×

Direction finding

  • US 4,489,327 A
  • Filed: 03/23/1982
  • Issued: 12/18/1984
  • Est. Priority Date: 03/24/1981
  • Status: Expired due to Fees
First Claim
Patent Images

1. A direction finding system for assessing the bearing of a received radio signal, comprisingfirst and second fixed antenna arrangements having response patterns arranged substantially at 90°

  • to each other and defining a first set of perpendicular axes for receiving the said radio signal,a single radio receiver,signal processing means operative to produce a first output representing the radio signal as received by the first antenna arrangement during a first time period, operative to produce a second output representing the radio signal as received by the second antenna arrangement during a second time period, operative to produce a third output representing the sum of selected proportions of the first and second outputs during a third time period, and operative to produce a fourth output representing the difference of selected proportions of the first and second outputs during a fourth time period, andoutput means operative to produce the ratio of the first and second outputs to derive a first set of four bearing angle values relative to said first set of axes, and operative to produce the ratio of the third and fourth outputs to derive a second set of four bearing angle values relative to a second set of perpendicular axes shifted by a selected angle relative to said first set of axes, whereby two of the bearing angle values of the first set coincide in space with two of the bearing angle values of the second set, such that the bearing of said received radio signal is one of said coincident bearing angle values.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×