BKG Ntrip State Space Server (BNS) Version 1.3

The BKG Ntrip State Space Server (BNS) is a program for transforming GNSS satellite clocks and orbits into corrections to Broadcast Ephemeris. These corrections are then encode in a (premature) RTCM Version 3.x format and uploaded to NTRIP broadcasters like http://www.euref-ip.net/home or http://www.igs-ip.net/home. BNS is created as a tool for service providers with real-time access to a network of continentally or globally distributed GNSS reference stations.

BNS has been developed for the Federal Agency for Cartography and Geodesy (BKG) within the framework of EUREF's Real-time GNSS Project (EUREF-IP, IP for Internet Protocol) and the Real-Time IGS Pilot Project (RTIGS PP).

BNS is released under the GNU General Public License (GPL). Binaries for BNS are available for Windows, 32-bit and 64-bit Linux (compiled under -m32 32-bit compatibility mode), Solaris, and Mac OS X systems. The MinGW compiler (Version 5.3.1) is used to produce the Windows binary. It is likely that BNS can be compiled on other systems where a GNU compiler and Qt Version 4.4.3 are available.

Before running, please ensure that you have installed the latest version available. This can be obtained from http://igs.bkg.bund.de/index_ntrip_down.htm. We are continuously working on the program and would appreciate any comments, suggestions, or bug reports. They can be emailed to [euref-ip@bkg.bund.de] or [igs-ip@bkg.bund.de].

Contents

1. Purpose
2. Functioning
3. Modes & Resources
4. Options
5. Limitations
6. Authors
7. Annex

1. Purpose

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 and 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.

In order to support applications following the state space approach, the purpose of BNS is to

2. Functioning

The procedures taken by BNS to generate clock and orbit corrections to Broadcast Ephemeris in radial, along-track and cross-track components are as follow:

Then, epoch by epoch:

Although it is not compulsory, because BNS puts a significant load on the communication link, it is recommended that BNS, the Broadcast Ephemeris server (i.e. BNC), and the server providing orbits and clocks (i.e. RTNet) are run on the same host.

3. Modes & Resources

Apart from its regular window mode, BNS can be run as a background job in a 'no window' mode using processing options from a previously saved configuration.

BNS requires access to the Internet with a minimum of about 1 kbits/sec per stream depending on the number of GNSS systems. You need to make sure that the connection can sustain the required bandwidth.

It requires the clock of the host computer to be properly synchronized.

4. Options

This section describes BNS's top menu bar, its processing options and its bottom menu bar.

The usual handling of BNS is that you first select severs for 'RINEX Ephemeris' and 'Clocks & Orbits'. You then select an NTRIP broadcaster for stream upload ('Broadcast Corrections') before you start the program ('Start'). Records of BNS's activities are shown in the 'Logs' canvas in the middle of the main window.

As a default, configuration files for running BNS on Unix/Linux/Mac 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 'BNS.ini'.

The default file name 'BNS.ini' 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 BNS. See annexed 'Configuration Example' for a complete set of configuration options.

4.1. Top Menu Bar
4.1.1 File
4.1.2 Help
4.2. Proxy
4.3. General
      4.3.1. Logfile
      4.3.2. Append Files
      4.3.3. Auto Start
4.4. RINEX Ephemeris
      4.4.1. Host & Port
      4.4.2. Save
4.5. Clocks & Orbits
      4.5.1. Listening Port
      4.5.2. Save
4.6. Broadcast Corrections
      4.6.1. Host & Port
      4.6.2. Mountpoint & Password
      4.6.3. System
      4.6.4. Save
      4.6.5. Center of Mass
4.7. Broadcast Ephemeris
      4.7.1. Host & Port
      4.7.2. Mountpoint & Password
      4.7.3. Sampling
4.8. RINEX Clocks
      4.8.1. Directory
      4.8.2. Interval & Sampling
4.9. SP3 Orbits
      4.9.1. Directory
      4.9.2. Interval & Sampling
4.10. Bottom Menu Bar
4.10.1 Start
4.10.2 Stop
4.11. Command Line Options
4.11.1 No Window
4.11.2 Configuration File

4.1. Top Menu Bar

The top menu bar allows to select a font for the BNS windows, save configured options or quit the program execution. It also provides access to a program documentation.

4.1.1 File

The 'File' button lets you

4.1.2 Help

The 'Help' button provides access to

BNS 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 will appear immediately; it disappears as soon as the focus is shifted to something else. The dialogs on some operating systems may provide a "?" button that users can click; they then click the relevant widget to pop up the help text.

4.2. Proxy - for usage in a protected LAN

If you are running BNS 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 BNS. If you don't know the address 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 Casters. If these are not possible, you might need to run BNS outside your LAN on a host that has unobstructed connection to the Internet.

4.3. General Options

The following describes general settings for BNC's logfile, file handling and auto-start.

4.3.1 Logfile - optional

Records of BNS's activities are shown in the Log section on the bottom of the main window. These logs can be saved into a file when a valid path is specified in the 'Log (full path)' field. The message log covers the communication status between BNS 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 'Log (full path)' is an empty option field, meaning that BNS logs will not saved into a file.

4.3.2 Append Files

When BNS 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 BNS, a system crash or when BNS had 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 BNS.

4.3.3 Auto Start - optional

You may like to auto-start BNS at startup time in window mode with preassigned configuration options. This may be required i.e. immediately after booting your system. Tick 'Autostart' to supersede the usage of the 'Start' button. Make sure that you maintain a link to BNS for that in your Autostart directory (Windows systems) or call BNS in a script below directory /etc/init.d (Unix/Linux/Mac systems).

4.4. RINEX Ephemeris

BNS requires GNSS Broadcast Ephemeris in RINEX Version 3 Navigation file format from an IP address and port. This information can be provided in real-time by the 'BKG Ntrip Client' (BNC) program. Note that whenever a new set of Broadcast Ephemeris becomes available, BNS needs it immediately.

The following is an example log of Broadcast Ephemeris records in RINEX Version 3 Navigation file format for satellite GPS PRN32 and GLONASS PRN04:

G32 2008 07 22 12 00 00  3.08818183839e-04  2.72848410532e-12  0.00000000000e+00
     1.10000000000e+01 -4.00312500000e+01  4.63269297026e-09  9.74027926504e-01
    -2.19419598579e-06  1.39143558918e-02  8.25151801109e-06  5.15381674576e+03
     2.16000000000e+05 -8.56816768646e-08 -3.26801342873e-02 -2.94297933578e-07
     9.68688494953e-01  2.30468750000e+02 -1.30607654294e+00 -8.26105839196e-09
    -3.62872257943e-10  1.00000000000e+00  1.48900000000e+03  0.00000000000e+00
     2.00000000000e+00  0.00000000000e+00 -2.79396772385e-09  1.10000000000e+01
     0.00000000000e+00  0.00000000000e+00
R04 2008 07 22 08 15 14  4.76110726595e-05  0.00000000000e+00  2.88600000000e+04
    -1.76267827148e+04 -4.64202880859e-01  1.86264514923e-09  0.00000000000e+00
    -1.79631489258e+04 -3.41343879700e-01 -2.79396772385e-09  6.00000000000e+00
    -4.20270556641e+03  3.50097942352e+00  0.00000000000e+00  0.00000000000e+00

4.4.1 Host & Port - mandatory

Enter the IP address and port number of a Broadcast Ephemeris server like BNC to establish a persistent socket connection, see section 'Flow Chart' under 'Help' for socket communication details. If BNS runs on the same host as BNC, 127.0.0.1 should be used as the server's IP address. Make sure that this server is up and running before you start BNS.

4.4.2 Save - optional

Specify the full path to a file where received Broadcast Ephemeris will be logged. Beware that the size of this file can rapidly increase. Default is an empty option field meaning that logging is disabled.

4.5. Clocks & Orbits

BNS requires GNSS clocks and orbits in the IGS Earth-Centered-Earth-Fixed (ECEF) reference system in a SP3-like format referred to CoM and not containing the conventional periodic relativistic effect. They can be provided by a real-time GNSS engine such as RTNet. The sampling rate should not be much greater than 10 sec. Note that otherwise in IP streaming involved tools on the NTRIP Broadcaster or client side may respond with a timeout.

Below you find an example of precise clocks and orbits coming in a SP3-like format from a real-time GNSS engine. Each epoch starts with an asterisk character followed by the time as year, month, day of month, hour, minute and second. Subsequent records provide the following set of parameters for each satellite:

Example:

*  2009 12  7 13 11  30.00000000
PG02  22354.452213 -13767.325289   1772.434231    228.750524     -0.001932  -0.522   0.321  -0.041   0.000   0.000  60.0  22377.342363 -13753.550786   1583.545731
PG03 -11102.768914  16968.159551  16622.454893    518.437937      0.001957   1.012  -1.908  -1.508   0.000   0.000  60.0 -11129.949019  16837.402637  16736.552194
PG04  24167.186374  -3628.894484 -11005.210034     19.658309     -0.001319  -2.103   0.034   0.921   0.000   0.000  60.0  24101.853298  -3576.088512 -11164.914026
PG05  14447.045279  -8140.619149  20744.274083     -7.120008     -0.004342  -0.381   0.215  -0.547   0.000   0.000  60.0  14578.754091  -8053.151311  20686.754446
...
...

4.5.1 Listening Port - mandatory

BNS is listening at an IP port for incoming GNSS clocks and orbits in a SP3-like format. Enter the respective IP port number to setup a server socket for incoming data, see section 'Flow Chart' under 'Help' for socket communication details. Make sure that the software providing clocks and orbits is up and running before you start BNS.

4.5.2 Save - optional

Specify the full path to a file where received clocks and orbits from a real-time engine will be logged. Beware that the size of this file can rapidly increase. Default is an empty option field meaning that logging is disabled.

4.6. Broadcast Corrections

BNS can upload the resulting stream(s) of clock and orbit corrections to Broadcast Ephemeris to an NTRIP Broadcaster. Both EUREF and IGS operate an NTRIP broadcaster at http://www.euref-ip.net/home and http://www.igs-ip.net/home which can be used for stream upload. The stream's format is RTCM Version 3.x.

BNS allows to configure two Broadcast Corrections streams refering do different reference systems for upload to different NTRIP broadcasters. You may use this functionality for parallel support of a backup NTRIP broadcaster or for simultaneous support of two reference systems.

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.

4.6.1 Host & Port - optional

Specify the 'Host' IP name or number of an NTRIP Broadcaster to upload the stream. An empty option field means that you don't want to upload corrections to Broadcast Ephemeris.

Enter the NTRIP Caster's IP 'Port' number for stream upload. Note that NTRIP Casters are often configured to provide access on more than one port, usually port 80 and 2101. If you experience communication problems on port 80, you should try to use the alternative port(s).

4.6.2 Mountpoint & Password - mandatory if 'Host' is set

Each stream on an NTRIP Caster is defined using a unique source ID called mountpoint. An NTRIP Server like BNS uploads a stream to the Caster by referring to a dedicated mountpoint that has been set by the Caster 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.

In NTRIP Version 1.0 stream upload may be protected through an upload 'Password'. Enter the password you received from the Caster operator along with the mountpoint(s).

4.6.3 System - mandatory if 'Host' is set

BNS refers its clock and orbit corrections to a specific reference system. Available options are

IGS05: As the clocks and orbits coming from real-time GNSS engine are expected to be in the IGS05 system, no transformation is carried out if this option is selected.

ETRF2000: The formulars for the transformation 'ITRF2005->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-V7.pdf. The following 14 Helmert Transformation Parameters were introduced:

Translation in X at epoch To:  0.0541 m
Translation in Y at epoch To:  0.0502 m
Translation in Z at epoch To: -0.0538 m
Translation rate in X: -0.0002 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 : 0.00000000040
Scale rate: 0.00000000008 /y
To: 2000.0

NAD83: Formulars for the transformation 'ITRF2005->NAD83' are taken from 'Chris Pearson, Robert McCaffrey, Julie L. Elliott, Richard Snay 2010: HTDP 3.0: Software for Coping with the Coordinate Changes Associated with Crustal Motion, Journal of Surveying Engineering'.

Translation in X at epoch To:  0.9963 m
Translation in Y at epoch To: -1.9024 m
Translation in Z at epoch To: -0.5219 m
Translation rate in X:  0.0005 m/y
Translation rate in Y: -0.0006 m/y
Translation rate in Z: -0.0013 m/y
Rotation in X at epoch To: 25.915 mas
Rotation in Y at epoch To:  9.426 mas
Rotation in Z at epoch To: 11.599 mas
Rotation rate in X:  0.067 mas/y 
Rotation rate in Y: -0.757 mas/y
Rotation rate in Z: -0.051 mas/y
Scale at epoch To : 0.00000000078
Scale rate: -0.00000000010 /y
To: 1997.0

GDA94: The formulars for the transformation 'ITRF2000->GDA94' are taken from 'John Dawson, Alex Woods 2010: ITRF to GDA94 coordinate transformations', Journal of Applied Geodesy, 4 (2010), 189199, de Gruyter 2010. DOI 10.1515/JAG.2010.019'.

Translation in X at epoch To: -0.07973 m
Translation in Y at epoch To: -0.00686 m
Translation in Z at epoch To:  0.03803 m
Translation rate in X:  0.00225 m/y
Translation rate in Y: -0.00062 m/y
Translation rate in Z: -0.00056 m/y
Rotation in X at epoch To:  0.0351 mas
Rotation in Y at epoch To: -2.1211 mas
Rotation in Z at epoch To: -2.1411 mas
Rotation rate in X: -1.4707 mas/y 
Rotation rate in Y: -1.1443 mas/y
Rotation rate in Z: -1.1701 mas/y
Scale at epoch To : 0.000000006636
Scale rate: 0.000000000294 /y
To: 1994.0

SIRGAS2000: The formulars for the transformation 'ITRF2005->SIRGAS2000' were provided via personal communication from CGED-Coordenacao de Geodesia, IBGE/DGC - Diretoria de Geociencias, Brazil..

Translation in X at epoch To: -0.0051 m
Translation in Y at epoch To: -0.0065 m
Translation in Z at epoch To: -0.0099 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:  0.150 mas
Rotation in Y at epoch To:  0.020 mas
Rotation in Z at epoch To:  0.021 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 : 0.000000000000
Scale rate: -0.000000000000 /y
To: 2000.0

SIRGAS95: The formulars 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

Custom: The default numbers shown as examples are those for a transformation from ITRF2005 to ETRF2000'.

4.6.4 Save - optional

The clock and orbit corrections streamed by BNS to the NTRIP Caster can be logged locally. Specify a full 'Save stream' path here to save this information to a local file. Default value for 'Save stream' is an empty option field, meaning that logging is disabled.

The file is in plain ASCII format comprising records containing the following set of parameters:

The following is an example file contents based on combined orbit and clock corrections for GPS and GLONASS carried in RTCM Version 3.x message Type 1060 and 1066:

1489 325606.0 G31    18     -1.021      0.110   -1.308   -0.120
1489 412006.0 R10    18      7.342      1.393    4.858   -2.634
1489 412006.0 R19    18      4.696      2.358    1.707   -2.907
...
1489 325607.0 G30    80      6.022      0.591   -0.318    0.022
1489 325607.0 G31    18     -1.022      0.110   -1.308   -0.120
1489 412007.0 R10    18      7.341      1.390    4.860   -2.636
1489 412007.0 R19    18      4.698      2.356    1.706   -2.906
...

4.6.5 Center of Mass - optional

BNS allows to either refer orbit/clock 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.

4.7. Broadcast Ephemeris

BNS can upload a stream carrying Broadcast Ephemeris in RTCM Version 3 format to an NTRIP Caster.

4.7.1 Host & Port - optional

Specify the 'Host' IP name or number 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 Caster's IP 'Port' number for stream upload. Note that NTRIP Casters are often configured to provide access on more than one port, usually port 80 and 2101. If you experience communication problems on port 80, you should try to use the alternative port(s).

4.7.2 Mountpoint & Password - mandatory if 'Host' is set

Each stream on an NTRIP Caster is defined using a unique source ID called mountpoint. An NTRIP Server like BNS uploads a stream to the Caster by referring to a dedicated mountpoint that has been set by the Caster 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.

4.7.3 Sampling - mandatory if 'Host' is set

Select the Broadcast Ephemeris sampling interval in seconds. Defaut is '5' meaning that a complete set of Broadcast Ephemeris is uploaded every 5 seconds.

4.8. RINEX Clocks

The clock corrections generated by BNS can be logged separately in Clock RINEX format. The file naming follows the RINEX convention.

Note that clocks in the Clock RINEX files are not corrected for the conventional periodic relativistic effect.

4.8.1 Directory - optional

Here you can specify the path to where the Clock RINEX files will be stored. If the specified directory does not exist, BNS will not create Clock RINEX files. Default value for 'Directory' is an empty option field, meaning that logging of Clock RINEX files is disabled.

4.8.2 Interval & Sampling - mandatory if 'Directory' is set

Select the length of the Clock RINEX file generated. The default value is 1 day.

Select the Clock RINEX sampling interval in seconds. A value of zero '0' tells BNS to store all received epochs into Clock RINEX. This is the default value.

4.9. SP3 Orbits

The orbit corrections generated by BNS can be logged separately in SP3 Orbit files. The file naming follows the IGS convention.

Note that clocks in the SP3 Orbit files are not corrected for the conventional periodic relativistic effect.

4.9.1 Directory - optional

Here you can specify the path to where the SP3 Orbit files will be stored. If the specified directory does not exist, BNS will not create SP3 Orbit files. Default value for 'Directory' is an empty option field, meaning that logging of SP3 Orbit files is disabled.

4.9.2 Interval & Sampling - mandatory if 'Directory' is set

Select the length of the SP3 Orbit file generated. The default value is 1 day.

Select the SP3 Orbit file sampling interval in seconds. A value of zero '0' tells BNS to store all received epochs into SP3 Orbit files. This is the default value.

4.10. Bottom Menu Bar

The bottom menu bar allows to start or stop the execution of BNS and provides access to BNC's online help funtion.

4.10.1 Start

Hit 'Start' to start receiving IGS orbits and clocks and convert them into corrections to Broadcast Ephemeris. Note that when started, BNS by default will begin with new files which might overwrite existing files when necessary unless the option 'Append files' is ticked.

4.10.2 Stop

Hit the 'Stop' button in order to stop BNS.

4.11. Command Line Options

Command line options are available to run BNS in 'no window' mode or let it read a specific 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 'BNS.ini'.

4.11.1 No Window - optional

Apart from its regular windows mode, BNS can be started on all systems as a background job with command line option '-nw'. BNS will then run in 'no window' mode, using processing options from its configuration file on disk. Terminate BNS using Windows Task Manager when running it in 'no window' mode on Windows systems.

Example:

bns.exe -nw

4.11.2 Configuration File - optional

The default configuration file name is 'BNS.ini'. You may change this name at startup time using the command line option '--conf <confFileName>'. This allows to run several BNS jobs in parallel on the same host using different sets of configuration options. confFileName stands either for the full path to a configuration file or just for a file name. If you introduce only a filename, the corresponding file will be saved in the current working directory from where BNS is started.

Example:

./bns --conf MyConfig.ini

This leads to a BNS job using configuration file 'MyConfig.ini'. The configuration file will be saved in the current working directory.

5. Limitations

6. Authors

The BKG Ntrip State Space Server (BNS) Qt Graphic User Interface (GUI) has been developed for the Federal Agency for Cartography and Geodesy (BKG) by Leos Mervart, Czech Technical University Prague, Department of Geodesy. BNS includes a GNU GPL open source RTCM 3.x encoder, written for BKG by Dirk Stoecker, Alberding GmbH, Schoenefeld.

Georg Weber
Federal Agency for Cartography and Geodesy (BKG)
Frankfurt, Germany
[euref-ip@bkg.bund.de] or [igs-ip@bkg.bund.de]

7. Annex

7.1. Revision History
7.2. RTCM
      7.2.1 RTCM NTRIP
      7.2.2 RTCM Version 3.x
7.3. Configuration Example
7.4. Links

7.1 Revision History

Dec 2008  Version 1.0   [Add] Source code and binaries published.
Jun 2010  Version 1.1   [Add] Upgrade to Qt Version 4.4.3
[Add] Enable/disable tab widgets
[Add] User defined configuration file name
[mod] Switch to configuration files in ini-Format
[Add] Auto start
[Add] Drag and drop ini files
[Add] Optional reference to Center of Mass
[Mod] Update following RTCM 091-2009-SC104-542 document
[Add] NAD, GDA, SIRGAS transformations
[Mod] Update of SSR messages following draft dated 2010-04-12
Oct 2010  Version 1.2   [Bug] GLONASS ephemeris time
[Bug] Complete acceleration term in GLONASS ephemeris calculation
Jan 2011  Version 1.3   [Add] Plausibility check for incoming broadcast ephemeris
[Bug] Added Mutext in slotMessage to avoid freezing
[Mod] Use always the latest received set of broadcast ephemeris
[Mod] Socket communication for stream upload to caster
[Mod] Use old ephemeris if new one is too recenty
[Mod] Transformation parameters for GDA94 updated

7.2. RTCM

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.

7.2.1 NTRIP

'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 1.0 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. 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.

NTRIP is an open none-proprietary protocol. Major characteristics of NTRIP's dissemination technique are:

The NTRIP Version 2 transport protocol is not implemented in BNS.

7.2.2 RTCM Version 3.x

RTCM Version 3.x has been developed as a better alternative to RTCM Version 2.x. Service providers and vendors have asked for a standard that would be efficient, easy to use, and easily adaptable to new situations.

RTCM is in the process of developing new Version 3 message types to carry satellite clock and orbit corrections in real-time. Based on the latest available proposal, the following premature messages currently under discussion of relevance to BNS are listed here:

RTCM Version 3.x streams carrying these messages may be used for example to support real-time Precise Point Positioning (PPP) applications using the 'state space' approach.

7.3. Configuration Example

The following table's left column is an example for the contents of a configuration file 'BNS.ini'. It enables the upload of streams CLCK1 and CLCK2 to www.igs-ip.net. Clock RINEX files and SP3 Orbit files are saved to a directory /home/weber/rinex :

OptionAffiliation
[General]Settings: Group
proxyHost=Proxy: Host
proxyPort=Proxy: Port
logFile=/home/weber/rinex/bns.logGeneral: Logfile (full path)
fileAppend=0General: Append files
autoStart=0General: Auto start
ephHost=clock-ip.bkg.bund.deRINEX Ephemeris: Host
ephPort=6000RINEX Ephemeris: Port
ephEcho=/home/weber/rinex/eph.rnxRINEX Ephemeris: Save (full path)
clkPort=7000Clocks & Orbits: Listening port
inpEcho=/home/weber/rinex/ClocksOrbits.datClocks & Orbits: Save (full path)
outHost1=www.igs-ip.netBroadcast Corrections I: Host
outPort1=2101Broadcast Corrections I: Port
mountpoint_1=CLCK1Broadcast Corrections I: Mountpoint
password1=pwBroadcast Corrections I: Password
refSys_1=IGS05Broadcast Corrections I: System
outFile_1=/home/weber/rinex/CLCK1Broadcast Corrections I: Save (full path)
CoM_1=2Broadcast Corrections I: Center of Mass
outHost2=www.igs-.netBroadcast Corrections II: Host
outPort2=2101Broadcast Corrections II: Port
mountpoint_2=CLCK2Broadcast Corrections II: Mountpoint
password2=pwBroadcast Corrections II: Password
refSys_2=ETRF2000Broadcast Corrections II: System
outFile_2=/home/weber/rinex/CLCK2Broadcast Corrections II: Save (full path)
CoM_2=0Broadcast Corrections II: Center of Mass
outHost3=www.igs-.netBroadcast Corrections III: Host
outPort3=2101Broadcast Corrections III: Port
mountpoint_3=CLCK3Broadcast Corrections III: Mountpoint
password3=pwBroadcast Corrections III: Password
refSys_3=ETRF2000Broadcast Corrections III: System
outFile_3=/home/weber/rinex/CLCK3Broadcast Corrections III: Save (full path)
CoM_3=0Broadcast Corrections III: Center of Mass
outHost4=www.igs-.netBroadcast Corrections IV: Host
outPort4=2101Broadcast Corrections IV: Port
mountpoint_4=CLCK4Broadcast Corrections IV: Mountpoint
password4=pwBroadcast Corrections IV: Password
refSys_4=ETRF2000Broadcast Corrections IV: System
outFile_4=/home/weber/rinex/CLCK4Broadcast Corrections IV: Save (full path)
CoM_4=0Broadcast Corrections IV: Center of Mass
outHost5=www.igs-.netBroadcast Corrections V: Host
outPort5=2101Broadcast Corrections V: Port
mountpoint_5=CLCK5Broadcast Corrections V: Mountpoint
password5=pwBroadcast Corrections V: Password
refSys_5=ETRF2000Broadcast Corrections V: System
outFile_5=/home/weber/rinex/CLCK5Broadcast Corrections V: Save (full path)
CoM_5=0Broadcast Corrections V: Center of Mass
outHost6=www.igs-.netBroadcast Corrections VI: Host
outPort6=2101Broadcast Corrections VI: Port
mountpoint_6=CLCK6Broadcast Corrections VI: Mountpoint
password6=pwBroadcast Corrections VI: Password
refSys_6=ETRF2000Broadcast Corrections VI: System
outFile_6=/home/weber/rinex/CLCK6Broadcast Corrections VI: Save (full path)
CoM_6=0Broadcast Corrections VI: Center of Mass
outHostEph=www.igs-ip.netBroadcast Ephemeris: Host
outPortEph=2101Broadcast Ephemeris: Port
mountpoint_Eph=BRDC0Broadcast Ephemeris: Mountpoint
passwordEph=passBroadcast Ephemeris: Password
samplEph=5Broadcast Ephemeris: Sampling
trafo_dx=0.0541Broadcast Corrections: System > Custom
trafo_dy=0.0502Broadcast Corrections: System > Custom
trafo_dz=-0.0538Broadcast Corrections: System > Custom
trafo_dxr=-0.0002Broadcast Corrections: System > Custom
trafo_dyr=0.0001Broadcast Corrections: System > Custom
trafo_dzr=-0.0018Broadcast Corrections: System > Custom
trafo_ox=0.000891Broadcast Corrections: System > Custom
trafo_oy=0.005390Broadcast Corrections: System > Custom
trafo_oz=-0.008712Broadcast Corrections: System > Custom
trafo_oxr=0.000081Broadcast Corrections: System > Custom
trafo_oyr=0.000490Broadcast Corrections: System > Custom
trafo_ozr=-0.000792Broadcast Corrections: System > Custom
trafo_sc=0.40Broadcast Corrections: System > Custom
trafo_scr=0.08Broadcast Corrections: System > Custom
trafo_t0=2000.0Broadcast Corrections: System > Custom
rnxPath=/home/weber/rinexRINEX Clocks: Directory
rnxIntr=1 dayRINEX Clocks: Interval
rnxSampl=30RINEX Clocks: Sampling
sp3Path=/home/weber/rinexSP3 Orbits: Directory
sp3Intr=1 daySP3 Orbits: Interval
sp3Sampl=300SP3 Orbits: Sampling
startTab=0Internal memory: Top tab
font="Helvetica [Adobe],8,-1,5,75,0,0,0,0,0"Internal memory: Used font

7.4 Links

NTRIP  http://igs.bkg.bund.de/index_ntrip.htm
EUREF-IP NTRIP broadcaster  http://www.euref-ip.net/home
IGS-IP NTRIP broadcaster  http://www.igs-ip.net/home
NTRIP broadcaster overview  http://www.rtcm-ntrip.org/home
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