The LAAS VHF Data Broadcast Modeling, Siting, Flight Inspection, and Flight Test Results

Trent A. Skidmore, Aaron A. Wilson, Mark R. Dickinson and Orville K. Nyhus

Abstract:	This paper is a comprehensive look at the key elements necessary to demonstrate the fielded performance of a given LAAS VHF Data Broadcast (VDB) subsystem. The VDB is a critical element of the Local Area Augmentation System (LAAS) as well as the corresponding Ground Based Augmentation System (GBAS) developed by the International Civil Aviation Organization (ICAO). The VDB is used to transfer GPS (and GNSS) differential corrections, integrity, and final approach segment information from the LAAS (GBAS) ground facility to aircraft conducting approaches to the LAAS (GBAS) serviced airport. The paper includes the theoretical background and simulation results of a model for determining the optimal VDB transmit antenna height and location. The model considers factors such as antenna gain pattern, single versus multi-element arrays, horizontal, vertical, and elliptical polarization effects, aircraft position, and the required LAAS service (coverage) volume. The validity of this VDB Antenna Model Program (VAMP) is then demonstrated by flight test. Results of the flight test campaign, performed at the Federal Aviation Administration’s William J. Hughes Technical Center in Atlantic City, New Jersey, show that the VAMP is well suited for predicting coverage performance under a variety of operational conditions. Data is presented comparing measured field strength performance with that predicted by the VAMP for the key regions of the LAAS service volume: at a minimum vectoring altitude of 2000 feet (AGL) and throughout the coverage region for other select LAAS operations such as terminal area guidance and surface operations. Key aspects of VDB-related flight inspection are also discussed.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	1190 - 1199
Cite this article:	Skidmore, Trent A., Wilson, Aaron A., Dickinson, Mark R., Nyhus, Orville K., "The LAAS VHF Data Broadcast Modeling, Siting, Flight Inspection, and Flight Test Results," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 1190-1199.
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