Performance Evaluation of a Global IGS-Based Differential GPS System

Don English, Gene Howell, and Wang Tang

Abstract:	Differential GPS (DGPS) has long been recognized as a very cost-effective testing tool to evaluate the position and velocity accuracy of other navigation systems. Typical Differential GPS operation involves a reference station, installed at a precisely surveyed location, which provides pseudorange corrections to all users in the vicinity. With several advances in correlation technology and multipath reduction, it is believed that the achievable positioning accuracy of DGPS is on the order of a meter. A major problem associated with the single station DGPS operation is that the accuracy degrades as the separation between the reference station and user increases due to spatial decorrelation. One method to overcome this problem is to install many reference stations so that users spread over a large area will always be in close proximity to a reference station. Obviously, this is not a desirable nor feasible solution for areas such as the North Atlantic Ocean. The objective of this paper is to describe ARINC’s IGS-based Differential GPS (AIDGPS) system. AIDGPS is a post-processed Wide Area DGPS system which derives its corrections from data from the International GPS Service (IGS) for Geodyna- mics. The IGS routinely provides pseudorange and carrier phase measurements from more than 60 glob- ally distributed stations. By relying on the IGS, the AIDGPS user does not need to establish a unique reference station network. Since the IGS network is comprised of dual-frequency receivers, AIDGPS is able to measure and compensate for delays due to the ionosphere. This paper will introduce the AIDGPS system and describe its utilization of the IGS. Detailed algorithms and accuracy performance of the AIDGPS system also will be discussed.
Published in:	Proceedings of the 8th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1995) September 12 - 15, 1995 Palm Springs, CA
Pages:	517 - 523
Cite this article:	English, Don, Howell, Gene, Tang, Wang, "Performance Evaluation of a Global IGS-Based Differential GPS System," Proceedings of the 8th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1995), Palm Springs, CA, September 1995, pp. 517-523.
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