More Results from the Investigation of Airborne Multipath Errors

Tim Murphy, Matt Harris, Preston Geren, Tom Pankaskie, Barbara Clark and Jason Burns

Abstract:	The development of Ground Based Augmentation Systems (GBAS) to support Category II/III approach and landing operations is underway. Given improvements in GBAS ground stations, airborne multipath is apparently the largest error source affecting the accuracy and integrity of GBAS. A previous paper described a program designed to investigate and quantify the effects of multipath from the airframe as well as from short delay ground bounce multipath during landing operations. The program includes development of an electromagnetic modeling capability which predicts amplitude, time delay and phase characteristics of airframe multipath. The program also includes the collection of a very large amount of GPS code and carrier phase measurement collected during flight testing of the 777-300ER and 737- NG airplanes. The flight test observations have been used to validate the modeling capability. The modeling capability will be exercised to develop an Airborne Multipath Model (AMM) suitable for standardization. A second paper presented the first results of the study described by the previous paper. These results include observations from the flight testing as well as predictions from the high fidelity electromagnetic modeling capability. This paper in the series will give the final results of the program. The paper will include a comparison of the predicted errors with the flight test observations is included in the results. The paper outlines work done to develop an improved AMM. This program is expected to be an important step in the development of GBAS to support CAT II/III approach and landing operations.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	2670 - 2687
Cite this article:	Murphy, Tim, Harris, Matt, Geren, Preston, Pankaskie, Tom, Clark, Barbara, Burns, Jason, "More Results from the Investigation of Airborne Multipath Errors," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 2670-2687.
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