Multipath Simulation Software Developed for the Design of a Low Multipath DGPS Antenna for the U. S. Coast Guard

Charles E. Rodgers

Abstract:	Adroit Systems, Inc., under a contract to the U.S. Coast Guard (USCG), has developed a multipatb simulation soft- ware package. The software will calculate the antenna gain pattern needed to maintain a specified pseudorange or car- rier phase multipath error level The calculated gain is a function of the auta’s polar&&ion characteristics, the electromagnetic and geometric properties of the antenna’s enviromnent, and GPS satellite elevation. In addition, Adroit has developed a modified version of this software that calculates au antenna% pseudorange error for a given GPS satellite elevation, antenna gain, aud anteuua polariza- tion. This sofhvare package can potentially be used as a DGPS b&e station site evaluation tool. This paper describes the theory behind the sohare. It shows how multipath is aflected by the reflecting surface’s chartics, the path length of the satellite signal, the height of the antenna, and the polarization discrimination of the antenna. It also includes the simulation results that were used as antenna desigu goals for a differential GPS (DGPS) base station au&ma for the USCG. The DGPS antenua was designed to have improved gain at the horizon for tracking low elevation satellites. It also incorporates enhanced multipath suppression. Several candidate anten- nas were designed, and their expected performauce was evaluated using the modified version of the software.
Published in:	Proceedings of the 5th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1992) September 16 - 18, 1992 Albuquerque, NM
Pages:	43 - 50
Cite this article:	Rodgers, Charles E., "Multipath Simulation Software Developed for the Design of a Low Multipath DGPS Antenna for the U. S. Coast Guard," Proceedings of the 5th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1992), Albuquerque, NM, September 1992, pp. 43-50.
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