| 摘要 |
A navigation system for a vehicle travelling along a highway that has an interrogator mounted on the vehicle and, a retrodirective transponder mounted alongside the highway for updating vehicle location. For collision avoidance systems, interrogators transmit and receive fore and aft, and transponders are mounted to respond to signals fore and aft of the vehicle. The transponder modulates information onto the interrogation signal, and retransmits the encoded interrogation signal back in the direction of arrival of the collected interrogation signal. The responder uses a Van Atta array antenna and is capable of responding to an interrogator signal incident over a wide solid angle of arrival while retrodirectively retransmitting without amplification substantially all of the collected signal within a narrow solid angle. The responder may be implemented using monolithic microwave integrated circuit technology (MMIC), thus being suitable for high volume production.
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