초록 ▼

A coherent-on-receive radar for determining the velocity of and distance to targets. The radar conventionally includes a transmitter of non-coherent pulses, an antenna for transmitting the pulses into space and receiving return signals from targets upon which the pulses impinge, a local oscillator a

A coherent-on-receive radar for determining the velocity of and distance to targets. The radar conventionally includes a transmitter of non-coherent pulses, an antenna for transmitting the pulses into space and receiving return signals from targets upon which the pulses impinge, a local oscillator and a phase detecting circuit responsive to the return signal and local oscillator signal for determining the phase difference between the respective signals. In accordance with the invention the radar includes a sample and hold circuit used in conjunction with the phase detecting circuit, prior to the receipt of any return signal, for storing for each transmitted pulse its phase difference from the local oscillator signal phase. The stored signal is used to modify the phase of one or the other of return signals sent to the phase detector or local oscillator signal as sent to the phase detector so the detector in effect detects the phase difference between each transmitted pulse and the return signals resulting therefrom.

대표청구항 ▼

In a coherent-on-receive radar system of the type which includes: first means for producing periodic radio frequency (rf) pulses which are not necessarily in phase with one another, second means for transmitting the periodic pulses into space and for receiving return pulses reflected from targets (i

In a coherent-on-receive radar system of the type which includes: first means for producing periodic radio frequency (rf) pulses which are not necessarily in phase with one another, second means for transmitting the periodic pulses into space and for receiving return pulses reflected from targets (if any) impinged by the transmitted pulses; third means for producing an rf reference signal having a reference phase; and fourth means responsive to each second means return pulse and third means signal for producing a signal, a parameter of which represents the phase difference between the pulse and signal from the second and third means respectively, the improvement comprising: fifth means for providing to said fourth means, at a time following the transmission of each periodic pulse and before any return signals from any targets of interest are received, a signal corresponding to the phase of said transmitted pulse; said fourth means being responsive to the signal from said fifth means and third means for determining the difference in phase between the transmitted pulse and reference signal; sixth means for storing a signal repesenting said phase difference between said transmitted pulse and reference signal until the next successive transmitted pulse occurs; and seventh means responsive to the stored signal for altering the phase of one of the return signal and reference phase signal as applied to the fourth means whereby said fourth means produces signals representing substantially the phase difference between the transmitted pulse and resulting return signals.