FAA - Wilcox Electric Category IIIB Feasibility Demonstration Program Flight Test Results

Wilcox Electric has been working since June 1994 on a contract from the General Services Administration under the technical cognizance of the FAAs Satellite Program Office to demonstrate the feasibility of a local area DGPS to provide Category III B autoland capability. Accuracy and integrity features supported by actual technical demonstrations are the principal focus of the program although the contractor must also show how the proposed system design would satisfy continuity of service and availability requirements if developed for production and operational use. Wilcox has been assisted in this effort by Litton Aero Products, NovAtel Communications and Federal Express. The focus in this paper is on the Category III B accuracy requirements, the system approach directed toward meeting these requirements, and the flight test results which demonstrate the actual in-flight capability of the system to conduct Category III B autolands. The basic system approach is described. It utilizes high accuracy C/A code tracking with emphasis on design features which enhance accuracy and integrity. One noteworthy enhancement is the use of the new MEDLL (Multipath Estimating Delay Lock Loop) technology in the ground station. This is followed by a description of the flight test program at the FAA Technical Center, Atlantic City, NJ, including a discussion of the ground station installation, the avionics installation in the FEDEX Boeing B727 and the data acquisition systems. Test results based on in-depth statistical analysis (provided by the FAA Technical Center and MITREKAASD) of 102 successful autolands are presented.