The collins/DASA CAT-IIIB GPS landing system: analysis of ground and airborne segment performance

摘要

Since 1994, a Rockwell Collins and Daimler-Benz Aerospace team has been participating in an on-going Boeing/Industry sponsored program to demonstrate the feasibility of GPS Landing System (GLS) for aircraft precision approach. This program is addressing the ddvelopment of GLS requirements, simulation modeling for design and certification, and flight and laboratory testing of GLS equipment. The Collins/DASA team successfully demonstrated prototpe Cat-IIIB GLS equipment in a flight test program in July-august 1995. In this paper results from detailed analyses of the GLS ground and airborne systems are presented. Two important GLS performance issues are addressed. The first is an evaluation of multipath at the ground station, since this is the limiting factor in GLS accuracy and integrity. The second is left/right channel tracking in the airbore equipment. A unique aspect of this flight test program was that dual channel GLS equipment was used. This gave the opportunity to analyze the channel-to-channel differences in the GLS position solutions and deviation commands. This is critical since the Channel Monitoring and Voting (CMV) algorithms used in current dual-dual and tripleex autopilots were designed based on specific Instrument landing System (ILS) error characteristics. The impact of GLS error characteristics on CMV design will be discussed.