Changeset 6624 in ntrip


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Timestamp:
Mar 3, 2015, 4:41:01 PM (10 years ago)
Author:
weber
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  • trunk/BNC/src/bnchelp.html

    r6614 r6624  
    523523<p><a name="rinex"><h4>3.4. RINEX Observations</h4></p>
    524524<p>
    525 Observations will be converted to RINEX if they come in either RTCM Version 2 or RTCM Version 3 format. Depending on the RINEX version and incoming RTCM message types, files generated by BNC may contain data from GPS, GLONASS, Galileo, SBAS, QZSS and BeiDou. In case an observation type is listed in the RINEX header but the corresponding observation is unavailable, its value is set to zero '0.000'. Note that the 'RINEX TYPE' field in the RINEX Version 3 Observation file header is always set to 'M(MIXED)' or 'Mixed' even if the file only contains data from one system.
    526 </p>
    527 <p>
    528 It is important to understand that converting RTCM streams to RINEX files requires a-priori information on observation types for specifying a complete RINEX header. Regarding the RINEX Version 2 file header, BNC simply introduces all observation types defined in the Version 2 standard and later reports "0.000" for all observations which are not received. However, following this approach is not possible for RINEX Version 3 files from RTCM Version 3 MSM streams because of the huge number of observation types which might in principle show up. The solution implemented in BNC is to start with RINEX Version 3 observation type records from skeleton files (see section 'Skeleton Extension') and switch to a default selection of observation types when such skeleton file is not available or it does not contain the required information. The 'Default selection of observation types specified' for a RINEX Version 3 file would be as follows:
     525Observations will be converted to RINEX if they come in either RTCM Version 2 or RTCM Version 3 format. Depending on the RINEX version and incoming RTCM message types, files generated by BNC may contain data from GPS, GLONASS, Galileo, SBAS, QZSS and/or BeiDou. In case an observation type is listed in the RINEX header but the corresponding observation is unavailable, its value is set to zero '0.000'. Note that the 'RINEX TYPE' field in the RINEX Version 3 Observation file header is always set to 'M(MIXED)' or 'Mixed' even if the file only contains data from one system.
     526</p>
     527<p>
     528It is important to understand that converting RTCM streams to RINEX files requires a-priori information on observation types for specifying a complete RINEX header. Regarding the RINEX Version 2 file header, BNC simply introduces all observation types defined in the Version 2 standard and later reports "0.000" for all observations which are not received. However, following this approach is not possible for RINEX Version 3 files from RTCM Version 3 MSM streams because of the huge number of observation types which might in principle show up. The solution implemented in BNC is to start with RINEX Version 3 observation type records from skeleton files (see section 'Skeleton Extension') and switch to a default selection of observation types when such skeleton file is not available or does not contain the required information. The following is a default selection of observation types specified for a RINEX Version 3 file:
    529529</p>
    530530<pre>
    … …  
    545545</p>
    546546<p>
    547 The screenshot below shows an example setup of BNC when converting streams to RINEX. Streams are coming from various NTRIP Broadcasters as well as from a serial communication link. Specifying a decoder string 'ZERO' means to not convert the affected stream contents but save its contents as received.
     547The screenshot below shows an example setup of BNC when converting streams to RINEX. Streams are coming from various NTRIP Broadcasters as well as from a serial communication link. Specifying a decoder string 'ZERO' means to not convert the affected stream but save its contents as received.
    548548</p>
    549549<p><img src="IMG/screenshot16.png"/></p>
    … …  
    688688<p><a name="rnxvers2"><h4>3.4.7 Version 2 - optional</h4></p>
    689689<p>
    690 GNSS observation data are generally hold available by BNC according to attributes defined in RINEX Version 3. These attributes describe the tracking mode or channel of observations. Capital letters specifying observation attributes are C, D, I, L, M, P, Q, S, W, X, Y, and N, see RINEX Version 3 documentation.
    691 </p>
    692 <p>There are two applications where BNC can output observation data following RINEX Version 2:
    693 <ul>
    694 <li>
    695 Saving incoming observation streams in RINEX Version 2 format.
    696 </li>
    697 <li>
    698 'Edit/Concatenate' RINEX 3 files and save them in Version 2 format.
    699 </li>
    700 </ul>
    701 As the Version 2 format ignores observation attributes, BNC is forced to map RINEX Version 3 to RINEX Version 2 although this can't be done in one-to-one correspondance. Hence we introduce a priority list of attributes for mapping Version 3 to Version 2.
    702 </p>
    703 <p>
    704 The default priority list is an empty option string meaing a priority of 'CWPX_?' attributes when mapping RINEX 3 to RINEX 2. (Noch nicht fertig.)
     690GNSS observation data are generally hold available by BNC according to attributes as defined in RINEX Version 3. These attributes describe the tracking mode or channel when generating the observation signals. Capital letters specifying signal generation attributes are A, B, C, D, I, L, M, N, P, Q, S, W, X, Y, and Z, see RINEX Version 3 documentation. Although RINEX Version 3 with its signal generation attributes is the internal processing and default output format of BNC, there are two applications where the program can produce data in RINEX Version 2 format:
     691<ol type=1>
     692<li>When saving the contents of incoming observation streams in RINEX Version 2 files as described in this section.</li>
     693<li>When editing or concatenating RINEX 3 files to save them in Version 2 format, see section on 'RINEX Editing & QC'.</li>
     694</ol>
     695As the Version 2 format ignores signal generation attributes, BNC is forced to map RINEX Version 3 to RINEX Version 2 although this can't be done in one-to-one correspondance. Hence we introduce a 'Signal priority' list of attributes (characters, forming a string) for mapping Version 3 to Version 2.
     696</p>
     697<p>
     698The default 'Signal priority' list is an empty option string meaning a priority sequence of 'CWPX_?' attributes when mapping RINEX 3 to RINEX 2. The meaning of this sequence of characters - take it as an example - is as follows:
     699<ul>
     700<li>Signals with attribute 'C' enjoy the highest priority. If such a Version 3 observation becomes available it is presented as RINEX Version 2 observation if that is the format you wish to see. Observations with other attributes are ignored.</li>
     701<li>If no signal with 'C' attribute is available but we have an observation with 'W' attribute, BNC presents that one as RINEX Version 2 observation and ignores all observations with other attributes. The same applies mutatis mutandis to observations with P and X attributes.</li>
     702<li>If no signal with 'C', 'W', 'P', or 'X' attribute is availalbe but a signal with undefined (blank, '_') generation attribute exists, BNC presents that one as RINEX Version 2 observation.</li>
     703<li>If no signal with 'C', 'W', 'P', 'X', or '_' generation attribute exists then the question mark '?' tells BNC to present the first of any other appearing signal as RINEX Version 2 observation.</li>
     704</ul>
     705</p>
     706<p>
     707You may like to specify you own 'Signal priority' string for producing RINEX Version 2 files. If you neither convert observation streams to RINEX Version 2 nor concatenate RINEX Version 3 to Version 2 files then the 'Version 2' option is meaningless.
    705708</p>
    706709
    … …  
    712715<p><a name="ephemeris"><h4>3.5. RINEX Ephemeris</h4></p>
    713716<p>
    714 Broadcast Ephemeris can be saved as RINEX Navigation files when received via RTCM Version 3 e.g. as message types 1019 (GPS) or 1020 (GLONASS) or 1044 (QZSS) or 1045 and 1046 (Galileo). 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
     717Broadcast Ephemeris can be saved as RINEX Navigation files when received via RTCM Version 3 e.g. as message types 1019 (GPS) or 1020 (GLONASS) or 1044 (QZSS) or 1043 (SBAS) or 1045 and 1046 (Galileo) or 63 (tentative, BeiDou). The file name convention follows the details given in section 'RINEX File Names' except that the first four characters are 'BRDC' and the last character is
    715718</p>
    716719<ul>
    … …  
    16561659<ul>
    16571660<li>requires pulling in addition a stream carrying satellite orbit and clock corrections to Broadcast Ephemeris in the form of RTCM Version 3 'State Space Representation' (SSR) messages. Note that for BNC these Broadcast Corrections need to be referred to the satellite's Antenna Phase Center (APC). Streams providing such messages are listed on <u>http://igs.bkg.bund.de/ntrip/orbits</u>. Stream 'CLK11' on NTRIP Broadcaster 'products.igs-ip.net:2101' is an example.</li>
    1658 <li>may require pulling a stream carrying Broadcast Ephemeris available as RTCM Version 3 message types 1019, 1020, 1044, 1045 and 1046. This is a must only when the stream coming from the receiver does not contain Broadcast Ephemeris or provides them only at very low repetition rate. Streams providing such messages are listed on <u>http://igs.bkg.bund.de/ntrip/ephemeris</u>. Stream 'RTCM3EPH' on caster 'products.igs-ip.net:2101' is an example.</li>
     1661<li>may require pulling a stream carrying Broadcast Ephemeris available as RTCM Version 3 message types 1019, 1020, 1043, 1044, 1045, 1046 and 63 (tentative). This is a must only when the stream coming from the receiver does not contain Broadcast Ephemeris or provides them only at very low repetition rate. Streams providing such messages are listed on <u>http://igs.bkg.bund.de/ntrip/ephemeris</u>. Stream 'RTCM3EPH' on caster 'products.igs-ip.net:2101' is an example.</li>
    16591662</ul>
    16601663</p>
    … …  
    27112714<p><a name="gettable"><h4>3.19.1.1.4 Get Table</h4></p>
    27122715<p>
    2713 Use the 'Get Table' button to download the source-table from the NTRIP Broadcaster. Pay attention to data fields 'format' and 'format-details'. Keep in mind that BNC can only decode and convert streams that come in RTCM Version 2, RTCM Version 3, or RTNET format. For access to observations, Broadcast Ephemeris and Broadcast Corrections in RTCM format streams must contain a selection of appropriate message types as listed in the Annex, cf. data field 'format-details' for available message types and their repetition rates in brackets. Note that in order to produce RINEX Navigation files RTCM Version 3 streams containing message types 1019 (GPS) and 1020 (GLONASS) and 1044 (QZSS) and 1045, 1046 (Galileo) are required. Select your streams line by line, use +Shift and +Ctrl when necessary. The figure below provides an example source-table.
     2716Use the 'Get Table' button to download the source-table from the NTRIP Broadcaster. Pay attention to data fields 'format' and 'format-details'. Keep in mind that BNC can only decode and convert streams that come in RTCM Version 2, RTCM Version 3, or RTNET format. For access to observations, Broadcast Ephemeris and Broadcast Corrections in RTCM format streams must contain a selection of appropriate message types as listed in the Annex, cf. data field 'format-details' for available message types and their repetition rates in brackets. Note that in order to produce RINEX Navigation files RTCM Version 3 streams containing message types 1019 (GPS) and 1020 (GLONASS) and 1043 (SBAS) and 1044 (QZSS) and 1045, 1046 (Galileo) and 63 (tentative, BeiDou) are required. Select your streams line by line, use +Shift and +Ctrl when necessary. The figure below provides an example source-table.
    27142717</p>
    27152718<p>
    … …  
    31063109[Mod] SNR and MP visualization depending on RINEX observation attribute<br>
    31073110[Bug] Saastamoinen tropospheric correction for very high elevation receivers<br>
    3108 [Add] Comparison of SP3 files
     3111[Add] Comparison of SP3 files<br>
    31093112[Add] RTCMv3 SBAS Broadcast Ephemeris message 1043<br>
     3113[Add] RTCMv3 BeiDou Broadcast Ephemeris message 63, tentative<br>
    31103114</td>
    31113115</tr>
    … …  
    32443248<li>Type 1045, Galileo F/NAV ephemeris.</li>
    32453249<li>Type 1046, Galileo I/NAV ephemeris.</li>
     3250<li>Type   63, BeiDou ephemeris, tentative.</li>
    32463251<li>Type 4088 and 4095, Proprietary messages.
    32473252</li>
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