Abstract

An airplane precision approach guidance system and method. The airplane precision approach guidance system includes: (i) GPS landing system (GLS) components (12) for receiving and processing signals from GPS satellites (30) and a GPS ground station (32) and generating a first set of velocities; (ii) an inertial reference system (IRS)(20) for generating a second set of velocities; and (iii) guidance software (24) for generating a cross-runway velocity and a lateral distance from runway centerline based on received runway centerline information and the generated first and second set of velocities. The airplane precision approach guidance system also includes flight instruments (26) and an autopilot system (28) for receiving and processing the information produced by the guidance software. The guidance software may be executed by a conventional airplane processor, such as the GLS processor, the IRS processor or the airplane's autopilot processor, or by a separate stand-alone processor. The runway centerline information may be stored at the ground station or in local memory. The ground station can also provide differential GPS information. In airplanes that include redundant systems, voting is used to determine which IRS supplies the second set of velocities.