Bernese GPS Software Version 5.0 - Bernese GNSS Software

8. Initial Phase Ambiguities and Ambiguity Resolution
cluster number. If two ambiguities refer to the same cluster number, this implies that they
have been resolved relative to each other (see e.g., ambiguities 1, 4, and 5 in Figure 8.4).
Any double-difference ambiguity created from two such single-difference ambiguities is then
known.
8.3 Ambiguity Resolution Algorithms
There are four ambiguity resolution strategies implemented in program GPSEST of the
Bernese GPS Software Version 5.0 : ROUND, SIGMA, SEARCH, and QIF which may be selected
in panel “GPSEST 3.2: General Options 2” (Figure 8.5). Different algorithms use different
combinations of the L1 and L2 observations. Let us mention, that for the QIF strategy
both L1 and L2 observations are required, the SEARCH strategy gives the best results with
observations on both frequencies, too, and that the remaining strategies ROUND and SIGMA
work actually with one carrier (or one linear combination) only. It is possible to use 2 linear
combinations in one run, but the ambiguity resolution is performed independently on both
carriers. Which of these strategies is recommended for which solution will be discussed in
Section 8.4.
Selecting the “Resolution strategy” NONE deactivates the ambiguity resolution. Note that
the group of options “HANDLING OF AMBIGUITIES” are only activated if phase baseline
observation files are selected in the first panel of GPSEST.
Figure 8.5: Ambiguity resolution strategy selection for GPSEST.
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