Anti-Multipath Triangulation (AMT) for Positioning in Dense Urban Environments

J. Stone and M. Chansarkar

Abstract:	In urban environments, multipath is the dominant factor contributing to accuracy degradation in GPS receivers. Conventional methods of multipath mitigation, designed primarily for open-sky applications, do not effectively accommodate the urban setting. An alternative approach to dealing with multipath in urban environments involves development of a statistical model that accurately captures behavior of pseudorange error distributions observed in real data, such as asymmetry, fat-tails, interdependence among errors, and dependence on multiple observable factors. Given this statistical model, location can be estimated by maximizing likelihood or minimizing expected squared error. If error distributions were Gaussian, this would be equivalent to solving a weighted-least-squares problem. However, complexities associated with an accurate statistical model make estimation a computational challenge. Anti-multipath triangulation (AMT) is a proprietary technology developed to address this challenge. This algorithm solves the maximum likelihood problem in less than ten milliseconds on a typical server or a few hundred milliseconds on an embedded processor.
Published in:	Proceedings of the 17th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2004) September 21 - 24, 2004 Long Beach Convention Center Long Beach, CA
Pages:	1165 - 1168
Cite this article:	Stone, J., Chansarkar, M., "Anti-Multipath Triangulation (AMT) for Positioning in Dense Urban Environments," Proceedings of the 17th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2004), Long Beach, CA, September 2004, pp. 1165-1168.
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