Radar

Claim 1

A pulse Doppler radar utilising rapidly switched p.r.f.'s, having a spectrum analyser adapted to mix a Doppler shifted frequency derived from a target return with frequency swept signals derived by application of a train of first pulses to a dispersive delay line, the first pulses being spaced apart by time intervals proportional to the prevailing p.r.f., the spectrum analyser further including means for processing the mixing products to produce a train of second pulses of the same frequency as the first pulses and whose timing in relation to the first pulses is representative of the Doppler shift, the radar further including integration means for integrating the train of second pulses, which integration means comprises a plurality of integrators sequentially connectible by a commutator means to receive the output signals of the spectrum analyser, each integrator being connected to integrate spectrum analyser output pulses corresponding to a predetermined range of Doppler shifted frequencies, and means for changing the commutation of the integrator in synchronism with changes in the p.r.f. of the radar such that each integrator is arranged to receive the signals at all p.r.f.'s corresponding a predetermined unambiguous range of Doppler shifted frequencies.