US Patent 9069077 Traffic information services-broadcast (TIS-B) traffic snooping

An ADS-B system associated with an aircraft is configured to furnish an indication whether the aircraft is within coverage of air traffic information transmitted by an air traffic control ground station. The ADS-B system receives transmissions from an air traffic control ground station that include air traffic information and a client list comprising identification addresses of aircraft included in the air traffic information. The ADS-B system determines whether the aircraft is within a range of a second aircraft and whether the second aircraft is included in the air traffic information by comparing an identification address of the second aircraft with the identification addresses in the client list. The ADS-B system furnishes an indication that the aircraft is within coverage of the air traffic information when the second aircraft is included in the air traffic information and the aircraft is within the range of the second aircraft.