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TEQC 29 Sept 1998 Release Notes

GPS/GLONASS enhancements

Select your favorite build of teqc in the usual way, but be sure to save your current version in case any new bugs show up. There are a number of significant issues relating to this beta-release of teqc with GLONASS capability, indexed below. Other information on these and other minor bug fixes and enhancements can be found at 1998 Sept 29 bug fixes and at 1998 Sept 29 release log.

Recall that all teqc email traffic will now be handled via an on-line email forum ,teqcunavco.org, to which users can subscribe/unsubscribe. This will continue to be an unmoderated email forum.

--Lou Estey


Z-18 translation

For translationing Z-18 data with this version of teqc, the Z-18 receiver must be run using the GPS time base (rather than the GLONASS time base). To translate the B/E/S fileset into RINEX:

	teqc +nav GPS_RINEX_NAV,GLO_RINEX_NAV Bfile > mixed_RINEX_OBS
First, note that the argument for the "+nav" option takes the two RINEX NAV filenames seperated by a comma (no whitespace, please!). The GPS RINEX NAV filename is assumed to occur first; the GLONASS RINEX NAV filename is assumed to occur second. (There are other ways of obtaining these RINEX files, but I'm just showing the simpliest way to get them.)

Also, this default mode does not apply pseudorange smoothing corrections to the C1, P1, and P2 observables. Also, the L1 phase value is obtained from the P1-code block (rather than the C/A-code block as is the usual with the Berne translator ASRINEXO); this default behaviour is equivalent to including the option "-Ashtech_CA_L1". To apply the pseudorange smoothing corrections:

	teqc +smooth +nav GPS_RINEX_NAV,GLO_RINEX_NAV Bfile > mixed_RINEX_OBS
To use the L1 value in the C/A-code block:
	teqc +Ashtech_CA_L1 +nav GPS_RINEX_NAV,GLO_RINEX_NAV Bfile > mixed_RINEX_OBS
To apply the pseudorange smoothing corrections and use the L1 value in the C/A-code block:
	teqc +smooth +Ashtech_CA_L1 +nav GPS_RINEX_NAV,GLO_RINEX_NAV Bfile > mixed_RINEX_OBS
Thus, four different styles of mixed RINEX OBS files can be generated with the main observables L1, L2, C1, P1, P2.

Furthermore, when tranlating B/E/S data from the Z-18, a special option is automatically turned on to adjust the phase data (for both GPS and GLONASS) for millisecond receiver clock resets. (Note: This is not known to be needed for B/E/S data from the Z-12.) This automatic option is equivalent to specifying "+msec_phs_adj". If you wish to translate into RINEX OBS without adjusting the phase data, include "-msec_phs_adj" on the command line.

In order to successfully translate the Z-18 GLONASS data into the RINEX OBS format, the frequency number of each GLONASS satellite must be known. If all goes well, this will be extracted from info in the E-file, whether or not converting this into the RINEX NAV files. Under extraordinary conditions (e.g. extremely short windows of data collection), the GLONASS navigation messages will be missing from the E-file, and the L1 and L2 GLONASS data will be translated incorrectly. In this case, you can supply the missing slot number to frequency number pairs in a small ASCII file, e.g.:

	15	4
	16	22
	17	24
	22	10
	9	6
Then supply this filename to teqc using the "-glonass_n" option:
	teqc -glonass_n slot_n_file { ...other option...} Bfile > mixed_RINEX_OBS

Remember that this is a beta-release. There are likely to be a few unknown bugs.


GG24 stream translation

The default translation of GG24 stream data into RINEX:

	teqc -week # -P -L2 -max_rx_ch 24 -max_rx_SVs 24 +msec_phs_adj
	  +nav GPS_RINEX_NAV,GLO_RINEX_NAV datafile > mixed_RINEX_OBS
which does not apply the pseudorange smoothing corrections and uses the L1 phase value from the P1-code block. Use "+smooth" and/or "+Ashtech_CA_L1" (see Z-18 above) to obtain the other three data sets for the RINEX OBS file. The "-week" option will probably be necessary to use; for "#", substitute the correct GPS week, the year:DOY, or year:month:day of the start of the data. The options "-P" and "-L2" specify that the receiver is P-codeless and does not track L2; the default set of RINEX observables are L1, C1, D1. The options "-max_rx_ch 24" and "-max_rx_SVs" are needed to inform teqc that the tracking capability of the GG24 is for 24 satellites (12 GPS + 12 GLONASS), rather than the usual 12 for most upper-end GPS-only receivers (e.g. the Z-12). The "+msec_phs_adj" option should correct the L1 phase data when millisecond receiver clock resets occur. Also, use the "-glonass_n" option to supply a slot vs. freq. number information file if necessary. As usual, the observables can be modified using the "-O.obs" option, e.g.
	teqc -O.obs ca+l1+d1+s1 {...other options...} datafile > mixed_RINEX_OBS
to obtain only the RINEX OBS observables C1, L1, D1, and S1 (in that order).

Remember that this is a beta-release. There are likely to be a few unknown bugs. One known bugs (due mainly to my lack of understanding the documentation on the SNG data structure):

  • There may be a problem in the GLONASS NAV file resolving the correct values to use to construct the "epoch of ephemeris" (main time stamp in file) and/or the "message frame time (sec of day UTC)".

GPS/GLONASS QC

To QC RINEX data, use the usual:

	teqc +qc -plot {...other options...} mixed_RINEX_OBS
The option "-plot" (turn off plot file creation) is done because the processing software for the plot files, gt and qcview are not yet ready to handle the mixed GPS/GLONASS plot files (though Jim Johnson is actively working on this).

Like with the Ashtech Z-18 and GG24 translation (see above), you may need to supply a slot vs. freq. number information filename using the "-glonass_n" option.

If using the Berne RINEX file naming convention, i.e. the .YYO or .YYo, .YYN or .YYn, and .YYG or .YYg suffixes for the RINEX OBS, GPS RINEX NAV, and GLONASS RINEX NAV respectively; or .OBS or .obs, .NAV or .nav, and .GLO or .glo suffixes: teqc will automatically search for the matching RINEX NAV files using the supplies RINEX OBS filename(s). Or you can force teqc to read specific NAV filename(s), which can be GPS RINEX NAV and/or GLONASS RINEX NAV:

	teqc +qc -plot -nav RINEX_NAV1,RINEX_NAV2 {...other options...} mixed_RINEX_OBS

For now, GLONASS observations are processed using a qc-lite mode, regardless of whether or not a GLONASS RINEX NAV file is use. (Basically, except the frequency number, the information in the GLONASS NAV file is ignored.)


initial OS builds for beta testing

A limited number of teqc are being done for this initial beta-test (uncompress/unzip as appropriate):

Last modified: Saturday, 10-May-2014 23:05:49 UTC

 

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