Patent ID: 6025800
Filing Date: 2000-02-15
Classification: G01C,G01S

Abstract:
System located on an aircraft for determining the position of the aircraft, comprising:transmitter located on the aircraft transmitting a transmit signal to terrain below the aircraft which will be reflected;first receiver located on the aircraft receiving a first reflected signal reflected back to the aircraft upon contact with terrain in a first area wherein the first area is terrain ahead of the aircraft;second receiver located on the aircraft receiving a second reflected signal reflected back to the aircraft upon contact with terrain in a second area wherein the second area is the terrain the aircraft is currently over wherein the first and second receivers are separated by a separation distance; andapparatus, located on the aircraft for determining position of the aircraft based on information received from the signal reflected back to the aircraft wherein the apparatus for determining first determines an approximate range to a highest point in the first area and an accurate range to a highest point in the second area.