Patent ID: 8072374

Claim:
A communications system including an automated dependent surveillance-broadcast system and a global positioning system integrated into a single unit comprising: a radio frequency receiver for receiving analog automated dependent surveillance-broadcast information at a selected transmission frequency and converting said information into digitized automatic dependent surveillance-broadcast information; a global positioning system receiver for receiving global positioning information including timing information; and a processing subsystem for decoding the digitized automated dependent surveillance-broadcast information in response to the timing information provided by the global positioning system receiver, wherein the radio frequency receiver comprises: analog processing circuitry for receiving the analog automated dependent surveillance-broadcast information at a selected transmission frequency and down-converting said analog information to an intermediate center frequency; circuitry for splitting the analog information into first and second sub-channels; circuitry for up-shifting the first sub-channel from the intermediate center frequency by a selected amount and for down-shifting the second sub-channel from the intermediate frequency by the selected amount; a first filter tuned to the frequency of the first sub-channel for generating a logic one output; and a second filter tuned to the frequency of the second sub-channel for generating a logic zero output.