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1.. index:: BNC overview
2
3BNC Overview
4************
5
6.. index:: GNSS supported
7
8Supported GNSS and applications
9===============================
10
11.. only:: latex
12
13 .. raw:: latex
14
15 BNC is permanently completed to finally support all existing GNSS systems throughout all features of the program. Table~\ref{tab:rtcm3_status_bnc} shows in detail which GNSS systems are supported so far by particular applications when using the latest BNC version. Application areas named here are:
16
17.. only:: html
18
19 BNC is permanently completed to finally support all existing GNSS systems throughout all features of the program. :numref:`Table %s <tab_BNC_RTCM>` shows in detail which GNSS systems are supported so far by particular applications when using the latest BNC version. Application areas named here are:
20
21* Decoding of RTCM or RTNET [#f_rtnet]_ streams
22* RINEX and SP3 file input and output
23* Encoding of SSR and ephemeris messages
24* Upload of SSR and ephemeris messages
25* PPP (Precise Point Positioning)
26* Combining/merging SSR or ephemeris messages from various real-time sources
27
28It is indicated when a message implementation in BNC could so far only be based on a 'RTCM Proposal'.
29
30.. index:: RTCM Version 3 message implementation
31
32.. only:: latex
33
34 .. raw:: latex
35
36 \begin{landscape}
37 \begin{small}
38 \begin{longtabu} to \linewidth
39 {p{2.5cm}p{4cm}p{2.5cm}>{\centering}X>{\centering}X>{\centering}X>{\centering}X>{\centering}X>{\centering}X>{\centering\arraybackslash}X}
40 \caption{Status of RTCM Version 3 message implementations in BNC supporting various GNSS systems.}\\
41 \label{tab:rtcm3_status_bnc}
42 \textbf{Message} &\textbf{Description}&\textbf{GNSS}&\textbf{RTCM}&\textbf{Decoding}&\textbf{RINEX}&\textbf{Encoding}&\textbf{Upload}&\textbf{PPP} &\textbf{Combin.}\\
43 \textbf{Type \#} & & & \textbf{Proposal} & & \textbf{SP3} & & & & \\
44 \endfirsthead
45 \textbf{Message} &\textbf{Description} &\textbf{GNSS}&\textbf{RTCM}&\textbf{Decoding}&\textbf{RINEX}&\textbf{Encoding}&\textbf{Upload}&\textbf{PPP} &\textbf{Combin.}\\
46 \textbf{Type \#} & & & \textbf{Proposal} & & \textbf{SP3} & & & & \\
47 \hline
48 \endhead
49 \hline
50 \multicolumn{10}{r}{Continued at next page}\\
51 \endfoot
52 \endlastfoot
53 \hline
54 \multicolumn{10}{l}{\textbf{General}}\\
55 \hline
56 1005,1006 &Station & & &x & & & & & \\
57 1007,1008 &Antenna & & &x & & & & & \\
58 1033 &Receiver, Antenna & & &x & & & & & \\
59 1013 &System Parameters & & &x & & & & & \\
60 \hline
61 \multicolumn{10}{l}{\textbf{Navigation}}\\
62 \hline
63 1019 &Ephemeris &GPS & &x &x &x &x &x &x \\
64 1020 &Ephemeris &GLONASS & &x &x &x &x &x &x \\
65 1045 &Ephemeris &Galileo F/Nav & &x &x &x &x & & \\
66 1046 &Ephemeris &Galileo I/Nav &x &x &x &x &x &x & \\
67 1043 &Ephemeris &SBAS &x &x &x &x &x & & \\
68 1044 &Ephemeris &QZSS & &x &x &x &x & & \\
69 63 &Ephemeris &BDS &x &x &x &x &x &x & \\
70 \hline
71 \multicolumn{10}{l}{\textbf{Observation}}\\
72 \hline
73 1001-4 &Conventional Messages &GPS & &x &x & & &x & \\
74 1009-12 &Conventional Messages &GLONASS & &x &x & & &x & \\
75 \hline
76 \multicolumn{10}{l}{\textbf{Observation}}\\
77 \hline
78 1071-77 &Multiple Signal Message &GPS & &x &x & & &x & \\
79 1081-87 &Multiple Signal Message &GLONASS & &x &x & & &x & \\
80 1091-97 &Multiple Signal Message &Galileo & &x &x & & &x & \\
81 1101-07 &Multiple Signal Message &SBAS &x &x &x & & & & \\
82 1111-17 &Multiple Signal Message &QZSS & &x &x & & & & \\
83 1121-27 &Multiple Signal Message &BDS & &x &x & & &x & \\
84 \hline
85 \multicolumn{10}{l}{\textbf{SSR I}}\\
86 \hline
87 1057 &Orbit Corrections &GPS & &x &x &x &x &x &x \\
88 1063 &Orbit Corrections &GLONASS & &x &x &x &x &x &x \\
89 1240 &Orbit Corrections &Galileo &x &x &x &x &x &x & \\
90 1246 &Orbit Corrections &SBAS &x &x &x &x &x & & \\
91 1252 &Orbit Corrections &QZSS &x &x &x &x &x & & \\
92 1258 &Orbit Corrections &BDS &x &x &x &x &x &x & \\
93 1058 &Clock Corrections &GPS & &x &x &x &x &x &x \\
94 1064 &Clock Corrections &GLONASS & &x &x &x &x &x &x \\
95 1241 &Clock Corrections &Galileo &x &x &x &x &x &x & \\
96 1247 &Clock Corrections &SBAS &x &x &x &x &x & & \\
97 1253 &Clock Corrections &QZSS &x &x &x &x &x & & \\
98 1259 &Clock Corrections &BDS &x &x &x &x &x &x & \\
99 1059 &Code Biases &GPS & &x &x &x &x &x & \\
100 1065 &Code Biases &GLONASS & &x &x &x &x &x & \\
101 1242 &Code Biases &Galileo &x &x &x &x &x &x & \\
102 1248 &Code Biases &SBAS &x &x &x &x &x & & \\
103 1254 &Code Biases &QZSS &x &x &x &x &x & & \\
104 1260 &Code Biases &BDS &x &x &x &x &x &x & \\
105 1061, 1062 &User Range Accuracy, HR &GPS & &x & & & & & \\
106 1067, 1068 &User Range Accuracy, HR &GLONASS & &x & & & & & \\
107 1244, 1245 &User Range Accuracy, HR &Galileo &x &x & & & & & \\
108 1250, 1251 &User Range Accuracy, HR &SBAS &x &x & & & & & \\
109 1256, 1257 &User Range Accuracy, HR &QZSS &x &x & & & & & \\
110 1262, 1263 &User Range Accuracy, HR &BDS &x &x & & & & & \\
111 1060 &Comb. Orbits \& Clocks &GPS & &x &x &x &x &x &x \\
112 1066 &Comb. Orbits \& Clocks &GLONASS & &x &x &x &x &x &x \\
113 1243 &Comb. Orbits \& Clocks &Galileo &x &x &x &x &x &x & \\
114 1249 &Comb. Orbits \& Clocks &SBAS &x &x &x &x &x & & \\
115 1255 &Comb. Orbits \& Clocks &QZSS &x &x &x &x &x & & \\
116 1261 &Comb. Orbits \& Clocks &BDS &x &x &x &x &x &x & \\
117 \hline
118 \multicolumn{10}{l}{\textbf{SSR II}}\\
119 \hline
120 1264 &VTEC &GNSS &x &x &x &x &x & & \\
121 1265 &Phase Biases &GPS &x &x &x &x &x & & \\
122 1266 &Phase Biases &GLONASS &x &x &x &x &x & & \\
123 1267 &Phase Biases &Galileo &x &x &x &x &x & & \\
124 1268 &Phase Biases &SBAS &x &x &x &x &x & & \\
125 1269 &Phase Biases &QZSS &x &x &x &x &x & & \\
126 1270 &Phase Biases &BDS &x &x &x &x &x & & \\
127 \hline
128 \end{longtabu}
129 \end{small}
130 \end{landscape}
131
132.. index:: RTCM Version 3 message implementation
133
134.. only:: html
135
136 .. _tab_BNC_RTCM:
137 .. table:: Status of RTCM Version 3 message implementations in BNC supporting various GNSS systems.
138
139 =============== ======================= ============= ============ ============ ============= ============ ============ ============ ============
140 **Message #** **Description** **GNSS** **RTCM** **Decoding** **RINEX/SP3** **Encoding** **Upload** **PPP** **Combin.**
141 **Proposal**
142 =============== ======================= ============= ============ ============ ============= ============ ============ ============ ============
143 **General**
144 -------------------------------------------------------------------------------------------------------------------------------------------------
145 1005,1006 Station x
146 1007,1008 Antenna x
147 1033 Receiver, Antenna x
148 1013 System Parameters x
149 **Navigation**
150 -------------------------------------------------------------------------------------------------------------------------------------------------
151 1019 Ephemeris GPS x x x x x x
152 1020 Ephemeris GLONASS x x x x x x
153 1045 Ephemeris Galileo F/Nav x x x x
154 1046 Ephemeris Galileo I/Nav x x x x x
155 1043 Ephemeris SBAS x x x x x
156 1044 Ephemeris QZSS x x x x
157 63 Ephemeris BDS x x x x x x
158 **Observation**
159 -------------------------------------------------------------------------------------------------------------------------------------------------
160 1001-4 Conventional Messages GPS x x x
161 1009-12 Conventional Messages GLONASS x x x
162 **Observation**
163 -------------------------------------------------------------------------------------------------------------------------------------------------
164 1071-77 Multiple Signal Message GPS x x x
165 1081-87 Multiple Signal Message GLONASS x x x
166 1091-97 Multiple Signal Message Galileo x x x
167 1101-07 Multiple Signal Message SBAS x x x
168 1111-17 Multiple Signal Message QZSS x x
169 1121-27 Multiple Signal Message BDS x x x
170 **SSR I**
171 -------------------------------------------------------------------------------------------------------------------------------------------------
172 1057 Orbit Corrections GPS x x x x x x
173 1063 Orbit Corrections GLONASS x x x x x x
174 1240 Orbit Corrections Galileo x x x x x x
175 1246 Orbit Corrections SBAS x x x x x
176 1252 Orbit Corrections QZSS x x x x x
177 1258 Orbit Corrections BDS x x x x x x
178 1058 Clock Corrections GPS x x x x x x
179 1064 Clock Corrections GLONASS x x x x x x
180 1241 Clock Corrections Galileo x x x x x x
181 1247 Clock Corrections SBAS x x x x x
182 1253 Clock Corrections QZSS x x x x x
183 1259 Clock Corrections BDS x x x x x x
184 1059 Code Biases GPS x x x x x
185 1065 Code Biases GLONASS x x x x x
186 1242 Code Biases Galileo x x x x x x
187 1248 Code Biases SBAS x x x x x
188 1254 Code Biases QZSS x x x x x
189 1260 Code Biases BDS x x x x x x
190 1061, 1062 User Range Accuracy, HR GPS x
191 1067, 1068 User Range Accuracy, HR GLONASS x
192 1244, 1245 User Range Accuracy, HR Galileo x x
193 1250, 1251 User Range Accuracy, HR SBAS x x
194 1256, 1257 User Range Accuracy, HR QZSS x x
195 1262, 1263 User Range Accuracy, HR BDS x x
196 1060 Comb. Orbits & Clocks GPS x x x x x x
197 1066 Comb. Orbits & Clocks GLONASS x x x x x x
198 1243 Comb. Orbits & Clocks Galileo x x x x x x
199 1249 Comb. Orbits & Clocks SBAS x x x x x
200 1255 Comb. Orbits & Clocks QZSS x x x x x
201 1261 Comb. Orbits & Clocks BDS x x x x x x
202 **SSR II**
203 -------------------------------------------------------------------------------------------------------------------------------------------------
204 1264 VTEC GNSS x x x x x
205 1265 Phase Biases GPS x x x x x
206 1266 Phase Biases GLONASS x x x x x
207 1267 Phase Biases Galileo x x x x x
208 1268 Phase Biases SBAS x x x x x
209 1269 Phase Biases QZSS x x x x x
210 1270 Phase Biases BDS x x x x x
211 =============== ======================= ============= ============ ============ ============= ============ ============ ============ ============
212
213.. index:: BNC data flow
214
215Data Flow
216=========
217
218BNC can be used in different contexts with varying data flows. Typical real-time communication follows the Ntrip protocol over TCP/IP (probably via SSL), RTSP/RTP or UDP, plain TCP/IP protocol, or serial communication links. Stream content could be observations, ephemeris, satellite orbit/clock products or NMEA sentences.
219
220:numref:`Fig. %s <fig_1>` shows a flow chart of BNC connected to a GNSS receiver providing observations via serial or TCP communication link for the purpose of Precise Point Positioning. :numref:`Fig. %s <fig_2>` shows the conversion of RTCM streams to RINEX files. :numref:`Fig. %s <fig_3>` shows a flow chart of BNC feeding a real-time GNSS engine which estimates precise orbits and clocks. BNC is used in this scenario to encode correctors to RTCM Version 3 and upload them to an Ntrip Broadcaster. :numref:`Fig. %s <fig_4>` shows BNC combining several Broadcast Correction streams to disseminate the combination product while saving results in SP3 and Clock RINEX files.
221
222.. _fig_1:
223.. figure:: figures/fig_1.png
224 :scale: 100 %
225
226 Flowchart, BNC connected to a GNSS rover for Precise Point Positioning.
227
228.. _fig_2:
229.. figure:: figures/fig_2.png
230 :scale: 100 %
231
232 Flowchart, BNC converting RTCM streams to RINEX batches.
233
234.. _fig_3:
235.. figure:: figures/fig_3.png
236 :scale: 100 %
237
238 Flowchart, BNC feeding a real-time GNSS engine and uploading encoded Broadcast Corrections
239
240.. _fig_4:
241.. figure:: figures/fig_4.png
242 :scale: 100 %
243
244 Flowchart, BNC combining Broadcast Correction streams.
245
246.. index:: BNC handling
247
248Handling
249========
250
251Although BNC is mainly a real-time tool to be operated online, it can be run offline
252
253* To simulate real-time observation situations for debugging purposes;
254* For post processing purposes.
255
256Furthermore, apart from its regular window mode, BNC can be run as a batch/background job in a 'no window' mode, using processing options from a previously saved configuration or from command line.
257
258Unless it runs offline, BNC
259
260* 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;
261* Requires the clock of the host computer to be properly synchronized;
262* 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.
263
264The main window of BNC shows a 'Top menu bar' section, a 'Settings' sections with panels to set processing options, a 'Streams' section, a section for 'Log' tabs, and a 'Bottom menu bar' section :numref:`(Fig. %s) <fig_5>`.
265
266.. _fig_5:
267.. figure:: figures/fig_5.png
268 :scale: 100 %
269
270 Sections on BNC's main window.
271
272Running BNC in interactive mode requires graphics support. This is also required in batch mode when producing plots. Windows and Mac OS X systems always support graphics. However, when using BNC in batch mode on Linux systems for producing plots, you need to make sure that at least a virtual X-Server like 'Xvfb' is installed and the '-display' command line option is used.
273
274The usual handling of BNC is that you first select a number of streams ('Add Stream'). Any stream configured to BNC shows up on the 'Streams' canvas in the middle of BNC's main window. You then go through BNC's various configuration panels to set a combination of input, processing and output options before you start the program ('Start'). Most configuration panels are dedicated to a certain function of BNC. If the first option field on such a configuration panel is empty, the affected functionality is deactivated.
275
276Records of BNC's activities are shown in the 'Log' tab which is part of the 'Log' canvas. The bandwidth consumption per stream, the latency of incoming observations, and a PPP time series for coordinate displacements are also part of that canvas and shown in the 'Throughput', 'Latency' and 'PPP Plot' tabs.
277
278Configuration options are usually first set using BNC's Graphical User Interface (GUI), then saved in a configuration file. For routine operations in batch mode all of BNC's configuration options can be extracted from the configuration file and applied using the program's Command Line Interface (CLI).
279
280.. index:: BNC limitations
281
282Limitations
283===========
284
285* In 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.
286* Using RTCM Version 3 to produce RINEX files, BNC will properly handle most message types. However, 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).
287* Using RTCM Version 2, 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 stream carrying message types 1019 (GPS ephemeris) and 1020 (GLONASS ephemeris).
288* BNC'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 content 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.
289* EUREF as well as IGS adhere to an Open Data policy. Streams are made available through Ntrip Broadcasters at www.euref-ip.net, www.igs-ip.net, products.igs-ip.net, and mgex.igs-ip.net 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.
290* Once BNC has been started, many of its configuration options cannot be changed as long as it is stopped. See chapter 'Reread Configuration' for on-the-fly configuration exceptions.
291* Drag and drop of configuration files is currently not supported on Mac OS X. On such system you have to start BNC via command line.
292
293.. rubric:: Footnotes
294
295.. [#f_rtnet] RTNet, GPS Solutions Inc., http://gps-solutions.com
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