Raytheon Company

David A Marquis

Mark E Russell

Ronald A Wagner

Dean L Shollenberger

I Shaun Carnes, Deceased

Walter S Justice

A CW radar range measuring system having a transmitter adapted to transmit a continuous wave radar signal phase encoded in accordance with a code and a receiver adapted to receive a radar return from the transmitted radar signal. The receiver includes an analog to digital converter section for converting a sequence of samples of the radar return into a corresponding sequence of digital words. A digital correlator/integrator is fed by the digital words and the code for providing an indication of radar return energy as a function of range from the transmitter. A processor is fed by the digital correlator/integrator for determining, from the indicated energy, target range. The system includes a frequency spectrum analyzer for determining a frequency spectrum of the digital words and wherein the processor determines the target Doppler frequency from such determined frequency spectrum. In one embodiment of the invention, the digital correlator/integrator is fed the digital words and the frequency analyzer is coupled between the digital correlator/integrator and the processor. In another embodiment of the invention the frequency analyzer is fed the digital words and the digital correlator/integrator is coupled between the frequency analyzer and the processor. In still another embodiment, target range may be determined to an accuracy less than that corresponding to a time delay of 1/f.sub.s, the rate the at which the phase of the transmitted signal is phase encoded.

CW radar range measuring system with improved range resolution

A radar system having a transmitter for transmitting a series of radio frequency (RF) pulses with sequential, incrementally changing carrier frequencies. A receiver receives energy from multiple scattering points of an object reflecting such transmitted RF pulses. The received energy from each one of such scattering points includes a series of radio frequency (RF) pulses corresponding to the transmitted pulses delayed in time, .tau., from the transmitted pulses an amount proportional to the range to such scattering point and shifted in frequency from the carrier frequency an amount proportional to the velocity of such scattering point. The receiver includes a heterodyning section, responsive to a range tracking error signal, .epsilon..sub.R, and a velocity tracking error signal, .DELTA..sub.VEL, for producing a series of pulsed signals for each one of the scattering points. Each one of the pulsed signals for any given scatterer sequentially changes in phase, .phi., at a rate, .DELTA..phi./.DELTA.T, related to the range to the scattering point producing such one of the pulsed signal series. A processor, responsive to each of the series of pulsed signals produced by the heterodyning section, unambiguously determines from the frequency spectrum thereof the range tracking error signal, .epsilon..sub.R, and velocity tracking error signal, .DELTA..sub.VEL, for each of the scattering points as well as the range centroid.

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Medford, MA, United States of America

David A Marquis