Cascaded digital integrator target detection system

Claim 2

A target detection system comprising: first means for selectively updating each of a first plurality of multibit words respectively associated with a plurality of range intervals in a radar sweep as a function of the amplitude of video target returns for each of the plurality of range intervals; second means coupled to said first means for selectively updating each of a second plurality of multibit words respectively associated with the plurality of range intervals in the radar sweep as a function of the amplitude of a scaled down portion of each of the updated first plurality of multibit words from said first means; and third means coupled to said second means for generating a signal output indicative of the azimuth center and range of each target detected in any of the range intervals in the radar sweep.

Claim 3

The target detection system in claim 1 wherein each of said first and second means comprises: accumulator means for storing the associated plurality of multibit words respectively associated wIth the plurality of range intervals in the radar sweep; and a first control circuit, coupled to said accumulator means, being responsive to the multibit words applied thereto for generating control signals to selectively cause said accumulator means to sequentially update and restore as updated multibit words its previously stored multibit words by incrementing or decrementing each previously stored multibit word associated with each range interval as a function of the amplitude of the corresponding multibit word applied thereto.

Claim 4

The target detection system of claim 2 wherein said accumulator means comprises: first memory means having input and output circuits for storing the multibit word for each range interval in the radar sweep; and a second control circuit, coupled to said first memory means and said first control circuit, being responsive to the multibit words and control signals applied thereto for sequentially updating each of the previously stored multibit words at said output circuit of said first memory means and restoring same in said input circuit of said first memory means.

Claim 5

The target detection system of claim 3 wherein said second control circuit includes: fourth means coupled to said first control circuit for decrementing any previously stored multibit word by a first predetermined quantity when the amplitude of the corresponding multibit word applied thereto does not exceed a first level; fifth means coupled to said first control circuit for incrementing any previously stored multibit word by a second predetermined quantity when the amplitude of the corresponding multibit word applied thereto is above a second level; and sixth means coupled to said first control circuit for incrementing any previously stored multibit number by the amplitude of the corresponding multibit word applied thereto when the amplitude of the corresponding multibit word applied thereto is between the first and second levels.

Claim 6

The target detection system of claim 4 wherein said second control circuit further includes: a first gating circuit, coupled to said fourth, fifth and sixth means, being responsive to the control signals from said first control circuit for selectively returning updated multibit words from said fourth, fifth and sixth means to said input circuit of said first memory means as a function of the amplitude of the multibit words applied to said first control circuit.

Claim 7

The target detection system of claim 5 wherein said third means includes: threshold detection means, coupled to said accumulator means of said second means, being responsive to the updated and previously stored multibit words therefrom associated with each range interval for developing and storing an active bit signal representing the presence of a target signal in any of the plurality of range intervals in the radar sweep; and peak detection means, coupled to said threshold detection means and to said accumulator means of said second means, for generating a signal output indicative of the azimuth center and range of each target detected.

Claim 8

The target detection system of claim 6 wherein said threshold detection means comprises: comparator means, coupled to said accumulator means of said second means and adapted to receive a detection threshold signal of a preselected amplitude, for developing the active bit signal for any given range interval when the amplitude of the updated multibit word for the given range interval exceeds that of the detection threshold signal while the amplitude of the previously stored multibit word for the given range interval is less than that of the detection threshold signal; second memory means coupled to said comparator means for storing and periodically reading out any active bit signal developed by said comparator means; and first gating means coupled to said second memory means for causing the active bit signal for any given range interval to be restored in said second memory means as lonG as said peak detection means does not generate a signal output indicative of the azimuth center and range of each target detected.

Claim 9

The target detection system of claim 7 wherein said peak detection means comprises: a peak detector circuit, responsive to the updated and previously stored multibit words from said accumulator means of said second means for each range interval and to the active bit signal from said second memory means for each corresponding range interval, for generating a first signal; and second gating means, coupled to said peak detector circuit, being responsive to each first signal therefrom for developing the signal output indicative of the azimuth center and range of each target detected.

Claim 10

The target detection system of claim 8 wherein said second gating means includes: seventh means coupled to said peak detector circuit and adapted to receive sequences of range information signals; and eigth means coupled to said peak detector circuit and adapted to receive sequences of azimuth information signals, said seventh and eighth means being respectively responsive to each first signal from said peak detector circuit for providing the signal output indicative of the range and azimuth center of each target detected.

Claim 11

The target detection system of claim 9 wherein said eighth means includes: means responsive to the azimuth information signals for compensating for a predetermined error in the azimuth center of each target detected.

Claim 12

A target detector system responsive to a plurality of quantized video returns corresponding to a plurality of range intervals over a plurality of radar sweeps for performing antenna beam weight shaping as a part of the detection process comprising: a plurality of up-down counter means coupled in series and responsive to the quantized video returns for performing the antenna beam shape weighting while detecting the presence of targets in any of the range intervals, said plurality of up-down counter means having selectable decrementing constants as a function of a desired impulse response for the system; and means coupled to said plurality of up-down counter means for generating signals indicative of the azimuth center and range of each target detected in any of the range intervals.

Claim 13

A target detector system responsive to a plurality of quantized video returns corresponding to a plurality of range intervals over a plurality of radar sweeps for performing antenna beam weight shaping as a part of the detection process comprising: a plurality of up-down counter means coupled in series and responsive to the quantized video returns for performing the antenna beam shape weighting while detecting the presence of targets in any of the range intervals, said plurality of up-down counter means having selectable decrementing constants as a function of a desired impulse response for the system; and means coupled to said plurality of up-down counter means for generating signals indicative of the azimuth center and range of each target detected in any of the range intervals.

Claim 14

In a radar receiving system, a target detector system for performing antenna beam shape weighting while detecting the presence of target signals in any of a plurality of range intervals in each of a plurality of radar sweeps comprising: a video quantizer responsive to radar video from any range interval in any radar sweep for providing a corresponding multibit word whose numerical value is a function of the peak of the radar video from that range interval; first accumulator means coupled to said video quantizer for storing multibit words respectively associated with the plurality of range intervals; a first control circuit, coupled to said first accumulator means, being responsive to the multibit words from said video quantizer for causing said first accumulator means to sequentially update and restore as updated multibit words its old stored multibit words by incrementing or decrementing each old stored multibit word associated with each range interval as a function of the amplitude of the multibit word from said video quantizer for the corresponding range interval; second accumulator means coupled to said first accumulator means for storing multibit words associated with the plurality of range intervals; a second control circuit, coupled to said second accumulator means, being responsive to a scaled down portion of the updated multibit words from said first accumulator for causing said second accumulator means to update and restore as updated multibit words its old stored multibit words by incrementing or decrementing each old stored multibit word associated with each range interval as a function of the amplutude of the scaled down portion of the updated multibIt word from said first accumulator means for the corresponding range interval; threshold detection means, coupled to said second accumulator means, being responsive to the old and updated multibit words therefrom associated with each range interval for developing and storing an active bit signal representing the presence of a target signal in any of the plurality of range intervals in a radar sweep; and peak detection means coupled to said second accumulator means and said threshold detection means for generating a signal indicative of the azimuth center and range of each target detected.

Claim 15

In a radar receiving system, a target detector system for performing antenna beam shape weighting while detecting the presence of target signals in any of a plurality of range intervals in each of a plurality of radar sweeps comprising: a video quantizer responsive to radar video from any range interval in any radar sweep for providing a corresponding multibit word whose numerical value is a function of the peak of the radar video from that range interval; first accumulator means coupled to said video quantizer for storing multibit words respectively associated with the plurality of range intervals; a first control circuit, coupled to said first accumulator means, being responsive to the multibit words from said video quantizer for causing said first accumulator means to sequentially update and restore as updated multibit words its old stored multibit words by incrementing or decrementing each old stored multibit word associated with each range interval as a function of the amplitude of the multibit word from said video quantizer for the corresponding range interval; second accumulator means coupled to said first accumulator means for storing multibit words associated with the plurality of range intervals; a second control circuit, coupled to said second accumulator means, being responsive to a scaled down portion of the updated multibit words from said first accumulator for causing said second accumulator means to update and restore as updated multibit words its old stored multibit words by incrementing or decrementing each old stored multibit word associated with each range interval as a function of the amplutude of the scaled down portion of the updated multibIt word from said first accumulator means for the corresponding range interval; threshold detection means, coupled to said second accumulator means, being responsive to the old and updated multibit words therefrom associated with each range interval for developing and storing an active bit signal representing the presence of a target signal in any of the plurality of range intervals in a radar sweep; and peak detection means coupled to said second accumulator means and said threshold detection means for generating a signal indicative of the azimuth center and range of each target detected.