197 S2P 40.875 COCO0 J01 C1C 39927130.880 L1C 209818564.350 704 D1C -1175.392 S1C 41.562 C2L 39927135.634 L2L 163495064.612 704 D2L -915.829 S2L 40.562 C5Q 39927138.784 L5Q 156682808.818 704 D5Q -877.788 S5Q 44.375 COCO0 C01 C2I 37949052.545 L2I 197610628.940 704 D2I 179.818 S2I 44.500 C7I 37949047.569 L7I 152805027.848 704 D7I 139.094 S7I 46.812 COCO0 C02 C2I 36636436.522 L2I 190775621.693 704 D2I 166.143 S2I 48.188 C7I 36636433.422 L7I 147519844.394 704 D7I 128.449 S7I 50.625 COCO0 C03 C2I 36481125.870 L2I 189966778.019 666 D2I 178.936 S2I 48.688 C7I 36481123.342 L7I 146894352.298 653 D7I 138.364 S7I 50.312 ... COCO0 C10 C2I 35632229.616 L2I 185546695.648 704 D2I 327.212 S2I 49.625 C7I 35632229.807 L7I 143476633.351 704 D7I 252.998 S7I 50.812 > 1850 120557.0000000 ...
The source code for BNC comes with a perl script named 'test_tcpip_client.pl' that allows you to read BNC's (synchronized or unsynchronized) ASCII observation output from the IP port and print it on standard output.
Note that any socket connection of an application to BNC's synchronized or unsynchronized observations ports is recorded in the 'Log' tab on the bottom of the main window together with a connection counter, resulting in log records like 'New client connection on sync/usync port: # 1'.
The following figure shows the screenshot of a BNC configuration where a number of streams is pulled from different NTRIP Broadcasters to feed a GNSS engine via IP port output.
Figure 16: Synchronized BNC output via IP port to feed a GNSS real-time engine.
BNC can produce synchronized observations in ASCII format on your local host (IP 127.0.0.1) through an IP 'Port'. Synchronized means that BNC collects all observation data for any specific epoch which become available within a certain number of latency seconds (see 'Wait for Full Obs Epoch' option). It then - epoch by epoch - outputs whatever has been received. The output comes block wise per stream. Specify an IP port number here to activate this function. The default is an empty option field, meaning that no binary synchronized output is generated.
3.9.2 Wait for Full Obs Epoch - mandatory if 'Port' is set
When feeding a real-time GNSS network engine waiting for synchronized observations epoch by epoch, BNC drops whatever is received later than 'Wait for full obs epoch' seconds. A value of 3 to 5 seconds could be an appropriate choice for that, depending on the latency of the incoming streams and the delay acceptable for your real-time GNSS product. Default value for 'Wait for full obs epoch' is 5 seconds.
Note that 'Wait for full obs epoch' does not affect the RINEX Observation file content. Observations received later than 'Wait for full obs epoch' seconds will still be included in the RINEX Observation files.
3.9.3 Sampling - mandatory if 'File' or 'Port' is set
Select the synchronized observation output sampling interval in seconds. A value of zero '0' tells BNC to send/store all received epochs. This is the default value.
Specify the full path to a 'File' where synchronized observations are saved in plain ASCII format. The default value is an empty option field, meaning that no ASCII output file is created.
Beware that the size of this file can rapidly increase depending on the number of incoming streams. The name of the file can be changed on-the-fly, to prevent it from becoming too large. This option is primarily meant for testing and evaluation.
3.9.5 Port (unsynchronized) - optional
BNC can produce unsynchronized observations from all configured streams in ASCII format on your local host (IP 127.0.0.1) through an IP 'Port'. Unsynchronized means that BNC immediately forwards any received observation to the port. Nevertheless, the output comes block wise per stream. Specify an IP port number here to activate this function. The default is an empty option field, meaning that no unsynchronized output is generated.
You may use BNC to feed a serial connected device like a GNSS receiver. For that an incoming stream can be forwarded to a serial port. Depending on the stream contents the receiver may use it for Differential GNSS, Precise Point Positioning or any other purpose supported by its firmware.
Note that receiving a VRS stream requires the receiver sending NMEA sentences (mode 'Manual' or 'Auto') to the Ntrip Broadcaster. The following figure shows the data flow when pulling a VRS stream or a physical (none-VRS) stream.
Figure 17: Flowcharts, BNC forwarding a stream to a serial connected receiver; sending NMEA sentences is mandatory for VRS streams.
The following figure shows the screenshot of an example situation where BNC pulls a VRS stream from an NTRIP Broadcaster to feed a serial connected RTK rover.
Figure 18: BNC pulling a VRS stream to feed a serial connected RTK rover.
Enter a 'Mountpoint' to forward its corresponding stream to a serial connected GNSS receiver.
When selecting one of the serial communication options listed below, make sure that you pick those configured to the serial connected receiver.
3.10.2 Port Name - mandatory if 'Mountpoint' is set
Enter the serial 'Port name' selected on your host for communication with the serial connected receiver. Valid port names are
Windows: COM1, COM2 Linux: /dev/ttyS0, /dev/ttyS1 FreeBSD: /dev/ttyd0, /dev/ttyd1 Digital Unix: /dev/tty01, /dev/tty02 HP-UX: /dev/tty1p0, /dev/tty2p0 SGI/IRIX: /dev/ttyf1, /dev/ttyf2 SunOS/Solaris: /dev/ttya, /dev/ttyb
Note that you must plug a serial cable in the port defined here before you start BNC.
3.10.3 Baud Rate - mandatory if 'Mountpoint' is set
Select a 'Baud rate' for the serial output link. Note that using a high baud rate is recommended.
3.10.4 Flow Control - mandatory if 'Mountpoint' is set
Select a 'Flow control' for the serial output link. Note that your selection must equal the flow control configured to the serial connected device. Select 'OFF' if you don't know better.
3.10.5 Parity - mandatory if 'Mountpoint' is set
Select the 'Parity' for the serial output link. Note that parity is often set to 'NONE'.
3.10.6 Data Bits - mandatory if 'Mountpoint' is set
Select the number of 'Data bits' for the serial output link. Note that often '8' data bits are used.
3.10.7 Stop Bits - mandatory if 'Mountpoint' is set
Select the number of 'Stop bits' for the serial output link. Note that often '1' stop bit is used.
3.10.8 NMEA - mandatory if 'Mountpoint' is set
The 'NMEA' option supports the so-called 'Virtural Reference Station' (VRS) concept which requires the receiver to send approximate position information to the NTRIP Broadcaster. Select 'no' if you don't want BNC to forward or upload any NMEA message to the NTRIP broadcaster in support of VRS.
Select 'Auto' to automatically forward NMEA messages of type GGA from your serial connected receiver to the NTRIP broadcaster and/or save them in a file.
Select 'Manual GPGGA' or 'Manual GNGGA' if you want BNC to produce and upload GPGGA or GNGGA NMEA messages to the NTRIP broadcaster because your serial connected receiver doesn't generate these messages. A Talker ID 'GP' preceding the GGA string stands for GPS solutions while a Talker ID 'GN' stands for multi constellation solutions.
Note that selecting 'Auto' or 'Manual' works only for VRS streams which show up under the 'Streams' canvas on BNC's main window with 'nmea' stream attribute set to 'yes'. This attribute is either extracted from the NTRIP broadcaster's sourcetable or introduced by the user through editing the BNC configuration file.
3.10.9 File - optional if 'NMEA' is set to 'Auto'
Specify the full path to a file where NMEA messages coming from your serial connected receiver are saved. Default is an empty option field, meaning that no NMEA messages will be saved on disk.
3.10.10 Height - mandatory if 'NMEA' is set to 'Manual'
Specify an approximate 'Height' above mean sea level in meters for the reference station introduced through 'Mountpoint'. Together with the latitude and longitude from the NTRIP broadcaster sourcetable the height information is used to build GGA messages to be sent to the NTRIP broadcaster.
For adjusting latitude and longitude values of a VRS stream given in the 'Streams' canvas you can double click the latitude/longitude data fields, specify appropriate values and then hit Enter.
This option is only relevant when option 'NMEA' is set to 'Manual GPGGA' or 'Manual GNGGA' respectively.
3.10.11 Sampling - mandatory if 'NMEA' is set to 'Manual'
Select a sampling interval in seconds for manual generation and upload of NMEA GGA sentences.
A sampling rate of '0' means, that a GGA sentence will be send only once to initialize the requested VRS stream. Note that some VRS systems need GGA sentences at regular intervals.
At any time an incoming stream might become unavailable or corrupted. In such cases, it is important that the BNC operator and/or the stream providers become aware of the situation so that necessary measures can be taken to restore the stream. Furthermore, continuous attempts to decode a corrupted stream can generate unnecessary workload for BNC. Outages and corruptions are handled by BNC as follows:
Stream outages: BNC considers a connection to be broken when there are no incoming data detected for more than 20 seconds. When this occurs, BNC will attempt to reconnect at a decreasing rate. It will first try to reconnect with 1 second delay and again in 2 seconds if the previous attempt failed. If the attempt is still unsuccessful, it will try to reconnect within 4 seconds after the previous attempt and so on. The wait time doubles each time with a maximum wait time of 256 seconds.
Stream corruption: Not all bits chunk transfers to BNC's internal decoders return valid observations. Sometimes several chunks might be needed before the next observation can be properly decoded. BNC buffers all the outputs (both valid and invalid) from the decoder for a short time span (size derived from the expected 'Observation rate') and then determines whether a stream is valid or corrupted.
Outage and corruption events are reported in the 'Log' tab. They can also be passed on as parameters to a shell script or batch file to generate an advisory note to BNC operator or affected stream providers. This functionality lets users utilize BNC as a real-time performance monitor and alarm system for a network of GNSS reference stations.
3.11.1 Observation Rate - optional
BNC can collect all returns (success or failure) coming from a decoder within a certain short time span to then decide whether a stream has an outage or its content is corrupted. This procedure needs a rough a priory estimate of the expected observation rate of the incoming streams.
An empty option field (default) means that you don't want explicit information from BNC about stream outages and incoming streams that cannot be decoded.
3.11.2 Failure Threshold - mandatory if 'Observation rate' is set
Event 'Begin_Failure' will be reported if no data is received continuously for longer than the 'Failure threshold' time. Similarly, event 'Begin_Corrupted' will be reported when corrupted data is detected by the decoder continuously for longer than this 'Failure threshold' time. The default value is set to 15 minutes and is recommended so not to inundate user with too many event reports.
Note that specifying a value of zero '0' for the 'Failure threshold' will force BNC to report any stream failure immediately. Note also that for using this function you need to specify the 'Observation rate'.
3.11.3 Recovery Threshold - mandatory if 'Observation rate' is set
Once a 'Begin_Failure' or 'Begin_Corrupted' event has been reported, BNC will check for when the stream again becomes available or uncorrupted. Event 'End_Failure' or 'End_Corrupted' will be reported as soon as valid observations are again detected continuously throughout the 'Recovery threshold' time span. The default value is set to 5 minutes and is recommended so not to inundate users with too many event reports.
Note that specifying a value of zero '0' for the 'Recovery threshold' will force BNC to report any stream recovery immediately. Note also that for using this function you need to specify the 'Observation rate'.
3.11.4 Script - optional if 'Observation rate' is set
As mentioned previously, BNC can trigger a shell script or a batch file to be executed when one of the events described are reported. This script can be used to email an advisory note to network operator or stream providers. To enable this feature, specify the full path to the script or batch file in the 'Script' field. The affected stream's mountpoint and type of event reported ('Begin_Outage', 'End_Outage', 'Begin_Corrupted' or 'End_Corrupted') will then be passed on to the script as command line parameters (%1 and %2 on Windows systems or $1 and $2 on Unix/Linux/Mac OS X systems) together with date and time information.
Leave the 'Script' field empty if you do not wish to use this option. An invalid path will also disable this option.
Examples for command line parameter strings passed on to the advisory 'Script' are:
FFMJ0 Begin_Outage 08-02-21 09:25:59 FFMJ0 End_Outage 08-02-21 11:36:02 Begin was 08-02-21 09:25:59
Sample script for Unix/Linux/Mac OS X systems:
#!/bin/bash sleep $((60*RANDOM/32767)) cat > mail.txt <<EOF Advisory Note to BNC User, Please note the following advisory received from BNC. Stream: $* Regards, BNC EOF mail -s "NABU: $1" email@address < mail.txt
Note the sleep command in this script which causes the system to wait for a random period of up to 60 seconds before sending the email. This should avoid overloading your mail server in case of a simultaneous failure of many streams.
This section describes several miscellaneous options which can be applied to a single stream (mountpoint) or to all configured streams.
The following figure shows RTCM message numbers and observation types contained in stream 'CUT07' and the message latencies recorded every 2 seconds.
Figure 19: RTCM message numbers, latencies and observation types.
Specify a mountpoint to apply one or several of the 'Miscellaneous' options to the corresponding stream. Enter 'ALL' if you want to apply these options to all configured streams. An empty option field (default) means that you don't want BNC to apply any of these options.
BNC can average latencies per stream over a certain period of GPS time, the 'Log latency' interval. Mean latencies are calculated from the individual latencies of one (first incoming) observation or Broadcast Correction per second. The mean latencies are then saved in BNC's logfile. Note that computing correct latencies requires the clock of the host computer to be properly synchronized. Note further that visualized latencies from the 'Latency' tab on the bottom of the main window represent individual latencies and not the mean latencies for the logfile.
Latency: Latency is defined in BNC by the following equation:
UTC time provided by BNC's host
- GPS time of currently processed epoch
+ Leap seconds between UTC and GPS time
--------------
= Latency
Statistics: BNC counts the number of GPS seconds covered by at least one observation. It also estimates an observation rate (independent from the a priory specified 'Observation rate') from all observations received throughout the first full 'Log latency' interval. Based on this rate, BNC estimates the number of data gaps when appearing in subsequent intervals.
Latencies of observations or corrections to Broadcast Ephemeris and statistical information can be recorded in the 'Log' tab at the end of each 'Log latency' interval. A typical output from a 1 hour 'Log latency' interval would be:
08-03-17 15:59:47 BRUS0: Mean latency 1.47 sec, min 0.66, max 3.02, rms 0.35, 3585 epochs, 15 gaps
Select a 'Log latency' interval to activate this function or select the empty option field if you do not want BNC to log latencies and statistical information.
When configuring a GNSS receiver for RTCM stream generation, the firmware's setup interface may not provide details about RTCM message types and observation types. As reliable information concerning stream contents should be available i.e. for NTRIP Broadcaster operators to maintain the broadcaster's source-table, BNC allows to scan RTCM streams for incoming message types and printout some of the contained meta-data. Contained observation types are also printed because such information is required a-priori for the conversion of RTCM Version 3 MSM streams to RINEX Version 3 files. The idea for this option arose from 'inspectRTCM', a comprehensive stream analyzing tool written by D. Stoecker.
Tick 'Scan RTCM' to scan RTCM Version 2 or 3 streams and log all contained
Note that in RTCM Version 2 the message types 18 and 19 carry only the observables of one frequency. Hence it needs two type 18 and 19 messages per epoch to transport the observations from dual frequency receivers.
Please note further that RTCM Version 3 message types 1084 for GLONASS don't contain GLONASS channel numbers. Observations from these messages can only be decoded when you include 1020 GLONASS ephemeris messages to your stream which contain the channels. You could also consider adding a second stream carrying 1087 GLONASS observation messages or 1020 GLONASS ephemeris messages as both contain the GLONASS channel numbers.
Logged time stamps refer to message reception time and allow understanding repetition rates. Enter 'ALL' if you want to log this information from all configured streams. Beware that the size of the logfile can rapidly increase depending on the number of incoming RTCM streams.
This option is primarily meant for testing and evaluation. Use it to figure out what exactly is produced by a specific GNSS receiver's configuration. An empty option field (default) means that you don't want BNC to print the message type numbers and antenna information carried in RTCM streams.
BNC can output streams related to the above specified 'Mountpoint' through a TCP/IP port of your local host. Enter a port number to activate this function. The stream contents remains untouched. BNC does not decode or reformat the data.
Be careful when keyword 'ALL' is specified as 'Mountpoint' for involving all incoming streams together because the affiliation of data to certain streams gets lost in the output.
An empty option field (default) means that you don't want BNC to apply the TCP/IP port output option.
BNC can derive coordinates for a rover position following the Precise Point Positioning (PPP) approach. It uses either code or code plus phase data from one or more GNSS systems in ionosphere free linear combinations P3 or L3. Besides pulling a stream of observations from a dual frequency GNSS receiver, this also
When using the PPP option, it is important to understand which effects are corrected by BNC.
The provider of an orbit/clock corrections stream may switch with his service at any time from a duty to a backup server installation. This shall be noted in the SSR stream through a change of the Issue Of Data (IOD SSR) parameter. The PPP option in BNC will immediately reset all ambiguities in such a situation.
PPP options are specified in BNC through the following four panels.
3.13.1 PPP (1): Input and Output
This panel provides options for specifying the input and output streams and files required by BNC for real-time or post processing PPP.
3.13.1.1 Data Source - optional
Choose between input from 'Real-time Streams' or 'RINEX Files' for PPP with BNC in real-time or post processing mode.
Real-time Streams
When choosing 'Real-time Streams' BNC will do a PPP solutions in real-time. This requires pulling an GNSS observations stream, Broadcast Ephemeris messages and a stream containing corrections to Broadcast Ephemeris. Streams must come in RTCM Version 2 or RTCM Version 3 format.
If you don't pull Broadcast Corrections BNC will switch with its solution to 'Single Point Positioning' (SPP) mode.
RINEX Files
This input mode allows you to specify RINEX Observation, RINEX Navigation and Broadcast Correction files. BNC accepts RINEX Version 2 as well as RINEX Version 3 Observation or Navigation file formats. Files carrying Broadcast Corrections must have the format produced by BNC through the 'Broadcast Corrections' panel.
Specifying only a RINEX Observation and a RINEX Navigation file and no Broadcast Corrections file leads BNC to a 'Single Point Positioning' (SPP) solution.
Debugging
Note that for debugging purposes BNC's real-time PPP functionality can also be used offline. Apply the 'File Mode' 'Command Line' option for that to read a file containing synchronized observations, orbit and clock correctors, and Broadcast Ephemeris. Example:
bnc.exe --conf c:\temp\PPP.bnc --file c:\temp\RAW
Such a file (here: 'RAW') must be saved beforehand using BNC's 'Raw output file' option.
3.13.1.2 RINEX Observation File - mandatory if 'Data source' is set to 'RINEX Files'
Specify one or more RINEX Observation files. The file format can be RINEX Version 2 or RINEX Version 3.
3.13.1.3 RINEX Navigation File - mandatory if 'Data source' is set to 'RINEX Files'
Specify one or more RINEX Navigation files. The file format can be RINEX Version 2 or RINEX Version 3.
3.13.1.4 Correction File - optional if 'Data source' is set to 'RINEX Files'
Specify one or more Broadcast 'Correction files' as saved beforehand using BNC. The file contents is basically the ASCII representation of a RTCM Version 3 Broadcast Correction (SSR) stream.
If you don't specify a 'Correction file' BNC will fall back from a PPP solution to a Single Point Positioning (SPP) solution.
3.13.1.5 Corrections Stream - optional if 'Data source' is set to 'Real-Time Streams'
Specify a Broadcast Ephemeris 'Corrections stream' from the list of selected 'Streams' you are pulling if you want BNC to correct your satellite ephemeris accordingly. Note that the stream's orbit and clock corrections must refer to the satellite Antenna Phase Center (APC). Streams providing such corrections are made availabel e.g. through the International GNSS Service (IGS) and listed on http://igs.bkg.bund.de/ntrip/orbits. The stream format must be RTCM Version 3 containing so-called SSR messages. Streams 'IGS03' and 'CLK11' supporting GPS plus GLONASS are examples.
If you don't specify a 'Corrections stream' BNC will fall back from a PPP solution to a Single Point Positioning (SPP) solution.
3.13.1.6 Coordinates - mandatory
Enter the full path to an ASCII file which specifies all streams or files from stationary or mobile receivers you potentially may want to process. The 'Coordinates' file must contain one record per stream or file with the following parameters separated by blank characters:
'JPSREGANT_SD_E ' (no radome) 'LEIAT504 NONE' (no radome) 'LEIAR25.R3 LEIT' (radome)Leave antenna name blank if you don't want to correct observations for APC offsets and variations or if you don't know the antenna name.
Records in the 'Coordinates' file with exclamation mark '!' in the first column or blank records will be understood as comment lines and ignored.
The following is an example contents for a 'Coordinates' file. Here each record describes the mountpoint of a stream available from the global IGS real-time reference station network. A-priory coordinates are followed by North/East/Up excentricity components of the ARP followed by the antenna name and radom in use.
! ! Station X[m] Y[m] Z[m] North[m] EAST[m] UP[m] Antenna Radom ! ----------------------------------------------------------------------------------------------------------- ADIS0 4913652.6612 3945922.7678 995383.4359 0.0000 0.0000 0.0010 TRM29659.00 NONE ALIC0 -4052052.5593 4212836.0078 -2545104.8289 0.0000 0.0000 0.0015 LEIAR25.R3 NONE BELF0 3685257.8823 -382908.8992 5174311.1067 0.0000 0.0000 0.0000 LEIAT504GG LEIS BNDY0 -5125977.4106 2688801.2966 -2669890.4345 0.0000 0.0000 0.0000 ASH701945E_M NONE BRAZ0 4115014.0678 -4550641.6105 -1741443.8244 0.0000 0.0000 0.0080 LEIAR10 NONE CAGZ0 4893379.8326 772650.6854 4004180.1625 0.0000 0.0000 0.0945 JPSREGANT_DD_E NONE CALG0 -1635378.1748 -3665371.5746 4941664.3370 0.0000 0.0000 0.0000 SOK702 NONE CONZ0 1492004.6119 -4887911.2671 -3803640.2397 0.0000 0.0000 0.0574 LEIAR25.R3 LEIT CTWN0 5023564.4285 1677795.7211 -3542025.8392 0.0000 0.0000 0.0000 ASH701941.B NONE CUT07 -2364337.4408 4870285.6055 -3360809.6280 0.0000 0.0000 0.0000 TRM59800.00 SCIS DHLG3 -2319099.4261 -4799846.4583 3490090.4018 0.0000 0.0000 0.1224 ASH701945B_M SCIS FAA10 -5247393.4678 -3076866.6580 -1911521.1749 0.0000 0.0000 0.1262 LEIAR25.R4 NONE GANP0 3929181.3480 1455236.9105 4793653.9880 0.0000 0.0000 0.3830 TRM55971.00 NONE HLFX0 2018905.6037 -4069070.5095 4462415.4771 0.0000 0.0000 0.1000 TPSCR.G3 NONE KIRU0 2251420.6255 862817.3340 5885476.8395 0.0000 0.0000 0.0620 ASH701945C_M SNOW LHAZ0 -106941.9272 5549269.8041 3139215.1564 0.0000 0.0000 0.1330 ASH701941.B NONE LMMF7 2993387.3587 -5399363.8649 1596748.0983 0.0000 0.0000 0.0000 TRM57971.00 NONE MAO07 -5466067.0979 -2404333.0198 2242123.1929 0.0000 0.0000 0.0000 LEIAR25.R3 LEIT NICO0 4359415.5252 2874117.1872 3650777.9614 0.0000 0.0000 0.0650 LEIAR25.R4 LEIT NKLG7 6287385.7320 1071574.7606 39133.1088 -0.0015 -0.0025 3.0430 TRM59800.00 SCIS NURK7 5516756.5103 3196624.9684 -215027.1315 0.0000 0.0000 0.1300 TPSCR3_GGD NONE OHIX7 1525809.2353 -2432478.7568 -5676166.2639 0.0000 0.0000 0.0660 LEIAR25.R4 LEIT ONSA0 3370658.3928 711877.2903 5349787.0603 0.0000 0.0000 0.9950 AOAD/M_B OSOD PDEL0 4551595.9072 -2186892.9495 3883410.9685 0.0000 0.0000 0.0000 LEIAT504GG NONE RCMN0 5101056.6270 3829074.4206 -135016.1589 0.0000 0.0000 0.0000 LEIAT504GG LEIS REUN0 3364098.9668 4907944.6121 -2293466.7379 0.0000 0.0000 0.0610 TRM55971.00 NONE REYK7 2587384.0890 -1043033.5433 5716564.1301 0.0000 0.0000 0.0570 LEIAR25.R4 LEIT RIO27 1429907.8578 -3495354.8953 -5122698.5595 0.0000 0.0000 0.0350 ASH700936C_M SNOW SMR50 927077.1096 -2195043.5597 -5896521.1344 0.0000 0.0000 0.0000 TRM41249.00 TZGD SUWN0 -3062023.1604 4055447.8946 3841818.1684 0.0000 0.0000 1.5700 TRM29659.00 DOME TASH7 1695944.9208 4487138.6220 4190140.7391 0.0000 0.0000 0.1206 JAV_RINGANT_G3T NONE UFPR0 3763751.6731 -4365113.9039 -2724404.5331 0.0000 0.0000 0.1000 TRM55971.00 NONE UNB30 1761287.9724 -4078238.5659 4561417.8448 0.0000 0.0000 0.3145 TRM57971.00 NONE VILL0 4849833.5863 -335048.8133 4116015.0652 0.0000 0.0000 0.0437 AOAD/M_T NONE WIND7 5633708.8016 1732017.9297 -2433985.5795 0.0000 0.0000 0.0460 ASH700936C_M SNOW WTZR0 4075580.3797 931853.9767 4801568.2360 0.0000 0.0000 0.0710 LEIAR25.R3 LEIT WUH27 -2267749.9761 5009154.5504 3221294.4429 0.0000 0.0000 0.1206 JAV_RINGANT_G3T NONE YELL7 -1224452.8796 -2689216.1863 5633638.2832 0.0000 0.0000 0.1000 AOAD/M_T NONE
Note that the only mandatory parameter in this is the 'Station' parameter standing for an observation stream's mountpoint or RINEX file name. The following shows further valid examples for records of a 'Coordinates' file.
! ! Station X[m] Y[m] Z[m] N[m] E[m] U[m] Antenna Radom ! --------------------------------------------------------------------------------------- FFMJ1 4053455.7384 617729.8393 4869395.8214 0.000 0.000 0.045 TITZ1 3993780.4501 450206.8969 4936136.9886 WARN SASS1 0.0 0.0 0.0 0.000 0.000 0.031 TPSCR3_GGD CONE
In this file
PPP results are shown in the 'Log' tab on the bottom of BNC's main window. Depending on the processing options, the following values are shown about once per second (example):
15-06-30 11:40:24 2015-06-30_11:40:22.000 CUT07 X = -2364337.6864 Y = 4870283.8106 Z = -3360808.3099 NEU: +0.1543 +0.2121 -1.0190 TRP: +2.4022 +0.0009 15-06-30 11:40:25 2015-06-30_11:40:23.000 CUT07 X = -2364337.6861 Y = 4870283.8111 Z = -3360808.3105 NEU: -0.9782 +0.0916 -2.3544 TRP: +2.4017 +0.0013 15-06-30 11:40:26 2015-06-30_11:40:24.000 CUT07 X = -2364337.6884 Y = 4870283.8123 Z = -3360808.3103 NEU: -0.5606 -0.0938 -1.9498 TRP: +2.4018 +0.0016
The selected mountpoint in that is followed by a PPP time stamp in GPS Time, the number of processed satellites, and XYZ coordinates with their formal errors as derived from the implemented filter in [m]. The implemented algorithm includes outlier and cycle slip detection. The maximum for accepted residuals is hard coded to 10 meters for code observations and 10 centimeters for phase observations.
More detailed PPP results are saved in BNC's logfile. Depending on the selected processing options you find
Results of Epoch 2015-06-30_10:37:00.000 -------------------------------------- 2015-06-30_10:37:00.000 BANCROFT: -2364339.137 4870286.804 -3360814.597 -24882.876 2015-06-30_10:37:00.000 RES cIF G05 1.5881 2015-06-30_10:37:00.000 RES cIF G07 2.7378 2015-06-30_10:37:00.000 RES cIF G10 -0.7913 2015-06-30_10:37:00.000 RES cIF G13 -0.8838 2015-06-30_10:37:00.000 RES cIF G28 -2.2195 2015-06-30_10:37:00.000 RES cIF G30 1.1955 2015-06-30_10:37:00.000 RES lIF G05 -0.0137 2015-06-30_10:37:00.000 RES lIF G07 0.0069 2015-06-30_10:37:00.000 RES lIF G10 0.0206 2015-06-30_10:37:00.000 RES lIF G13 0.0061 2015-06-30_10:37:00.000 RES lIF G28 -0.0167 2015-06-30_10:37:00.000 RES lIF G30 0.0002 2015-06-30_10:37:00.000 RES lIF R05 0.0114 2015-06-30_10:37:00.000 RES lIF R06 0.0038 2015-06-30_10:37:00.000 RES lIF R07 -0.0169 2015-06-30_10:37:00.000 RES lIF R09 0.0106 2015-06-30_10:37:00.000 RES lIF R16 -0.0109 2015-06-30_10:37:00.000 CLK 0.0000 -2.9038 +- 0.6250 2015-06-30_10:37:00.000 AMB lIF G05 2569.0000 +25.6866 +- 5.6947 el = 44.28 epo = 27 2015-06-30_10:37:00.000 AMB lIF G07 960.0000 +25.4561 +- 5.6987 el = 39.75 epo = 27 2015-06-30_10:37:00.000 AMB lIF G10 1266.0000 +24.7084 +- 5.6950 el = 53.91 epo = 27 2015-06-30_10:37:00.000 AMB lIF G13 -3098.0000 +25.4074 +- 5.8291 el = 22.07 epo = 27 2015-06-30_10:37:00.000 AMB lIF G28 1741.0000 +25.4311 +- 5.6952 el = 54.09 epo = 27 2015-06-30_10:37:00.000 AMB lIF G30 -601.0000 +25.6923 +- 5.6987 el = 65.78 epo = 27 2015-06-30_10:37:00.000 AMB lIF R05 -500.0000 +6.5369 +- 35.3675 el = 30.11 epo = 24 2015-06-30_10:37:00.000 AMB lIF R06 -505.0000 +5.5080 +- 35.3072 el = 87.28 epo = 5 2015-06-30_10:37:00.000 AMB lIF R07 -768.0000 -1.2722 +- 35.4211 el = 34.99 epo = 6 2015-06-30_10:37:00.000 AMB lIF R09 343.0000 -2.1249 +- 35.3255 el = 51.23 epo = 27 2015-06-30_10:37:00.000 AMB lIF R16 -78.0000 -2.0550 +- 35.3383 el = 55.29 epo = 27 2015-06-30_10:37:00.000 OGG -4.1622 +2.2266 +- 3.7714 2015-06-30_10:37:00.000 TRP 2.4018 -0.0078 +- 0.0997 2015-06-30_10:37:00.000 CUT07 X = -2364337.4403 +- 0.0262 Y = 4870285.6044 +- 0.0403 Z = -3360809.6277 +- 0.0315 dN = -0.0004 +- 0.0200 dE = 0.0000 +- 0.0200 dU = -0.0012 +- 0.0500
3.13.1.8 ANTEX File - optional
IGS provides a file containing absolute phase center corrections for GNSS satellite and receiver antennas in ANTEX format. Entering the full path to such an ANTEX file is required for correcting observations for antenna phase center offsets and variations. It allows you to specify the name of your receiver's antenna (as contained in the ANTEX file) to apply such corrections.
Default is an empty option field, meaning that you don't want to correct observations for antenna phase center offsets and variations.
The NMEA sentences generated about once per second are pairs of
Specify the full path to a file where Point Positioning results are saved as NMEA messages. The default value for 'NMEA file' is an empty option field, meaning that BNC will not saved NMEA messages into a file.
The following is an example for an NMEA output file from BNC.
$GPRMC,112348,A,3200.233,S,11553.688,E,,,300615,,*A $GPGGA,112348,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*5D $GPRMC,112349,A,3200.233,S,11553.688,E,,,300615,,*B $GPGGA,112349,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*5C $GPRMC,112350,A,3200.233,S,11553.688,E,,,300615,,*3 $GPGGA,112350,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*54 $GPRMC,112351,A,3200.233,S,11553.688,E,,,300615,,*2 $GPGGA,112351,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*55 $GPRMC,112352,A,3200.233,S,11553.688,E,,,300615,,*1 $GPGGA,112352,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*56 $GPRMC,112353,A,3200.233,S,11553.688,E,,,300615,,*0 $GPGGA,112353,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*57 $GPRMC,112354,A,3200.233,S,11553.688,E,,,300615,,*7 $GPGGA,112354,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*50 $GPRMC,112355,A,3200.233,S,11553.688,E,,,300615,,*6 $GPGGA,112355,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*51 $GPRMC,112356,A,3200.233,S,11553.688,E,,,300615,,*5 $GPGGA,112356,3200.2332035,S,11553.6880127,E,1,13,1.4,23.971,M,0.0,M,,*52 ...
3.13.1.10 SNX TRO File - optional
BNC estimates the tropospheric delay according to equation
T(z) = T_apr(z) + dT / cos(z)where T_apr is the a-priori tropospheric delay derived from Saastamoinen model.
By default BNC does not estimate troposphere parameters. Tick 'Estimate tropo' to estimate troposphere parameters together with the coordinates and save T_apr and dT/cos(z) in BNC's logfile.
The following is an example for a SINEX Troposphere file, see https://igscb.jpl.nasa.gov/igscb/data/format/sinex_tropo.txt for a complete documentation.
%=TRO 0.01 BNC 15:181:38193 BNC 15:181:38193 15:181:84600 P CUT0 +FILE/REFERENCE DESCRIPTION BNC generated SINEX TRO file OUTPUT Total Troposphere Zenith Path Delay Product SOFTWARE BNC 2.12 HARDWARE MAC INPUT Orbit and Clock information used from BRDC and RTCM-SSR streams -FILE/REFERENCE +TROP/DESCRIPTION *KEYWORD______________________ VALUE(S)______________ SAMPLING INTERVAL 1 SAMPLING TROP 1 ELEVATION CUTOFF ANGLE 10 TROP MAPPING FUNCTION Saastamoinen SOLUTION_FIELDS_1 TROTOT STDEV -TROP/DESCRIPTION +TROP/STA_COORDINATES *SITE PT SOLN T STA_X_______ STA_Y_______ STA_Z_______ SYSTEM REMARK CUT0 A 1 P -2364337.441 4870285.605 -3360809.628 ITRF08 -TROP/STA_COORDINATES +TROP/SOLUTION *SITE EPOCH_______ TROTOT STDEV CUT0 15:181:38193 0.0 0.0 CUT0 15:181:38194 2402.0 100.0 CUT0 15:181:38195 2402.0 100.0 CUT0 15:181:38196 2402.1 100.0 CUT0 15:181:38197 2402.0 100.0 CUT0 15:181:38198 2401.8 100.0 CUT0 15:181:38199 2401.6 99.9 CUT0 15:181:38200 2401.7 99.9 CUT0 15:181:38201 2401.6 99.9 CUT0 15:181:38202 2401.5 99.9 CUT0 15:181:38203 2401.3 99.9 CUT0 15:181:38204 2401.0 99.9 CUT0 15:181:38205 2400.8 99.9 CUT0 15:181:38206 2400.5 99.9 CUT0 15:181:38207 2400.3 99.9 CUT0 15:181:38208 2399.8 99.9 CUT0 15:181:38209 2399.6 99.9 CUT0 15:181:38210 2399.3 99.9 CUT0 15:181:38211 2398.9 99.8 CUT0 15:181:38212 2398.5 99.8 CUT0 15:181:38213 2397.9 99.8 CUT0 15:181:38214 2397.3 99.8 CUT0 15:181:38215 2396.7 99.8 CUT0 15:181:38216 2396.2 99.8 CUT0 15:181:38217 2395.6 99.8 CUT0 15:181:38218 2395.1 99.7 CUT0 15:181:38219 2394.6 99.7 CUT0 15:181:38220 2394.0 99.7 CUT0 15:181:38221 2393.2 99.7 -TROP/SOLUTION %=ENDTROP
3.13.2 PPP (2): Processed Stations
3.13.2.1 Sigma North/East/Height - mandatory
Enter a sigma in meters for the initial XYZ coordinate. A value of 100.0 (default) may be an appropriate choice. However, this value may be significantly smaller (i.e. 0.01) when starting for example from a station with known XZY position in Quick-Start mode.
3.13.2.2 Noise North/East/Height - mandatory
Enter a sigma in meters for the 'White Noise' of estimated XYZ coordinate components. A value of 100.0 (default) may be appropriate when considering possible sudden movements of a rover.
3.13.2.3 Tropo Sigma - mandatory if 'Estimate tropo' is set
Enter a sigma in meters for the a-priory model based tropospheric delay estimation. A value of 0.1 (default) may be an appropriate choice.
3.13.2.4 Tropo Noise - mandatory if 'Estimate tropo' is set
Enter a sigma in meters per second to describe the expected variation of the tropospheric effect. Supposing 1Hz observation data, a value of 3e-6 (default) would mean that the tropospheric effect may vary for 3600 * 3e-6 = 0.01 meters per hour.
Specify the IP port number of a local port where Point Positioning results become available as NMEA messages. The default value for 'NMEA Port' is an empty option field, meaning that BNC does not provide NMEA messages vi IP port. Note that the NMEA file output and the NMEA IP port output are the same.NASA's 'World Wind' software (see http://worldwindcentral.com/wiki/NASA_World_Wind_Download) can be used for real-time visualization of positions provided through BNC's NMEA IP output port. You need the 'GPS Tracker' plug-in available from http://worldwindcentral.com/wiki/GPS_Tracker for that. The 'Word Wind' map resolution is not meant for showing centimeter level details.
Note that Tomoji Takasu has written a program called RTKPLOT for visualizing NMEA strings. It is available from http://www.rtklib.com and compatible with the NMEA file and port output of BNC's 'PPP' client option.
3.13.3 PPP (3): Processing Options
BNC allows using different Point Positioning processing options depending on the capability of the involved receiver and the application in mind. It also allows introducing specific sigmas for code and phase observations as well as for reference coordinates and troposphere estimates. You may also like to carry out your PPP solution in Quick-Start mode or enforce BNC to restart a solution if the length of an outage exceeds a certain threshold.
3.13.3.1 Linear Combinations - mandatory
By default BNC applies a Point Positioning solution using an ionosphere free P3 linear combination of code observations. Tick 'Use phase obs' for an ionosphere free L3 linear combination of phase observations.
By default BNC does not process GLONASS but only GPS observations when in Point Positioning mode. Tick 'Use GLONASS' to use GLONASS observations in addition to GPS (and Galileo if specified) for estimating coordinates in Point Positioning mode.
By default BNC does not process Galileo but only GPS observations when in Point Positioning mode. Tick 'Use Galileo' to use Galileo observations in addition to GPS (and GLONASS if specified) for estimating coordinates in Point Positioning mode.
3.13.3.2 Code Observations - mandatory
You may like to introduce specific sigmas for code and phase observations and for the estimation of troposphere parameters.
3.13.3.3 Phase Observations - mandatory if 'Use Phase Obs' is set
When 'Use phase obs' is set in BNC, the PPP solution will be carried out using both, code and phase observations. A sigma of 10.0 m for code observations and a sigma of 0.02 m for phase observations (defaults) are used to combine both types of observations. As the convergence characteristic of a PPP solution can be influenced by the ratio of the sigmas for code and phase, you may like to introduce you own sigmas for code and phase observations which differ from the default values.
Specify a sigma for code observations. Default is 10.0 m.
Specify a sigma for phase observations. Default is 0.02 m.
3.13.3.4 Elevation Depending Weighting - optional
3.13.3.5 Minimum Number of Observations - optional
3.13.3.6 Minimum Elevation - optional
3.13.3.7 Wait for Clock Corrections - optional
Zero value (or empty field) means that BNC processes each epoch of data immediately after its arrival using satellite clock corrections available at that time. Non-zero value 'Sync Corr' means that the epochs of data are buffered and the processing of each epoch is postponed till the satellite clock corrections not older than 'Sync Corr' are available. Specifying a value of half the update rate of the clock corrections as 'Sync Corr' (i.e. 5 sec) may be appropriate. Note that this causes an additional delay of the PPP solutions in the amount of half of the update rate.
Using observations in sync with the corrections can avoid a possible high frequency noise of PPP solutions. Such noise could result from processing observations regardless of how late after a clock correction they were received. Note that applying the 'Sync Corr' option significantly reduces the PPP computation effort for BNC.
Default is an empty option field, meaning that you want BNC to process observations immediately after their arrival through applying the latest received clock correction.
3.13.3.8 Seeding - optional if XYZ is set
Enter the length of a startup period in seconds for which you want to fix the PPP solution to a known XYZ coordinate. Constraining coordinates is done in BNC through setting the 'XYZ White Noise' temporarily to zero.
This so-called Quick-Start option allows the PPP solutions to rapidly converge after startup. It requires that the antenna remains unmoved on the know position throughout the defined period. A value of 60 is likely to be an appropriate choice for 'Quick-Start'. Default is an empty option field, meaning that you don't want BNC to start in 'Quick-Start' mode.
You may need to create your own reference coordinate through running BNC for an hour in normal mode before applying the 'Quick-Start' option. Don't forget to introduce a realistic sigma 'XYZ Ini' according to the coordinate's precision.
The following figure provides the screenshot of an example PPP session with BNC.
Figure 20: Real-time Precise Point Positioning with BNC, PPP Panel 1.
Figure 21: Precise Point Positioning with BNC, PPP Panel 2.
Figure 22: Precise Point Positioning with BNC, PPP Panel 3.
Figure 23: BNC in 'Quick-Start' mode (PPP, Panel 2)
3.13.3.NN Averaging - optional if XYZ is set
3.13.3.NN Maximal Solution Gap - optional if Quick-Start is set
You make like to track your rover position using Google Maps or Open StreetMap as a background map. Track maps can be produced with BNC in 'Real-time Streams' mode or in 'RINEX Files' post processing mode with data coming from files.
When in 'Post Processing' mode you should not forget to specify a proxy under the 'Network' panel if that is operated in front of BNC.
PPP time series of North (red), East (green) and Up (blue) displacements will be plotted in the 'PPP Plot' panel when this option is ticked. Values will be either referred to an XYZ reference coordinate (if specified) or referred to the first estimated XYZ coordinate. The sliding PPP time series window will cover the period of the latest 5 minutes.
Note that a PPP time series makes only sense for a stationary operated receiver.
3.13.4.2 Audio Response - optional if Quick-Start is set
For natural hazard prediction and monitoring it may be appropriate to generate audio alerts. For that you can specify an 'Audio response' threshold in meters. A beep is produced by BNC whenever a horizontal PPP coordinate component differs by more than the threshold value from the specified marker coordinate.
Default is an empty option field, meaning that you don't want BNC to produce acoustic warning signals.
Figure 24: Track of positions from BNC with Google Maps in the background.
The 'Open Map' button opens a windows showing a map according to options specified below.
3.13.4.3.1 Google/OSM - mandatory before pushing 'Open Map'
Specify either 'Google' or 'OSM' as the background for your rover positions.
3.13.4.4 Dot-properties - mandatory before pushing 'Open Map'
3.13.4.4.1 Size - mandatory before pushing 'Open Map'
Specify the size of dots showing the rover position. A dot size of '3' may be appropriate. The maximum possible dot size is '10'. An empty option field or a size of '0' would mean that you don't want BNC to show the rover's track on the map.
3.13.4.4.2 Color - mandatory before pushing 'Open Map'
Specify the color of dots showing the rover track.
3.13.4.5 Post Processing Speed - mandatory before pushing 'Open Map'
With BNC in PPP post processing mode you can specify the speed of computations as appropriate for visualization. Note that you can adjust 'Speed' on-the-fly while BNC is processing your observatins.
BNC allows processing several orbit and clock correction streams in real-time to produce, encode, upload and save a combination of Broadcast Corrections from various providers. All corrections must refer to satellite Antenna Phase Centers (APC). It is so far only the satellite clock corrections which are combined while orbit corrections in the combination product as well as the product update rates are just taken over from one of the incoming Broadcast Correction streams. Combining only clock corrections using a fixed orbit reference has the possibility to introduce some analysis inconsistencies. We may therefore eventually consider improvements on this approach. The clock combination can be based either on a plain 'Single-Epoch' or on a Kalman 'Filter' approach.
In the Kalman Filter approach satellite clocks estimated by individual Analyses Centers (ACs) are used as pseudo observations within the adjustment process. Each observation is modeled as a linear function (actually a simple sum) of three estimated parameters: AC specific offset, satellite specific offset common to all ACs, and the actual satellite clock correction which represents the result of the combination. These three parameter types differ in their statistical properties. The satellite clock offsets are assumed to be static parameters while AC specific and satellite specific offsets are stochastic parameters with appropriate white noise. The solution is regularized by a set of minimal constraints. After a change of one of the three values 'SSR Provider ID', 'SSR Solution ID', or 'IOD SSR', the satellite clock offsets belonging to the corresponding analysis center are reset in the adjustment.
Removing the AC-dependent biases as well as possible is a major issue with clock combinations. Since they vary in time, it can be tricky to do this. Otherwise, there will be artificial jumps in the combined clock stream if one or more AC contributions drop out for certain epochs. Here the Kalman Filter approach is expected to do better than the Single-Epoch approach.
In view of IGS real-time products, the 'Combine Corrections' functionality has been integrated in BNC because
Note that the combination process requires real-time access to Broadcast Ephemeris. So, in addition to the orbit and clock correction streams BNC must pull a stream carrying Broadcast Ephemeris in the form of RTCM Version 3 messages. Stream 'RTCM3EPH' on caster products.igs-ip.net is an example for that.
A combination is carried out following a specified sampling interval. BNC waits for incoming Broadcast Corrections for the period of one such intervall. Corrections received later than that will be ignored. If incoming streams have different rates, only epochs that correspond to the sampling interval are used.
With respect to IGS, it is important to understand that a major effect in the combination of GNSS orbit and clock correction streams is the selection of ACs to include. It is likely that a combination product could be improved in accuracy by using only the best two or three ACs. However, with only a few ACs to depend on, the reliability of the combination product could suffer and the risk of total failures increases. So there is an important tradeoff here that must be considered when selecting streams for a combination. The major strength of a combination product is its reliability and stable median performance which can be much better than that of any single AC product.
This comment applies in situations where we have a limited number of solutions to combine and their quality varies significantly. The situation may be different when the total number of ACs is larger and the range of AC variation is smaller. In that case, a standard full combination is probably the best.
The following recursive algorithm is used to detect orbit outliers in the Kalman Filter combination when Broadcast Corrections are provided by several ACs:
Step 1: We don't produce a combination for a certain satellite if only one AC provides corrections for it.
Step 2: A mean satellite position is calculated as the average of positions from all ACs.
Step 3: For each AC and satellite the 3D distance between individual and mean satellite position is calculated.
Step 4: We find the greatest difference between AC specific and mean satellite positions.
Step 5: If that is less than a threshold, the conclusion is that we don't have an outlier and can proceed to the next epoch.
Step 6: If that is greater than a threshold, then corrections of the affiliated AC are ignored for the affected epoch and the outlier detection restarts with step 1.
Note that BNC can produce an internal PPP solution from combined Broadcast Corrections. For that you have to specify the keyword 'INTERNAL' as 'Corrections' mountpoint in the PPP (1) panel.
The part of BNC which enables the combination of Broadcast Corrections is not intended for publication under GNU General Public License (GPL). However, pre-compiled BNC binaries which support the 'Combine Corrections' option are made available.
3.14.1 Combine Corrections Table - optional
Hit the 'Add Row' button, double click on the 'Mountpoint' field, enter a Broadcast Corrections mountpoint from the 'Streams' section and hit Enter. Then double click on the 'AC Name' field to enter your choice of an abbreviation for the Analysis Center (AC) providing the Antenna Phase Center (APC) related stream. Finally, double click on the 'Weight' field to enter a weight to be applied to this stream in the combination.
The sequence of entries in the 'Combine Corrections' table is not of importance. Note that the orbit information in the final combination stream is just copied from one of the incoming streams. The stream used for providing the orbits may vary over time: if the orbit providing stream has an outage then BNC switches to the next remaining stream for getting hold of the orbit information.
It is possible to specify only one Broadcast Ephemeris corrections stream in the 'Combine Corrections' table. Instead of combining corrections from several sources, BNC will then merge the single corrections stream with Broadcast Ephemeris to save results in SP3 and/or Clock RINEX format when specified accordingly under the 'Upload Corrections' panel. Note that in such a BNC application you must not pull more than one Broadcast Ephemeris corrections stream even if a second stream would provide the same corrections from a backup caster.
Default is an empty 'Combine Corrections' table meaning that you don't want BNC to combine orbit and clock correction streams.
3.14.1.1 Add Row, Delete - optional
Hit 'Add Row' button to add another row to the 'Combine Corrections' table or hit the 'Delete' button to delete the highlighted row(s).
The following screenshots describe an example setup of BNC when combining Broadcast Correction streams and uploading them to an NTRIP Broadcaster. Note that this application requires specifying options under panels 'Combine Corrections' and 'Upload Corrections'. The example uses the combination product to simultaneously carry out an 'INTERNAL' PPP solution which allows monitoring the quality of the combination product in the space domain.
Figure 25: BNC combining Broadcast Correction streams.
Figure 26: BNC uploading the combined Broadcast Corrections stream.
Figure 27: 'INTERNAL' PPP with BNC using combined Broadcast Corrections stream.
3.13.1.2 Method - mandatory if 'Combine Corrections' table is populated
Select a clock combination method. Available options are Kalman 'Filter' and 'Single-Epoch. It is suggested to use the Kalman Filter approach in case the combined stream of Broadcast Corrections is intended for Precise Point Positioning.
3.14.1.3 Maximal Residuum - mandatory if 'Combine Corrections' table is populated
BNC combines all incoming clocks according to specified weights. Individual clock estimates that differ by more than 'Maximal Residuum' meters from the average of all clocks will be ignored.
It is suggested to specify a value of about 0.2 m for the Kalman Filter combination approach and a value of about 3.0 meters for the Single-Epoch combination approach.
Default is a 'Maximal Residuum' of 999.0 meters
3.14.1.4 Sampling - mandatory if 'Combine Corrections' table is populated
Specify a combination sampling interval. Orbit and clock corrections will be produced following that interval. A value of 10 sec may be an appropriate choice.
3.14.1.5 Use GLONASS - optional
You may tick the 'Use GLONASS' option in case you want to produce an GPS plus GLONASS combination and both systems are supported by the Broadcast Correction streams participating in the combination.
BNC can upload streams carrying orbit and clock corrections to Broadcast Ephemeris in radial, along-track and cross-track components if they are
The orbit and clock corrections to Broadcast Ephemeris are usually referred to the latest set of broadcast messages, which are generally also received in real-time by a GNSS rover. However, the use of the latest broadcast message is delayed for a period of 60 seconds, measured from the time of complete reception of ephemeris and clock parameters, in order to accommodate rover applications to obtain the same set of broadcast orbital and clock parameters. This procedure is recommended in the RTCM SSR standard.
Because the stream delivery process may put a significant load on the communication link between BNC and the real-time GNSS engine, it is recommended to run both programs on the same host. However, doing so is not compulsory.The usual handling of BNC when uploading a stream with Broadcast Corrections is that you first specify Broadcast Ephemeris and Broadcast Correction streams. You then specify an NTRIP Broadcaster for stream upload before you start the program.
'RTNET' Stream Format
When uploading an SSR stream generated according to b. then BNC requires precise GNSS orbits and clocks in the IGS Earth-Centered-Earth-Fixed (ECEF) reference system and in a specific ASCII format named 'RTNET' because the data may come from a real-time engine such as RTNET. The sampling interval for data transmission should not exceed 15 sec. Note that otherwise tools involved in IP streaming such as NTRIP Broadcasters or NTRIP Clients may respond with a timeout.
Below you find an example for the 'RTNET' ASCII format coming from a real-time GNSS engine. Each epoch begins with an asterisk character followed by the time as year, month, day of month, hour, minute and second. Subsequent records can provide
<SatelliteID> <key> <numValues> <value1 value2 ...> <key> <numValues> <value1 value2 ...> ...
The following satellite specific keys and values are currently specified in BNC:
| Key | Values |
| APC | Satellite Antenna Phase Center coordinates in meters |
| Clk | Satellite clock correction in meters, relativistic correction applied like in broadcast clocks |
| Vel | Satellite velocity in meters per second |
| CoM | Satellite Center of Mass coordinates in meters |
| CodeBias | Satellite Code Biases in meters with two characters for frequency and tracking mode per bias as defined in RINEX 3 and preceded by total number of biases |
| YawAngle | Satellite Yaw Angle in radian, restricted to be in [0, 2π], which shall be used for the computation of phase wind-up correction |
| YawRate | Satellite Yaw Rate in radian per second, which is the rate of Yaw Angle |
| PhaseBias | Satellite Phase Biases in meters with two characters for frequency and tracking mode per bias as defined in RINEX 3, preceded by total number of biases and followed by Signal Wilde-Lane Integer Indicator as well as Signal Discontinuity Counter |
| Key | Values |
| IND | Stands for phase bias information and is followed by Dispersive Bias Consistency Indicator and MW Consistency Indicator |
| VTEC | Stands for Vertical TEC information and is followed by Update Interval and Number of Ionospheric Layers |
Because each keyword is associated to a certain number of values, an 'old' BNC could be operated with an incoming 'new' RTNET stream containing so far unknown keys - they would just be skipped in BNC.
Example for 'RTNET' stream contents and format:
* 2015 6 11 15 10 40.000000 VTEC 0 1 0 6 6 450000.0 20.4660 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 5.3590 9.6580 0.0000 0.0000 0.0000 0.0000 0.0000 -6.3610 -0.1210 1.1050 0.0000 0.0000 0.0000 0.0000 -2.7140 -1.8200 -0.9920 -0.6430 0.0000 0.0000 0.0000 1.9140 -0.5180 0.2530 0.0870 -0.0110 0.0000 0.0000 2.2950 1.0510 -0.9540 0.6220 -0.0720 -0.0810 0.0000 -0.9760 0.7570 0.2320 -0.2520 0.1970 -0.0680 -0.0280 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.2720 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 1.1100 -1.0170 0.0000 0.0000 0.0000 0.0000 0.0000 -1.1500 0.5440 0.9890 0.0000 0.0000 0.0000 0.0000 -0.3770 -0.1990 0.2670 -0.0470 0.0000 0.0000 0.0000 0.6550 -0.0130 -0.2310 -0.4810 -0.3510 0.0000 0.0000 0.2360 -0.0710 0.0280 0.1900 -0.0810 0.0710 IND 0 1 G01 APC 3 -14442611.532 -13311059.070 -18020998.395 Clk 1 -1426.920500 Vel 3 2274.647600 -28.980300 -1787.861900 CoM 3 -14442612.572 -13311059.518 -18020999.539 CodeBias 6 1W -3.760000 1C -3.320000 2W -6.200000 2X -5.780000 1H -3.350000 5I -5.430000 YawAngle 1 -0.315600 YawRate 1 0.0 PhaseBias 3 1C 3.9473 1 2 4 2W 6.3143 1 2 4 5I 6.7895 1 2 4 G02 APC 3 -8859103.160 14801278.856 20456920.800 Clk 1 171219.083500 Vel 3 -2532.296700 -161.275800 -1042.884100 CoM 3 -8859103.418 14801279.287 20456921.395 CodeBias 6 1W 3.930000 1C 3.610000 2W 6.480000 2X 0.000000 1H 3.580000 5I 0.000000 YawAngle 1 -0.693500 YawRate 1 0.0 PhaseBias 2 1C -4.0902 1 2 4 2W -6.7045 1 2 4 G03 APC 3 -13788295.679 -22525098.353 2644811.508 Clk 1 104212.074300 Vel 3 102.263400 -429.953400 -3150.231900 CoM 3 -13788296.829 -22525099.534 2644811.518 CodeBias 6 1W -2.650000 1C -2.160000 2W -4.360000 2X -4.480000 1H -2.070000 5I -5.340000 YawAngle 1 -0.428800 YawRate 1 0.0 PhaseBias 3 1C 2.9024 1 2 2 2W 4.6124 1 2 2 5I 5.3694 1 2 2 .. R01 APC 3 -6783489.153 -23668850.753 6699094.457 Clk 1 - 45875.658100 Vel 3 -267.103000 -885.983700 -3403.253200 CoM 3 -6783489.307 -23668853.173 6699095.274 CodeBias 4 1P -2.496400 1C -2.490700 2P -4.126600 2C -3.156200 R02 APC 3 -11292959.022 -10047039.425 20577343.288 Clk 1 41215.750900 Vel 3 -476.369400 -2768.936600 -1620.000600 CoM 3 -11292959.672 -10047040.710 20577345.344 CodeBias 4 1P 0.211200 1C 0.391300 2P 0.349100 2C 0.406300 R03 APC 3 -9226469.614 9363128.850 21908853.313 Clk 1 13090.322800 Vel 3 -369.088600 -2964.934500 1111.041000 CoM 3 -9226470.226 9363129.442 21908855.791 CodeBias 4 1P 2.283800 1C 2.483800 2P 3.775300 2C 3.785500 .. E11 APC 3 2965877.898 17754418.441 23503540.946 Clk 1 33955.329000 Vel 3 -1923.398100 1361.709200 -784.555800 CoM 3 2965878.082 17754418.669 23503541.507 CodeBias 3 1B 1.382100 5Q 2.478400 7Q 2.503300 E12 APC 3 -14807433.144 21753389.581 13577231.476 Clk 1 -389652.211900 Vel 3 -1082.464300 825.868400 -2503.982200 CoM 3 -14807433.366 21753389.966 13577231.926 CodeBias 3 1B 0.386600 5Q 0.693300 7Q 0.534700 E19 APC 3 -15922225.351 8097517.292 23611910.403 Clk 1 -2551.650800 Vel 3 -183.377800 -2359.143700 684.105100 CoM 3 -15922225.569 8097517.329 23611910.995 CodeBias 3 1B -1.777000 5Q -3.186600 7Q -3.069100 .. EOE
Note that the end of an epoch in the incoming stream is indicated by an ASCII string 'EOE' (for End Of Epoch).
When using clocks from Broadcast Ephemeris (with or without applied corrections) or clocks from SP3 files, it may be important to understand that they are not corrected for the conventional periodic relativistic effect. Chapter 10 of the IERS Conventions 2003 mentions that the conventional periodic relativistic correction to the satellite clock (to be added to the broadcast clock) is computed as dt = -2 (R * V) / c^2 where R *V is the scalar product of the satellite position and velocity and c is the speed of light. This can also be found in the GPS Interface Specification, IS-GPS-200, Revision D, 7 March 2006.
3.15.1 Add, Delete Row - optional
Hit 'Add Row' button to add a row to the stream 'Upload Table' or hit the 'Delete' button to delete the highlighted row(s).
Having an empty 'Upload Table' is default and means that you don't want BNC to upload orbit and clock correction streams to any NTRIP Broadcaster.
3.15.2 Host, Port, Mountpoint, Password - optional
Specify the domain name or IP number of an NTRIP Broadcaster for uploading the stream. Furthermore, specify the caster's listening IP port, an upload mountpoint and an upload password. Note that NTRIP Broadcasters are often configured to provide access through more than one port, usually ports 80 and 2101. If you experience communication problems on port 80, you should try to use the alternative port(s).
BNC uploads a stream to the NNTRIP Broadcaster by referring to a dedicated mountpoint that has been set by its operator. Specify here the mountpoint based on the details you received for your stream from the operator. It is often a four character ID (capital letters) plus an integer number.
The stream upload may be protected through an upload 'Password'. Enter the password you received from the NTRIP Broadcaster operator along with the mountpoint(s).
If 'Host', 'Port', 'Mountpoint' and 'Password' are set, the stream will be encoded in RTCM's 'State Space Representation' (SSR) messages and uploaded to the specified broadcaster following the NTRIP Version 1 transport protocol.
3.15.3 System - mandatory if 'Host' is set
BNC allows configuring several Broadcast Correction streams for upload so that they refer to different reference systems and different NTRIP Broadcasters. You may use this functionality for parallel support of a backup NTRIP Broadcaster or for simultaneous support of various regional reference systems. Available options for transforming orbit and clock corrections to specific target reference systems are
Because a mathematically strict transformation to a regional reference system is not possible on the BNC server side when a scale factor is involved, the program follows an approximate solution. While orbits are transformed in full accordance with given equations, a transformed clock is derived through applying correction term
dC = (s - 1) / s * ρ / c
where s is the transformation scale, c is the speed of light, and ρ are the topocentric distance between an (approximate) center of the transformation's validity area and the satellite.
From a theoretical point of view this kind of approximation leads to inconsistencies between orbits and clocks and is therefore not allowed. However, it has been proved that resulting errors in Precise Point Positioning are on millimeter level for horizontal components and below the one centimeter for height components. The Australian GDA94 transformation with its comparatively large scale parameter is an exception in this as discrepancies may reach up to two centimeters there.
IGS08: As the orbits and clocks coming from real-time GNSS engine are expected to be in the IGS08 system, no transformation is carried out if this option is selected.
ETRF2000: The formulas for the transformation 'ITRF2008->ETRF2000' are taken from 'Claude Boucher and Zuheir Altamimi 2008: Specifications for reference frame fixing in the analysis of EUREF GPS campaign', see http://etrs89.ensg.ign.fr/memo-V8.pdf. The following 14 Helmert Transformation Parameters were introduced:
Translation in X at epoch To: 0.0521 m Translation in Y at epoch To: 0.0493 m Translation in Z at epoch To: -0.0585 m Translation rate in X: 0.0001 m/y Translation rate in Y: 0.0001 m/y Translation rate in Z: -0.0018 m/y Rotation in X at epoch To: 0.891 mas Rotation in Y at epoch To: 5.390 mas Rotation in Z at epoch To: -8.712 mas Rotation rate in X: 0.081 mas/y Rotation rate in Y: 0.490 mas/y Rotation rate in Z: -0.792 mas/y Scale at epoch To : 0.00000000134 Scale rate: 0.00000000008 /y To: 2000.0
NAD83: Formulas for the transformation 'ITRF2008->NAD83' are taken from 'Chris Pearson, Richard Snay 2013: Introducing HTDP 3.1 to transform coordinates across time and spatial reference frames', GPS Solutions, January 2013, Volume 17, Issue 1, pp 1-15.
Translation in X at epoch To: 0.99343 m Translation in Y at epoch To: -1.90331 m Translation in Z at epoch To: -0.52655 m Translation rate in X: 0.00079 m/y Translation rate in Y: -0.00060 m/y Translation rate in Z: -0.00134 m/y Rotation in X at epoch To: -25.91467 mas Rotation in Y at epoch To: -9.42645 mas Rotation in Z at epoch To: -11.59935 mas Rotation rate in X: -0.06667 mas/y Rotation rate in Y: 0.75744 mas/y Rotation rate in Z: 0.05133 mas/y Scale at epoch To : 0.00000000171504 Scale rate: -0.00000000010201 /y To: 1997.0
GDA94: The formulas for the transformation 'ITRF2008->GDA94' are taken from 'John Dawson, Alex Woods 2010: ITRF to GDA94 coordinate transformations', Journal of Applied Geodesy, 4 (2010), 189-199, de Gruyter 2010. DOI 10.1515/JAG.2010.019'.
Translation in X at epoch To: -0.08468 m Translation in Y at epoch To: -0.01942 m Translation in Z at epoch To: 0.03201 m Translation rate in X: 0.00142 m/y Translation rate in Y: 0.00134 m/y Translation rate in Z: 0.00090 m/y Rotation in X at epoch To: 0.4254 mas Rotation in Y at epoch To: -2.2578 mas Rotation in Z at epoch To: -2.4015 mas Rotation rate in X: -1.5461 mas/y Rotation rate in Y: -1.1820 mas/y Rotation rate in Z: -1.1551 mas/y Scale at epoch To : 0.000000009710 Scale rate: 0.000000000109 /y To: 1994.0
SIRGAS2000: The formulas for the transformation 'ITRF2008->SIRGAS2000' were provided via personal communication from CGED-Coordenacao de Geodesia, IBGE/DGC - Diretoria de Geociencias, Brazil..
Translation in X at epoch To: 0.0020 m Translation in Y at epoch To: 0.0041 m Translation in Z at epoch To: 0.0039 m Translation rate in X: 0.0000 m/y Translation rate in Y: 0.0000 m/y Translation rate in Z: 0.0000 m/y Rotation in X at epoch To: 0.170 mas Rotation in Y at epoch To: -0.030 mas Rotation in Z at epoch To: 0.070 mas Rotation rate in X: 0.000 mas/y Rotation rate in Y: 0.000 mas/y Rotation rate in Z: 0.000 mas/y Scale at epoch To : -0.000000001000 Scale rate: 0.000000000000 /y To: 0000.0
SIRGAS95: The formulas for the transformation 'ITRF2005->SIRGAS95' were provided via personal communication from Gustavo Acuha, Laboratorio de Geodesia Fisica y Satelital at Zulia University (LGFS-LUZ), parameters based on values from Table 4.1 of "Terrestrial Reference Frames (April 10, 2009), Chapter 4" in http://tai.bipm.org/iers/convupdt/convupdt_c4.html..
Translation in X at epoch To: 0.0077 m Translation in Y at epoch To: 0.0058 m Translation in Z at epoch To: -0.0138 m Translation rate in X: 0.0000 m/y Translation rate in Y: 0.0000 m/y Translation rate in Z: 0.0000 m/y Rotation in X at epoch To: 0.000 mas Rotation in Y at epoch To: 0.000 mas Rotation in Z at epoch To: -0.003 mas Rotation rate in X: 0.000 mas/y Rotation rate in Y: 0.000 mas/y Rotation rate in Z: 0.000 mas/y Scale at epoch To : 0.00000000157 Scale rate: -0.000000000000 /y To: 1995.4
DREF91: 'Referenzkoordinaten fuer SAPOS, Empfehlungen der Projektgruppe SAPOS-Koordinatenmonitoring 2008', Personal communication with Peter Franke, BKG, Germany. The following 14 Helmert Transformation Parameters were introduced:
Translation in X at epoch To: -0.0118 m Translation in Y at epoch To: 0.1432 m Translation in Z at epoch To: -0.1117 m Translation rate in X: 0.0001 m/y Translation rate in Y: 0.0001 m/y Translation rate in Z: -0.0018 m/y Rotation in X at epoch To: 3.291 mas Rotation in Y at epoch To: 6.190 mas Rotation in Z at epoch To: -11.012 mas Rotation rate in X: 0.081 mas/y Rotation rate in Y: 0.490 mas/y Rotation rate in Z: -0.792 mas/y Scale at epoch To : 0.00000001224 Scale rate: 0.00000000008 /y To: 2000.0
Custom: Feel free to specify your own 14 Helmert Transformation parameters for transformations from IGS08/ITRF2008 into your own target system.
Figure 28: Setting Custom Transformation Parameters window, example for 'ITRF2008->GDA94'.
3.15.4 Center of Mass - optional
BNC allows to either refer Broadcast Corrections to the satellite's Center of Mass (CoM) or to the satellite's Antenna Phase Center (APC). By default corrections refer to APC. Tick 'Center of Mass' to refer uploaded corrections to CoM.
Specify a path for saving the generated orbit corrections as SP3 orbit files. If the specified directory does not exist, BNC will not create SP3 orbit files. The following is a path example for a Linux system:
/home/user/BNC${GPSWD}.sp3
Note that '${GPSWD}' produces the GPS Week and Day number in the file name.
Default is an empty option field, meaning that you don't want BNC to save the uploaded stream contents in daily SP3 files.
As an SP3 file contents should be referred to the satellites Center of Mass (CoM) while Broadcast Corrections are referred to the satellites APC, an offset has to be applied which is available from an IGS ANTEX file (see option 'ANTEX File' below). Hence you should specify the 'ANTEX File' path there if you want to save the stream contents in SP3 format. If you don't specify an 'ANTEX File' path, the SP3 file contents will be referred to the satellites APCs.
The file names for the daily SP3 files follow the convention for SP3 file names. The first three characters of each file name are set to 'BNC'. Note that clocks in the SP3 orbit files are not corrected for the conventional periodic relativistic effect.
In case the 'Combine Corrections' table contains only one Broadcast Corrections stream, BNC will merge that stream with Broadcast Ephemeris to save results in files specified here through SP3 and/or Clock RINEX file path. In such a case you have to define only the SP3 and Clock RINEX file path and no further option in the 'Upload Corrections' table.
Note that BNC outputs a complete list of SP3 'Epoch Header Records' even if no 'Position and Clock Records' are available for certain epochs because of stream outages. Note further that the 'Number of Epochs' in the first SP3 header record may not be correct because that number is not available when the file is created. Depending on your processing software (e.g. Bernese GNSS Software, BSW) it could therefore be necessary to correct an incorrect 'Number of Epochs' in the file before you use in Post Processing.
The clock corrections generated by BNC for upload can be logged in Clock RINEX format. The file naming follows the RINEX convention.
Specify a path for saving the generated clock corrections as Clock RINEX files. If the specified directory does not exist, BNC will not create Clock RINEX files. The following is a path example for a Linux system:
/home/user/BNC${GPSWD}.clk
Note that '${GPSWD}' produces the GPS Week and Day number in the file name.
Note further that clocks in the Clock RINEX files are not corrected for the conventional periodic relativistic effect.
3.15.7 Interval - mandatory if 'Upload Table' entries specified
Select the length of Clock RINEX files and SP3 Orbit files. The default value is 1 day.
BNC requires an orbit corrections sampling interval for the stream to be uploaded and sampling intervals for SP3 and Clock RINEX files. The outgoing stream's clock correction sampling interval follows that of incoming corrections and is therefore nothing to be specified here.
3.15.8.1 Orbits (Orb) - mandatory if 'Upload Table' entries specified
Select the stream's orbit correction sampling interval in seconds. A value of 60 sec may be appropriate.
A value of zero '0' tells BNC to upload all orbit correction samples coming in from the real-time GNSS engine along with the clock correction samples to produce combined orbit and clock corrections to Broadcast Ephemeris (1060 for GPS, 1066 for GLONASS).
Configuration examples:
Let us suppose a real-time network engine supporting BNC every 5 sec with GPS Broadcast Corrections for orbits, clocks and code biases in 'RTNET' stream format.3.15.8.2 SP3 - mandatory if 'SP3 File' is specified
Select the SP3 orbit file sampling interval in minutes. A value of 15 min may be appropriate. A value of zero '0' tells BNC to store all available samples into SP3 orbit files.
3.15.8.3 RINEX (RNX) - mandatory if 'RNX File' is specified
Select the Clock RINEX file sampling interval in seconds. A value of 10 sec may be appropriate. A value of zero '0' tells BNC to store all available samples into Clock RINEX files.
3.15.9 Custom Trafo - optional if 'Upload Table' entries specified
Hit 'Custom Trafo' to specify your own 14 parameter Helmert Transformation instead of selecting a predefined transformation through 'System' button.
The following screenshot shows the encoding and uploading of a stream of precise orbits and clocks coming from a real-time engine in 'RTNET' ASCII format. The stream is uploaded to NTRIP Broadcaster 'products.igs-ip.net'. It is referred to APC and IGS08. Uploaded data are locally saved in SP3 and Clock RINEX format. The SSR Provider ID is set to 3. The SSR Solution ID is and the Issue of Data SSR are set to 1. Required Broadcast Ephemeris are received via stream 'RTCM3EPH'.
Figure 29: Producing Broadcast Corrections from incoming precise orbits and clocks and uploading them to an NTRIP Broadcaster.
3.15.10 ANTEX File - mantatory if 'SP3 File' is specified
IGS provides a file containing absolute phase center variations for GNSS satellite and receiver antennas in ANTEX format. Entering the full path to such an ANTEX file is required here for referring the SP3 file contents to the satellite's Center of Mass (CoM). If you don't specify a ANTEX file, the SP3 file will contain orbit information which is referred to Antenna Phase Center (APC) instead of CoM.
BNC can upload a stream carrying Broadcast Ephemeris in RTCM Version 3 format to an NTRIP Broadcaster.
Specify the 'Host' IP number or URL of an NTRIP Broadcaster to upload the stream. An empty option field means that you don't want to upload Broadcast Ephemeris.
Enter the NTRIP Broadcaster's IP 'Port' number for stream upload. Note that NTRIP Broadcasters are often configured to provide access through more than one port, usually ports 80 and 2101. If you experience communication problems on port 80, you should try to use the alternative port(s).
3.16.2 Mountpoint & Password - mandatory if 'Host' is set
BNC uploads a stream to the NTRIP Broadcaster by referring to a dedicated mountpoint that has been set by its operator. Specify the mountpoint based on the details you received for your stream from the operator. It is often a four character ID (capital letters) plus an integer number.
The stream upload may be protected through an upload 'Password'. Enter the password you received from the NTRIP Broadcaster operator along with the mountpoint.
3.16.3 Sampling - mandatory if 'Host' is set
Figure 30: Producing a Broadcast Ephemeris stream from navigation messages of globally distributed RTCM streams and uploading them in RTCM Version 3 format to an NTRIP Broadcaster.
Each stream on an NTRIP Broadcaster (and consequently on BNC) is defined using a unique source ID called mountpoint. An NTRIP Client like BNC accesses the desired stream by referring to its mountpoint. Information about streams and their mountpoints is available through the source-table maintained by the NTRIP Broadcaster.
Streams selected for retrieval are listed under the 'Streams' canvas on BNC's main window. The list provides the following information either extracted from source-table(s) produced by the NTRIP Broadcasters or introduced by BNC's user:
| 'resource loader' | NTRIP Broadcaster URL and port, or TCP/IP host and port, or UDP port, or Serial input port specification. |
| 'mountpoint' | Mountpoint introduced by NTRIP Broadcaster, or Mountpoint introduced by BNC's user. |
| 'decoder' | Name of decoder used to handle the incoming stream content according to its format; editable. |
| 'lat' | Approximate latitude of reference station, in degrees, north; editable if 'nmea' = 'yes'. |
| 'long' | Approximate longitude of reference station, in degrees, east; editable if 'nmea' = 'yes'. |
| 'nmea' | Indicates whether or not streaming needs to be initiated by BNC through sending NMEA-GGA message carrying position coordinates in 'lat' and 'long'. |
| 'ntrip' | Selected NTRIP transport protocol version (1, 2, 2s, R, or U), or 'N' for TCP/IP streams without NTRIP, or 'UN' for UDP streams without NTRIP, or 'S' for serial input streams without NTRIP. |
| 'bytes' | Number of bytes received. |
To remove a stream from the 'Streams' canvas in the main window, highlight it by clicking on it and hit the 'Delete Stream' button. You can also remove multiple streams simultaneously by highlighting them using +Shift and +Ctrl.
3.17.3 Reconfigure Stream Selection On-the-fly
The streams selection can be changed on-the-fly without interrupting uninvolved threads in the running BNC process.
Window mode: Hit 'Reread & Save Configuration' while BNC is in window mode and already processing data to let changes of your streams selection immediately become effective.
No window mode: When operating BNC online in 'no window' mode (command line option -nw), you force BNC to reread its 'mountPoints' configuration option from disk at pre-defined intervals. Select '1 min', '1 hour', or '1 day' as 'Reread configuration' option to reread the 'mountPoints' option every full minute, hour, or day. This lets a 'mountPoints' option edited in between in the configuration file become effective without terminating uninvolved threads. See annexed section 'Configuration Examples' for a configuration file example and a list of other on-the-fly changeable options.
The section on the bottom of the main window provides online control of BNC's activities. Tabs are available to show the records saved in a logfile, for a plot to control the bandwidth consumption, for a plot showing stream latencies, and for time series plots of PPP results.
Records of BNC's activities are shown in the 'Log' tab. They can be saved into a file when a valid path is specified in the 'Logfile (full path)' field.
The bandwidth consumption per stream is shown in the 'Throughput' tab in bits per second (bps) or kilo bits per second (kbps). The following figure shows an example for the bandwidth consumption of incoming streams.
Figure 31: Bandwidth consumption of incoming streams.
The latency of observations in each incoming stream is shown in the 'Latency' tab in milliseconds or seconds. Streams not carrying observations (i.e. those providing only Broadcast Ephemeris messages) or having an outage are not considered here and shown in red color. Note that the calculation of correct latencies requires the clock of the host computer to be properly synchronized. The next figure shows an example for the latency of incoming streams.
Figure 32: Latency of incoming streams.
Precise Point Positioning time series of North (red), East (green) and Up (blue) coordinate components are shown in the 'PPP Plot' tab when a 'Origin' option is defined. Values are either referred to reference coordinates (if specified) or referred to the first estimated set of coordinate components. The time as given in format [hh:mm] refers to GPS Time. The sliding PPP time series window covers a period of 5 minutes. Note that it may take up to 30 seconds or more till the first PPP solutions becomes available. The following figure shows the screenshot of a PPP time series plot of North, East and Up coordinate components.
Figure 33: Time series plot of PPP session.
The bottom menu bar allows to add or delete streams to BNC's configuration and to start or stop it. It also provides access to BNC's online help function. The 'Add Stream' button opens a window that allows user to select one of several input communication links, see figure below.
Figure 34: Steam input communication links.
Button 'Add Stream' allows you to pull streams either from a NTRIP Broadcaster or from a TCP/IP port, UPD port, or serial port.
3.19.1.1 Add Stream - Coming from Caster
Button 'Add Stream' > 'Coming from Caster' then opens a window that allows user to select data streams from an NTRIP Broadcaster according to their mountpoints and show a distribution map of offered streams.
3.19.1.1.1 Caster Host and Port - mandatory
Enter the NTRIP Broadcaster host IP and port number. Note that EUREF and IGS operate NTRIP Broadcasters at http://www.euref-ip.net/home, http://www.igs-ip.net/home, http://www.products.igs-ip.net/home and http://mgex.igs-ip.net/home.
3.19.1.1.2 Casters Table - optional
It may be that you are not sure about your NTRIP Broadcasters host and port number or you are interested in other broadcaster installations operated elsewhere. Hit 'Show' for a table of known broadcasters maintained at www.rtcm-ntrip.org/home. A window opens which allows selecting a broadcaster for stream retrieval, see figure below.
Figure 35: Casters table.
3.19.1.1.3 User and Password - mandatory for protected streams
Streams on NTRIP Broadcasters may be protected. Enter a valid 'User' ID and 'Password' for access to protected streams. Accounts are usually provided per NTRIP Broadcaster through a registration procedure. Register through http://register.rtcm-ntrip.org for access to protected streams from EUREF and IGS.
Use the 'Get Table' button to download the source-table from the NTRIP Broadcaster. Pay attention to data fields 'format' and 'format-details'. Keep in mind that BNC can only decode and convert streams that come in RTCM Version 2, RTCM Version 3, or RTNET format. For access to observations, Broadcast Ephemeris and Broadcast Corrections in RTCM format streams must contain a selection of appropriate message types as listed in the Annex, cf. data field 'format-details' for available message types and their repetition rates in brackets. Note that in order to produce RINEX Navigation files RTCM Version 3 streams containing message types 1019 (GPS) and 1020 (GLONASS) and 1043 (SBAS) and 1044 (QZSS) and 1045, 1046 (Galileo) and 63 (tentative, BDS/BeiDou) are required. Select your streams line by line, use +Shift and +Ctrl when necessary. The figure below provides an example source-table.
The contents of data field 'nmea' tells you whether a stream retrieval needs to be initiated by BNC through sending an NMEA-GGA message carrying approximate position coordinates (virtual reference station).
Hit 'OK' to return to the main window. If you wish you can click on 'Add Stream' and repeat the process again to retrieve streams from different casters.
Figure 36: Broadcaster source-table.
3.19.1.1.5 NTRIP Version - mandatory
Some limitations and deficiencies of the NTRIP Version 1 stream transport protocol are solved in NTRIP Version 2. Improvements mainly concern a full HTTP compatibility in view of requirements coming from proxy servers. Version 2 is backwards compatible to Version 1. Options implemented in BNC are:
1: NTRIP Version 1, TCP/IP.
2: NTRIP Version 2 in TCP/IP mode.
2s: NTRIP Version 2 in TCP/IP mode via SSL.
R: NTRIP Version 2 in RTSP/RTP mode.
U: NTRIP Version 2 in UDP mode.
If NTRIP Version 2 is supported by the broadcaster:
Select option '1' if you are not sure whether the broadcaster supports NTRIP Version 2.
Button 'Map' opens a window to show a distribution map of the caster's streams. You may like to zoom in or out using the mouse. Left button: draw a rectangle to zoom, right button: zoom out, middle button: zoom back.
Figure 37: Stream distribution map derived from NTRIP Broadcaster source-table.
3.19.1.2 Add Stream - Coming from TCP/IP Port
Button 'Add Stream' > 'Coming from TCP/IP Port' allows to retrieve streams via TCP directly from an IP address without using the NTRIP transport protocol. For that you:
Streams directly received from a TCP/IP port show up with an 'N' for 'No NTRIP' in the 'Streams' canvas on BNC's main window. Latitude and longitude are to be entered just for informal reasons.
Note that this option works only if no proxy server is involved in the communication link.
3.19.1.3 Add Stream - Coming from UDP Port
Button 'Add Stream' > 'Coming from UDP Port' allows to pick up streams arriving directly at one of the local host's UDP ports without using the NTRIP transport protocol. For that you:
Streams directly received at a UDP port show up with a 'UN' for 'UDP, No NTRIP' in the 'Streams' canvas section on BNC's main window. Latitude and longitude are to be entered just for informal reasons.
3.19.1.4 Add Stream - Coming from Serial Port
Button 'Add Stream' > 'Coming from Serial Port' allows to retrieve streams from a GNSS receiver via serial port without using the NTRIP transport protocol. For that you:
Windows: COM1, COM2 Linux: /dev/ttyS0, /dev/ttyS1 FreeBSD: /dev/ttyd0, /dev/ttyd1 Digital Unix: /dev/tty01, /dev/tty02 HP-UX: /dev/tty1p0, /dev/tty2p0 SGI/IRIX: /dev/ttyf1, /dev/ttyf2 SunOS/Solaris: /dev/ttya, /dev/ttyb
When selecting one of the serial communication options listed above, make sure that you pick those configured to the serial connected GNSS receiver.
Streams received from a serial connected GNSS receiver show up with an 'S' (for Serial Port, no NTRIP) in the 'Streams' canvas section on BNC's main window. Latitude and longitude are to be entered just for informal reasons.
The following figure shows a BNC example setup for pulling a stream via serial port on a Linux operating system.
Figure 38: BNC setup for pulling a stream via serial port.
Button 'Delete Stream' allows you to delete streams previously selected for retrieval as listed under the 'Streams' canvas on BNC's main window.
Button 'Map' opens a window to show a distribution map of the streams selected for retrieval as listed under the 'Streams' canvas. You may like to zoom in or out using the mouse. Left button: draw a rectangle to zoom, right button: zoom out, middle button: zoom back.
Hit 'Start' to start retrieving, decoding or converting GNSS data streams in real-time. Note that 'Start' generally forces BNC to begin with fresh RINEX which might overwrite existing files when necessary unless the option 'Append files' is ticked.
Hit the 'Stop' button in order to stop BNC.
Command line options are available to run BNC in 'no window' mode or let it read data offline from one or several files for debugging or Post Processing purposes. BNC will then use processing options from the involved configuration file. Note that the self-explaining contents of the configuration file can easily be edited. It is possible to introduce a specific configuration file name instead of using the default name 'BNC.bnc'.
3.20.1 No Window Mode - optional
Apart from its regular windows mode, BNC can be started on all systems as a batch job with command line option '-nw'. BNC will then run in 'no window' mode, using processing options from its configuration file on disk. Terminate BNC using Windows Task Manager when running it in 'no window' mode on Windows systems.
Example:
bnc.exe -nw
It is obvious that BNC requires graphics support when started in interactive mode. But, note that it also requires graphics support when producing plots in batch mode (option -nw). Windows and Mac OS X systems always support graphics. For producing plots in batch mode on Linux systems you must make sure that at least a virtual X-Server such as 'Xvfb' is installed and the '-display' option is used. The following is an example shell script to execute BNC in batch mode for producing QC plots from RINEX files. It could be used via 'crontab':
#!/bin/bash # Save string localhost echo "localhost" > /home/user/hosts # Start virtual X-Server, save process ID /usr/bin/Xvfb :29 -auth /home/user/hosts -screen 0 1280x1024x8 & psID=`echo $!` # Run BNC application with defined display variable /home/user/BNC/bnc --conf /dev/null --key reqcAction Analyze --key reqcObsFile ons12090.12o --key reqcNavFile brdc2090.12p --key reqcOutLogFile multi.txt --key reqcPlotDir /home/user --display localhost:29 --nw # BNC done, kill X-server process kill $psID
Although BNC is primarily a real-time online tool, for debugging purposes it can be run offline to read data from a file previously saved through option 'Raw output file'. Enter the following command line option for that
--file <inputFileName>
and specify the full path to an input file containing previously saved data. Example:Note that when running BNC offline, it will use options for file saving, interval, sampling, PPP etc. from its configuration file.
Note further that option '--file' forces BNC to appy the '-nw' option for running in 'no window' mode.
3.20.3 Configuration File - optional
Example:
./bnc --conf MyConfig.bnc
This leads to a BNC job using configuration file 'MyConfig.bnc'. The configuration file will be saved in the current working directory.
3.20.4 Configuration Options - optional
BNC applies options from the configuration file but allows updating every one of them on the command line while the contents of the configuration file remains unchanged. The command line syntax for that looks as follows
--key <keyName> <keyValue>
where <keyName> stands for the name of an option contained in the configuration file and <keyValue> stands for the value you want to assign to it. The following is a syntax example for a complete command line:
bnc --nw --conf <confFileName> --key <keyName1> <keyValue1> --key <keyName2> <keyValue2> ...
Example:
./bnc --conf CONFIG.bnc --key proxyPort 8001 --key rnxIntr "1 day"
5.1. Revision History
5.2. RTCM
5.2.1 NTRIP Version 1
5.2.2 NTRIP Version 2
5.2.3 RTCM Version 2
5.2.4 RTCM Version 3
5.3. Configuration Examples
5.4. Further Reading
| Dec 2006 | Version 1.0b | [Add] First Beta Binaries published based on Qt 4.2.3. |
| Jan 2007 | Version 1.1b | [Add] Observables C2, S1, and S2 [Add] Virtual reference station access [Bug] RTCM2 decoder time tag fixed [Mod] Small letters for public RINEX skeleton files [Add] Online help through Shift+F1 |
| Apr 2007 | Version 1.2b | [Bug] Output only through IP port [Bug] Method 'reconnecting' now thread-save [Add] ZERO decoder added [Mod] Download public RINEX skeletons once per day [Mod] Upgrade to Qt Version 4.2.3 [Mod] Replace 'system' call for RINEX script by 'QProcess' [Add] HTTP Host directive for skeleton file download [Add] Percent encoding for user IDs and passwords [Bug] Exit execution of calling thread for RTCM3 streams [Bug] Signal-slot mechanism for threads |
| May 2007 | Version 1.3 | [Add] Source code published. |
| Jul 2007 | Version 1.4 | [Bug] Skip messages from proxy server [Bug] Call RINEX script through 'nohup' |
| Apr 2008 | Version 1.5 | [Add] Handle ephemeris from RTCM Version 3 streams [Add] Upgrade to Qt Version 4.3.2 [Add] Optional RINEX v3 output [Add] SBAS support [Bug] RINEX skeleton download following stream outage [Add] Handle ephemeris from RTIGS streams [Add] Monitor stream failure/recovery and latency [Mod] Redesign of main window [Bug] Freezing of About window on Mac OS X [Bug] Fixed problem with PRN 32 in RTCMv2 decoder [Bug] Fix for Trimble 4000SSI receivers in RTCMv2 decoder [Mod] Major revision of input buffer in RTCMv2 decoder |
| Dec 2008 | Version 1.6 | [Mod] Fill blank columns in RINEXv3 with 0.000 [Add] RTCMv3 decoder for orbit and clock corrections [Add] Check RTCMv3 streams for incoming message types [Add] Decode RTCMv2 message types 3, 20, 21, and 22 [Add] Loss of lock and lock time indicator [Bug] Rounding error in RTCMv3 decoder concerning GLONASS height [Mod] Accept GLONASS in RTCMv3 when transmitted first [Add] Leap second 1 January 2009 [Add] Offline mode, read data from file [Add] Output antenna descriptor, coordinates and eccentricities from RTCMv3 [Add] Reconfiguration on-the-fly [Mod] Binary output of synchronized observations [Add] Binary output of unsynchronized observations [Bug] Fixed problem with joined RTCMv3 blocks |
| Dec 2008 | Version 1.6.1 | [Mod] HTTP GET when no proxy in front |
| Nov 2009 | Version 1.7 | [Bug] RINEX Navigation file format [Add] Upgrade to Qt Version 4.5.2 [Add] Support of NTRIP v2 [Add] Rover support via serial port [Add] Show broadcaster table from www.rtcm-ntrip.org [Add] Enable/disable panel widgets [Add] User defined configuration file name [Mod] Switch to configuration files in ini-Format [Add] Daily logfile rotation [Add] Read from TCP/IP port, by-pass NTRIP transport protocol [Add] Save NMEA messages coming from rover [Add] Auto start [Add] Drag and drop ini files [Add] Read from serial port, by-pass NTRIP transport protocol [Mod] Update of SSR messages following RTCM 091-2009-SC104-542 [Add] Read from UPD port, by-pass NTRIP transport protocol [Mod] Output format of Broadcast Corrections [Add] Throughput plot [Add] Latency plot |
| Nov 2009 | Version 1.8 | [Mod] On-the-fly reconfiguration of latency and throughput plots |
| Feb 2010 | Version 2.0 | [Mod] Change sign of Broadcast Corrections [Add] Real-time PPP option |
| Jun 2010 | Version 2.1 | [Bug] SSR GLONASS message generation [Add] PPP in Post Processing mode [Mod] Update of SSR messages following draft dated 2010-04-12 [Mod] Generating error message when observation epoch is wrong |
| Jul 2010 | Version 2.2 | [Bug] GLONASS ephemeris time |
| Aug 2010 | Version 2.3 | [Mod] Internal format for saving raw streams [Bug] Outlier detection in GLONASS ambiguity resolution [Mod] Format of PPP logs in logfile [Bug] Complete acceleration terms for GLONASS ephemeris [Bug] Handling ephemeris IOD's in PPP mode |
| Dec 2010 | Version 2.4 | [Add] Output of averaged positions when in PPP mode [Mod] Use always the latest received set of Broadcast Ephemeris [Add] QuickStart PPP option [Mod] Improvement of data sharing efficiency among different threads [Mod] Design of PPP panel section [Add] Sigmas for observations and parameters [Add] Stream distribution map [Bug] GPS Ephemeris in RINEX v3 format |
| Feb 2011 | Version 2.5 | [Add] PPP option for sync of clock observations and corrections [Add] Drafted RTCMv3 Galileo ephemeris messages 1045 [Add] Drafted RTCMv3 Multiple Signal Messages [Add] Optional specification of sigmas for coordinates and troposphere in PPP [Add] Include Galileo in SPP [Add] Include Galileo observations in output via IP port [Add] Include Galileo observations in output via RINEXv3 files [Mod] Interface format for feeding a real-time engine with observations [Add] Correct observations for antenna phase center offsets [Add] Combine orbit/clock correction streams [Add] Specify corrections mountpoint in PPP panel |
| Apr 2011 | Version 2.6 | [Add] Complete integration of BNS in BNC [Add] SP3 and Clock RINEX output [Add] PPP in Post Processing Mode [Add] Some RINEX editing & QC functionality [Add] Threshold for orbit outliers in combination solution [Add] Real-time engine becomes orbit/clock server instead of client [Mod] 'EOE' added to orbit/clock stream from engine [Add] Correction for antenna eccentricities [Add] Quick start mode for PPP [Mod] Design of format for feeding engine changed to follow RINEX v3 [Mod] Implementation of SSR message encoding modified according to standard [Add] SSL/TLS Support of NTRIP Version 2 [Mod] Switch to Qt version 4.7.3 [Add] RINEX editing, concatenation and quality check [Add] Reading all configuration options from command line [Mod] RTCMv3 Galileo Broadcast Ephemeris message 1045 [Mod] Change default configuration file suffix from 'ini' to 'bnc' [Add] Specific rates for orbits and clocks in streams and SP3/RNX files |
| May 2012 | Version 2.6 | [Add] Version 2.6 published |
| Sep 2012 | Version 2.7 | [Bug] Bug in L5 decoding fixed [Bug] Bug in on-the-fly configuration fixed [Add] Clock RINEX file header extended [Add] Decoding/converting BeiDou and QZSS added [Add] Work on RINEX v2 and v3 quality check started [Mod] Source code completely re-arranged [Add] QWT and QWTPOLAR graphics libraries added [Add] RINEX QC through multipath analysis sky plot [Add] RINEX QC through signal-to-noise ratio sky plot [Add] RINEX QC through satellite availability plot [Add] RINEX QC through satellite elevation plot [Add RINEX QC through PDOP plot [Bug] Short periodic outages in PPP time series when 'Sync Corr' set to zero |Add] Log observation types contained in RTCM Version 3 MSM streams [Add] Reading RINEX v3 observation type header records from RINEX skeleton files [Add] Logfile for RINEX file editing and concatenation [Add] Save PNG plot files on disk [Mod] Plot stream distribution map from NTRIP Broadcaster source-table [Add] Plot stream distribution map from selected sources [Add] Version 2.7 published |
| Mar 2013 | Version 2.8 | [Mod] Started work on new version in Sep 2012 [Bug] Epoch special event flag in RINEX concatenation [Bug] Limit RINEX v2 records length to 80 characters [Bug] SSR message update interval indicator [Bug] Fixed SSR stream encoding and upload [Add] Concatenate RINEX v3 navigation files containing Galileo ephemeris [Mod] Plausibility check of GLONASS ephemeris [Add] Correcting clocks for scale factor involved in transformation [Mod] Orbit/clock interpolation in SSR stream encoding and upload to caster [Add] Version 2.8 published |
| Jul 2013 | Version 2.9 | [Add] Started work on new version in Mar 2013 [Bug] SSR stream upload buffering disabled [Mod] Format for feeding a connected GNSS engine [Mod] RTNET format for receiving data from a connected GNSS engine [Add] Include Galileo in SPP [Add] RINEX QC multipath an SNR sky plots for GLONASS and Galileo [Add] Bias estimation for GLONASS clocks in PPP [Add] Trace positions on GM or OSM maps [Add] Version 2.9 published |
| Dec 2013 | Version 2.10 | [Add] Started work on new version in Aug 2013 [Bug] Clock RINEX und SP3 file generation on Windows systems [Bug] Broadcast Ephemeris generation [Add] Transformation ITRF2008 to NAD83 and DREF91 [Add] CodeBias added to RTNET stream format [Bug] GPS L2 in 'Feed Engine' output [Mod] Made C1 in BeiDou default observation type instead of C2 [Add] Feed engine output sorted per stream [Add] Feed engine output file name change on-the-fly [Add] 'Append files' option for RINEX observation files [Mod] Broadcast Corrections ASCII file output for message 1058 & 1064 modified [Bug] GPS L2 phase data in RINEX2 [Bug] GLONASS frequency numbers [Add] RTCMv3 Galileo Broadcast Ephemeris message 1046 [Add] Reset ambiguities in PPP when orbit/clock correction IDs change [Add] Satellite clock offsets are reset in adjustment for combination when orbit/clock correction IDs change [Add] Version 2.10 published |
| Sep 2014 | Version 2.11 | [Add] Started work on new version in Dec 2013 [Mod] SIRGAS transformation parameters adjusted [Mod] Antex file updated [Mod] RTCM SSR messages updated [Bug] GLONASS code biases [Mod] Maximum number of GNSS observations increased [Mod] Loss of lock handling changed [Add] Raw stream output through TCP/IP port [Add] Version 2.11.0 published |
| Sep 2014 | Version 2.12 |
[Add] Started work on new version in Sep 2014 [Mod] RINEX file concatenation [Add] Observation code selection in RINEX file editing [Mod] Routine handling of data input and output in RINEX format re-written [Mod] QC routines re-written with the goal of handling all signal types [Add] Machine-readable output of RINEX QC [Add] Additionl PPP client for parallel processing of an arbitrary number of stations in separate threads [Add] PPP processing of any number of linear combinations of GNSS measurements selected by user [Add] Decoding RTCM SSR phase bias messages [Add] Decoding RTCM SSR ionospheric model messages, single-layer model for total electron content [Add] RTCMv3 QZSS Broadcast Ephemeris message 1044 [Add] Handle old-fashioned SNR values in RINEX [Mod] SNR and MP visualization depending on RINEX observation attribute [Bug] Saastamoinen tropospheric correction for very high elevation receivers [Add] Comparison of SP3 files [Add] RTCMv3 SBAS Broadcast Ephemeris message 1043 [Add] RTCMv3 BeiDou Broadcast Ephemeris message 63, tentative [Bug] VRS support in sending NMEA in Auto/Manual mode to NTRIP Broadcaster [Add] Forwarding NMEA GNGGA to NTRIP Broadcaster [Bug] Stream failure/recovery reports |
The Radio Technical Commission for Maritime Services (RTCM) is an international non-profit scientific, professional and educational organization. Special Committees provide a forum in which governmental and non-governmental members work together to develop technical standards and consensus recommendations in regard to issues of particular concern. RTCM is engaged in the development of international standards for maritime radionavigation and radiocommunication systems. The output documents and reports prepared by RTCM Committees are published as RTCM Recommended Standards. Topics concerning Differential Global Navigation Satellite Systems (DGNSS) are handled by the Special Committee SC 104.
Personal copies of RTCM Recommended Standards can be ordered through http://www.rtcm.org/orderinfo.php.
'Networked Transport of RTCM via Internet Protocol' Version 1.0 (NTRIP) stands for an application-level protocol streaming Global Navigation Satellite System (GNSS) data over the Internet. NTRIP is a generic, stateless protocol based on the Hypertext Transfer Protocol HTTP/1.1. The HTTP objects are enhanced to GNSS data streams.
NTRIP Version 1 is an RTCM standard designed for disseminating differential correction data (e.g. in the RTCM-104 format) or other kinds of GNSS streaming data to stationary or mobile users over the Internet, allowing simultaneous PC, Laptop, PDA, or receiver connections to a broadcasting host. NTRIP supports wireless Internet access through Mobile IP Networks like GSM, GPRS, EDGE, or UMTS.
NTRIP is implemented in three system software components: NTRIP Clients, NTRIP Servers and NTRIP Broadcasters. The NTRIP Broadcaster is the actual HTTP server program whereas NTRIP Client and NTRIP Server are acting as HTTP clients.
NTRIP is an open none-proprietary protocol. Major characteristics of NTRIP's dissemination technique are:
The NTRIP Broadcaster maintains a source-table containing information on available NTRIP streams, networks of NTRIP streams and NTRIP Broadcasters. The source-table is sent to an NTRIP Client on request. Source-table records are dedicated to one of the following: Data Streams (record type STR), Casters (record type CAS), or Networks of streams (record type NET).
Source-table records of type STR contain the following data fields: 'mountpoint', 'identifier', 'format', 'format-details', 'carrier', 'nav-system', 'network', 'country', 'latitude', 'longitude', 'nmea', 'solution', 'generator', 'compr-encryp', 'authentication', 'fee', 'bitrate', 'misc'.
Source-table records of type NET contain the following data fields: 'identifiey', 'operator', 'authentication', 'fee', 'web-net', 'web-str', 'web-reg', 'misc'.
Source-table records of type CAS contain the following data fields: 'host', 'port', 'identifier', 'operator', 'nmea', 'country', 'latitude', 'longitude', 'misc'.
The major changes of NTRIP Version 2 compared to Version 1.0 are:
NTRIP Version 2 allows to either communicating in TCP/IP mode or in RTSP/RTP mode or in UDP mode whereas Version 1 is limited to TCP/IP only. It furthermore allows using the Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL) cryptographic protocols for secure NTRIP communication over the Internet.
Transmitting GNSS carrier phase data can be done through RTCM Version 2 messages. Please note that only RTCM Version 2.2 and 2.3 streams may include GLONASS data. Messages that may be of interest here are:
RTCM Version 3 has been developed as a more efficient alternative to RTCM Version 2. Service providers and vendors have asked for a standard that would be more efficient, easy to use, and more easily adaptable to new situations. The main complaint was that the Version 2 parity scheme was wasteful of bandwidth. Another complaint was that the parity is not independent from word to word. Still another was that even with so many bits devoted to parity, the actual integrity of the message was not as high as it should be. Plus, 30-bit words are awkward to handle. The Version 3 standard is intended to correct these weaknesses.
RTCM Version 3 defines a number of message types. Messages that may be of interest here are:
The following are so-called 'State Space Representation' (SSR) messages:
The following are so-called 'Multiple Signal Messages' (MSM):
The following are proposed 'Multiple Signal Messages' (MSM) under discussion for standardization:
BNC comes with a number of configuration examples which can be used on all operating systems. Copy the complete directory 'Example_Configs' which comes with the software including sub-directories 'Input' and 'Output' to your disc. There are two ways to start BNC using one of the example configurations:
Although it's not a must, we suggest that you always create BNC configuration files with the file name extension '.bnc'.
We furthermore suggest for convenience reasons that you configure your system to automatically start BNC when you double-click a file with the file name extension '.bnc'. The following describes what to do on Windows systems to associate the BNC program to such configuration files:
Some of the presented example configuration files contain a user ID 'Example' with a password 'Configs' for accessing a few GNSS streams from public Ntrip Broadcasters. This generic account is arranged for convenience reasons only. Please be so kind as to replace the generic account details as well as the place holders 'User' and 'Pass' by the personal user ID and password you receive following an online registration through http://register.rtcm-ntrip.org.
Note that the account for an Ntrip Broadcaster is usually limited to pulling a specified maximum number of streams at the same time. As running some of the example configurations requires pulling several streams, it is suggested to make sure that you don't exceed your account's limits.
Make also sure that sub-directories 'Input' and 'Output' which are part of the example configurations exist on your system or adjust the affected example configuration options according to your needs.
Some BNC options require antenna phase center variations as made available from IGS through so-called ANTEX files at ftp://igs.org/pub/station/general. An example ANTEX file 'igs08.atx' is part of the BNC package for convenience.
The example configurations assume that no proxy protects your BNC host. Should a proxy be operated in front of BNC then you need to introduce its IP and port in the 'Network' panel.
You should be able to run all configuration examples without changing their options. However, configurations 'Upload.bnc' and 'UploadPPP.bnc' are exceptions because they require an input stream from a connected network engine.
The following table's left column is a list of options as contained in BNC's configuration files (default: BNC.bnc).
| Option | Affiliation |
| [General] | Settings: Group |
| startTab= | Internal: Top panel index |
| statusTab= | Internal: Bottom panel index |
| font= | Internal: Used font |
| casterUrlList= | Internal: Visited URLs |
| mountPoints= | Add Streams: broadcaster:port/mountpoint |
| ntripVersion= | Add Stream: NTRIP Version |
| proxyHost= | Network: Proxy host |
| proxyPort= | Network: Proxy port |
| sslCaCertPath= | Network: Path to SSL certificates |
| ignoreSslErrors= | Network: Ignore ssl authorization errors |
| logFile= | General: Logfile (full path) |
| rnxAppend= | General: Append files |
| onTheFlyInterval= | General: Reread configuration |
| autoStart= | General: Auto start |
| rawOutFile= | General: Raw output file (full path) |
| rnxPath= | RINEX Observations: Directory |
| rnxIntr= | RINEX Observations: Interval |
| rnxSample= | RINEX Observations: Sampling |
| rnxSkel= | RINEX Observations: Skeleton extension |
| rnxScript= | RINEX Observations: Uplod script |
| rnxV3= | RINEX Observation: Version 3 |
| ephPath= | RINEX Ephemeris: Directory |
| ephIntr= | RINEX Ephemeris: Interval |
| outEphPort= | RINEX Ephemeris: Port |
| ephV3= | RINEX Ephemeris: Version 3 |
| corrPath= | Broadcast Corrections: Directory, ASCII |
| corrIntr= | Broadcast Corrections: Interval |
| corrPort= | Broadcast Corrections: Port |
| outPort= | Feed Engine: Port |
| waitTime= | Feed Engine: Wait for full obs epoch |
| binSampl= | Feed Engine: Sampling |
| outFile= | Feed Engine: File (full path) |
| outUPort= | Feed Engine: Port (unsynchronized) |
| serialMountPoint= | Serial Output: Mountpoint |
| serialPortName= | Serial Output: Port name |
| serialBaudRate= | Serial Output: Baud rate |
| serialFlowControl= | Serial Output: Flow control |
| serialDataBits= | Serial Output: Data bits |
| serialParity= | Serial Output: Parity |
| serialStopBits= | Serial Output: Stop bits |
| serialAutoNMEA= | Serial Output: NMEA |
| serialFileNMEA= | Serial Output: NMEA file name |
| serialHeightNMEA= | Serial Output: Height |
| obsRate= | Outages: Observation rate |
| adviseFail= | Outages: Failure threshold |
| adviseReco= | Outages: Recovery threshold |
| adviseScript= | Outages: Script (full path) |
| miscMount= | Miscellaneous: Mountpoint |
| perfIntr= | Miscellaneous: Log latency |
| scanRTCM= | Miscellaneous: Scan RTCM |
| pppSPP= | PPP Client: PPP/SPP |
| pppMount= | PPP Client: Observations Mountpoint |
| pppCorrMount= | PPP Client: Corrections Mountpoint |
| pppRefCrdX= | PPP Client: X coordinate of plot origin |
| pppRefCrdY= | PPP Client: Y coordinate of plot origin |
| pppRefCrdZ= | PPP Client: Z coordinate of plot origin |
| pppRefdN= | PPP Client: North eccentricity |
| pppRefdE= | PPP Client: East eccentricity |
| pppRefdU= | PPP Client: Up eccentricity |
| nmeaFile= | PPP Client: NMEA outputfile |
| nmeaPort= | PPP Client: NMEA IP output port |
| pppPlotCoordinates= | PPP Client: Plot NEU time series |
| postObsFile= | PPP Client: Observations file |
| postNavFile= | PPP Client: Navigation file |
| postCorrFile= | PPP Client: Corrections file |
| postOutFile= | PPP Client: Output file |
| pppAntenna= | PPP Client: Antenna name |
| pppAntex= | PPP Client: Path to ANTEX file |
| pppUsePhase= | PPP Client: Use phase data |
| pppEstTropo= | PPP Client: Estimate troposphere |
| pppGLONASS= | PPP Client: Use GLONASS |
| pppGalileo= | PPP Client: Use Galileo |
| pppSync= | PPP Client: Sync observations and corrections |
| pppAverage= | PPP Client: Lenght of time window for moving average |
| pppQuickStart= | PPP Client: Quick-Start period |
| pppMaxSolGap= | PPP Client: Maximal Solution Gap |
| pppSigmaCode= | PPP Client: Sigma for Code observations |
| pppSigmaPhase= | PPP Client: Sigma for Phase observations |
| pppSigmaCrd0= | PPP Client: Sigma for initial XYZ coordinate |
| pppSigmaCrdP= | PPP Client: White noise for XYZ |
| pppSigmaTrp0= | PPP Client: Sigma for initial tropospheric delay |
| pppSigmaTrpP= | PPP Client: White noise for tropospheric delay |
| pppAudioResponse= | PPP Client: Threshold for audio response |
| mapSpeed= | PPP Client: Offline processing speed for mapping |
| mapWinDotColor= | PPP Client: Color of dots and cross hair on map |
| mapWinDotSize= | PPP Client: Size of dots on map |
| useOsmMap= | PPP Client: Select Google maps or OSM |
| reqcAction= | Reqc: Action |
| reqcComment= | Reqc: Additional comments |
| reqcEndDateTime= | Reqc: Stop time |
| reqcNavFile= | Reqc: Navigation file |
| reqcNewAntennaName= | Reqc: New antenna |
| reqcNewMarkerName= | Reqc: New marker |
| reqcNewReceiverName= | Reqc: New receiver |
| reqcObsFile= | Reqc: Observations file |
| reqcOldAntennaName= | Reqc: Old antenna |
| reqcOldMarkerName= | Reqc: Old marker |
| reqcOldReceiverName= | Reqc: Old receiver |
| reqcOutLogFile= | Reqc: Output logfile |
| reqcPlotDir | Reqc: QC plots directory |
| reqcRnxVersion= | Reqc: RINEX version |
| reqcRunBy= | Reqc: Operators name |
| reqcSampling= | Reqc: RINEX sampling |
| reqcSkyPlotSystem= | Reqc: GNSS system specification |
| reqcStartDateTime= | Reqc: Start time |
| combineStreams= | Combination: List of correction streams |
| cmbMethod=Filter | Combination: Approach |
| cmbMaxres= | Combination: Clock outlier threshold |
| cmbSampl= | Combination: Orbit and clock sampling |
| uploadIntr= | Upload Corrections: File interval |
| uploadMountpointsOut= | Upload Corrections: Upload streams |
| uploadSamplClkRnx= | Upload Corrections: Clock sampling |
| uploadSamplSp3= | Upload Corrections: Orbit sampling |
| uploadSamplRtcmEphCorr= | Upload Corrections: Orbit sampling |
| trafo_dx= | Upload Corrections: Translation X |
| trafo_dy= | Upload Corrections: Translation Y |
| trafo_dz= | Upload Corrections: Translation Z |
| trafo_dxr= | Upload Corrections: Translation change X |
| trafo_dyr= | Upload Corrections: Translation change Y |
| trafo_dzr= | Upload Corrections: Translation change Z |
| trafo_ox= | Upload Corrections: Rotation X |
| trafo_oy= | Upload Corrections: Rotation Y |
| trafo_oz= | Upload Corrections: Rotation Z |
| trafo_oxr= | Upload Corrections: Rotation change X |
| trafo_oyr= | Upload Corrections: Rotation change Y |
| trafo_ozr= | Upload Corrections: Rotation change Z |
| trafo_sc= | Upload Corrections: Scale |
| trafo_scr= | Upload Corrections: Scale change |
| trafo_t0= | Upload Corrections: Reference year |
| uploadEphHost= | Upload Ephemeris: Host |
| uploadEphPort= | Upload Ephemeris: Port |
| uploadEphMountpoint= | Upload Ephemeris: Moutpoint |
| uploadEphPassword= | Upload Ephemeris: Password |
| uploadEphSample= | Upload Ephemeris: Sampling |
Note that the following configuration options saved on disk can be changed/edited on-the-fly while BNC is already processing data:
| Links | |
| NTRIP | http://igs.bkg.bund.de/ntrip/index |
| EUREF-IP NTRIP Broadcaster | http://www.euref-ip.net/home |
| IGS-IP NTRIP Broadcaster | http://www.igs-ip.net/home |
| IGS products NTRIP Broadcaster | http://products.igs-ip.net/home |
| IGS M-GEX NTRIP Broadcaster | http://mgex.igs-ip.net/home |
| IGS Central Bureau NTRIP Broadcaster | http://rt.igs.org |
| IGS Real-time Service | http://rts.igs.org |
| Distribution of IGS-IP streams | http://www.igs.oma.be/real_time/ |
| Completeness and latency of IGS-IP data | http://www.igs.oma.be/highrate/ |
| NTRIP Broadcaster overview | http://www.rtcm-ntrip.org/home |
| NTRIP Open Source software code | http://software.rtcm-ntrip.org |
| EUREF-IP Project | http://www.epncb.oma.be/euref_IP |
| Real-time IGS Pilot Project | http://www.rtigs.net/pilot |
| Radio Technical Commission for Maritime Services | http://www.rtcm.org |
| Publications | |
| Louis H. Estey and Charles M. Meertens | TEQC: The Multi-Purpose Toolkit for GPS/GLONASS Data, GPS Solutions, Vol. 3, No. 1, pp. 42-49, 1999. |
| Weber, G., D. Dettmering, H. Gebhard and R. Kalafus | Networked Transport of RTCM via Internet Protocol (Ntrip), IP-Streaming for Real-Time GNSS Applications, ION GNSS 2005. |
| Weber, G, L. Mervart, Z. Lukes, C. Rocken and J. Dousa | Real-time Clock and Orbit Corrections for Improved Point Positioning via NTRIP, ION GNSS 2007. |
| Mervart, L., Z. Lukes, C. Rocken and T. Iwabuchi | Precise Point Positioning With Ambiguity Resolution in Real-Time, ION GNSS 2008. |
| Weber, G. and L. Mervart | The BKG Ntrip Client (BNC), Report on EUREF Symposium 2007 in London, Mitteilungen des Bundesamtes fuer Kartographie und Geodaesie, Band 42, Frankfurt, 2009. |
| Weber, G. and L. Mervart | Real-time Combination of GNSS Orbit and Clock Correction Streams Using a Kalman Filter Approach, ION GNSS 2010. |
| Huisman, L., P. Teunissen and C. Hu | GNSS Precise Point Positioning in Regional Reference Frames Using Real-time Broadcast Corrections, Journal of Applied Geodesy, Vol. 6, pp15-23, 2012. |