Difference-in-time-of-arrival direction finders and signal sorters
First Claim
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1. In a system responsive to the difference-in-time-of-arrival of received radio-wave signals;
- wherein said system comprises at least first and second antennas spaced apart by a predetermined distance for receiving radio-wave signals within a given frequency band, variable time delay means for relatively time delaying the radio-wave signals received by one of said first and second antennas with respect to the radio-wave signals received by the other of said first and second antennas by an amount determined by said time delay means, and auto-correlation means responsive to the correlation between the delayed radio-wave signals received by said one of said first and second antennas and the radio-wave signals received by said other of said first and second antennas;
the improvement wherein said auto-correlation means comprises;
first means responsive to the relative phases of the relatively delayed radio-wave signals received by said one of said first and second antennas and the radio-wave signals received by said other of said first and second antennas for deriving a given output therefrom in which solely in-phase relatively delayed radio-wave signals received respectively by said first and second antennas are substantially cancelled and out-of-phase relatively delayed radio-wave signals received respectively by said first and second antennas are substantially passed; and
second means including variable gain and delay means and responsive to said output of said first means applied thereto for reducing the relative power of said out-of-phase relatively delayed radio-wave signals with respect to that of said in-phase relatively delayed radio-wave signals in an output of said auto-correlation means.
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Abstract
A difference-in-time-of-arrival direction finder includes auto-correlation means that includes means for substantially reducing, at the output of the auto-correlation means, the unwanted noise power of all uncorrelated unselected incoming radio-waves received at two spaced antennas that arrive from any direction other than a certain direction with respect to the wanted signal correlated power of that selected one incoming radio-wave arriving from the certain direction with respect to the line connecting the antennas specified by a given signal time delay provided by a delay line associated with one of the antennas.
69 Citations
19 Claims
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1. In a system responsive to the difference-in-time-of-arrival of received radio-wave signals;
- wherein said system comprises at least first and second antennas spaced apart by a predetermined distance for receiving radio-wave signals within a given frequency band, variable time delay means for relatively time delaying the radio-wave signals received by one of said first and second antennas with respect to the radio-wave signals received by the other of said first and second antennas by an amount determined by said time delay means, and auto-correlation means responsive to the correlation between the delayed radio-wave signals received by said one of said first and second antennas and the radio-wave signals received by said other of said first and second antennas;
the improvement wherein said auto-correlation means comprises;first means responsive to the relative phases of the relatively delayed radio-wave signals received by said one of said first and second antennas and the radio-wave signals received by said other of said first and second antennas for deriving a given output therefrom in which solely in-phase relatively delayed radio-wave signals received respectively by said first and second antennas are substantially cancelled and out-of-phase relatively delayed radio-wave signals received respectively by said first and second antennas are substantially passed; and second means including variable gain and delay means and responsive to said output of said first means applied thereto for reducing the relative power of said out-of-phase relatively delayed radio-wave signals with respect to that of said in-phase relatively delayed radio-wave signals in an output of said auto-correlation means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- wherein said system comprises at least first and second antennas spaced apart by a predetermined distance for receiving radio-wave signals within a given frequency band, variable time delay means for relatively time delaying the radio-wave signals received by one of said first and second antennas with respect to the radio-wave signals received by the other of said first and second antennas by an amount determined by said time delay means, and auto-correlation means responsive to the correlation between the delayed radio-wave signals received by said one of said first and second antennas and the radio-wave signals received by said other of said first and second antennas;
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16. In a system responsive to the difference-in-time-of-arrival of received radio-wave signals;
- wherein said system comprises first and second antennas spaced apart by a predetermined distance for receiving radio-wave signals within a given frequency band, variable time delay means for time delaying the radio-wave signals received by one of said first and second antennas with respect to the radio-wave signals received by the other of said first and second antennas by an amount determined by said time delay means, and auto-correlation means responsive to the correlation between the delayed radio-wave signals received by said one of said first and second antennas and the radio-wave signals received by said other of said first and second antennas;
the improvement wherein said given frequency band is a relatively-low frequency band and the phase difference between said radio-wave signals received by said first and second antennas have certain values, and wherein said system further comprises;first phase-multiplier means inserted only between said one of said first and second antennas and a first input of said auto-correlation means and second phase-multiplier means inserted only between said other of said first and second antennas and a second input of said auto-correlation means for deriving values of the phase difference between said radio-wave signals at said first and second inputs to said auto-correlation means which are increased with respect to said certain values thereof. - View Dependent Claims (17, 18)
- wherein said system comprises first and second antennas spaced apart by a predetermined distance for receiving radio-wave signals within a given frequency band, variable time delay means for time delaying the radio-wave signals received by one of said first and second antennas with respect to the radio-wave signals received by the other of said first and second antennas by an amount determined by said time delay means, and auto-correlation means responsive to the correlation between the delayed radio-wave signals received by said one of said first and second antennas and the radio-wave signals received by said other of said first and second antennas;
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19. In a system responsive to the difference-in-time-of-arrival of received radio-wave signals;
- wherein said system comprises first and second antennas spaced apart by a predetermined distance for receiving radio-wave signals within a given frequency band, variable time delay means for time delaying the radio-wave signals received by one of said first and second antennas with respect to the radio-wave signals received by the other of said first and second antennas by a selected amount determined by the setting of said variable time delay means, and auto-correlation means responsive to the delayed radio-wave signals received by said one of said first and second antennas applied as a first input thereto and the radio-wave signals received by said other of said first and second antennas applied as a second input thereto for deriving a radio-wave output therefrom; and
wherein said radio-wave first and second inputs to said auto-correlation means includes a correlated component having a value corresponding to the radio-wave power of a given received signal having a difference-in-time-of-arrival at said first and second antennas substantially equal to said selected amount of time delay and an uncorrelated component having a value corresponding to the radio-wave power of all received signals having a difference-in-time-of-arrival at said first and second antennas substantially unequal to said selected amount of time delay;
the improvement wherein said auto-correlation means comprises;means including power dissipating means for dissipating more of the radio-wave power of said uncorrelated component than of the radio-wave power of said correlated component; whereby the ratio of said correlated component to said uncorrelated component in the output of said auto-correlation means is increased with respect to the ratio of said correlated component to said uncorrelated component in the first and second inputs to said auto-correlation means.
- wherein said system comprises first and second antennas spaced apart by a predetermined distance for receiving radio-wave signals within a given frequency band, variable time delay means for time delaying the radio-wave signals received by one of said first and second antennas with respect to the radio-wave signals received by the other of said first and second antennas by a selected amount determined by the setting of said variable time delay means, and auto-correlation means responsive to the delayed radio-wave signals received by said one of said first and second antennas applied as a first input thereto and the radio-wave signals received by said other of said first and second antennas applied as a second input thereto for deriving a radio-wave output therefrom; and
Specification