Single composite pulse moving target indicator radar system

Claim 2

A single composite pulse MTI radar system comprising in combination means for transmitting single composite radar pulses of length T at a predetermined pulse repetition frequency, said pulses being simultaneously composed of a first component having a frequency sweep from f1 to f2 over the pulse length T and a second component having a frequency sweep from f2 to f1 over the pulse length T, means for receiving target reflected pulses and for processing said pulses including a pair of pulse compression filter means for providing compressed pulses of said first and second pulse components in separate circuit paths, and means for subtracting said processed pulses whereby a signal output is produced only for pulses reflected from moving targets.

Claim 3

The system of claim 1 wherein said frequency sweeps are linear over the period T.

Claim 4

The system of claim 1 further comprising means for rectifying said subtracted signals to provide rectified signals, means for integrating said rectified signals to provide a voltage, and threshold means for detecting the amplitude level of said voltage.

Claim 5

A single composite pulse MTI radar system for transmitting pulses of r.f. energy and for receiving target reflected pulses comprising in combination oscillator means for generating an r.f. signal, means for linearly frequency modulating said oscillator means from a first frequency f1 to a second frequency f2, constituting an up sweep modulation, further oscillator means for generating an r.f. signal, means for linearly frequency modulating said further oscillator means from a first frequency f2 to a second frequency f1, constituting a down sweep modulation; pulse generator means for operating said up sweep and down sweep modulator means during repetitive pulse intervals t1 to t2, means for adding the outputs of said r.f. signal oscillator means whereby a single composite pulse having up sweep and down sweep modulation components is simultaneously produced, means for amplifying said single composite r.f. pulse, antenna means for transmitting said single composite r.f. pulse and for receiving a target reflected echo of said single composite r.f. pulse, means for connecting said amplifier means to said antenna means, a first mixer having two inputs and an output, first local oscillator means for providing a signal at the lower side band freQuency of said single composite r.f. pulse, means for applying said first local oscillator means signal and said target reflected pulse to said first mixer inputs, a second mixer having two inputs and an output, second local oscillator means for providing a signal at the upper sideband frequency of said single composite r.f. pulse, means for applying said second local oscillator signal and said target reflected pulse to said second mixer inputs, first and second pulse compression filter means connected to the outputs of said first and second mixers, respectively, for providing separate compressed pulse outputs representative of said composite pulse to up sweep and down sweep modulation components and for substantially simultaneously suppressing said down sweep and up sweep modulation components, respectively, first and second means connected to said first and second filter means, respectively, for envelope detecting said compressed pulses, means for inverting one of said detected pulses, and means for adding said inverted and non-inverted pulses whereby a signal output representative of a moving target is provided.

Claim 6

A single composite pulse MTI radar system for transmitting pulses of r.f. energy and for receiving target reflected pulses comprising in combination oscillator means for generating an r.f. signal, means for linearly frequency modulating said oscillator means from a first frequency f1 to a second frequency f2, constituting an up sweep modulation, further oscillator means for generating an r.f. signal, means for linearly frequency modulating said further oscillator means from a first frequency f2 to a second frequency f1, constituting a down sweep modulation; pulse generator means for operating said up sweep and down sweep modulator means during repetitive pulse intervals t1 to t2, means for adding the outputs of said r.f. signal oscillator means whereby a single composite pulse having up sweep and down sweep modulation components is simultaneously produced, means for amplifying said single composite r.f. pulse, antenna means for transmitting said single composite r.f. pulse and for receiving a target reflected echo of said single composite r.f. pulse, means for connecting said amplifier means to said antenna means, a first mixer having two inputs and an output, first local oscillator means for providing a signal at the lower side band freQuency of said single composite r.f. pulse, means for applying said first local oscillator means signal and said target reflected pulse to said first mixer inputs, a second mixer having two inputs and an output, second local oscillator means for providing a signal at the upper sideband frequency of said single composite r.f. pulse, means for applying said second local oscillator signal and said target reflected pulse to said second mixer inputs, first and second pulse compression filter means connected to the outputs of said first and second mixers, respectively, for providing separate compressed pulse outputs representative of said composite pulse to up sweep and down sweep modulation components and for substantially simultaneously suppressing said down sweep and up sweep modulation components, respectively, first and second means connected to said first and second filter means, respectively, for envelope detecting said compressed pulses, means for inverting one of said detected pulses, and means for adding said inverted and non-inverted pulses whereby a signal output representative of a moving target is provided.