Range-gated moving target signal processor

Claim 2

A range-gated doppler processor having an input terminal and comprising range-gated signal-averaging means responsively coupled to said input terminal for providing a time-averaged signal; and first differential signal combining means responsively coupled to said input terminal and to said range-gated signal-averaging means for providing a non-zero frequency output.

Claim 3

The device of claim 1 in which there is further provided means for compensatory signal-shaping of a periodic input signal, to be applied to said input terminal, and comprising first and second range-gated memory means arranged for operation in synchronism with said range-gated signal averaging means, an alternate one of said first and second memory means being adapted for storing at least a portion of a periodic input signal and the other of said first and second memory means being connected to said input terminal during successive periods of said periodic signal.

Claim 4

The device of claim 2 in which each said memory means comprises an R-C network having a time constant much less than the time interval represented by the range-gating of said range-gated doppler processor.

Claim 5

The device of claim 1 in which said doppler processor further includes bandpass limiting means, comprising variable-gain range-gated signal averaging means coupled to said input terminal and operated in synchronism with said first mentioned signal averaging means and having a time constant substantially different from that of said first mentioned signal averaging means for providing a second time-averaged signal; and second differential signal combining means responsive to the magnitude of said range-gated non-zero frequency output and the magnitude of the difference between said first mentioned and said second time-averaged signals.

Claim 6

The device of claim 4 in which there is further included range-gated peak detection means limiting the response of said second differential signal combining means to the peak detected magnitudes of said range-gated non-zero frequency and of said difference.

Claim 7

The device of claim 1 in which there is further provided range-gated signal integrating means responsive to the magnitude of said range-gated non-zero frequency output.

Claim 8

The device of claim 6 in which said integrating means comprises an R-C network having a time constant substantially greater than the period of a range-time repetition interval of said range gated doppler processor.

Claim 9

In a non-coherent receiver of a pulsed energy system, a range-gated doppler processor comprising a plurality of switched R-C signal storage networks, each switched-on for a preselected interval corresponding to a successive one of a plurality of range bins-to-be-sampled of a range trace signal for providing a stored time-averaged signal indicative of the clutter content at such interval; and differential signal-combining means responsive to the sequential outputs of said switched R-C networks and said range trace signal for providing a clutter-free moving target signal.

Claim 10

In a non-coherent receiver of a pulsed energy system, a range-gated doppler processor comprising a plurality of switched R-C signal storage networks, each switched-on for a preselected interval corresponding to a successive one of a plurality of range bins-to-be-sampled of a range trace signal for providing a stored time-averaged signal indicative of the clutter content at such interval; and differential signal-combining means responsive to the sequential outputs of said switched R-C networks and said range trace signal for providing a clutter-free moving target signal.

Claim 11

The device of claim 8 in which said switched R-C networks comprise a single common input series resistor; a plurality of switchable output shunt capacitors; and switching means responsive to a system trigger of said pulsed energy system for switching a successive one of said plurality of capacitors into circuit with said resistor for a preselected interval corresponding to a successive one of said plurality of range bins.

Claim 12

The device of claim 8 in which there is provided range-coherent integration means for integrating said clutter-free moving target signal, comprising unipolar conductive means having an input responsive to said moving target signal; and a like second plurality of switched R-C signal storage networks as said first mentioned plurality, corresponding networks of said first and second plurality of networks being connected to be switched in synchronism.

Claim 13

The device of claim 8 in which there is provided peak detection means for distinguishing a moving target component from amid a range-gated clutter referenced range trace signal and comprising a first and a second unipolar current source responsive to said stored, time-averaged signal and said clutter-free moving target signal, respectively; a first and second like plurality of switchable shunt-connected signal storage elements as said R-C networks, said first plurality of signal storage elements being shunt connected across the output of said first unipolar current source and said second plurality of signal storage elements being shunt connected across the output of said second unipolar current source, corresponding ones of said storage elements and said R-C signal storage networks being connected to be switched in synchronism; and second-mentioned differential signal-combining means having first and second inputs respectively responsively coupled to the respective output of said first and second unipolar current source.

Claim 14

The device of claim 11 in which there is provided range-coherent integration means for integrating said clutter-free moving target signal, comprising unipolar conductive means having an input responsive to said moving target signal; and a like second plurality of switched R-C signal storage networks as said first mentioned plurality, corresponding networks of said first and second plurality of networks being connected to be switched in synchronism.

Claim 15

The device of claim 8 in which there is further provided range-gated moving target signal peak detection means comprising a unipolar current source responsive to said clutter-free moving target signal; and a like plurality of switchable shunt-connected signal storage elements as said R-C networks, said signal storage elements being shunt connected across the output of said unipolar current source, and arranged to be switched in synchronism with corresponding ones of the R-C networks.

Claim 16

The device of claim 8 in which there is further provided means for range-gated compensatory signal shaping of the range-trace output signal of the non-coherent receiver prior to doppler processing thereof and comprising a like first and second plurality of switchable shunt connected signal storage means as said plurality of R-C networks, corresponding ones of said elements and said networks being arranged to be switched in synchronism; a first and second double throw switch operated in synchronism between alternate switching states in response to a system trigger of said pulsed energy system, said first switch coupling an alternate one of said first and second pluralities of switched storage elements to said receiver and said second switch coupling the other of said first and second pluralities of storage elements to an input of said range-gated doppler processor.

Claim 17

The device of claim 8 in which there is further provided band-pass limiting means comprising a like second plurality of switched R-C signal storage networks as said first plurality of networks, corresponding networks of said first and second plurality of networks being switched in synchronism, second differential signal-combining means being responsive to the difference between the output of said first and second pluralities of switched networks; and third differential signal combining means having a first and second unidirectionally conductive input respectively responsively coupled to a respective output of said first and second differential signal combining means.

Claim 18

The device of claim 8 in which there is further provided means for range-gated compensatory signal-shaping and clutter bandpass limiting of the doppler processing and comprising a like first and second plurality of switchable shunt connected signal storage means as said plurality of R-C networks, corresponding ones of said elements and said networks being elements arranged to be switched in synchronism; a first and second double throw switch operated in synchronism between alternate switching states in response to a system trigger of said pulsed energy system, said first switch coupling an alternate one of said first and second pluralities of switched storage elements to said receiver and said second switch coupling the other of said first and second pluralities of storage elements to an input of said range-gated doppler processor; a like second plurality of switched R-C signal storage networks as said first plurality of networks, corresponding networks of said first and second plurality of networks being switched in synchronism; second differential signal-combining means being responsive to the difference between the outputs of said first and second pluralities of switched networks; and third differential signal combining means having a first and second unidirectionally conductive input respectively responsively coupled to a respective output of said first and second differential signal combining means.

Claim 19

The device of claim 16 in which there is provided peak detection means for distinguishing a moving target component from amid a range-gated clutter referenced range trace signal and comprising a first and a second unipolar current source responsive to said stored, time-averaged signal and said clutter-free moving target signal, respectively; a first and second like plurality of switchable shunt-connected signal storage elements as said R-C networks, said first plurality of signal storage elements being shunt connected across said first unipolar input of said third differential signal combining means and said second plurality of signal storage elements being shunt connected across said second unipolar input of said third differential signal combining means, corresponding ones of said storage elements and said R-C signal storage networks being connected to be switched in synchronism.

Claim 20

A range-gated doppler processor for cooperation with the receiver of a pulsed energy system and comprising seven like pluralities of separately switchable shunt-connected signal integrating elements, a corresponding element of each plurality of elements being switched-on for a preselected interval corresponding to a successive one of a plurality of range bins-to-be-sampled; a first and second double-throw switch operated in synchronism between alternate switching states in response to a system trigger of said pulsed energy system, said first switch coupling an alternate one of a first and second plurality of said seven pluralities of switchable signal integrating elements to said receiver and said second switch coupling the other of said first and second pluralities to an output thereof; three differential signal combining means, a first input of a first one of said differential signal combining means being connected to the output of said second switch, a first output of said second differential signal combining means being connected to a third one of said pluralities of shunt-connected signal integrating elements, a second input of each of said first and second differential signal combining means being commonly connected to a fourth one of said pluralities of integrating elements, a first and second input of said third differential signal combining means being respectively connected to a respective one of fifth and sixth ones of said pluralities of signal integrating elements; first and second series resistors connecting a respective one of said third and fourth pluralities of signal integrating elements with the output of said second double throw switch; a third series resistor interconnecting the seventh one of said pluralities of integrating elements and the output of said third differential signal combining means; first unidirectionally conductive means interconnecting said fifth plurality of integrating elements and an output of said first differential signal combining means; and second unidirectionally conductive means interconnecting said sixth plurality of integrating elements and an output of said second differential signal combining means.

Claim 21

A range-gated doppler processor for cooperation with the receiver of a pulsed energy system and comprising seven like pluralities of separately switchable shunt-connected signal integrating elements, a corresponding element of each plurality of elements being switched-on for a preselected interval corresponding to a successive one of a plurality of range bins-to-be-sampled; a first and second double-throw switch operated in synchronism between alternate switching states in response to a system trigger of said pulsed energy system, said first switch coupling an alternate one of a first and second plurality of said seven pluralities of switchable signal integrating elements to said receiver and said second switch coupling the other of said first and second pluralities to an output thereof; three differential signal combining means, a first input of a first one of said differential signal combining means being connected to the output of said second switch, a first output of said second differential signal combining means being connected to a third one of said pluralities of shunt-connected signal integrating elements, a second input of each of said first and second differential signal combining means being commonly connected to a fourth one of said pluralities of integrating elements, a first and second input of said third differential signal combining means being respectively connected to a respective one of fifth and sixth ones of said pluralities of signal integrating elements; first and second series resistors connecting a respective one of said third and fourth pluralities of signal integrating elements with the output of said second double throw switch; a third series resistor interconnecting the seventh one of said pluralities of integrating elements and the output of said third differential signal combining means; first unidirectionally conductive means interconnecting said fifth plurality of integrating elements and an output of said first differential signal combining means; and second unidirectionally conductive means interconnecting said sixth plurality of integrating elements and an output of said second differential signal combining means.

Claim 22

In a direction-scanning pulsed-energy system having a receiver, airborne moving target indicating means characterized by a range-gated doppler processor having an input terminal coupled to said receiver of said system and comprising range-gated signal-averaging means responsively coupled to said input terminal for providing a time-averaged signal, and differential signal combining means responsively coupled to said input terminal and to said range-gated signal-averaging means for providing a non-zero frequency output; and plan-position indicator means responsively coupled to said doppler processor for displaying moving targets detected at intermediate ranges, and further coupled to said receiver of said system for displaying non-doppler processed signals received from ranges outside said intermediate ranges.

Claim 23

In a direction-scanning pulsed-energy system having a receiver, airborne moving target indicating means characterized by a range-gated doppler processor having an input terminal coupled to said receiver of said system and comprising range-gated signal-averaging means responsively coupled to said input terminal for providing a time-averaged signal, and differential signal combining means responsively coupled to said input terminal and to said range-gated signal-averaging means for providing a non-zero frequency output; and plan-position indicator means responsively coupled to said doppler processor for displaying moving targets detected at intermediate ranges, and further coupled to said receiver of said system for displaying non-doppler processed signals received from ranges outside said intermediate ranges.

Claim 24

The device of claim 19 in which said indicator means includes first gating means for cyclically gating-on the input from said doppler processor during a time interval corresponding to an intermediate range interval; second gating means for gating the input from said receiver, said first and second gating means being synchronously operated in mutually exclusive states; range-gate cursor signal generating means for generating display signals for demarcating the intermediate range interval; and display signal summing means coupled to said first and second gating means and said cursor signal generating means.