Bernese GPS Software Version 5.0 - Bernese GNSS Software

daily large NEQ
ADDNEQ2 small NEQ
GPSEST
CRD
TRP
study of
troposphere
TRP before
stacking
CRD
Figure 9.12: Generate small normal equation files.
9.5 Typical Applications
archive for
multy-year solution
because they are not considered by ADDNEQ2 (as a result of the diagonal structure of weight
matrix P p in Eqn. (9.10)). Clusters of baselines have, therefore, to be carefully selected for
having minimum overlaps in order to minimize the effects of neglecting these correlations.
Clusters of baselines may be defined either in program SNGDIF using a cluster definition file
(description in Section 22.8.16) or may be automatically generated using program MKCLUS
(see Section 19.12.2.1).
9.5.2 Generate Small Normal Equation Files
For reasonably large networks the troposphere parameters constitute a large fraction of all
estimated parameters and are responsible for large normal equation files. It makes sense
for experimental purposes to set up a number of additional parameters in GPSEST. It
may, however, be advantageous to archive smaller normal equation files for later use for
coordinate time series analysis. Such a reduction of normal equation size may be performed
with program ADDNEQ2.
Suppose, see Figure 9.12, that daily runs of program GPSEST generate large normal equation
files containing coordinate and troposphere parameters. These normal equations may be
used in different ADDNEQ2 runs for studying variations in troposphere delay. In a separate
ADDNEQ2 run, with a single normal equation file as input, the troposphere parameters
may be pre-eliminated before stacking and a small normal equation file may be written
containing only coordinate parameters.
Alternatively to the pre-elimination of all troposphere parameters the option
EXCEPT FOR BOUNDARIES may be used (see Section 9.4.4). Troposphere parameters then
remain accessible at the day boundaries for stacking of a series of normal equations. Note,
however, that in this case you may still end up with a large number of parameters when
stacking many normal equations.
9.5.3 Back-Substitution of Coordinates
Because troposphere parameters are highly correlated with the station height, troposphere
estimates are improved if they are obtained, e.g., from a weekly solution instead of a daily
solution. One may, therefore, be tempted to combine large daily normal equation files,
containing station coordinate and troposphere parameters, to a single weekly solution and
extract both types of parameters from this ADDNEQ2 run.
Bernese GPS Software Version 5.0 Page 209