ApplicationNo. 572997 filed on 04/30/1975
US Classes:342/463Having plural transmitters or receivers
ExaminersPrimary: Wilbur, Maynard R.
Assistant: Berger, Richard E.
Attorney, Agent or Firm
International ClassG01S 5/06 (20060101)
AbstractApparatus is provided to determine the relative shift of position of a vehicle carrying a transmitter transmitting at a predetermined frequency. A plurality of receivers are positioned to receive the signal transmitted, and each includes a counter for advancing a count representative of the number of cycles of signal received. A computer receives the counts from the receiver to determine the relative shift of vehicle position. Preferably, a reference transmitter is provided for transmitting a reference signal of predetermined frequency, which, when processed with the signal received from the vehicle, provides a difference or "beat" frequency which provides the basis for cycle counting at a reduced rate.