2A. Detection and analysis of GNSS multipath

Multipath effect is generated when a signal arrives at the antenna by multiple
paths instead of one direct path. It is, to a large extent, dependent on the
surrounding environment of the antenna and the satellite geometry. Despite
all the efforts put into the mitigation of multipath errors, it remains the
dominant error source that cannot be ignored for GNSS precise positioning
and other GNSS applications. In this thesis report, two methods have been
developed with Trimble Business Center and MATLAB to study the presence
and performance of multipath effect. The first method – Trimble baseline
analysis focuses on the height change pattern of the study station with regard
to its reference station over time. The second method – RINEX analysis
focuses on the change of the geometry-free combination of pseudorange
codes and carrier phase measurements over time. These two methods have
been firstly tested on station KTH and then applied on station Vidsel and station
Botsmark. Various forms of results all indicate the existence of multipath
effect on the three suspicious stations. The height value of the study station
has a variation pattern on a daily basis because of multipath.