Bernese GPS Software Version 5.0 - Bernese GNSS Software

6. Data Preprocessing
Preprocessing for a
double-difference analysis
code phase
RNXSMT
GPSEST
RESRMS
RESCHK
SATMRK
RXOBV3
CODSPP
SNGDIF
if a bad station
detected
MAUPRP
GPSEST
RESRMS
RESCHK
SATMRK
RINEX observations
Alternative way for
preprocessing
code phase
SNGDIF
RNXSMT
RXOBV3
CODSPP
MAUPRP
Preprocessing for a
zero-difference analysis
code phase
Double-difference processing Zero-difference processing
if a bad station
detected
RNXSMT
RXOBV3
CODSPP
GPSEST
RESRMS
RESCHK
SATMRK
Figure 6.1: Functional flow diagram for the preprocessing part in the Bernese GPS Software.
Gray boxes indicate programs, applied to code and phase in a single run
or in separate runs.
in Section 6.4), and clean the single-difference phase observation files (program MAUPRP,
description in Section 6.5). If you are going to use the Melbourne-Wübbena linear combination
for ambiguity resolution (see Section 8.4) you should use RNXSMT to smooth the
code observations (description in Section 6.2).
For zero-difference solutions, e.g., to estimate receiver or satellite clock corrections, usually
the program RNXSMT is used to screen code and phase observations and to smooth the
code data. The receiver clock synchronization (program CODSPP) is used to prepare a priori
station clock corrections which are stored in the observation files. The disadvantage of
cleaning phase observations using RNXSMT is that the phase data can only be cleaned with
code measurement accuracy. If you have excellent high rate satellite clocks available you
may use program MAUPRP instead of (or in addition to) program RNXSMT to clean the
phase observation files.
The program SNGDIF removes marked observations and keeps the phase ambiguities from
the zero-difference observation files while generating baseline files. If you form baselines
after a zero-difference preprocessing you can, therefore, perform a double difference solution
with the same observations as for a zero-difference analysis. In some cases (e.g., LEO data)
this preprocessing procedure may be preferable also for a double-difference analysis.
Independent from the chosen preprocessing strategy an additional post-fit residual screening
(see Section 6.6) is highly recommended (double difference case) or even mandatory (zerodifference
case). The procedure involves the following steps (that may be iterated):
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iterations