Verification of the Shuttle Microwave Scanning Beam Landing System accuracy

A Microwave Scanning Beam Landing System (MSBLS) is the principal sensor for Shuttle autoland operations. MSBLS azimuth, elevation, and distance measurements are provided for use by the Shuttle navigation system during this critical period of flight. Each MSBLS installation is subjected to a thorough evaluation, which begins with a precise alignment of the scanning beam antennas. Alignment is followed by aircraft flight tests with a laser tracker for reference position measurements. Coverage and accuracy models were developed and used to predict MSBLS performance for each of the Shuttle landings. An important part of this effort is the evaluation of MSBLS measurements that were made during the landing phase of recent orbital flights. Error estimates are made by comparing these measurements with a best estimate of the trajectory (BET).