Raytheon Company

Dean L Shollenberger

I Shaun Carnes, Deceased

Mark E Russell

David A Marquis

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 for processing a series of radar returns to determine Doppler velocity of an object. Each one of the radar returns is produced in response the object reflecting each one of a series of transmitted radar pulses. The series of radar returns is processed in a sequence of successive dwells. Each one of the dwells has a predetermined number of radar returns. The radar system includes a system clock for producing a series of clock pulses. A range gate is provided for sampling each one of a series of radar returns produced in response to a each one of a series of transmitted radar pulse. The range gate has a time duration equal to an integer number of, N, clock pulse periods. A range gate positioning system initiates the range gate a selected time, .DELTA., after each one of the transmitted pulses. The positioning system determines the selected time, .DELTA., as an integer number of, M, clock pulse periods for a predetermined number of transmitted pulses and then subsequently changes such integer M to a different integer number, M'. More particularly, the range gate positioning system determines the integer number, M, in accordance with a predetermined fractional offset, .delta., of a clock pulse period, T, of the position of an object within the clock pulse period, T, from a predetermined desired position within the clock pulse period, T, and the integer M' being determined in accordance with the Doppler velocity of the object. The range gate positioning system determines M' is accordance with the number of PRIs per clock pulse period the object moves relative to the radar system) and determines M in accordance with M=�1-(.delta./T)!M'.

Radar system

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.

Growing community of inventors

Townsend, MA, United States of America

Dean L Shollenberger