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Radar apparatus

  • US 4,691,204 A
  • Filed: 12/31/1984
  • Issued: 09/01/1987
  • Est. Priority Date: 12/29/1983
  • Status: Expired due to Fees
First Claim
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1. In a radar apparatus for detecting a distance from an emitter of the radar apparatus to an underground object to be detected comprising a control device which outputs a timing pulse for controlling the timing of transmitting a detecting pulse used for detecting a buried object in the ground, a transmitter which transmits said detecting pulse from said control device to said buried object through an antenna, a receiver for receiving an echo signal reflected back from said buried object, and a display device for displaying said echo signal received from said receiver, the improvement comprising a calculation device for calculating time differences between said timing pulse from said control device and the time of receipt of signals of two or more different frequencies from said receiver to produce time difference signals, a calculation device for calculating said distance by solution of simultaneous equations based on the equation ##EQU5## where d=distance from said radar apparatus to said underground object to be detectedε

  • =electric permittivity of the medium of the groundμ

    =magnetic permeability of the medium of the groundσ

    =electric conductivity of the medium of the groundω

    i =angular frequencies of electromagnetic waves received by said receiver (5)ti =delay time from transmition of pulse from said radar apparatus to reception thereof reflected from said underground objecti=1, 2 and 3 corresponding to said different frequenciesrelating to the speed of propagation of an electromagnetic wave for said different frequencies and said time differences, and a control device which controls said calculation device to start the calculation of said distance.

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