Bernese GPS Software Version 5.0 - Bernese GNSS Software

6.5 Preprocessing Phase Observations
The epoch-differences of the receiver clock values estimated in program MAUPRP (δk(t2) −
δk(t1) in Eqns. (6.4)) using the phase observations have to confirm the code based receiver
clock values from program CODSPP within a user specified limit (option “Minimum size of a
clock event” in panel “MAUPRP 7: Clock Events”). If the two clock values are different MAUPRP
reports a clock event, identifies it and, if possible, corrects it. This is important if code and
phase observations will be introduced together into the program GPSEST for the estimation
of clock corrections.
Some receivers generate jumps with the size of a multiple of one millisecond. If such msjumps
are not correctly handled by the receiver or the RINEX converter they may be
repaired by MAUPRP in an analogous way like the clock jumps. Otherwise a new ambiguity
needs to be inserted for each satellite.
If several clock events occur within a short time interval (specified in option “Mark observations
up to a time interval”), the magnitude of all these events are summed up. If this sum is below
the detection limit for clock events the receiver clock problem affects only the few epochs
between the two events. All observations of these epochs are marked to eliminate the clock
event. In this way the number of additional ambiguities may be reduced.
6.5.5 Kinematic Stations
In analogy to the change of the receiver clock between epochs (δk(t2) − δk(t1)) needed in
Eqns. (6.4) for the screening of zero-difference files, the change of the position between
epochs t1 and t2 needs to be estimated for kinematic stations. This step is performed for
zero-difference as well as for single-difference files if the option “Kinematic coordinate estimation”
in panel “MAUPRP 6: Epoch-Difference Solution” is enabled. Usually the ionosphere-free linear
combination L3 is used for this estimation (see option “Frequency for the solution”).
Because four parameters must be estimated for each epoch-difference the redundancy is
small if, e.g., only five or six satellites are observed. This will have, of course, an effect on
the reliability of the cycle slip detection. The situation may be improved if good kinematic
positions can be introduced as a priori information from a “Kinematic input coordinates” file to
be specified in panel “MAUPRP 1: Input Files”. In this case the epoch-difference estimates for
the change of the positions may be constrained using the “A priori coordinate/baseline vector
sigmas” in panel “MAUPRP 6: Epoch-Difference Solution”.
If a kinematic coordinate file is introduced and the “Kinematic coordinate estimation” is disabled
(e.g., if the accuracy of the introduced kinematic coordinates is better than expected from
the epoch-difference solution in program MAUPRP) only those epochs are used as a priori
for which the file gives the flag K (indicating a good kinematic position). For any other flag
all observations of the epoch are marked.
6.5.6 Screening of LEO Data
In the case of preprocessing data from a LEO either a standard orbit or a kinematic coordinate
file may be introduced. A receiver on board of a LEO must be labeled in any case
with the marker type SPACEBORNE in the station information file.
Screening of phase observations from spaceborne receivers may be done with program
MAUPRP in zero-difference mode if high-rate precise GPS clock corrections are introduced
Bernese GPS Software Version 5.0 Page 121