Performance of a WAAS Geostationary Satellite Ranging Signal

Kevin J. Barltrop and Bryant D. Elrod

Abstract:	A key component of the Wide Area Augmentation System (WAAS) concept is the use of geostationary satellite signals to provide data links and additional ranging capability for the GPS community. The Federal Aviation Administration (FAA) has been testing this concept for several years within the National Satellite Test Bed (NSTB) via an Inmarsat-2 satellite (AOR-W) and a supporting test bed up-link station (TUS) located at COMSAT facilities in Southbury, Connecticut. In order to provide a navigation quality ranging signal, the timing of the broadcast must be precisely controlled. The fundamental issues for closed-loop control via ground-based “bent-pipe” monitoring of the ranging signal are discussed and refined from experience gained with live signals broadcast at L-band (-1547 MHz) and at the GPS Ll frequency (1575.42 MHz). The resulting performance has been measured and assessed as it applies to the WAAS signal specification defined by the FAA. This paper presents the requirements adopted for ranging signal control, and the resulting system signal control performance as measured with both Inmarsat-2 and Inmarsat-3 satellites.
Published in:	Proceedings of the 1997 National Technical Meeting of The Institute of Navigation January 14 - 16, 1997 Loews Santa Monica Hotel Santa Monica, CA
Pages:	849 - 858
Cite this article:	Barltrop, Kevin J., Elrod, Bryant D., "Performance of a WAAS Geostationary Satellite Ranging Signal," Proceedings of the 1997 National Technical Meeting of The Institute of Navigation, Santa Monica, CA, January 1997, pp. 849-858.
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