Passive direction finding system
First Claim
1. A passive direction finding system comprising;
- at least one set of spaced apart antennas;
delay means operatively connected to the output of one of said at least one set of antennas and having a plurality of output taps thereon;
mixer means operatively associated with each of said output taps on said delay means and receiving an output therefrom;
oscillator means for producing an output signal at the output thereof;
said mixer means also operatively receiving the output signal from said oscillator means;
signal conditioning means operatively associated with said mixer means and receiving the output therefrom for amplifying and clipping the output of said mixer means;
said signal conditioning means and said mixer means being instrumented so that they are equivalent in number to the number of output taps on said delay means and correspond to a predetermined number of channels;
other mixer means operatively coupled to the output of the other of said at least one set of antennas and receiving the output therefrom;
said other mixer means also receiving an output signal from said oscillator means;
other signal conditioning means operatively coupled to the output of said other mixer means for amplifying and clipping the output of said mixer means;
said other mixer means and other signal conditioning means being instrumented so that they correspond to a reference channel;
and correlator means operatively coupled to said signal conditioning means and said other signal conditioning means for determining the correlation between signals present in said channels and said reference channel.
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Abstract
A passive direction finding system incorporating at least one set of spacapart antennas, the incoming signal at one antenna being coupled through a delay line having a multiplicity of taps thereon, a plurality of channels equal in number to the number of delay taps and signal processing means coupled to the output of said channels, a reference channel coupled to the output of the other antenna, phase shifting means for varying the phase of the reference channel signal, a frequency modulated oscillator which provides an output signal that is beat against the outputs of the delay line and the output of the second antenna, and a correlator coupled to the output of the channels for determining when correlation exists between a signal from the first antenna and the second antenna to indicate direction of an incoming signal with respect to the baseline between the set of antennas.
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Citations
9 Claims
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1. A passive direction finding system comprising;
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at least one set of spaced apart antennas; delay means operatively connected to the output of one of said at least one set of antennas and having a plurality of output taps thereon; mixer means operatively associated with each of said output taps on said delay means and receiving an output therefrom; oscillator means for producing an output signal at the output thereof; said mixer means also operatively receiving the output signal from said oscillator means; signal conditioning means operatively associated with said mixer means and receiving the output therefrom for amplifying and clipping the output of said mixer means; said signal conditioning means and said mixer means being instrumented so that they are equivalent in number to the number of output taps on said delay means and correspond to a predetermined number of channels; other mixer means operatively coupled to the output of the other of said at least one set of antennas and receiving the output therefrom; said other mixer means also receiving an output signal from said oscillator means; other signal conditioning means operatively coupled to the output of said other mixer means for amplifying and clipping the output of said mixer means; said other mixer means and other signal conditioning means being instrumented so that they correspond to a reference channel; and correlator means operatively coupled to said signal conditioning means and said other signal conditioning means for determining the correlation between signals present in said channels and said reference channel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification