GPS Vehicle Location Tracking in Dense High-Rise Environments With the Minimum Range Error Algorithm

Esmond Mok and Lawrence Lau

Abstract:	GPS Vehicle Navigation System (VNS) in stand alone mode works well only for open areas. In the case of obstruction of the line of sight between satellites and receiver, without sufficient number of satellites being visible and successfully tracked, position determination is not possible. Such GPS VNS is not effective and unreliable when use in the dense high-rise urban environments, where GPS signals are frequently obstructed by tall buildings. Integrating a Dead Reckoning (DR) System with the GPS positioning system is a common approach for tackling the problem. A simple low-cost DR system usually consists of a digital compass and an odometer. The DR's heading information can be seriously distorted by sources of changing magnetic fields, and the reliability of the odometer-derived distance would be reduced if the travel distance is long due to accumulation of errors. A new vehicle tracking algorithm called “Minimum Range Error Algorithm” (MRERA) is proposed to track vehicles in dense high-rise environments without the use of DR. With this algorithm, it is possible to identify which section of road network the vehicle is located, even when insufficient number of satellites are available for position fix. The algorithm makes full use of the available GPS pseudorange data to generate a time series of MRERA Indicator Value (MIV) referenced to selected road points, with their coordinates interpolated from the known road alignment information. By tracking the change of MIV of these selected road points, the road point nearest to the vehicle’s position can be identified. This paper first reviews the methods commonly used for tackling “Canyon Effect” in satellite-based positioning. The Minimum Range Error Algorithm (MRERA) is then introduced. Finally, Field test results are discussed and analyzed.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	2564 - 2570
Cite this article:	Mok, Esmond, Lau, Lawrence, "GPS Vehicle Location Tracking in Dense High-Rise Environments With the Minimum Range Error Algorithm," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 2564-2570.
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