MULTIPLE DIGIT CODE DIRECTION FINDER SELF-ADJUSTING TO DIFFERENT FREQUENCIES

• US 3,631,496 A
• Filed: 10/22/1965
• Issued: 12/28/1971
• Est. Priority Date: 10/22/1965
• Status: Expired due to Term

• Current Assignee: Charles Fink, Fred E. Burnham, Maury I. Marks
• Original Assignee: Charles Fink, Fred E. Burnham, Maury I. Marks
• Inventors: Fink, Charles, Burnham, Fred E., Marks, Maury I.
• Application Number:
  US04/501,231
• Time in Patent Office: 2,258 Days
• US Class Current: 342/444
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured

Abstract

A direction finding system producing a multiple digit code representing the direction of an emitted signal and including means for resolving ambiguities when the signal arrives at an angle normally giving rise to digit changeover.

Claims

1. A direction of finding system comprising:

a pair of spaced antennas, and a rapid digital processing system responsive to the signals from the antennas to provide a digital code representative of the angle between an incoming wave referenced to a plane containing said pair of antennas, said digital processing system including a first decision making means for determining whether the sum of the signals from the antennas is greater or less than the difference between said signals and producing a digital indication, and including a second decision making means, including phase-advancing and -retarding means for one of said signals, for determining whether the sum of the other signal and the phase-advanced signal is greater or less than the sum of the other signal and the phase-retarded signal and producing a second digital indication.

2. A digital beam direction-finding system comprising:

a pair of spaced antenna elements, means for adding the signals from said elements, means for differencing the signals from said elements, means for comparing the amplitude of said added signals with the amplitude of said difference signals and producing a digital code indicative of the greater amplitude, means for phase advancing the signals from one of said elements, means for equally phase retarding the signal from the same element, means for separately adding the signal from the other element with each of the phase-advanced and -retarded signals to produce first and second processed signals, means for comparing the amplitudes of said first and second processed signals and producing a second digital code indicative of the greater amplitude, and means responsive to the first and second digital code to determine direction.

3. A digital direction finding system having two displaced antenna elements responsive to an incoming beam comprising:

means for comparing the amplitude of the sum of signals from said elements with the amplitude of the difference of the signals from said elements and producing a digital code indicative of the greater amplitude, means for equally phase-advancing and -retarding the signal from one of said elements, means for separately adding the signal from the other element with each of the phase-advanced and phase-retarded signal to obtain a first and second processed signal and producing an additional digital code indicative of the greater amplitude, and means responsive to said digital code and additional digital code to determine the direction of the beam.

4. A digital system for determining the direction of an incoming wave referenced to an antenna array comprising:

a first pair of spaced antenna elements in said array, digital decision making means responsive solely to the comparative amplitudes of the signals from said antenna elements for producing a multiple digit code indicative of the direction of the incoming wave within a given one of a plurality of wide angular sectors, a second pair of spaced antenna elements spaced more widely apart than the first pair, a second digital decision making means responsive solely to the comparative amplitudes of the signals from said second pair Of antenna elements for producing a second multiple digit code indicative of the direction of the incoming wave within any one of a plurality of narrower angular sectors than said wide angular sectors, and means responsive to said first and second digital codes for determining that one of the narrower sectors falling within the given wide angular sector.

5. In the system of claim 4, an additional pair of antenna elements spaced more widely apart than said second pair and an additional digital decision making means solely responsive to the comparative amplitudes of the signals from said additional pairs of elements for producing an additional digital code indicative of the direction of the incoming wave within any one of a plurality of still narrower angular sectors than said narrow angular sectors, and means responsive to said first, second, and additional digital codes for determining that one of the still narrower angular sectors falling both within the narrower angular sector and the wide angular sector.

6. In a direction finding system for an incoming wave, an antenna array comprising a plurality of pairs of spaced antenna elements, with each pair being progressively spaced further apart than the preceding pair, a digital processing system for each pair of elements responsive solely to the comparative amplitudes of signals from its associated pair of elements, the digital processing system for each pair of elements beginning with the most closely spaced elements determining the positioning of the incoming wave within progressively smaller angular sectors and each producing a multiple digit code indicative of said positioning, and means responsive to the digital codes from said processing systems for determining the location of said incoming wave.

7. In a direction-finding antenna array, a pair of spaced antenna elements, a digital processing system responsive solely to the amplitudes of signals from said elements to produce a multiple digit code indicative of the angular position of an incoming wave referenced to the common axis of said elements, said digital processing system including means for frequency multiplying the signal from each element, and including means for adding and subtracting the amplitudes of said frequency multiplied signals and producing a digital code indicative of whether the added amplitude is greater or less than the subtracted amplitudes.

8. In the antenna array of claim 7, said digital processing means further including means for adding and subtracting the amplitudes of signals from said antenna elements and producing a second digital code indicative of whether the added amplitudes is greater or less than the subtracted amplitudes.

9. In the antenna array of claim 7, said digital processing means further including means for equally phase advancing and phase retarding the signal from one of said elements, and including means for separately adding the signal from the other of said elements with each of the phase advanced and retarded signals, and additionally including means for comparing the amplitudes of said separately added signals and producing a digital code indicative of the greater amplitude.

10. A digital direction finding system that is self-adjusting to different frequencies of an incoming wave comprising:

a pair of spaced antenna elements, a digital processing system responsive solely to the amplitudes of signals from said elements to produce a multiple digit code indicative of the angular position of an incoming wave referenced to the common axis of said elements, and means responsive to the frequency of the incoming wave for translating the digital code to the correct code for the frequency received.

11. A substantially instantaneous direction finding system for traveling waves comprising:

a pair of spaced transducers, means for combining the signals from said transducers to obtain a processed signal whose amplitude varies according to the direction of the incoming wave referenced to said transducers, and digitizing means for obtaining from said processed signal a multiple digit code representative of the direction of the incoming wave.

12. In the system of claim 11, a system of indicators energized by said code for substantially instantaneously indicating the direction of the wave.

13. In the system of claim 11, an additional pair of transducers oriented along a different axis than said first-mentioned pair, means responsive to said additional pair to produce a second digital code representing the direction of the wave referenced to said additional pair, and means correlating said first and second digital codes to more precisely determine the direction of the wave.

14. A direction-finding system comprising:

an array of spaced transducers, a plurality of independent modules each responsive to signals from a pair of transducers of said array to provide different digits of a digital code representing the direction of an incoming wave referenced to the axis of said array, with one of the modules producing at least a two-digit code from a pair of transducers, and means for correlating the different digits to provide a code representing the direction of the wave.

15. In the system of claim 14, means responsive to the frequency of the wave to translate the code number.

16. In the system of claim 14, each of the modules independently responding to said signals whereby additional modules may be added to determine the direction with greater definition.

17. In the system of claim 14, each of the modules comprising a means for combining a pair of signals to obtain a processed signal whose amplitude varies according to the direction of the wave, receiver means for detecting the amplitude, and means for producing a digital code representing direction.

18. A direction-finding system comprising:

an array of spaced transducers, a plurality of independent modules each responsive to signals from said array to provide different digits of a digital code representing the direction of an incoming wave referenced to the axis of said array, and means for correlating the different digits to provide a code representing the direction of the wave, an additional array of spaced transducers disposed along a different axis than said first array, a second plurality of independent modules each responsive to signals from said array to provide different digits of a second digital code representing the direction of an incoming wave referenced to the axis of said additional array, and means correlating said second code with said first-mentioned code to determine the direction of the wave referenced to both arrays.