FAA´s DGPS CAT III feasibility program: update and test methodology

The FAA has established a program to evaluate the technical feasibility of using guidance from the satellite-based Global Positioning System (GPS) for Category III (CAT III) precision approaches. A combination of flight tests, analyses and simulations will be used to evaluate differential GPS (DGPS) and associated monitoring techniques for CAT III application. Emphasis will be placed on meeting accuracy and integrity requirements for a complete DGPS-based CAT III autoland capability. Contractors will be required to provide the ground and airborne equipment for computing DGPS-based aircraft position and velocity. Contractors will also provide a demonstration aircraft completely equipped with a DGPS-based capability. Feasibility will be demonstrated by meeting either sensor accuracy requirements for CAT III applications or total system accuracy requirements. It is expected that meeting total system accuracy requirements would place less demand on the accuracy of the DGPS-based sensor than meeting sensor requirements, but more demand on automatic total system performance monitoring in the aircraft. This paper presents an updated schedule of program activities and describes the test methodology in detail