A Proposed GPS Block IIF Satellite Design with Civilian Dual Frequency and WAAS Signals

Steve Steiner, Rich Cole, Mohan Ananda, Prem Munjal, and K.T. Woo

Abstract:	The United States Air Force and, in particular, the GPS Joint Program Office (JPO) is acquiring the GPS follow- on satellites known as Block HF. It is estimated that about 33 Block IIF satellites will be procured. This paper presents a Strawman design for integration of the Global Positioning System (GPS) and the Wide Area Augmentation System (WAAS) into a seamless architecture to provide the highest level of system performance to both DOD and the civilian community. This architecture consists of three basic features: 1) incorporation of the transmission of the WAAS signal from GPS satellites, 2) transmission of dual frequency civil signals to facilitate ionospheric delay estimation by civil users, and 3) uplink of WAAS data from WAAS ground stations to Block IIF satellites. The proposed design retains all Block IIR satellite features such as crosslink ranging and autonomous navigation, and adds new capabilities to uplink WAAS data from the WAAS ground station to any Block IIF satellite. This uplink data would be crosslinked to all Block IIF satellites so that updated data could be downlinked on the WAAS signal within six seconds to meet the WAAS integrity and availability requirements. This use of Block IIF satellites could eliminate the need for additional geostationary satellites beyond the three necessary for the initial state WAAS. This paper presents two designs for crosslinking WAAS data. One design consists of a Frequency Division Multiplexing (FDM) scheme using a UHF frequency band between 286 and 286.3 MHz and the second design utilizes a 60-GHz frequency crosslink. A cost benefit tradeoff should facilitate selection of the approach that should be implemented. This paper also presents a system architecture of WAAS with Block IIF satellites to supplement the geostationary satellites which already exist in the initial WAAS design to transmit the WAAS signal.
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:	1857 - 1868
Cite this article:	Steiner, Steve, Cole, Rich, Ananda, Mohan, Munjal, Prem, Woo, K.T., "A Proposed GPS Block IIF Satellite Design with Civilian Dual Frequency and WAAS Signals," 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. 1857-1868.
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