Examination of RTCA/DO-198 Position Reconstruction Algorithms for Area Navigation with the Microwave Landing System.

摘要

Use of the Microwave Landing System (MLS) for ara navigation and computed centerline approach requires that the MLS avionics determine the aircraft position in Cartesian coordinates relative to the runway centerline. The inputs to the avionics are the locations of the three MLS ground units and the three observations of distance, azimuth angle, and elevation angle. When the three ground units are not collocated, this process requires an iterative algorithm. A March 1988 publication of the Radio Technical Commission for Aeronautics (RTCA) presents five such algorithms. These algorithms have various problems, such as errors in the analyses and/or computer code, and divergence or false solutions, etc., within the minimum coverage area of the MLS. This report, which identifies the various problems and offers corrections, concentrates on the two algorithms that assume a conical MLS azimuth antenna, as that is likely to be the only type that will be developed. Keywords: Computed centerline approach; Microwave landing system; Position reconstruction algorithm. (JHD)