A Flight Test Comparison of Two GPS/INS Integration Approaches

Ronald B. Dayton, John T. Nielson

Abstract:	In the navigation community the benefits of GPS/INS integration are well known. There is, however, some controversy as to which integration is "best" in a given situation. This paper presents possibly the first comparison, based on actual flight data, of two of the more popular approaches using the same navigation hardware. The two integrations each use a Kalman filter to process measurements from the GPS receiver to correct the INS navigation solution. The two methods differ in the type of GPS measurement-data used. The first configuration, termed the cascaded filter approach, uses the position and velocity outputs of an embedded GPS Kalman filter as measurement inputs to a larger system filter. The second configuration, known as the integrated filter approach, uses the unfiltered GPS pseudo-range and delta-range measurements as inputs to the system filter. The system was tested in both configurations, first in a mobile avionics laboratory (modified Greyhound bus) and then in a Beechcraft D-18 airplane. The results seem to indicate a performance advantage with the integrated filter approach. This comparison is part of an on-going effort begun at Boeing in 1980 to investigate GPS/INS integrations.
Published in:	Proceedings of the 2nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1989) September 27 - 29, 1989 The Broadmoor Hotel Colorado Spring, CO
Pages:	269 - 273
Cite this article:	Dayton, Ronald B., Nielson, John T., "A Flight Test Comparison of Two GPS/INS Integration Approaches," Proceedings of the 2nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1989), Colorado Spring, CO, September 1989, pp. 269-273.
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