Theory and Design of Pseudolites

H. Stewart Cobb, Clark E. Cohen, Bradford W. Parkinson

Abstract:	Ground-based GPS transmitters (often called pseudolites) can solve many different problems. For example, they can be used to improve the geometry of local position solutions, to transmit ref- erence data in digital or analog form for differential GPS users, and to assist algorithms for RAIM and for carrier-phase ambiguity resolution. In this paper, we catalog the uses of pseudolites and discuss the requirements these different uses place on the transmitted signals. We then propose some con- ceptual pseudolite designs for particular uses. Finally, we present two particular pseudolites we have constructed. The first is the “GPS marker beacon” used in Stanford’s Kinematic GPS Landing System (KGLS). This beacon is the size of a busi- ness card and is powered by a common g-volt bat- tery. KGLS flight tests using this beacon have demonstrated extreme/y precise realtime positioning (<2cm, lo) for aircraft in the landing pattern, and the additional information provided by the beacon allows high confidence in the integrity of the position solution. Our second pseudolite is the “Omni- Marker”, a reference station for differential GPS which provides reference information to users with latency less than 0.1 second.
Published in:	Proceedings of the 1994 National Technical Meeting of The Institute of Navigation January 24 - 26, 1994 Catamaran Resort Hotel San Diego, CA
Pages:	69 - 75
Cite this article:	Cobb, H. Stewart, Cohen, Clark E., Parkinson, Bradford W., "Theory and Design of Pseudolites," Proceedings of the 1994 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 1994, pp. 69-75.
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