Flight Trials of a Geostationary Satellite Based Augmentation System at High Latitudes and for Dual Satellite Coverage

Richard Fuller, Todd Walter, Sharon Houck ,Per Enge

Abstract:	Several flight demonstrations have taken place over the past few years to show how the Wide-Area Augmentation System (WAAS), currently under development for the Federal Aviation Administration, will increase GPS accuracy, availability, and integrity for aviation. These demonstrations have been carried out with the support of the National Satellite Test Bed (NSTB). Using the real-time GPS data available from the NSTB, flight tests were carried out to further show the possibilities of such a system to aviation. Some concern has been noted for users at high latitudes (> 55 degrees) as to whether they will be able to reap the full rewards of such a system. Special attention has been paid to ability to track geostationary signals reliably from high latitudes. By using the prototype wide area differential GPS flight software developed at Stanford University in coordination with the NSTB, flight trials have been conducted in Alaska using geostationary satellites as a data link. Results are presented showing flight performance at these high latitudes versus a carrier-phase smoothed local-area differential GPS truth system. Additionally, by post-processing the data, the effects of excluding some of the Alaskan NSTB reference stations on flight performance are shown. As we approach operational WAAS, there is interest in understanding the best strategy for integration of corrections from the multiple geostationary satellite signals that will become available. Flight tests have been done utilizing two geostationary satellites for GPS corrections. Performance results of the geostationary handover will be presented. In addition, by splitting the NSTB into two groups of stations the results of interoperation of GPS augmentation systems were flight demonstrated.
Published in:	Proceedings of the 1999 National Technical Meeting of The Institute of Navigation January 25 - 27, 1999 Catamaran Resort Hotel San Diego, CA
Pages:	405 - 414
Cite this article:	Fuller, Richard, Walter, Todd, Houck, Sharon, Enge, Per, "Flight Trials of a Geostationary Satellite Based Augmentation System at High Latitudes and for Dual Satellite Coverage," Proceedings of the 1999 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 1999, pp. 405-414.
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