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1<h3>BKG Ntrip Client (BNC) Version 1.7</h3>
2
3<p>
4The BKG Ntrip Client (BNC) is a program for simultaneously retrieving, decoding and converting real-time GNSS data streams from NTRIP broadcasters like <u>http://www.euref-ip.net/home</u> or <u>http://www.igs-ip.net/home</u>.
5</p>
6
7<p>
8BNC 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).
9</p>
10
11<p>
12BNC has been written under GNU General Public License (GPL). Binaries for BNC are available for Windows, 32-bit Linux, 64-bit Linux (compiled under -m32 32-bit compatibility mode), Solaris, and Mac systems. We used the MinGW Version 5.3.1 compiler to create the Windows binary. It is likely that BNC can be compiled on other systems where a GNU compiler and Qt Version 4.5.2 are installed.
13</p>
14
15<p>
16Please ensure that you have installed the latest version of BNC available from <u>http://igs.bkg.bund.de/index_ntrip_down.htm</u>. We are continuously working on the program and would appreciate if you could send any comments, suggestions, or bug reports to [euref-ip@bkg.bund.de] or [igs-ip@bkg.bund.de].
17</p>
18
19<h3>Contents</h3>
20<p>
21<h4>
22<a href=#purpose>1. Purpose</a><br>
23<a href=#resources>2. Modes & Resources</a><br>
24<a href=#options>3. Options</a><br>
25<a href=#limits>4. Limitations</a><br>
26<a href=#authors>5. Authors</a><br>
27<a href=#annex>8. Annex</a><br>
28</h4>
29</p>
30
31<p><a name="purpose"><h3>1. Purpose</h3></p>
32
33<p> The purpose of BNC is to
34
35<ul>
36<li>retrieve real-time GNSS data streams available through NTRIP transport protocol,</li>
37<li>retrieve real-time GNSS data streams via TCP directly from an IP address without using the NTRIP transport protocol, and/or</li>
38<li>retrieve real-time GNSS data streams from a serial port without using the NTRIP transport protocol, and/or</li>
39<li>generate high-rate RINEX Observation and Navigation files to support near real-time GNSS post-processing applications, and/or</li>
40<li>generate ephemeris and synchronized or unsynchronized observations epoch by epoch through an IP port to support real-time GNSS network engines, and/or</li>
41<li>generate clock and orbit corrections to broadcast ephemeris through an IP port to support real-time Precise Point Positioning on GNSS rovers, and/or</li>
42<li>generate synchronized clock and orbit corrections to broadcast ephemeris epoch by epoch through an IP port to support the combination of such streams as coming simultaneously from various correction providers, and/or</li>
43<li>monitor the performance of a network of real-time GNSS data streams to generate advisory notes, and/or</li>
44<li>scan RTCM streams for incoming antenna information as well as message types and their repetition rates, and/or</li>
45<li>feed a stream into a GNSS receiver via serial communication link.</li>
46</ul>
47</p>
48<p>
49BNC supports decoding the following GNSS data formats:
50</p>
51<p>
52<ul>
53<li>RTCM Version 2.x containing message types 18 and 19 or 20 and 21 together with 3 and 22 (GPS and GLONASS), </li>
54<li>RTCM Version 3.x containing message types 1002 (GPS, SBAS) or 1004 (GPS), 1010 or 1012 (GLONASS), 1019 or 1020 (broadcast ephemeris), 1057-1068 (premature State Space Representation messages for GPS and GLONASS)</li>
55<li>RTIGS containing GPS record types 200 (observations) and 300 (ephemeris).</li>
56</ul>
57BNC allows to by-pass its decoding and conversion algorithms, leave whatever is received untouched and save it in files.
58</p>
59<p><a name="resources"><h3>2. Modes & Resources</h3></p>
60<p>
61Although BNC is a real-time tool to be operated in online mode, it can be run offline for post processing of data made availabe from a file. Furthermore, apart from its regular window mode, BNC can be run as a batch/background job in a 'no window' mode using processing options from previously saved configuration.
62</p>
63<p>
64Unless in offline mode, BNC
65</p>
66<ul>
67<li>requires access to the Internet with a minimum of about 2 to 6 kbits/sec per stream depending on the stream format and the number of visible satellites. You need to make sure that the connection can sustain the required bandwidth.</li>
68<li>requires the clock of the host computer to be properly synchronized.</li>
69<li>has the capacity to retrieve hundreds of GNSS data streams simultaneously. Please be aware that such usage may incur a heavy load on the NTRIP broadcaster side depending on the number of streams requested. We recommend limiting the number of streams where possible to avoid unnecessary workload.</li>
70</ul>
71</p>
72
73<p><a name="options"><h3>3. Options</h3></p>
74<p>
75This section describes BNC's top menu bar, its processing options and bottom menu bar.
76</p>
77<p>
78The 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 tabs to select a combination of processing options before you start the program ('Start'). Records of BNC's activities are shown in the 'Logs' canvas on the bottom of the main window.
79</p>
80<p>
81As a default, configuration files for running BNC 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 'BNC.ini'.</p>
82<p>
83The default file name 'BNC.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 BNC. Some configuration options can be changed on-the-fly. See annexed 'Configuration Example' for a complete set of configuration options.
84</p>
85<p>
863.1. <a href=#topmenu>Top Menu Bar</a><br>
873.1.1 <a href=#file>File</a><br>
883.1.2 <a href=#help>Help</a><br>
893.2. <a href=#proxy>Proxy</a><br>
903.3. <a href=#general>General</a><br>
91&nbsp; &nbsp; &nbsp; 3.3.1. <a href=#genlog>Logfile</a><br>
92&nbsp; &nbsp; &nbsp; 3.3.2. <a href=#genapp>Append Files</a><br>
93&nbsp; &nbsp; &nbsp; 3.3.3. <a href=#genconf>Reread Configuration</a><br>
94&nbsp; &nbsp; &nbsp; 3.3.4. <a href=#genstart>Auto Start</a><br>
953.4. <a href=#rinex>RINEX Observations</a><br>
96&nbsp; &nbsp; &nbsp; 3.4.1. <a href=#rnxname>File Names</a><br>
97&nbsp; &nbsp; &nbsp; 3.4.2. <a href=#rnxdir>Directory</a><br>
98&nbsp; &nbsp; &nbsp; 3.4.3. <a href=#rnxinterval>File Interval</a><br>
99&nbsp; &nbsp; &nbsp; 3.4.4. <a href=#rnxsample>Sampling</a><br>
100&nbsp; &nbsp; &nbsp; 3.4.5. <a href=#rnxskl>Skeleton Extension</a><br>
101&nbsp; &nbsp; &nbsp; 3.4.6. <a href=#rnxscript>Script</a><br>
102&nbsp; &nbsp; &nbsp; 3.4.7. <a href=#rnxvers>Version</a><br>
1033.5. <a href=#ephemeris>RINEX Ephemeris</a><br>
104&nbsp; &nbsp; &nbsp; 3.5.1. <a href=#ephdir>Directory</a><br>
105&nbsp; &nbsp; &nbsp; 3.5.2. <a href=#ephint>Interval</a><br>
106&nbsp; &nbsp; &nbsp; 3.5.3. <a href=#ephport>Port</a><br>
107&nbsp; &nbsp; &nbsp; 3.5.4. <a href=#ephvers>Version</a><br>
1083.6. <a href=#correct>Broadcast Corrections</a><br>
109&nbsp; &nbsp; &nbsp; 3.6.1. <a href=#corrdir>Directory</a><br>
110&nbsp; &nbsp; &nbsp; 3.6.2. <a href=#corrint>Interval</a><br>
111&nbsp; &nbsp; &nbsp; 3.6.3. <a href=#corrport>Port</a><br>
112&nbsp; &nbsp; &nbsp; 3.6.4. <a href=#corrwait>Wait for Full Epoch</a><br>
1133.7. <a href=#syncout>Feed Engine</a><br>
114&nbsp; &nbsp; &nbsp; 3.7.1. <a href=#syncport>Port</a><br>
115&nbsp; &nbsp; &nbsp; 3.7.2. <a href=#syncwait>Wait for Full Epoch</a><br>
116&nbsp; &nbsp; &nbsp; 3.7.3. <a href=#syncsample>Sampling</a><br>
117&nbsp; &nbsp; &nbsp; 3.7.4. <a href=#syncfile>File</a><br>
118&nbsp; &nbsp; &nbsp; 3.7.5. <a href=#syncuport>Port (unsynchronized)</a><br>
1193.8. <a href=#serial>Serial Output</a><br>
120&nbsp; &nbsp; &nbsp; 3.8.1. <a href=#sermount>Mountpoint</a><br>
121&nbsp; &nbsp; &nbsp; 3.8.2. <a href=#serport>Port Name</a><br>
122&nbsp; &nbsp; &nbsp; 3.8.3. <a href=#serbaud>Baud Rate</a><br>
123&nbsp; &nbsp; &nbsp; 3.8.4. <a href=#serflow>Flow Control</a><br>
124&nbsp; &nbsp; &nbsp; 3.8.5. <a href=#serparity>Parity</a><br>
125&nbsp; &nbsp; &nbsp; 3.8.6. <a href=#serdata>Data Bits</a><br>
126&nbsp; &nbsp; &nbsp; 3.8.7. <a href=#serstop>Stop Bits</a><br>
127&nbsp; &nbsp; &nbsp; 3.8.8. <a href=#serauto>NMEA</a><br>
128&nbsp; &nbsp; &nbsp; 3.8.9. <a href=#serfile>File</a><br>
129&nbsp; &nbsp; &nbsp; 3.8.10. <a href=#serheight>Height</a><br>
1303.9. <a href=#advnote>Outages</a><br>
131&nbsp; &nbsp; &nbsp; 3.9.1. <a href=#obsrate>Observation Rate</a><br>
132&nbsp; &nbsp; &nbsp; 3.9.2. <a href=#advfail>Failure Threshold</a><br>
133&nbsp; &nbsp; &nbsp; 3.9.3. <a href=#advreco>Recovery Threshold</a><br>
134&nbsp; &nbsp; &nbsp; 3.9.4. <a href=#advscript>Script</a><br>
1353.10. <a href=#misc>Miscellaneous</a><br>
136&nbsp; &nbsp; &nbsp; 3.10.1. <a href=#miscmount>Mountpoint</a><br>
137&nbsp; &nbsp; &nbsp; 3.10.2. <a href=#miscperf>Log Latency</a><br>
138&nbsp; &nbsp; &nbsp; 3.10.3. <a href=#miscscan>Scan RTCM</a><br>
1393.11. <a href=#streams>Streams</a><br>
140&nbsp; &nbsp; &nbsp; 3.11.1 <a href=#streamedit>Edit Streams</a><br>
141&nbsp; &nbsp; &nbsp; 3.11.2 <a href=#streamdelete>Delete Stream</a><br>
142&nbsp; &nbsp; &nbsp; 3.11.3 <a href=#streamconf>Reconfigure Streams On-the-fly</a><br>
1433.12. <a href=#bottom>Bottom Menu Bar</a><br>
144&nbsp; &nbsp; &nbsp; 3.12.1. <a href=#streamadd>Add Stream - Coming from Caster</a><br>
145&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 3.12.1.1 <a href=#streamhost>Caster Host and Port</a><br>
146&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 3.12.1.2 <a href=#streamtable>Casters Table</a><br>
147&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 3.12.1.3 <a href=#streamuser>User and Password</a><br>
148&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 3.12.1.4 <a href=#gettable>Get Table</a><br>
149&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 3.12.1.5 <a href=#ntripv>NTRIP Version</a><br>
150&nbsp; &nbsp; &nbsp; 3.12.2 <a href=#streamip>Add Stream - Coming from TCP/IP Port</a><br>
151&nbsp; &nbsp; &nbsp; 3.12.3 <a href=#streamudp>Add Stream - Coming from UDP Port</a><br>
152&nbsp; &nbsp; &nbsp; 3.12.4 <a href=#streamser>Add Stream - Coming from Serial Port</a><br>
153&nbsp; &nbsp; &nbsp; 3.12.5 <a href=#start>Start</a><br>
154&nbsp; &nbsp; &nbsp; 3.12.6 <a href=#stop>Stop</a><br>
1553.13. <a href=#cmd>Command Line Options</a><br>
156&nbsp; &nbsp; &nbsp; 3.13.1. <a href=#nw>No Window Mode</a><br>
157&nbsp; &nbsp; &nbsp; 3.13.2. <a href=#post>Offline Mode</a><br>
158&nbsp; &nbsp; &nbsp; 3.13.3. <a href=#conffile>Configuration File</a><br>
159</p>
160
161<p><a name="topmenu"><h4>3.1. Top Menu Bar</h4></p>
162<p>
163The top menu bar allows to select a font for the BNC windows, save configured options or quit the program execution. It also provides access to a program documentation.
164</p>
165
166<p><a name="file"><h4>3.1.1 File</h4></p>
167
168<p>
169The 'File' button lets you
170<ul>
171<li> select an appropriate font.<br>
172Use smaller font size if the BNC main window exceeds the size of your screen.
173</li>
174<li> save selected options in configuration file.<br>
175When using 'Save & Activate Options' while BNC is already processing data, some configuration options become immediately effective on-the-fly without interrupting uninvolved threads. See annexed section 'Configuration Example' for a list of on-the-fly changeable configuration options.
176</li>
177<li> quit the BNC program.
178</li>
179</ul>
180</p>
181
182<p><a name="help"><h4>3.1.2 Help</h4></p>
183
184<p>
185The 'Help' button provides access to
186<ul>
187<li>
188help contents.<br>
189You may keep the 'Help Contents' window open while configuring BNC.
190</li>
191<li>
192a 'Flow Chart' showing BNC linked to a real-time GNSS network engine such as RTNet.
193</li>
194<li>
195general information about BNC.<br>
196Close the 'About BNC' window to continue working with BNC.
197</li>
198</ul>
199</p>
200<p>
201BNC 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; they then click the relevant widget to pop up the help text.
202</p>
203
204<p><a name="proxy"><h4>3.2. Proxy - for usage in a protected LAN</h4></p>
205
206<p>
207If 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.</p>
208<p>
209Note 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.
210</p>
211<p><a name="general"><h4>3.3. General</h4></p>
212<p>
213The following defines general settings for BNC's logfile, file handling, reconfiguration on-the-fly, and auto-start.
214</p>
215
216<p><a name="genlog"><h4>3.3.1 Logfile - optional</h4></p>
217<p>
218Records of BNC's activities are shown in the 'Logs' canvas 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 saved into a file.
219</p>
220
221<p><a name="genapp"><h4>3.3.2 Append Files - optional</h4></p>
222<p>
223When 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.
224</p>
225
226<p><a name="genconf"><h4>3.3.3 Reread Configuration - optional</h4></p>
227<p>
228When 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 Example' for a configuration file example and a list of on-the-fly changeable options.
229</p>
230
231<p><a name="genstart"><h4>3.3.4 Auto Start - optional</h4></p>
232<p>
233You may like to auto-start BNC at startup time in window mode with preassigned 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 systems).
234</p>
235<p>
236 See BNC's command line option -nw for an auto-start of BNC in 'no window' mode.
237</p>
238
239<p><a name="rinex"><h4>3.4. RINEX Observations</h4></p>
240<p>
241Observations will be converted to RINEX if they come in either RTCM Version 2.x, RTCM Version 3.x, or RTIGS format. BNC's RINEX Observation files generally contain C1, C2, P1, P2, L1, L2, S1, and S2 observations. In case an observation is unavailable, its value is set to zero '0.000'. Note that the 'RINEX TYPE' field in the RINEX Observation file header is always set to 'M(MIXED)' even if the file does not contain any GLONASS or SABAS data.
242</p>
243
244<p><a name="rnxname"><h4>3.4.1 RINEX File Names</h4></p>
245<p>
246RINEX 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</p>
247<p>
248FRAN{ddd}{h}.{yy}O<br>
249WETT{ddd}{h}.{yy}O
250</p>
251<p>
252where 'ddd' is the day of year, 'h' is a letter which corresponds to an hour long UTC time block and 'yy' is the year.
253</p>
254<p>
255If there are 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</p>
256<p>
257FRAN{ddd}{h}_KFURT.{yy}O<br>
258FRAN{ddd}{h}_CE.{yy}O.
259</p>
260<p>
261If several streams show exactly the same mountpoint name (example: BRUS0 from <u>www.euref-ip.net</u> and BRUS0 from <u>www.igs-ip.net</u>), BNC adds an integer number to the file name leading i.e. to hourly RINEX Observation files like</p>
262<p>
263BRUS{ddd}{h}_0.{yy}O<br>
264BRUS{ddd}{h}_1.{yy}O.
265</p>
266<p>
267Note that RINEX file names for all intervals less than 1 hour follow the file name convention for 15 minutes RINEX Observation files i.e.</p>
268<p>
269FRAN{ddd}{h}{mm}.{yy}O
270</p>
271<p>
272where 'mm' is the starting minute within the hour.
273</p>
274
275<p><a name="rnxdir"><h4>3.4.2 Directory - optional</h4></p>
276<p>
277Here 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.
278</p>
279
280<p><a name="rnxinterval"><h4>3.4.3 File Interval - mandatory if 'Directory' is set</h4></p>
281<p>
282Select the length of the RINEX Observation file generated. The default value is 15 minutes.
283</p>
284
285<p><a name="rnxsample"><h4>3.4.4 Sampling - mandatory if 'Directory' is set </h4></p>
286<p>
287Select 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.
288</p>
289
290<p><a name="rnxskl"><h4>3.4.5 Skeleton Extension - optional</h4></p>
291<p>
292Whenever 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 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 <u>http://www.epncb.oma.be:80/stations/log/skl/brus.skl</u> for an example of a public RINEX header skeleton file for the Brussels EPN station.
293</p>
294<p>
295However, sometimes public RINEX header skeleton files are not available, its 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.
296</p>
297<p>
298Examples for personal skeleton file name convention: RINEX Observation files for mountpoints WETTZELL, FRANKFURT and FRANCE (same 4Char Station ID), BRUS0 from <u>www.euref-ip.net</u> and BRUS0 from <u>www.igs-ip.net</u> (same 4Char Station ID, identical mountpoint stings) would accept personal skeleton files named</p>
299<p>
300WETT.skl<br>
301FRAN_KFURT.skl<br>
302FRAN_CE.skl<br>
303BRUS_0.skl<br>
304BRUS_1.skl</p>
305<p>
306if 'Skeleton extension' is set to 'skl'.
307</p>
308<p>
309Note the following regulations regarding personal RINEX header skeleton files:
310<ul>
311<li>If such a file exists in the 'RINEX directory', the corresponding public RINEX header skeleton file is ignored. The RINEX header is generated solely from the contents of the personal skeleton.</li>
312<li>Personal skeletons should contain a complete first header record of type</li>
313<br>- &nbsp; RINEX VERSION / TYPE
314<li>They should then contain an empty header record of type</li>
315<br>- &nbsp; PGM / RUN BY / DATE
316<br>BNC will complete this line and include it in the actual RINEX file header.
317<li>They should further contain complete header records of type</li>
318<br>- &nbsp; MARKER NAME
319<br>- &nbsp; OBSERVER / AGENCY
320<br>- &nbsp; REC # / TYPE / VERS
321<br>- &nbsp; ANT # / TYPE
322<br>- &nbsp; APPROX POSITION XYZ
323<br>- &nbsp; ANTENNA: DELTA H/E/N
324<br>- &nbsp; WAVELENGTH FACT L1/2
325<li>They may contain any other optional complete header record as defined in the RINEX documentation.</li>
326<li>They should then contain empty header records of type</li>
327<br>- &nbsp; # / TYPES OF OBSERV
328<br>- &nbsp; TIME OF FIRST OBS
329<br>BNC will include these lines in the final RINEX file header together with an additional
330<br>- &nbsp; COMMENT
331<br>line describing the source of the stream.
332<li>They should finally contain an empty header record of type</li>
333<br>- &nbsp; END OF HEADER (last record)
334</ul>
335<p>
336If neither a public nor a personal RINEX header skeleton file is available for BNC, a default header will be used.
337</p>
338
339<p><a name="rnxscript"><h4>3.4.6 Script - optional</h4></p>
340<p>
341Whenever 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 systems).
342</p>
343<p>
344The 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.
345</p>
346<p>
347As 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 2 or 3 minutes after the end of each RINEX file 'Interval'.
348</p>
349
350<p><a name="rnxvers"><h4>3.4.7 Version - optional</h4></p>
351<p>
352The default format for RINEX Observation files is RINEX Version 2.11. Select 'Version 3' if you would like to save observations in RINEX Version 3 format.
353</p>
354
355<p><a name="ephemeris"><h4>3.5. RINEX Ephemeris</h4></p>
356<p>
357Broadcast ephemeris can be saved as RINEX Navigation files when received via RTCM Version 3.x as message types 1019 (GPS) and 1020 (GLONASS) or via RTIGS records type 300. 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
358</p>
359<ul>
360<li>'N' or 'G' for GPS or GLONASS ephemeris in two separate RINEX Version 2.11 Navigation files, or</li>
361<li>'P' for GPS plus GLONASS ephemeris saved together in one RINEX Version 3 Navigation file.
362</ul>
363
364<p><a name="ephdir"><h4>3.5.1 Directory - optional</h4></p>
365<p>
366Specify the 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.
367</p>
368
369<p><a name="ephint"><h4>3.5.2 Interval - mandatory if 'Directory' is set</h4></p>
370<p>
371Select the length of the RINEX Navigation file generated. The default value is 1 day.
372</p>
373
374<p><a name="ephport"><h4>3.5.3 Port - optional</h4></p>
375<p>
376BNC can output broadcast ephemeris in RINEX Version 3 ASCII format on your local host (IP 127.0.0.1) through an IP 'Port'. This function is introduced in order to support i.e. the 'BKG Ntrip Sate Space Server' (BNS) which transforms IGS clocks and orbits into corrections to broadcast ephemeris. 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.
377</p>
378<p>
379The source code for BNC comes with an example perl script 'test_bnc_eph.pl' that allows you to read BNC's ASCII ephemeris output from the IP port.
380</p>
381
382<p><a name="ephvers"><h4>3.5.4 Version - optional</h4></p>
383<p>
384Default format for RINEX Navigation files containing broadcast ephemeris is RINEX Version 2.11. Select 'Version 3' if you want to save the ephemeris in RINEX Version 3 format.
385</p>
386<p>
387Note that this does not concern the broadcast ephemeris output throug IP port which is always in RINEX Version 3 format.
388</p>
389
390<p><a name="correct"><h4>3.6. Broadcast Corrections</h4></p>
391<p>
392</p>
393RTCM is in the process of developing new Version 3 messages to transport satellite clock and orbit corrections in real-time. Based on the latest available proposal, the following premature messages currently under discussion have been implemented in BNC:
394<ul>
395<li>Message type 1057: GPS orbit corrections to Broadcast Ephemeris</li>
396<li>Message type 1058: GPS clock corrections to Broadcast Ephemeris</li>
397<li>Message type 1059: GPS code biases</li>
398<li>Message type 1060: Combined orbit and clock corrections to GPS Broadcast Ephemeris</li>
399<li>Message type 1061: GPS User Range Accuracy (URA)</li>
400<li>Message type 1062: High-rate GPS clock corrections to Broadcast Ephemeris</li>
401<li>Message type 1063: GLONASS orbit corrections to Broadcast Ephemeris</li>
402<li>Message type 1064: GLONASS clock corrections to Broadcast Ephemeris</li>
403<li>Message type 1065: GLONASS code biases</li>
404<li>Message type 1066: Combined orbit and clock corrections to GLONASS Broadcast Ephemeris</li>
405<li>Message type 1067: GLONASS User Range Accuracy (URA)</li>
406<li>Message type 1068: High-rate GLONASS clock corrections to Broadcast Ephemeris</li>
407</ul>
408<p>
409RTCM Version 3 streams carrying these messages may be used i.e. to support real-time Precise Point Positioning (PPP) applications.
410</p>
411<p>
412When using clocks from Broadcast Ephemeris (with or without applied corrections) or clocks from SP3 files, it may beimportant to understand that they are not corrected for the 2nd-order relativistic effect. The 2nd-order relativistic effect is a priodic time correction defined as -2 (R * V) / c^2 and includes the scalar product of satallite position and velocity divided by the speed of light raised to the second power.
413</p>
414
415<p>
416Orbit corrections are provided in along-track, cross-track and radial components. The along-track component is parallel to the velocity vector, the cross-track component is perpendicular to the plane of motion and the radial component is perpendicular to both along-track and cross-track components. The three components form an orthogonal system in WGS-84.
417</p>
418
419<p>
420Broadcast Corrrections can be saved by BNC in files. The file name convention for Broadcast Correction files follows the convention for RINEX files except for the last character of the file name suffix which is set to "C".
421</p>
422
423<p>
424The saved files contain parameters in plain ASCII format. The first five parameters in each record are:
425</p>
426<p>
427<ul>
428<li>RTCMv3 message type number</li>
429<li>SSR message update interval indicator</li>
430<ul>
431<li>0 = 1 sec</li>
432<li>1 = 2 sec</li>
433<li>2 = 5 sec</li>
434<li>3 = 10 sec</li>
435<li>4 = 15 sec</li>
436<li>5 = 30 sec</li>
437<li>6 = 60 sec</li>
438<li>7 = 120 sec</li>
439<li>8 = 240 sec</li>
440<li>9 = 300 sec</li>
441<li>10 = 600 sec</li>
442<li>11 = 900 sec</li>
443<li>12 = 1800 sec</li>
444<li>13 = 3600 sec</li>
445<li>14 = 7200 sec</li>
446<li>15 = 10800 sec</li>
447</ul>
448<li>GPS Week</li>
449<li>Second in GPS Week</li>
450<li>GNSS Indicator and Satellite Vehicle Pseudo Random Number</li>
451</ul>
452</p>
453<p>
454In case of RTCM message types 1057 or 1063 these parameters are followed by
455</p>
456<p>
457<ul>
458<li>IOD refering to Broadcast Ephemeris set</li>
459<li>Radial Component of Orbit Correction to Broadcast Ephemeris [m]</li>
460<li>Along-track Component of Orbit Correction to Broadcast Ephemeris [m]</li>
461<li>Cross-track Component of Orbit Correction to Broadcast Ephemeris [m]</li>
462<li>Velocity of Radial Component of Orbit Correction to Broadcast Ephemeris [m/s]</li>
463<li>Velocity of Along-track Component of Orbit Correction to Broadcast Ephemeris [m/s]</li>
464<li>Velocity of Cross-track Component of Orbit Correction to Broadcast Ephemeris [m/s]</li>
465<li>Acceleration of Radial Component of Orbit Correction to Broadcast Ephemeris [m/s**2]</li>
466<li>Acceleration of Along-track Component of Orbit Correction to Broadcast Ephemeris [m/s**2]</li>
467<li>Acceleration of Cross-track Component of Orbit Correction to Broadcast Ephemeris [m/s**2]</li>
468<p>
469</ul>
470</p>
471<p>
472Undefined parameters are set to zero "0.000".<br>Example:
473<pre>
474...
4751057 0 1538 211151.0 G18 1 0.034 0.011 -0.064 0.000 0.000 0.000 0.000 0.000 0.000
4761057 0 1538 211151.0 G16 33 -0.005 0.194 -0.091 0.000 0.000 0.000 0.000 0.000 0.000
4771057 0 1538 211151.0 G22 50 0.008 -0.082 -0.001 0.000 0.000 0.000 0.000 0.000 0.000
478...
4791063 0 1538 211151.0 R09 111 -0.011 -0.014 0.005 0.000 0.000 0.000 0.000 0.000 0.000
4801063 0 1538 211151.0 R10 43 0.000 -0.009 -0.002 0.000 0.000 0.000 0.000 0.000 0.000
4811063 0 1538 211151.0 R21 75 -0.029 0.108 0.107 0.000 0.000 0.000 0.000 0.000 0.000
482...
483</pre>
484<p>
485In case of RTCM message types 1058 or 1064 the first five parameters are followed by
486</p>
487<ul>
488<li>IOD set to zero "0"</li>
489<li>C0 polynomial coefficient for Clock Correction to Broadcast Ephemeris [m]</li>
490<li>C1 polynomial coefficient for Clock Correction to Broadcast Ephemeris [m/s]</li>
491<li>C2 polynomial coefficient for Clock Correction to Broadcast Ephemeris [m/s**2]</li>
492</ul>
493Example:
494</p>
495<pre>
496...
4971058 0 1538 211151.0 G18 0 1.846 0.000 0.000
4981058 0 1538 211151.0 G16 0 0.376 0.000 0.000
4991058 0 1538 211151.0 G22 0 2.727 0.000 0.000
500...
5011064 0 1538 211151.0 R08 0 8.956 0.000 0.000
5021064 0 1538 211151.0 R07 0 14.457 0.000 0.000
5031064 0 1538 211151.0 R23 0 6.436 0.000 0.000
504...
505</pre>
506</p>
507<p>
508In case of RTCM message types 1060 or 1066 the first five parameters are followed by
509<p>
510<ul>
511<li>IOD refering to Broadcast Ephemeris set</li>
512<li>C0 polynomial coefficient for Clock Correction to Broadcast Ephemeris [m]</li>
513<li>Radial Component of Orbit Correction to Broadcast Ephemeris [m]</li>
514<li>Along-track Component of Orbit Correction to Broadcast Ephemeris [m]</li>
515<li>Cross-track Component of Orbit Correction to Broadcast Ephemeris [m]</li>
516<li>C1 polynomial coefficient for Clock Correction to Broadcast Ephemeris [m]</li>
517<li>Velocity of Radial Component of Orbit Correction to Broadcast Ephemeris [m/s]</li>
518<li>Velocity of Along-track Component of Orbit Correction to Broadcast Ephemeris [m/s]</li>
519<li>Velocity of Cross-track Component of Orbit Correction to Broadcast Ephemeris [m/s]</li>
520<li>C2 polynomial coefficient for Clock Correction to Broadcast Ephemeris [m]</li>
521<li>Acceleration of Radial Component of Orbit Correction to Broadcast Ephemeris [m/s**2]</li>
522<li>Acceleration of Along-track Component of Orbit Correction to Broadcast Ephemeris [m/s**2]</li>
523<li>Acceleration of Cross-track Component of Orbit Correction to Broadcast Ephemeris [m/s**2]</li>
524</ul>
525Example:
526</p>
527<pre>
528...
5291060 0 1538 211610.0 G30 82 2.533 0.635 -0.359 -0.598 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
5301060 0 1538 211610.0 G31 5 -4.218 -0.208 0.022 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
5311060 0 1538 211610.0 G32 28 -2.326 0.977 -0.576 0.142 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
532...
5331066 0 1538 211610.0 R22 27 1.585 2.024 2.615 -2.080 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
5341066 0 1538 211610.0 R23 27 6.277 2.853 4.181 1.304 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
5351066 0 1538 211610.0 R24 27 0.846 1.805 13.095 6.102 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
536...
537</pre>
538</p>
539<p>
540In case of RTCM message types 1059 or 1065 the first five parameters are followed by
541<ul>
542<li>Number of Code Biases</li>
543<li>Indicator to specify the signal and tracking mode</li>
544<li>Code Bias</li>
545<li>Indicator to specify the signal and tracking mode</li>
546<li>Code Bias</li>
547<li>etc.</li>
548</ul>
549Example:
550</p>
551<pre>
552...
5531059 0 1538 211151.0 G18 2 0 -0.010 11 -0.750
5541059 0 1538 211151.0 G16 2 0 -0.040 11 -0.430
5551059 0 1538 211151.0 G22 2 0 -0.630 11 -2.400
556...
557</pre>
558
559<p><a name="corrdir"><h4>3.6.1 Directory - optional</h4></p>
560<p>
561Specify 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.
562</p>
563
564<p><a name="corrint"><h4>3.6.2 Interval - mandatory if 'Directory' is set</h4></p>
565<p>
566Select the length of the Broadcast Correction files. The default value is 1 day.
567</p>
568
569<p><a name="corrport"><h4>3.6.3 Port - optional</h4></p>
570<p>
571BNC 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.
572</p>
573<p>
574The output format equals the format used for saving Broadcast Corrections in a file with the exception that the Mountpoint is added at each line's end.
575</p>
576<p>
577The following is an example output for streams from Mountpoints RTCMSSR, CLK10 and CLK11:
578<pre>
579...
5801057 0 1538 211151.0 G18 1 0.034 0.011 -0.064 0.000 0.000 0.000 RTCMSSR
5811057 0 1538 211151.0 G16 33 -0.005 0.194 -0.091 0.000 0.000 0.000 RTCMSSR
5821057 0 1538 211151.0 G22 50 0.008 -0.082 -0.001 0.000 0.000 0.000 RTCMSSR
5831058 0 1538 211151.0 G18 0 1.846 0.000 RTCMSSR
5841058 0 1538 211151.0 G16 0 0.376 0.000 RTCMSSR
5851058 0 1538 211151.0 G22 0 2.727 0.000 RTCMSSR
5861059 0 1538 211151.0 G18 2 0 -0.010 11 -0.750 RTCMSSR
5871059 0 1538 211151.0 G16 2 0 -0.040 11 -0.430 RTCMSSR
5881059 0 1538 211151.0 G22 2 0 -0.630 11 -2.400 RTCMSSR
5891063 0 1538 211151.0 R09 111 -0.011 -0.014 0.005 0.0000 0.000 0.000 RTCMSSR
5901063 0 1538 211151.0 R10 43 0.000 -0.009 -0.002 0.0000 0.000 0.000 RTCMSSR
5911063 0 1538 211151.0 R21 75 -0.029 0.108 0.107 0.0000 0.000 0.000 RTCMSSR
5921064 0 1538 211151.0 R08 0 8.956 0.000 RTCMSSR
5931064 0 1538 211151.0 R07 0 14.457 0.000 RTCMSSR
5941064 0 1538 211151.0 R23 0 6.436 0.000 RTCMSSR
5951066 0 1538 211610.0 R24 27 0.846 1.805 13.095 6.102 0.000 0.000 0.000 0.000 CLK11
5961066 0 1538 211610.0 R23 27 6.277 2.853 4.181 1.304 0.000 0.000 0.000 0.000 CLK11
5971066 0 1538 211610.0 R22 27 1.585 2.024 2.615 -2.080 0.000 0.000 0.000 0.000 CLK11
5981060 0 1538 211610.0 G32 28 -2.326 0.977 -0.576 0.142 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 CLK10
5991060 0 1538 211610.0 G31 5 -4.218 -0.208 0.022 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 CLK10
6001060 0 1538 211610.0 G30 82 2.533 0.635 -0.359 -0.598 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 CLK10
601...
602</pre>
603</p>
604<p>
605The source code for BNC comes with an example perl script 'test_bnc_eph.pl' that allows you to read BNC's Broadcast Corrections from the IP port.
606</p>
607
608<p><a name="corrwait"><h4>3.6.4 Wait for Full Epoch - mandatory if 'Port' is set</h4></p>
609<p>
610When feeding a real-time GNSS network engine waiting epoch by epoch for synchronized Broadcast Corrections, BNC drops (only concering IP port output) whatever is received later than 'Wait for full epoch' seconds. A value of 2 to 5 seconds could be an appropriate choice for that, depending on the latency of the incoming Broadcast Corrections stream and the delay acceptable by your application. A message such as "COCK1: Correction overaged by 5 sec" shows up in BNC's logfile if 'Wait for full epoch' is exceeded.
611</p>
612
613<p><a name="syncout"><h4>3.7. Feed Engine</h4></p>
614<p>
615BNC can generate synchronized or unsynchronized observations epoch by epoch from all stations and satellites to feed a real-time GNSS network engine. The output can be produced in a binary format through an IP port and/or a plain ASCII format to save the observations in a local file. It comprises the following observations where available:</p>
616<p>
617StatID, SVPRN, GPSWeek, GPSWeeks, C1, C2, P1, P2, L1, L2, slip_cnt_L1, slip_cnt_L2, lock_timei_L1, lock_timei_L2, S1, S2, SNR1, SNR2
618</p>
619<p>
620Note that slip_cnt stands for the cumulative loss of continuity indicator, lock_timei for the lock time indicator, and SNR for the signal-to-noise ratio 'S' mapped to integer numbers 1 to 9. In case an observation is not available, its value is set to zero '0.000'. Loss of continuity indicator and lock time indicator are set to nedative values if undefined.
621</p>
622
623<p>The binary output is a continuous stream in the following order:</p>
624<pre>
625begEpoch
626t_obsInternal
627t_obsInternal
628...
629t_obsInternal
630endEpoch
631begEpoch
632t_obsInternal
633...
634</pre>
635
636<p>The corresponding structures are defined as follow:</p>
637<pre>
638 const char begEpoch[] = "BEGEPOCH";
639 const char endEpoch[] = "ENDEPOCH";
640...
641...
642class t_obsInternal {
643 public:
644 int flags;
645 char StatID[20+1]; // Station ID
646 char satSys; // Satellite System ('G' or 'R')
647 int satNum; // Satellite Number (PRN for GPS NAVSTAR)
648 int slot; // Slot Number (for Glonass)
649 int GPSWeek; // Week of GPS-Time
650 double GPSWeeks; // Second of Week (GPS-Time)
651 double C1; // CA-code pseudorange (meters)
652 double C2; // CA-code pseudorange (meters)
653 double P1; // P1-code pseudorange (meters)
654 double P2; // P2-code pseudorange (meters)
655 double L1; // L1 carrier phase (cycles)
656 double L2; // L2 carrier phase (cycles)
657 int slip_cnt_L1; // L1 cumulative loss of continuity indicator (negative value = undefined)
658 int slip_cnt_L2; // L2 cumulative loss of continuity indicator (negative value = undefined)
659 int lock_timei_L1; // L1 last lock time indicator (negative value = undefined)
660 int lock_timei_L2; // L2 last lock time indicator (negative value = undefined)
661 double S1; // L1 signal-to noise ratio
662 double S2; // L2 signal-to noise ratio
663 int SNR1; // L1 signal-to noise ratio (mapped to integer)
664 int SNR2; // L2 signal-to noise ratio (mapped to integer)
665};
666</pre>
667
668<p>
669The source code for BNC comes with an example program called 'test_bnc_qt.cpp' that allows you to read BNC's (synchronized or unsynchronized) binary observation output from the IP port and print the observations in a plain ASCII format on standard output.
670</p>
671<p>
672Note that any socket connection of an application to BNC's synchronized or unsynchronized observations ports is recorded in the 'Logs' canvas 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'.
673</p>
674
675<p><a name="syncport"><h4>3.7.1 Port - optional</h4></p>
676<p>
677BNC can produce synchronized observations in binary format on your local host (IP 127.0.0.1) through an IP 'Port'. Scynchronized means that BNC collects all data for any specific epoch which become available within a certain number of latency seconds (see 'Wait for Full Epoch' option). It then - epoch by epoch - outputs whatever has been received. 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.</p>
678<p>
679</p>
680
681<p><a name="syncwait"><h4>3.7.2 Wait for Full Epoch - mandatory if 'Port' is set</h4></p>
682<p>
683When feeding a real-time GNSS network engine waiting for synchronized input epoch by epoch, BNC drops whatever is received later than 'Wait for full 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 epoch' is 5 seconds.
684</p>
685<p>
686Note that 'Wait for full epoch' does not effect the RINEX Observation file content. Observations received later than 'Wait for full epoch' seconds will still be included in the RINEX Observation files.
687</p>
688
689<p><a name="syncsample"><h4>3.7.3 Sampling - mandatory if 'File' or 'Port' is set</h4></p>
690<p>
691Select 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.
692</p>
693
694<p><a name="syncfile"><h4>3.7.4 File - optional</h4></p>
695<p>
696Specifies 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.
697</p>
698<p>
699Beware that the size of this file can rapidly increase depending on the number of incoming streams. This option is primarily meant for testing and evaluation.
700</p>
701
702<p><a name="syncuport"><h4>3.7.5 Port (unsynchronized) - optional</h4></p>
703<p>
704BNC can produce unsynchronized observations from all configured streams in binary format on your local host (IP 127.0.0.1) through an IP 'Port'. Unscynchronized means that BNC immediately forwards any received observation to the port. Specify an IP port number here to activate this function. The default is an empty option field, meaning that no binary unsynchronized output is generated.</p>
705<p>
706
707<p><a name="serial"><h4>3.8. Serial Output</h4></p>
708<p>
709You may use BNC to feed a serial connected device like an GNSS receiver. For that one of the incoming streams can be forwarded to a serial port.
710</p>
711
712<p><a name="sermount"><h4>3.8.1 Mountpoint - optional</h4></p>
713<p>
714Enter a 'Mountpoint' to forward its corresponding stream to a serial connected GNSS receiver.
715</p>
716<p>
717When selecting the serial communication options listed below, make sure that you pick those configured to the serial connected receiver.
718</p>
719
720<p><a name="serport"><h4>3.8.2 Port Name - mandatory if 'Mountpoint' is set</h4></p>
721<p>
722Enter the serial 'Port name' selected on your host for communication with the serial connected receiver. Valid port names are
723</p>
724<pre>
725Windows: COM1, COM2
726Linux: /dev/ttyS0, /dev/ttyS1
727FreeBSD: /dev/ttyd0, /dev/ttyd1
728Digital Unix: /dev/tty01, /dev/tty02
729HP-UX: /dev/tty1p0, /dev/tty2p0
730SGI/IRIX: /dev/ttyf1, /dev/ttyf2
731SunOS/Solaris: /dev/ttya, /dev/ttyb
732</pre>
733<p>
734Note that you must plug a serial cable in the port defined here before you start BNC.
735</p>
736
737<p><a name="serbaud"><h4>3.8.3 Baud Rate - mandatory if 'Mountpoint' is set</h4></p>
738<p>
739Select a 'Baud rate' for the serial output link. Note that using a high baud rate is recommended.
740</p>
741
742<p><a name="serflow"><h4>3.8.4 Flow Control - mandatory if 'Mountpoint' is set</h4></p>
743<p>
744Select 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.
745</p>
746
747<p><a name="serparity"><h4>3.8.5 Parity - mandatory if 'Mountpoint' is set</h4></p>
748<p>
749Select the 'Parity' for the serial output link. Note that parity is often set to 'NONE'.
750</p>
751
752<p><a name="serdata"><h4>3.8.6 Data Bits - mandatory if 'Mountpoint' is set</h4></p>
753<p>
754Select the number of 'Data bits' for the serial output link. Note that often '8' data bits are used.
755</p>
756
757<p><a name="serstop"><h4>3.8.7 Stop Bits - mandatory if 'Mountpoint' is set</h4></p>
758<p>
759Select the number of 'Stop bits' for the serial output link. Note that often '1' stop bit is used.
760</p>
761
762<p><a name="serauto"><h4>3.8.8 NMEA - mandatory for VRS streams</h4></p>
763<p>
764Select 'Auto' to automatically forward all NMEA-GGA messages coming from your serial connected GNSS receiver to the NTRIP broadcaster and/or save them in a file.
765</p>
766<p>
767Forwarding valid NMEA-GGA messages to the NTRIP broadcaster is required for receiving 'Virtual Reference Station' (VRS) streams. Thus, in case your serial connected receiver is not capable to provide them, the alternative for VRS streams is a 'Manual' simulation of an initial NMEA-GGA message. Its contents is based on the approximate (editable) latitude/longitude from the broadcaster's source-table and an approximate VRS height to be specified.
768</p>
769<p>
770In summary: select 'Manual' only when handling a VRS stream and your serial connected GNSS receiver doesn't generate NMEA-GGA messages. Select 'Auto' otherweise.
771</p>
772
773<p><a name="serfile"><h4>3.8.9 File - optional if 'Auto' NMEA is set</h4></p>
774<p>Specify the full path to a file where NMEA messages coming from your serial connected receiver are saved.
775</p>
776<p><a name="serheight"><h4>3.8.10 Height - mandatory if 'Manual' NMEA is set</h4></p>
777<p>
778Specify an approximate 'Height' above mean sea level in meter for your VRS to simulate an inital NMEA-GGA message. Latitude and longitude for that (editable) are taken from the broadcaster's source-table.
779</p>
780<p>
781This option concerns only 'Virtual Reference Stations' (VRS). Its setting is ignored in case of streams coming from physical reference stations.
782</p>
783
784<p><a name="advnote"><h4>3.9. Outages</h4></p>
785
786<p>
787At various times, the 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 corrupted stream(s) can generate unnecessary workload for BNC. Outages and corruptions are handled by BNC as follows:
788</p>
789<p>
790<u>Stream outages:</u> 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.
791</p>
792<p>
793<u>Stream corruption:</u> 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.
794</p>
795<p>
796Outage and corruption events are reported in the 'Logs' canvas. 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 utilise BNC as a real-time performance monitor and alarm system for a network of GNSS reference stations.
797</p>
798
799<p><a name="obsrate"><h4>3.9.1 Observation Rate - mandatory if 'Failure threshold', 'Recovery threshold', and 'Script' is set</h4></p>
800<p>
801BNC 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.</p><p>An empty option field (default) means that you don't want an explicit information from BNC about stream outages and incoming streams that can not be decoded.
802</p>
803
804<p><a name="advfail"><h4>3.9.2 Failure Threshold - optional</h4></p>
805<p>
806Event '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 innundate user with too many event reports.
807</p>
808<p>
809Note 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'.
810</p>
811
812<p><a name="advreco"><h4>3.9.3 Recovery Threshold - optional</h4></p>
813<p>
814Once 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 innundate users with too many event reports.
815</p>
816<p>
817Note 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'.
818</p>
819
820<p><a name="advscript"><h4>3.9.4 Script - optional </h4></p>
821<p>
822As 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 systems) together with date and time information.
823</p>
824<p>
825Leave the 'Script' field empty if you do not wish to use this option. An invalid path will also disable this option.
826</p>
827<p>
828Examples for command line parameter strings passed on to the advisory 'Script' are:
829<pre>
830FFMJ0 Begin_Outage 08-02-21 09:25:59
831FFMJ0 End_Outage 08-02-21 11:36:02 Begin was 08-02-21 09:25:59
832</pre>
833Sample script for Unix/Linux/Mac systems:
834<pre>
835#!/bin/bash
836sleep $((60*RANDOM/32767))
837cat | mail -s "NABU: $1" email@address &lt;&lt;!
838Advisory Note to BNC User,
839Please note the following advisory received from BNC.
840Stream: $*
841Regards, BNC
842!
843</pre>
844</p>
845<p>
846Note 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 avoids overloading your mail server in case of a simultaneous failure of many streams.
847</p>
848
849<p><a name="misc"><h4>3.10. Miscellaneous</h4></p>
850<p>
851This section describes a number of miscellaneous options which can be applied for a single stream (mountpoint) or for all configured streams.
852</p>
853
854<p><a name="miscmount"><h4>3.10.1 Mountpoint - optional </h4></p>
855<p>
856Specify 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.
857</p>
858
859<p><a name="miscperf"><h4>3.10.2 Log Latency - optional </h4></p>
860<p>
861 BNC can average latencies per stream over a certain period of GPS time, the 'Performance log' interval. Mean latencies are calculated from the individual latencies of at most one (first incoming) observation or correction to Broadcast Ephemeris per second. Note that computing correct latencies requires the clock of the host computer to be properly synchronized.
862</p>
863<p>
864<u>Latency:</u> Latency is defined in BNC by the following equation:
865</p>
866<pre>
867 UTC time provided by BNC's host
868 - GPS time of currently processed epoch
869 + Leap seconds between UTC and GPS time
870 --------------
871 = Latency
872</pre>
873<p>
874<u>Statistics:</u> 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 'Performance log' interval. Based on this rate, BNC estimates the number of data gaps when appearing in subsequent intervals.
875</p>
876<p>
877Latencies of observations or corrections to Broadcast Ephemeris and statistical information can be recorded in the 'Logs' canvas at the end of each 'Performance log' interval. A typical output from a 1 hour 'Performance log' interval would be:
878</p>
879<pre>
88008-03-17 15:59:47 BRUS0: Mean latency 1.47 sec, min 0.66, max 3.02, rms 0.35, 3585 epochs, 15 gaps
881</pre>
882<p>
883Select a 'Performance log' interval to activate this function or select the empty option field if you do not want BNC to log latencies and statistical information.
884</p>
885
886
887<p><a name="miscscan"><h4>3.10.3 Scan RTCM - optional</h4></p>
888<p>
889When configuring a GNSS receiver for RTCM stream generation, the setup interface may not provide details about RTCM message 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. The idea for this option arose from 'InspectRTCM', a comprehensive stream analyzing tool written by D. Stoecker.
890</p>
891<p>
892Tick 'Scan RTCM' to scan RTCM Version 2.x or 3.x streams and log all contained
893</p>
894<ul>
895<li>numbers of incoming message types</li>
896<li>Antenna Reference Point (ARP) coordinates</li>
897<li>Antenna Phase Center (APC) coordinates</li>
898<li>antenna height above marker</li>
899<li>antenna descriptor.</li>
900</ul>
901</p>
902
903<p>
904Note that in RTCM Version 2.x the message types 18 and 19 carry only the observables of one frequence. Hence it needs two type 18 and 19 messages per epoch to transport the observations from dual frequency receivers.
905</p>
906<p>
907
908<p>Logged time stamps refer to message reception time and allow to understand 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.
909</p>
910<p>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.
911</p>
912
913<p><a name="streams"><h4>3.11. Streams</h4></p>
914<p>
915Each stream on an NTRIP broadcaster (and consequently on BNC) is defined using a unique source ID called mountpoint. An NTRIP client like BNC access the desired data stream by referring to its mountpoint. Information about streams and their mountpoints is available through the source-table maintained by the NTRIP broadcaster. Note that mountpoints could show up in BNC more than once when retrieving streams from several NTRIP broadcasters.
916</p>
917
918<p>
919Streams selected for retrieval are listed under the 'Streams' canvas section 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:
920</p>
921<p>
922<table>
923<tr><td>'resource loader'&nbsp; </td><td>NTRIP broadcaster URL and port, or<br>TCP/IP host and port, or<br>Serial input port specification.</td></tr>
924<tr><td>'mountpoint' &nbsp;</td><td>Mountpoint introduced by NTRIP broadcaster, or<br>Mountpoint introduced by BNC's user.</td></tr>
925<tr><td>'decoder' &nbsp;</td><td>Type of decoder used to handle the incoming stream content according to its format; editable.</td></tr>
926<tr><td>'lat' &nbsp;</td><td>Approximate latitude of reference station, in degrees, north; editable if 'nmea' = 'yes'.</td></tr>
927<tr><td>'long' &nbsp;</td><td>Approximate longitude of reference station, in degrees, east; editable if 'nmea' = 'yes'.</td></tr>
928<tr><td>'nmea' &nbsp;</td><td>Indicates whether or not streaming needs to be initiated by BNC through sending NMEA-GGA message carrying position coordinates in 'lat' and 'long'.</td></tr>
929<tr><td>'ntrip' &nbsp;</td><td>Selected NTRIP transport protocol version (1, 2, R, or U), or<br>'N' for TCP/IP streams without NTRIP, or<br>'UN' for UDP streams without NTRIP, or<br>'S' for serial input streams without NTRIP.</td></tr>
930<tr><td>'bytes' &nbsp;</td><td>Number of bytes received.
931</table>
932</p>
933
934<p><a name="streamedit"><h4>3.11.1 Edit Streams</h4></p>
935<ul>
936<li>
937BNC automatically allocates one of its internal decoders to a stream based on the stream's 'format' and 'format-details' as given in the source-table. However, there might be cases where you need to override the automatic selection due to incorrect source-table for example. BNC allows users to manually select the required decoder by editing the decoder string. Double click on the 'decoder' field, enter your preferred decoder and then hit Enter. The accepted decoder strings are 'RTCM_2.x', 'RTCM_3.x', and 'RTIGS'.
938</li>
939<li>
940In case you need to log the raw data as is, BNC allows users to by-pass its decoders and and directly save the input in daily log files. To do this specify the decoder string as 'ZERO'. The generated file names are created from the characters of the streams mountpoints plus two-digit numbers each for year, month, and day. Example: Setting the 'decoder' string for mountpoint WTZZ0 to 'ZERO' and running BNC on March 29, 2007 would save the raw data in a file named WTZZ0_070329.
941</li>
942<li>
943BNC can also retrieve streams from virtual reference stations (VRS). To initiate these streams, an approximate rover position needs to be sent in NMEA format to the NTRIP broadcaster. In return, a user-specific data stream is generated, typically by a Network-RTK software. VRS streams are indicated by a 'yes' in the source-table as well as in the 'nmea' column on the 'Streams' canvas in BNC's main window. They are customized exactly to the latitude and longitude transmitted to the NTRIP broadcaster via NMEA-GGA messages.
944<br>If NMEA-GGA messages are not coming from a serial connected GNSS rover, BNC simulates them from the default latitude and longitude of the source-table as shown in the 'lat' and 'long' columns on the 'Streams' canvas. However, in most cases you would probably want to change these defaults according to your requirement. Double-click on 'lat' and 'long' fields, enter the values you wish to send and then hit Enter. The format is in positive north latitude degrees (e.g. for northern hemisphere: 52.436, for southern hemisphere: -24.567) and eastern longitude degrees (example: 358.872 or -1.128). Only streams with a 'yes' in their 'nmea' column can be edited. The position must preferably be a point within the VRS service area of the network. RINEX files generated from these streams will contain an additional COMMENT line in the header beginning with 'NMEA' showing the 'lat' and 'long' used.
945<br>Note that when running BNC in a Local Area Network (LAN), NMEA strings may be blocked by a proxy server, firewall or virus scanner.
946</li>
947</ul>
948
949<p><a name="streamdelete"><h4>3.11.2 Delete Stream</h4></p>
950<p>
951To 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.</p>
952
953<p><a name="streamconf"><h4>3.11.3 Reconfigure Streams On-the-fly</h4></p>
954<p>
955The streams selection can be changed on-the-fly without interrupting uninvolved threads in the running BNC process.
956</p>
957<p>
958<u>Window mode:</u> Hit 'Save & Activate Options' while BNC is in window mode and already processing data to let changes of your streams selection immediately become effective.
959<p>
960<u>No window mode:</u> 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 Example' for a configuration file example and a list of other on-the-fly changeable options.
961</p>
962
963
964<p><a name="bottom"><h4>3.12. Bottom Menu Bar</h4></p>
965<p>
966The 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.
967</p>
968
969<p><a name="streamadd"><h4>3.12.1 Add Stream - Coming from Caster</h4></p>
970<p>
971Button 'Add Stream' > 'Coming from Caster' opens a window that allows user to select data streams from an NTRIP broadcaster according to their mountpoints.
972</p>
973
974<p><a name="streamhost"><h4>3.12.1.1 Caster Host and Port - mandatory</h4></p>
975<p>
976Enter the NTRIP broadcaster host IP and port number. Note that EUREF and IGS operate NTRIP broadcasters at <u>http://www.euref-ip.net/home</u> and <u>http://www.igs-ip.net/home</u>.
977</p>
978
979<p><a name="streamtable"><h4>3.12.1.2 Casters Table - optional</h4></p>
980<p>
981It may be that your 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 <u>www.rtcm-ntrip.org/home</u>. A window opens which allows to select a broadcaster for stream retrieval.
982</p>
983
984<p><a name="streamuser"><h4>3.12.1.3 User and Password - mandatory for protected streams</h4></p>
985<p>
986Some streams on NTRIP broadcasters may be restricted. 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 <u>http://igs.bkg.bund.de/index_ntrip_reg.htm</u> for access to protected streams on <u>www.euref-ip.net</u> and <u>www.igs-ip.net</u>.
987</p>
988
989<p><a name="gettable"><h4>3.12.1.4 Get Table</h4></p>
990<p>
991Use 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.x, RTCM Version 3.x, or RTIGS format. RTCM Version 2.x streams must contain message types 18 and 19 or 20 and 21 while RTCM Version 3.x streams must contain GPS or SBAS message types 1002 or 1004 and may contain GLONASS message types 1010 or 1012, see 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.x streams containing message types 1019 (GPS) and 1020 (GLONASS) are required. Select your streams line by line, use +Shift and +Ctrl when necessary.
992</p>
993<p>
994The 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).
995</p>
996<p>
997Hit '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.
998</p>
999
1000<p><a name="ntripv"><h4>3.12.1.5 NTRIP Version - mandatory</h4></p>
1001<p>
1002Some 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:
1003</p>
1004<p>
1005&nbsp; 1:&nbsp; NTRIP version 1, TCP/IP.<br>
1006&nbsp; 2:&nbsp; NTRIP version 2 in TCP/IP mode.<br>
1007&nbsp; R:&nbsp; NTRIP version 2 in RTSP/RTP mode.<br>
1008&nbsp; U:&nbsp; NTRIP version 2 in UDP mode.
1009</p>
1010<p>
1011If NTRIP version 2 is supported by the broadcaster:
1012</p>
1013<ul>
1014<li>Try using option '2' if your streams are otherwise blocked by a proxy server operated in front of BNC.</li>
1015<li>Option 'R' or 'U' may be selected if latency is more important than completeness for your application. Note that the latency reduction is likely to be in the order of 0.5 sec or less. Note further that options 'R' (RTSP/RTP mode) and 'U' (UDP mode) are not accepted by proxy servers and a mobile Internet Service Provider may not support it.</li>
1016</ul>
1017<p>
1018Select option '1' if you are not sure whether the broadcaster supports NTRIP version 2.</li>
1019</p>
1020
1021<p><a name="streamip"><h4>3.12.2 Add Stream - Coming from TCP/IP Port</h4></p>
1022<p>
1023Button '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:
1024<ul>
1025<li>Enter the IP address of the stream providing host.</li>
1026<li>Enter the IP port number of the stream providing host.</li>
1027<li>Specify a mountpoint. Recommended is a 4-character station ID. Example: FFMJ</li>
1028<li>Specify the stream format. Available options are 'RTCM_2', 'RTCM_3', 'RTIGS', and 'ZERO'.</li>
1029<li>Enter the approximate latitude of the stream providing rover in degrees. Example: 45.32.</li>
1030<li>Enter the approximate longitude of the stream providing rover in degrees. Example: -15.20.</li>
1031</ul>
1032</p>
1033<p>
1034Streams directly received from a TCP/IP port show up with an 'N' for 'No NTRIP' in the 'Streams' canvas section on BNC's main window . Latitude and longitude are to be entered just for informal reasons.
1035<p>
1036</p>
1037Note that this option works only if no proxy server is involved in the communication link.
1038</p>
1039
1040<p><a name="streamudp"><h4>3.12.3 Add Stream - Coming from UDP Port</h4></p>
1041<p>
1042Button '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:
1043<ul>
1044<li>Enter the local port number where the UDP stream arrives.</li>
1045<li>Specify a mountpoint. Recommended is a 4-character station ID. Example: FFMJ</li>
1046<li>Specify the stream format. Available options are 'RTCM_2', 'RTCM_3', 'RTIGS', and 'ZERO'.</li>
1047<li>Enter the approximate latitude of the stream providing rover in degrees. Example: 45.32.</li>
1048<li>Enter the approximate longitude of the stream providing rover in degrees. Example: -15.20.</li>
1049</ul>
1050</p>
1051<p>
1052Streams 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.
1053<p>
1054
1055<p><a name="streamser"><h4>3.12.4 Add Stream - Coming from Serial Port</h4></p>
1056<p>
1057Button '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:
1058<ul>
1059<li>Specify a mountpoint. Recommended is a 4-character station ID. Example: FFMJ</li>
1060<li>Specify the stream format. Available options are 'RTCM_2', 'RTCM_3', 'RTIGS', and 'ZERO'.</li>
1061<li>Enter the approximate latitude of the stream providing receiver in degrees. Example: 45.32.</li>
1062<li>Enter the approximate longitude of the stream providing receiver in degrees. Example: -15.20.</li>
1063<li>Enter the serial 'Port name' selected on your host for communication with the receiver. Valid port names are
1064<pre>
1065Windows: COM1, COM2
1066Linux: /dev/ttyS0, /dev/ttyS1
1067FreeBSD: /dev/ttyd0, /dev/ttyd1
1068Digital Unix: /dev/tty01, /dev/tty02
1069HP-UX: /dev/tty1p0, /dev/tty2p0
1070SGI/IRIX: /dev/ttyf1, /dev/ttyf2
1071SunOS/Solaris: /dev/ttya, /dev/ttyb
1072</pre>
1073</li>
1074<li>Select a 'Baud rate' for the serial input. Note that using a high baud rate is recommended.</li>
1075<li>Select the number of 'Data bits' for the serial input. Note that often '8' data bits are used.</li>
1076<li>Select the 'Parity' for the serial input. Note that parity is often set to 'NONE'.</li>
1077<li>Select the number of 'Stop bits' for the serial input. Note that often '1' stop bit is used.</li>
1078<li>Select a 'Flow control' for the serial link. Select 'OFF' if you don't know better.</li>
1079</ul>
1080</p>
1081<p>
1082When selecting the serial communication options listed above, make sure that you pick those configured to the serial connected GNSS receiver.
1083</p>
1084
1085<p>
1086Streams received from a serial connected GNSS receiver show up with an 'S' (for <u>S</u>erial Port, no NTRIP) in the 'Streams' canvas section on BNC's main window . Latitude and longitude are to be entered just for informal reasons.
1087<p>
1088
1089<p><a name="start"><h4>3.12.5 Start</h4></p>
1090<p>
1091Hit 'Start' to start retrieving, decoding, and 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.
1092</p>
1093
1094<p><a name="stop"><h4>3.12.6 Stop</h4></p>
1095<p>
1096Hit the 'Stop' button in order to stop BNC.
1097</p>
1098
1099<p><a name="cmd"><h4>3.13. Command Line Options</h4></p>
1100<p>
1101Command line options are available to run BNC in 'no window' mode or let it read data from a file in offline mode. BNC will then use processing options from the 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.ini'.
1102</p>
1103
1104<p><a name="nw"><h4>3.13.1 No Window Mode - optional</h4></p>
1105<p>
1106Apart from its regular windows mode, BNC can be started on all systems as a background/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.
1107</p>
1108<p>
1109Example:<br><br>
1110bnc.exe -nw
1111</p>
1112
1113<p><a name="post"><h4>3.13.2 Offline Mode - optional</h4></p>
1114<p>
1115Although BNC is primarily a real-time online tool, it can be run in offline mode to read data from a file for post processing purposes. Enter the following four command line options for that:
1116</p>
1117<p>
1118<ul>
1119<li>'--file &#060;<u>inputFileName</u>&#062;' to enter the full path to an input file containing data in RTCM Version 2.x, or Version 3.x, or RTIGS/SOC format.</li>
1120<li>'--format &#060;<u>format</u>&#062;' to enter one of the file format describing strings 'RTCM_2', 'RTCM_3' or 'RTIGS'.</li>
1121<li>'--date YYYY-MM-DD' to enter a date for the first epoch.</li>
1122<li>'--time HH:MM:SS' to enter a time for the first epoch.</li>
1123</ul>
1124<p>
1125Example:<br><br>
1126./bnc --file FFMJ.dat --format RTCM_3 --date 2008-10-27 --time 23:12:56
1127</p>
1128<p>
1129Note that it is necessary to define a date and time for the first epoch because RTCM streams do not contain complete time stamps as needed for RINEX. Note further that when running BNC in offline mode, it will use options for file saving, interval, sampling etc. from its configuration file.
1130</p>
1131
1132<p><a name="conffile"><h4>3.13.3 Configuration File - optional</h4></p>
1133The default configuration file name is 'BNC.ini'. You may change this name at startup time using the command line option '--conf &#060;<u>confFileName</u>&#062;'. This allows to run several BNC jobs in parallel on the same host using different sets of configuration options. <u>confFileName</u> 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 BNC is started.
1134</p>
1135<p>
1136Example:<br><br>
1137./bnc --conf MyConfig.ini
1138</p>
1139<p>
1140This leads to a BNC job using configuration file 'MyConfig.ini'. The configuration file will be saved in the current working directory.
1141</p>
1142
1143<p><a name="limits"><h3>4. Limitations</h3></p>
1144<ul>
1145<li>
1146In Qt-based desktop environments (like KDE) on Unix/Linux platforms it may happen that you experience a crash of BNC at startup even when running the program in the background using the '-nw' option. This is a known bug most likely resulting from an incompatibility of Qt libraries in the environment and in BNC. Entering the command 'unset SESSION_MANAGER' before running BNC may help as a work-around.
1147</li>
1148<li>
1149Currently BNC only handles GPS, SBAS and GLONASS data. Galileo is not yet supported.
1150</li>
1151<li>
1152BNC currently will only handle C1, C2, P1, P2, L1, L2, S1, and S2 observations as well as the cumulative loss of continuity and lock time indicators. Which observables and indicators are available on a particular stream will depend on the setup of source receiver and the data format used. RTCM Version 2.x streams do not carry signal-to-noise ratio 'S' values while RTCM Version 3.x streams can only transport one code observable per frequency. Note that signal-to-noise ratios 'S' are also logged mapped to integer numbers 1 to 9.
1153</li>
1154<li>
1155Using RTCM Version 3.x, BNC will properly handle message types 1002, 1004, 1010, and 1012. Note that when handling message types 1001, 1003, 1009 and 1011 where the ambiguity field is not set, the output will be no valid RINEX. All values will be stored modulo 299792.458 (speed of light).
1156</li>
1157Concerning the RTCM Version 3.x premature message types 1057-1068 (see RTCM document 091-2009-SC104-542 'Version 3 Proposed Messages – Set 10'), a final decision is not yet made. Note the what's implemented in BNC is just a temporary solutions.
1158<li>
1159Using RTCM Version 2.x, BNC will only handle message types 18 and 19 or 20 and 21 together with position and the antenna offset information carried in types 3 and 22. Note that processing carrier phase corrections and pseudo-range corrections contained in message types 20 and 21 needs access to broadcast ephemeris. Hence, whenever dealing with message types 20 and 21, make sure that broadcast ephemeris become available for BNC through also retrieving at least one RTCM Version 3.x stream carrying message types 1019 (GPS ephemeris) and 1020 (GLONASS ephemeris).
1160</li>
1161<li>
1162Streams coming in RTIGS format carry only GPS data.
1163</li>
1164<li>
1165BNC's 'Get Table' function only shows the STR records of a source-table. You can use an Internet browser to download the full source-table contents of any NTRIP broadcaster by simply entering its URL in the form of http://host:port. Data field number 8 in the NET records may provide information about where to register for an NTRIP broadcaster account.
1166</li>
1167<li>
1168EUREF as well as IGS adhere to an open data policy. Streams are made available through NTRIP broadcasters at <u>www.euref-ip.net</u> and <u>www.igs-ip.net</u> free of charge to anyone for any purpose. There is no indication up until now how many users will need to be supported simultaneously. The given situation may develop in such a way that it might become difficult to serve all registered users at the same times. In cases where limited resources on the NTRIP broadcaster side (software restrictions, bandwidth limitation etc.) dictates, first priority in stream provision will be given to stream providers followed by re-broadcasting activities and real-time analysis centers while access to others might be temporarily denied.
1169</li>
1170<li>
1171We experienced a limitation of the Standard Version of Microsoft Windows related to socket communication where sockets are not always handled properly. Since BNC makes intensive use of communication through sockets, we recommend to use the Server Version of Microsoft Windows when running BNC continuously for extended on a Windows platform.
1172</li>
1173<li>
1174The source code provided by NRCan for decoding RTIGS streams is 32-bit dependent. Hence the BNC executable generated for 64-bit Linux systems would only run when compiled using the -m32 compiler option.
1175</li>
1176<li>
1177Once BNC has been started, many of its configuration options can not be changed as long as it is stopped. See chapter 'Reread Configuration' for on-the-fly configuration exceptions.
1178</li>
1179<br>
1180</ul>
1181<p><a name="authors"><h3>5. Authors</h3></p>
1182<p>
1183The BKG Ntrip Client (BNC) 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. BNC includes the following GNU GPL software components:
1184<ul>
1185<li> RTCM 2.x decoder, written by Oliver Montenbruck, German Space Operations Center, DLR, Oberpfaffenhofen</li>
1186<li> RTCM 3.x decoder, written for BKG by Dirk Stoecker, Alberding GmbH, Schoenefeld</li>
1187<li> RTIGS decoder, written by Ken MacLeod, Natural Resources, Canada.</li>
1188</ul>
1189</p>
1190<p>
1191Georg Weber<br>
1192Federal Agency for Cartography and Geodesy (BKG)<br>
1193Frankfurt, Germany<br>
1194[euref-ip@bkg.bund.de] or [igs-ip@bkg.bund.de]
1195</p>
1196<p>
1197<b>Acknowledgements</b><br>
1198BNC's Help Contents has been proofread by Thomas Yan, University of New South Wales, Australia.<br>
1199Scott Glazier, OmniSTAR Australia, included the decoding of broadcast ephemeris from RTIGS streams and has been helpful in finding BNC's bugs.<br>
1200James Perlt, BKG, helped fixing bugs and redesigned BNC's main window.<br>
1201Andre Hauschild, German Space Operations Center, DLR, revised the RTCMv2 decoder.<br>
1202Zdenek Lukes, Czech Technical University Prague, Department of Geodesy, extended the RTCMv2 decoder to handle message types 3, 20, 21, and 22 and added loss of lock indicator.<br>
1203</p>
1204
1205<p><a name="annex"><h3>8. Annex</h3></p>
1206<p>
12078.1. <a href=#history>Revision History</a><br>
12088.2. <a href=#rtcm>RTCM</a><br>
1209&nbsp; &nbsp; &nbsp; 8.2.1 NTRIP <a href=#ntrip1>Version 1</a><br>
1210&nbsp; &nbsp; &nbsp; 8.2.2 NTRIP <a href=#ntrip2>Version 2</a><br>
1211&nbsp; &nbsp; &nbsp; 8.2.3 RTCM <a href=#rtcm2>Version 2.x</a><br>
1212&nbsp; &nbsp; &nbsp; 8.2.4 RTCM <a href=#rtcm3>Version 3.x</a><br>
12138.3. <a href=#rtigs>RTIGS</a><br>
1214&nbsp; &nbsp; &nbsp; 8.3.1 <a href=#soc>SOC</a><br>
12158.4. <a href=#config>Configuration Example</a><br>
12168.5. <a href=#links>Links</a><br>
1217</p>
1218
1219<p><a name=history><h3>8.1 Revision History</h3></p>
1220<table>
1221<tr></tr>
1222
1223<tr>
1224<td>Dec 2006 &nbsp;</td><td>Version 1.0b &nbsp;</td>
1225<td>[Add] First Beta Binaries published based on Qt 4.2.3.</td>
1226</tr>
1227
1228<tr>
1229<td>Jan 2007 &nbsp;</td><td>Version 1.1b &nbsp;</td>
1230<td>[Add] Observables C2, S1, and S2<br>[Add] Virtual reference station access<br>[Bug] RTCM2 decoder time tag fixed<br>[Mod] Small letters for public RINEX skeleton files<br>[Add] Online help through Shift+F1</td>
1231</tr>
1232
1233<tr>
1234<td>Apr 2007 &nbsp;</td><td>Version 1.2b &nbsp;</td>
1235<td>[Bug] Output only through IP port<br>[Bug] Method 'reconnecting' now thread-save<br> [Add] ZERO decoder added<br> [Mod] Download public RINEX skeletons once per day<br> [Mod] Upgrade to Qt Version 4.2.3<br> [Mod] Replace 'system' call for RINEX script by 'QProcess'<br> [Add] HTTP Host directive for skeleton file download<br> [Add] Percent encoding for user IDs and passwords<br> [Bug] Exit execution of calling thread for RTCM3 streams<br> [Bug] Signal-slot mechanism for threads</td>
1236</tr>
1237
1238<tr>
1239<td>May 2007 &nbsp;</td><td>Version 1.3 &nbsp;</td>
1240<td>[Add] Source code published.</td>
1241</tr>
1242
1243<tr>
1244<td>Jul 2007 &nbsp;</td><td>Version 1.4 &nbsp;</td>
1245<td>[Bug] Skip messages from proxy server<br> [Bug] Call RINEX script through 'nohup'</td>
1246</tr>
1247
1248<tr>
1249<td>Apr 2008 &nbsp;</td><td>Version 1.5 &nbsp;</td>
1250<td>[Add] Handle ephemeris from RTCM Version 3.x streams<br> [Add] Upgrade to Qt Version 4.3.2<br> [Add] Optional RINEX v3 output<br> [Add] SBAS support<br> [Bug] RINEX skeleton download following stream outage<br> [Add] Handle ephemeris from RTIGS streams<br> [Add] Monitor stream failure/recovery and latency<br> [Mod] Redesign of main window<br> [Bug] Freezing of About window on Mac systems<br> [Bug] Fixed problem with PRN 32 in RTCMv2 decoder<br> [Bug] Fix for Trimble 4000SSI receivers in RTCMv2 decoder<br> [Mod] Major revision of input buffer in RTCMv2 decoder</td>
1251</tr>
1252
1253<tr>
1254<td>Dec 2008 &nbsp;</td><td>Version 1.6 &nbsp;</td>
1255<td>[Mod] Fill blanc columns in RINEXv3 with 0.000<br> [Add] RTCMv3 decoder for clock and orbit corrections<br>[Add] Check RTCMv3 streams for incoming message types<br> [Add] Decode RTCMv2 message types 3, 20, 21, and 22<br> [Add] Loss of lock and lock time indicator<br> [Bug] Rounding error in RTCMv3 decoder concerning GLONASS height<br> [Mod] Accept GLONASS in RTCMv3 when transmitted first<br> [Add] Leap second 1 January 2009<br> [Add] Offline mode, read data from file<br> [Add] Output antenna descriptor, coordinates and excentricities from RTCMv3<br> [Add] Reconfiguration on-the-fly<br> [Mod] Binary ouput of synchronized observations<br> [Add] Binary output of unsynchronized observations<br> [Bug] Fixed problem with joined RTCMv3 blocks</td>
1256</tr>
1257
1258<tr>
1259<td>Dec 2008 &nbsp;</td><td>Version 1.6.1 &nbsp;</td>
1260<td>[Mod] HTTP GET when no proxy in front</td>
1261</tr>
1262
1263<tr>
1264<td>August 2009 &nbsp;</td><td>Version 1.7 &nbsp;</td>
1265<td>[Bug] RINEX navigation file format<br> [Add] Upgrade to Qt Version 4.5.2<br> [Add] Support of NTRIP v2<br> [Add] Rover support via serial port<br> [Add] Show broadcaster table from www.rtcm-ntrip.org<br> [Add] Enable/disable tab widgets<br> [Add] User defined configuration file name<br> [Mod] Switch to configuration files in ini-Format<br> [Add] Daily logfile rotation<br> [Add] Read from TCP/IP port, by-pass NTRIP transport protocol<br> [Add] Save NMEA messages coming from rover<br> [Add] Auto start<br> [Add] Drag and drop ini files<br> [Add] Read from serial port, by-pass NTRIP transport protocol<br> [Mod] Update following RTCM 091-2009-SC104-542 document<br> [Mod] Output format of Broadcast Corrections</td>
1266</tr>
1267
1268</table>
1269</p>
1270
1271<p><a name="rtcm"><h4>8.2. RTCM</h4></p>
1272
1273<p>
1274The 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.
1275<p>
1276Personal copies of RTCM Recommended Standards can be ordered through <u>http://www.rtcm.org/orderinfo.php</u>.
1277</p>
1278
1279<p><a name="ntrip1"><h4>8.2.1 NTRIP Version 1</h4></p>
1280
1281<p>
1282'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.
1283</p>
1284
1285<p>
1286NTRIP 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.
1287</p>
1288
1289<p>
1290NTRIP 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.
1291</p>
1292
1293<p>
1294NTRIP is an open none-proprietary protocol. Major characteristics of NTRIP's dissemination technique are:
1295<ul>
1296<li>Based on the popular HTTP streaming standard; comparatively easy to implement when having limited client and server platform resources available.</li>
1297<li>Application not limited to one particular plain or coded stream content; ability to distribute any kind of GNSS data.</li>
1298<li>Potential to support mass usage; disseminating hundreds of streams simultaneously for thousands of users possible when applying modified Internet Radio broadcasting software.</li>
1299<li>Considering security needs; stream providers and users don't necessarily get into contact, streams often not blocked by firewalls or proxy servers protecting Local Area Networks.</li>
1300<li>Enables streaming over mobile IP networks because of using TCP/IP.</li>
1301</ul>
1302</p>
1303
1304<p>
1305The 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).
1306</p>
1307
1308<p>
1309Source-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'.
1310</p>
1311<p>
1312Source-table records of type NET contain the following data fields: 'identifiey', 'operator', 'authentication', 'fee', 'web-net', 'web-str', 'web-reg', 'misc'.
1313</p>
1314<p>
1315Source-table records of type CAS contain the following data fields: 'host', 'port', 'identifier', 'operator', 'nmea', 'country', 'latitude', 'longitude', 'misc'.
1316</p>
1317
1318<p><a name="ntrip2"><h4>8.2.1 NTRIP Version 2</h4></p>
1319
1320<p>
1321The major changes of NTRIP version 2.0 compared to version 1.0 are:
1322</p>
1323
1324<ul>
1325<li>cleared and fixed design problems and HTTP protocol violations;</li>
1326<li>replaced non standard directives;</li>
1327<li>chunked transfer encoding;</li>
1328<li>improvements in header records;</li>
1329<li>source-table filtering; and</li>
1330<li>RTSP communication.</li>
1331</ul>
1332
1333<p>NTRIP version 2 allows to either communicate in TCP/IP mode or in RTSP/RTP mode whereas version 1 is limited to TCP/IP only.
1334</p>
1335
1336<p><a name="rtcm2"><h4>8.2.3 RTCM Version 2.x</h4></p>
1337<p>
1338Transmitting GNSS carrier phase data can be done through RTCM Version 2.x messages. Please note that only RTCM Version 2.2 and 2.3 streams may include GLONASS data. Messages that may be of some interest here are:
1339</p>
1340
1341<ul>
1342<li>
1343Type 1 message is the range correction message and is the primary message in code-phase differential positioning (DGPS). It is computed in the base receiver by computing the error in the range measurement for each tracked SV.
1344</li>
1345<li>
1346Type 2 message is automatically generated when a new set of satellite ephemeris is downloaded to the base receiver. It is the computed difference between the old ephemeris and the new ephemeris. Type 2 messages are used when the base station is transmitting Type 1 messages.
1347</li>
1348<li>
1349Type 3 and 22 messages are the base station position and the antenna offset. Type 3 and 22 are used in RTK processing to perform antenna reduction.
1350</li>
1351<li>
1352Type 6 message is a null frame filler message that is provided for data links that require continuous transmission of data, even if there are no corrections to send. As many Type 6 messages are sent as required to fill in the gap between two correction messages (type 1). Message 6 is not sent in burst mode.
1353</li>
1354<li>
1355Type 9 message serves the same purpose as Type 1, but does not require a complete satellite set. As a result, Type 9 messages require a more stable clock than a station transmitting Type 1 's, because the satellite corrections have different time references.
1356</li>
1357<li>
1358Type 16 message is simply a text message entered by the user that is transmitted from the base station to the rover. It is used with code-phase differential.
1359</li>
1360<li>
1361Type 18 and 20 messages are RTK uncorrected carrier phase data and carrier phase corrections.
1362</li>
1363<li>
1364Type 19 and 21 messages are the uncorrected pseudo-range measurements and pseudo-range corrections used in RTK.
1365</li>
1366<li>
1367Type 23 message provides the information on the antenna type used on the reference station.
1368</li>
1369<li>
1370Type 24 message carries the coordinates of the installed antenna's ARP in the GNSS coordinate system coordinates.
1371</li>
1372</ul>
1373
1374<p><a name="rtcm3"><h4>8.2.4 RTCM Version 3.x</h4></p>
1375<p>
1376RTCM Version 3.x has been developed as a more efficient alternative to RTCM Version 2.x. 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.x standard is intended to correct these weaknesses.
1377</p>
1378<p>
1379RTCM Version 3.x defines a number of message types. Messages that may be of interest here are:
1380</p>
1381<ul>
1382<li>Type 1001, GPS L1 code and phase.</li>
1383<li>Type 1002, GPS L1 code and phase and ambiguities and carrier to noise ratio.</li>
1384<li>Type 1003, GPS L1 and L2 code and phase.</li>
1385<li>Type 1004, GPS L1 and L2 code and phase and ambiguities and carrier to noise ratio.</li>
1386<li>Type 1005, Station coordinates XZY for antenna reference point.</li>
1387<li>Type 1006, Station coordinates XYZ for antenna reference point and antenna height.</li>
1388<li>Type 1007, Antenna descriptor and ID.</li>
1389<li>Type 1008, Antenna serial number.</li>
1390<li>Type 1009, GLONASS L1 code and phase.</li>
1391<li>Type 1010, GLONASS L1 code and phase and ambiguities and carrier to noise ratio.</li>
1392<li>Type 1011, GLONASS L1 and L2 code and phase.</li>
1393<li>Type 1012, GLONASS L1 and L2 code and phase and ambiguities and carrier to noise ratio.</li>
1394<li>Type 1013, Modified julian date, leap second, configured message types and interval.</li>
1395<li>Type 1014 and 1017, Network RTK (MAK) messages (under development).</li>
1396<li>Type 1019, GPS ephemeris.</li>
1397<li>Type 1020, GLONASS ephemeris.</li>
1398<li>Type 4088 and 4095, Proprietary messages (under development).
1399</li>
1400</ul>
1401
1402<p><a name="rtigs"><h4>8.3. RTIGS</h4></p>
1403<p>
1404RTIGS stands for a data format and transport protocol for GPS observations. It was defined by the Real-Time IGS Working Group (RTIGS WG). Its definition is based on the SOC format. Every RTIGS record has one of the following numbers:
1405</p>
1406<p>
1407Station record number 100<br>
1408Observation record (O_T) number 200<br>
1409Ephemeris record (E_T) number 300<br>
1410Meteorological record (M_T) number 400
1411</p>
1412<p>
1413Every station has one of the following unique numbers:
1414</p>
1415<p>
14161-99 reserved for JPL<br>
1417100-199 reserved for NRCan<br>
1418200-299 reserved for NGS<br>
1419300-399 reserved for ESOC<br>
1420400-499 reserved for GFZ<br>
1421500-599 reserved for BKG<br>
1422600-699 reserved for GEOSCIENCE AUS<br>
1423700-799 others<br>
1424etc
1425</p>
1426<p>
1427The number of bytes in each real time message includes the header as well as the data content, but NOT the pointer.
1428</p>
1429<p>
1430For example:
1431</p>
1432<ul>
1433<li>A station message is output once per hour and is 20 bytes.</li>
1434<li>An observation message is output once per second. The header is 12 bytes long and the SOC data is 21 bytes per PRN. So a typical RTIGSO_T message will be 390 bytes if 8 sats are being tracked.</li>
1435<li>An ephemeris message is output when the ephemeris is decoded by the GPS receiver. The time in the ephemeris header is the collected time. Only one ephemeris can be bundled in a RTIGSE_T message.<br>
1436A RTIGSE_T message contains one eph. The message consists of 12 header bytes and 72 ephemeris bytes, for a total of 84 bytes.</li>
1437<li>The RTIGSM_T (met) message should be issued once every 15 minutes. A basic met message consists of a 12 byte header and 3 longs (temp, press and relative humidity) for a total of 24 bytes.</li>
1438</ul>
1439<p>
1440All records are related to a station configuration indicated by the Issue of Data Station (IODS). The IODS will enable the user to identify the equipment and software that was used to derive the observation data.
1441</p>
1442<p>
1443Each record header contains the GPS Time in seconds which flows continuously from 6 Jan-1980 onwards.
1444</p>
1445<p>
1446The data payload of each record consists of observations. The structures indicate a pointer to data but in fact the broadcast messages do not contain the pointer, only the data. Users will have to manage the data and the pointer is shown in order to illustrate where the data is located in the message and one possible data management option.
1447</p>
1448<p>
1449All record data are in network byte order (Big Endian), i.e. IA32 users have to swap bytes.
1450</p>
1451<p>
1452Visit <u>http://igscb.jpl.nasa.gov/mail/igs-rtwg/2004/msg00001.html</u> for further details.
1453</p>
1454
1455<p><a name="soc"><h4>8.3.1 SOC</h4></p>
1456<p>
1457The SOC format has been designed in July 1999 by the Jet Propulsion Laboratory (JPL) and the California Institute of Technology (CalTech) to transport 1Hz GPS data with minimal bandwidth over the open Internet. SOC follows the 'little-endian' byte order meaning that the low-order byte of a number is stored in memory at the lowest address, and the high-order byte at the highest address. Because the transport layer is UDP, the format does not include sync bits, a checksum, or cyclic redundancy checksum (CRC). SOC allows to transport the GPS observable CA, P1, P2, L1, and L2, efficiently compressed down to 14 bytes with 1 mm range resolution and 0.02 mm phase resolution. SOC contains epochs for cycle slips, a stand-alone time-tag per epoch, a minimum representation of the receiver's clock solution, 3 SNR numbers, a unique site id, a modulo 12 hour sequence number and flags for receiver type and GPS health. SOC's simple structure comprises an 8 byte header, a 9 byte overhead for timetag, number of gps, etc., plus 21 data bytes per gps.
1458</p>
1459<p>
1460Visit <u>http://gipsy.jpl.nasa.gov/igdg/papers/SOC_FORMAT.ppt</u> for further details.
1461</p>
1462<p>
1463</p>
1464<p><a name="config"><h4>8.4. Configuration Example</h4></p>
1465<p>
1466The following table's left column is an example for the contents of a configuration file 'BNC.ini'. It enables the retrieval of stream ACOR0 form www.euref-ip.net for the generation of 15 min RINEX files. RINEX files are uploaded to an archive using script 'up2archive' :
1467</p>
1468<table>
1469<tr></tr>
1470<tr><td><b>Option</b></td><td><b>Affiliation</b></td></tr>
1471<tr><td>[General]</td><td>Settings: Group</td></tr>
1472<tr><td>adviseFail=15</td><td>Outages: Failure threshold</td></tr>
1473<tr><td>adviseReco=5</td><td>Outages: Recovery threshold</td></tr>
1474<tr><td>adviseScript=</td><td>Outages: Script (full path)</td></tr>
1475<tr><td>autoStart=0</td><td>General: Auto start</td></tr>
1476<tr><td>binSample=0</td><td>Feed Engine: Sampling</td></tr>
1477<tr><td>casterUrlList=http://user:pass@euref-ip:2101</td><td>Internal memory: Visited URLs</td></tr>
1478<tr><td>corrIntr=1 day</td><td>Broadcast Corrections: Interval</td></tr>
1479<tr><td>corrPath=</td><td>Broadcast Corrections: Directory </td></tr>
1480<tr><td>corrPort=</td><td>Broadcast Corrections: Port</td></tr>
1481<tr><td>corrTime=5</td><td>Broadcast Corrections: Wait for full epoch</td></tr>
1482<tr><td>ephIntr=15 min</td><td>RINEX Ephemeris: Interval</td></tr>
1483<tr><td>ephPath=</td><td>RINEX Ephemeris: Directory</td></tr>
1484<tr><td>ephV3=0</td><td>RINEX Ephemeris: Version 3</td></tr>
1485<tr><td>font=</td><td>Internal memory: Used font</td></tr>
1486<tr><td>logFile=/home/weber/bnc.log</td><td>General: Logfile (full path)</td></tr>
1487<tr><td>miscMount=</td><td>Miscellaneous: Mountpoint</td></tr>
1488<tr><td>mountPoints=//user:pass@www.euref-ip.net:2101<br>/ACOR0 RTCM_2.3 43.36 351.60 no 1</td><td>Streams: broadcaster:port/mountpoint</td></tr>
1489<tr><td>ntripVersion=1</td><td>Add Stream: NTRIP Version</td></tr>
1490<tr><td>obsRate=</td><td>Outages: Observation rate</td></tr>
1491<tr><td>onTheFlyInterval=1 day</td><td>General: Reread configuration</td></tr>
1492<tr><td>outEphPort=</td><td>RINEX Ephemeris: Port</td></tr>
1493<tr><td>outFile=</td><td>Feed Engine: File (full path)</td></tr>
1494<tr><td>outPort=</td><td>Feed Engine: Port</td></tr>
1495<tr><td>outUPort=</td><td>Feed Engine: Port (unsynchronized)</td></tr>
1496<tr><td>perfIntr=</td><td>Miscellaneous: Log latency</td></tr>
1497<tr><td>proxyHost=</td><td>Proxy: Proxy host</td></tr>
1498<tr><td>proxyPort=</td><td>Proxy: Proxy port</td></tr>
1499<tr><td>rnxAppend=2</td><td>General: Append files</td></tr>
1500<tr><td>rnxIntr=15 min</td><td>RINEX Observations: Interval</td></tr>
1501<tr><td>rnxPath=/home/user/rinex</td><td>RINEX Observations: Directory</td></tr>
1502<tr><td>rnxSample=0</td><td>RINEX Observations: Sampling</td></tr>
1503<tr><td>rnxScript=/home/user/rinex/up2archive</td><td>RINEX Observations: Script (full path)</td></tr>
1504<tr><td>rnxSkel=</td><td>RINEX Observations: Skeleton extension</td></tr>
1505<tr><td>rnxV3=0</td><td>RINEX Observation: Version 3</td></tr>
1506<tr><td>scanRTCM=0</td><td>Miscellaneous: Scan RTCM</td></tr>
1507<tr><td>serialAutoNMEA=Auto</td><td>Serial Output: NMEA</td></tr>
1508<tr><td>serialBaudRate=9600</td><td>Serial Output: Baud rate</td></tr>
1509<tr><td>serialDataBits=8</td><td>Serial Output: Data bits</td></tr>
1510<tr><td>serialHeightNMEA=</td><td>Serial Output: Height</td></tr>
1511<tr><td>serialMountPoint=</td><td>Serial Output: Mountpoint</td></tr>
1512<tr><td>serialParity=NONE</td><td>Serial Output: Parity</td></tr>
1513<tr><td>serialPortName=</td><td>Serial Output: Port name</td></tr>
1514<tr><td>serialStopBits=1</td><td>Serial Output: Stop bits</td></tr>
1515<tr><td>startTab=0</td><td>Internal memory: Top tab</td></tr>
1516<tr><td>waitTime=5</td><td>Feed Engine: Wait for full epoch</td></tr>
1517</table>
1518</p>
1519<p>
1520Note that the following configuration options saved on disk can be changed/edited on-the-fly while BNC is already processing data:
1521</p>
1522<p>
1523<ul>
1524<li>'mountPoints' to change the selection of streams to be processed, see section 'Streams',</li>
1525<li>'waitTime' to change the 'Wait for full epoch' option, see section 'Feed Engine', and</li>
1526<li>'binSampl' to change the 'Sampling' option, see section 'Feed Engine'.</li>
1527</ul>
1528</p>
1529
1530<p><a name="links"><h3>8.5 Links</h3></p>
1531<table>
1532<tr></tr>
1533<tr><td>NTRIP &nbsp;</td><td><u>http://igs.bkg.bund.de/index_ntrip.htm</u></td></tr>
1534<tr><td>EUREF-IP NTRIP broadcaster &nbsp;</td><td><u>http://www.euref-ip.net/home</u></td></tr>
1535<tr><td>IGS-IP NTRIP broadcaster &nbsp;</td><td><u>http://www.igs-ip.net/home</u></td></tr>
1536<tr><td>NTRIP broadcaster overview &nbsp;</td><td><u>http://www.rtcm-ntrip.org/home</u></td></tr>
1537<tr><td>EUREF-IP Project &nbsp;</td><td><u>http://www.epncb.oma.be/euref_IP</u></td></tr>
1538<tr><td>Real-time IGS Pilot Project &nbsp;</td><td><u>http://www.rtigs.net/pilot</u></td></tr>
1539<tr><td>Radio Technical Commission<br>for Maritime Services &nbsp;</td><td><u>http://www.rtcm.org</u>
1540</table>
1541
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