Transponder detection system and method

摘要

A transponder detection system (50) for detecting the presence at a detection area (22) of a vehicle (100) on which the transponder (3) is mounted. Two antenna arrays (32, 34) are located on opposite sides of the detection area (22), and have their boresights (B) directed to the detection area. For each array, a sum and difference signal of signals received from the transponder are measured. The sum channel signal is used to establish whether a transmission has occurred, and the difference channel signal is used to isolate any transponder that is at the detection area. <IMAGE>