An integrated GPS/INS/baro and radar altimeter system for aircraft precision approach landings

Currently, the Department of Defense (DOD) and the commercial airline industry are utilizing the Instrument Landing System (ILS) during aircraft landings for precision approaches. The replacement system for the aging ILS was thought to be the Microwave Landing System (MLS). Instead, use of the Global Positioning System (GPS) is now thought to be a viable replacement for ILS precision approaches. The majority of current precision landing research has exploited "stand-alone" GPS receiver techniques. This paper instead explores the possibilities of using an extended Kalman filter (EKF) that integrates an Inertial Navigation System (INS), GPS, Barometric Altimeter, Pseudolite and Radar Altimeter for aircraft precision approaches. This paper shows that integrating the INS, GPS, Barometric Altimeter and Radar Altimeter meets Federal Aviation Administration (FAA) requirements for a Category I precision approach, and additionally integrating a single Pseudolite meets FAA requirements for a category II precision approach.