One of the more recent areas of GNSS research of increasing popularity is the study of reflected GNSS signals. This will enable the use of GNSS as a passive radar system that can be used as an alternative to radar altimetry and for ground feature characterization. Of interest is also the possibility to use GNSS signals for object detection. The advantage of using GNSS signals as a passive radar system is that it has complete earth coverage. The signals are, however, weak and the computational load associated with the analysis is heavy.