RADAR

Assignee

Filed

Jul 5, 1989

Granted

Nov 26, 1991

Location

LONDON EN GB

Abstract

To provide stationary or mobile radar with the capability of measuring the true range profile, a radar system includes a voltage oscillator coupled to a duplexer via a pulse modulation circuit. A digital control circuit provides a sweeping 500 Mhz frequency (F) of 6N successive batches of pulses being incremented in steps of F/6N. Returns received in response to each transmitted pulse are then combined in a mixing circuit with the signal from the local oscillator to generate a signal IF; each signal is summed with signals for the same range cell derived from earlier pulses transmitted at the same frequency; thereafter the signals pass through a FFT circuit. To maintain the "dissected" spectrum centered at the 2Nth cell, respective summations are carried out in two circuits, and then differenced in and normalized by the total signal energy present in the true profile range obtained from a summing circuit, the output therefrom providing an error signal whose magnitude and sign are used to estimate any change required in the value of prf, fr, thereby to achieve the value of T which will maintain the dissected spectrum centered on the 2Nth range cell.

Source: Google Patents