Algorithms for Mapping the Urban Signal Environment for Navigation of Ground Vehicle Operations

Emma Zeller, Kirsten Strandjord

Peer Reviewed

Abstract:	GPS positioning in urban environments is challenging as tall buildings often block, reflect, or diffract signals. These signals then reach the receiver via a non-line-of-sight (NLOS) path, which may result in positioning errors such that a vehicle using conventional GPS will need to slow down or reroute its course. Improvements can be made through urban mapping that allows the specularity and visibility to be predicted at any location of interest within the mapped environment. Building footprints are raytraced to create a database of visibility and specular skyplots, which display the expected sky visibility and likelihood of specular reflections at any given location. Direct position estimation (DPE) is an alternative positioning approach that directly computes a multi-dimensional spatial correlogram that can be analyzed to determine the most likely user location. This approach requires a priori information about satellites, user location and clock bias, which are all readily established in urban environments. A driving experiment was performed with an equipped vehicle in downtown Denver CO. By examining several regions of interest with varying degrees of conventional GPS positioning success, the use of DPE as well as incorporating visibility and specularity predictions has been shown to improve positioning estimates.
Published in:	Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado
Pages:	1795 - 1808
Cite this article:	Zeller, Emma, Strandjord, Kirsten, "Algorithms for Mapping the Urban Signal Environment for Navigation of Ground Vehicle Operations," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 1795-1808. https://doi.org/10.33012/2022.18504
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