Process and system for the visual display of moving targets

A system for processing incoming echo signals from a receiver of a Doppler radar for the control of a moving-target display, said radar transmitting outgoing pulses with a time-varying pulse-repetition period, comprising:

• first and second demodulators connected to an intermediate frequency stage of the Doppler radar and to a source of two coherent reference signals in relative quadrature for feeding demodulation products of echo signals from a given range cell of the radar to a first and a second channel;
• arithmetic means in each of said channels for subtracting two demodulation products, derived from echo signals received in consecutive pulse-repetition periods, from each other to produce a respective difference signal;
• and
• weighting means with inputs connected to said channels and with outputs emitting respective components of a control signal in which the effects of the variations of said pulse-repetition period are substantially compensated at least for a selected Doppler frequency, said weighting means including a first pair of multipliers connected in parallel to said first channel, a second pair of multipliers connected in parallel to said second channel, a first adder inserted between one multiplier of each pair and one of said outputs, and a second adder inserted between the other multiplier of each pair and the other of said outputs, the multipliers of each pair respectively weighting each difference signal from the corresponding channel with a sine and a cosine function of a phase difference .DELTA..phi. dependent on the selected Doppler frequency and on a numerical difference between the current pulse-repetition period and a predetermined value.