Radar adaptive video processor

Claim 2

An adaptive radar video signal processor of a closed loop type wherein a feedback signal is produced for maintaining a constant average false alarm probability within selected range intervals and comprising: sampling means connected to receive said radar video signal for producing a plurality of samples of said video signal, a plurality of comparator means connected to receive said samples and said feedback signal for comparing each sample with said feedback signal and producing a distinct output signal for each video sample which exceeds said feedback signal level, summing means connected to receive said comparator means output signals and producing an output signal having a level proportional to the number of output signals produced by said plurality of comparator means, thresholding means connected to receive the output signal of said summing means for producing an output signal when said summing means output signal exceeds a preselected level, duty factor controlling means connected to receive said output signal from said thresholding means and producing an output signal therefrom having a predetermined duty factor, a plurality of selectively operable filter means each having an input connected to receive said output signal of the duty factor controlling means and producing signals proportional to the duty factor of said input signal, upon being combined said proportional signals constituting said feedback signal connected to said comparator means, and gate control means for selectively operating said filter means in response to said selected range intervals.

Claim 3

The apparatus of claim 1 wherein said sampling means comprises a multi-tapped delay line.

Claim 4

The apparatus of claim 2 wherein said duty factor controlling means comprises a pulse stretcher for producing pulses stretched by a predetermined factor.

Claim 5

The apparatus of claim 3 wherein said gate control means comprises a plurality of astable multivibrator means connected in cascade, each producing a pulse having a length corresponding to a preselected range interval, wherein a first of said astable multivibrator means is triggered upon radar range being equal to zero.

Claim 6

The apparatus of claim 4 wherein said predetermined duty factor equals 5 percent.

Claim 7

The apparatus of claim 5 wherein said thresholding means comprises an analog comparator in combination with a potentiometer having a preselected value.

Claim 8

A radar video signal processor including an acquisition detector producing a signal when a preselected ratio of hits per radar dwells is exceeded indicating correlation and also including an adaptive radar vido processor of a closed loop type wherein a feedback signal is produced for maintaining a constant average false alarm probability within selected range intervals, said adaptive radar video processor comprising, sampling means receiving said radar video signal and producing a plurality of samples therefrom, a plurality of comparator means connected to receive said samples with said feedback signal and producing a distinct output signal for each video sample which exceeds said Feedback signal level, summing means receiving said comparator means output signals and producing an output signal having a level proportional to the number of samples exceeding said feedback signal, a plurality of thresholding means each having a different preselected threshold level and each receiving said output signal from said summing means for producing output signals when said threshold levels are exceeded, said acquisition detector connected to receive a first of said output signals from the plurality of threshold means and producing said correlated output signal, first duty factor controlling means receiving a second output signal from said thresholding means and producing a signal therefrom having a predetermined duty factor, second duty factor controlling means receiving said correlated output signal and producing a signal having a predetermined duty factor, means receiving said first and second controlled duty factor signals for producing a combined signal therefrom, a plurality of selectively operable filter means receiving said combined signal for producing signals proportional to the duty factor of said combined signal, said filter means output signals being fed back to said comparator means, and a plurality of gate control means connected to said filter means for selectively operating said plurality of filter means in response to selected range intervals.

Claim 9

A radar video signal processor including an acquisition detector producing a signal when a preselected ratio of hits per radar dwells is exceeded indicating correlation and also including an adaptive radar vido processor of a closed loop type wherein a feedback signal is produced for maintaining a constant average false alarm probability within selected range intervals, said adaptive radar video processor comprising, sampling means receiving said radar video signal and producing a plurality of samples therefrom, a plurality of comparator means connected to receive said samples with said feedback signal and producing a distinct output signal for each video sample which exceeds said Feedback signal level, summing means receiving said comparator means output signals and producing an output signal having a level proportional to the number of samples exceeding said feedback signal, a plurality of thresholding means each having a different preselected threshold level and each receiving said output signal from said summing means for producing output signals when said threshold levels are exceeded, said acquisition detector connected to receive a first of said output signals from the plurality of threshold means and producing said correlated output signal, first duty factor controlling means receiving a second output signal from said thresholding means and producing a signal therefrom having a predetermined duty factor, second duty factor controlling means receiving said correlated output signal and producing a signal having a predetermined duty factor, means receiving said first and second controlled duty factor signals for producing a combined signal therefrom, a plurality of selectively operable filter means receiving said combined signal for producing signals proportional to the duty factor of said combined signal, said filter means output signals being fed back to said comparator means, and a plurality of gate control means connected to said filter means for selectively operating said plurality of filter means in response to selected range intervals.

Claim 10

The apparatus of claim 7 wherein said sampling means comprises a tapped delay line.

Claim 11

The apparatus of claim 8 wherein said thresholding means comprise analog comparators each in combination with a variable resistor means.

Claim 12

The apparatus of claim 9 wherein said first and second duty factor controlling means comprise first and second pulse stretching means having a first and second pulse stretch factor.

Claim 13

An adaptive video signal processor of a closed loop type wherein a feedback signal is produced for maintaining a constant average false alarm probability within selected range intervals and comprising, sampling means connected to receive said radar video signal and producing a plurality of samples therefrom, a plurality of comparator means each receiving an associated one of said plurality of signal samples and said feedback signal for producing an output signal when said associated sample exceeds said feedback signal, summing means connected to receive said output signals from said plurality of comparator means and producing an output signal of a level proportional to the number of comparator means output signals, thresholding means connected to receive said summing means output signal and producing an output signal when said summing means output signal exceeds a preselected level, means connected to receive said output signal from the thresholding means for maintaining the duty factor of said output signal from the thresholding means at a preselected level, a plurality of filter means selectively operable over preselected radar range intervals receiving said maintained duty factor signal, each filter means producing an output signal, said filter means output signals being combined to form said feedback signal and connected to said plurality of comparator means, and gating means for enabling selectively said filter means in response to preselected radar range intervals.

Claim 14

An adaptive video signal processor of a closed loop type wherein a feedback signal is produced for maintaining a constant average false alarm probability within selected range intervals and comprising, sampling means connected to receive said radar video signal and producing a plurality of samples therefrom, a plurality of comparator means each receiving an associated one of said plurality of signal samples and said feedback signal for producing an output signal when said associated sample exceeds said feedback signal, summing means connected to receive said output signals from said plurality of comparator means and producing an output signal of a level proportional to the number of comparator means output signals, thresholding means connected to receive said summing means output signal and producing an output signal when said summing means output signal exceeds a preselected level, means connected to receive said output signal from the thresholding means for maintaining the duty factor of said output signal from the thresholding means at a preselected level, a plurality of filter means selectively operable over preselected radar range intervals receiving said maintained duty factor signal, each filter means producing an output signal, said filter means output signals being combined to form said feedback signal and connected to said plurality of comparator means, and gating means for enabling selectively said filter means in response to preselected radar range intervals.

Claim 15

The apparatus of claim 11 wherein said sampling means comprises a signal delay line producing a plurality of time delayed signals.

Claim 16

The apparatus of claim 12 wherein said duty factor maintaining means comprises a pulse stretching device of the multivibrator type.

Claim 17

The apparatus of claim 14 further including a pulse repetition frequency M/N detection means connected to receive said output signals from said thresholding means and producing a pulse repetition frequency correlation signal therefrom, second means for maintaining a preselected duty factor connected to receive said M/N correlation signal, and Summing means receiving said first and second duty factor maintaining means output signals and producing an output signal therefrom connected to said filter means.