Bernese GPS Software Version 5.0 - Bernese GNSS Software

6. Data Preprocessing
RMS of kin. solution” in panel “CODSPP 4: Screening Options”) a search for the worst satellite
is initiated. Each satellite is excluded in turn and that satellite is identified for which the
maximum improvement of the solution is realized if its observation is not contributing. This
procedure is repeated until an acceptable solution is found or the redundancy becomes too
small (option “Min. degree of freedom”). In the latter case no epoch-solution is computed and
all observations of the corresponding epoch are marked. These observations are indicated
by the flag KIN in the summary of the bad observations in the CODSPP program output.
If kinematic coordinates are introduced for a station these positions are used as a priori
information for the epoch solutions. All positions in the kinematic coordinate file are
used if epoch-wise kinematic coordinates are estimated in the program run. If a kinematic
coordinate file is introduced and no kinematic positions are estimated (e.g., accuracy of
the introduced kinematic coordinates is better than expected from the estimation in program
CODSPP) then only those epochs are used as a priori which have the flag K (indicating
a good kinematic position) in the input kinematic coordinate file. For other flags all observations
of the epoch are marked.
In the case of LEO processing alternatively a standard orbit can be introduced instead of a
kinematic coordinate file. A receiver on board of a LEO must be labeled in any case with
the marker type SPACEBORNE in the station information file.
6.3.4 Extraction (CODXTR)
CODXTR (”Menu>Processing>Program output extraction>Code-based clock synchronization”) is the extraction
program for the CODSPP program output. It produces a short summary of all CODSPP
output of the following form:
### PG CODXTR: RMS LARGER THAN 999. M FOR STATION: BRMU 42501S004
FILE: ${P}/IGSRAPID/OBS/BRMU3390.CZO
RMS : 1629.07 M
69 FILES, MAX. RMS: 1629.07 M FOR STATION: BRMU 42501S004
MAX. BAD: 7.21 % FOR STATION: OHI3 66008M006
The summary file contains at least two lines. They give the number of code files that were
processed, the maximum RMS, and the station for which this maximum occurred. The RMS
value should be around 25 meters under SA conditions. With SA off the maximum RMS
value is expected to be about 2.5 meters. Using smoothed code obtained with RNXSMT we
can expect a RNS value below 1 meter.Values up to 300 meters are still acceptable although
they deserve special attention. The next line indicates the station with the largest number
of bad code observations. The percentage is usually below 10%.
In the above example the RMS of the station BRMU 42501S004 exceeds the user specified
option “RMS limit for a good station” in panel “CODXTR 2: Options”. The big RMS indicates
that the receiver clock synchronization failed and that the successful further processing of
the data is not guaranteed. The observation filenames of such stations may be listed in a
deletion file which may be used for removing the files in an automatic processing.
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