Homer E Jackson

US Patent:

39939979, Nov 23, 1976

Filed:

Dec 17, 1971

Appl. No.:

5/209322

Inventors:

Homer E. Jackson - McLean VA

Assignee:

Navsat Corporation - Washington DC

International Classification:

G08G 504
G01S 1100
G08G 500

US Classification:

343112CA

Abstract:

An aircraft collision avoidance system and method involves transmitting a stable reference frequency from a synchronous satellite to aircraft in a region being monitored. Each aircraft in the region receives the reference frequency and transmits a carrier, modulated with the received reference frequency, to other aircraft in a collision avoidance zone. At the other aircraft, an indication of impending collision is provided by measuring the rate of change of the carrier Doppler frequency shift received thereby from the first named aircraft. Sync pulses periodically modulate the reference frequency transmitted from the satellite for aircraft ranging and data control purposes. To limit the collision warning zone relative to each aircraft, the receiver thereof is deactivated at a predetermined time after each sync pulse is received from the satellite.