The Collins Aerospace GPS-4000S Global Positioning System Sensor provides GPS-based navigation and enables GPS-based approaches for aircraft equipped with flight management systems. The sensor’s Space Based Augmentation System (SBAS) capabilities enable use of GPS for primary means navigation in areas of SBAS coverage. This includes the United States' Wide Area Augmentation System as well as planned MTSAT Satellite-based Augmentation System in the European Geostationary Navigation Overlay System for Japan and Europe.
The GPS-4000S uses up to 10 GPS satellites and two geo-stationary SBAS satellites. However, you can calculate navigation with a minimum of four GPS satellites with acceptable geometry or three satellites plus calibrated barometric altitude. With additional satellites, the system's Receiver Autonomous Integrity Monitoring (RAIM) detects and isolates defective satellites while improving navigation accuracy. Predictive RAIM capability determines if the future satellite geometry at the destination airport will support planned arrival procedures.