Characterizing multipath in satellite navigation measurements for urban environments.

摘要

This thesis focuses on the characterization of multipath in satellite navigation measurements for urban environments using a modern receiver. In order to increase the accuracy of the Global Positioning System (GPS) in urban environments for the purpose of automobile navigation, the impact of multipath should be mitigated. However, to better understand the operational environment and the algorithms best suited for this, such locations must first be statistically characterized, which is the purpose of this thesis.; This goal will be accomplished by initially performing a literature survey on techniques to measure and assess multipath; and then collecting GPS data in urban environments such as downtown Denver and San Francisco using two different receivers. Range and position data were recorded for each receiver in order to characterized multipath in both the range and position domain. Raw IF data were also collected so that the data could be easily post processed using a reconfigurable software-based GPS receiver architecture.; Using methods identified in the literature search, the level of multipath error will be assessed for individual pseudoranges in urban environments and compared to the level of multipath in more open environments. Also, the stand alone performance of GPS will be evaluated in the position domain with respect to the geometric dilution of precision (GDOP) and satellite availability.