公开(公告)号：DE19501879A1

公开(公告)日：1996-07-25

申请号：DE19501879

申请日：1995-01-23

Applicant: SEXTANT AVIONIQUE

Inventor： PONCELET PHILIPPE ,  DAYOT ALAIN ,  COMBE HUBERT

IPC: G01S19/08 ,  G01S19/14 ,  G01C21/00 ,  G05D1/10

Abstract: The method uses a Doppler radar system (3) to provide horizontal speed data for two inertial navigation systems (1, 2) which are periodically and alternately recalibrated by a global positioning system (GPS). The coordinates expressed by the GPS (4) and the inertial navigation systems are compared (5, 6) and an alarm sounds if a threshold difference is exceeded. An altitude barometer (8) measures the 2-coordinate which is compared (7) with the GPS for a similar threshold difference. The height is checked at certain points by a radio transponder (9), adjusted (10) for local terrain and compared (12) with the altitude barometer to recalibrate the latter. A second ground-based GPS receiver at a known position compares its position with the GPS position and informs the aircraft of the lack of GPS availability of a discrepancy occurs.