Development and Validation of an Aircraft Multipath Model for Land-Based JPALS

Jan P. Weiss, Steve Anderson, Corey Fenwick, Lin Song, Penina Axelrad, Pete Belay, Ronald L. Brinkley

Abstract:	"This paper describes a new Advanced GNSS Multipath Model that integrates reflector environment geometries, satellite almanac data, and antenna/receiver models to simulate multipath errors. The complete model is comprised of five modules. The satellite motion module uses almanac or ephemeris data to compute satellite locations with respect to the antenna location. The environment module defines the reflector environment and the material properties of each object or group of objects. The ray-tracing module determines signal paths from the GPS satellite to the receiving antenna taking into account combinations of signal interactions (reflections, diffractions, and transmissions) with the reflector environment. The ray-antenna module applies the receiving antenna pattern and determines the multipath delay, relative amplitude, and relative phase. Both fixed radiation pattern and controlled radiation pattern antennas can be simulated. Finally, the tracking loop module simulates the receiver front-end and code and carrier phase tracking loop response to multipath. Code multipath validation results are presented for three environments. These are the University of Colorado Engineering Center rooftop, an F-18 jet, and a C-5 large transport aircraft. For each, 24 hours of real and simulated GPS multipath data are compared on the basis of multipath time histories and overall error statistic summaries. The results are promising. Multipath time histories often show good agreement in terms of magnitudes, frequencies, and times of activity. The multipath error 1-s statistics also show agreement in terms of both magnitude and trends across satellite elevation bins."
Published in:	Proceedings of the 61st Annual Meeting of The Institute of Navigation (2005) June 27 - 29, 2005 Royal Sonesta Hotel Cambridge, MA
Pages:	818 - 829
Cite this article:	Weiss, Jan P., Anderson, Steve, Fenwick, Corey, Song, Lin, Axelrad, Penina, Belay, Pete, Brinkley, Ronald L., "Development and Validation of an Aircraft Multipath Model for Land-Based JPALS," Proceedings of the 61st Annual Meeting of The Institute of Navigation (2005), Cambridge, MA, June 2005, pp. 818-829.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In