1. In a radar system wherein "in phase" and "quadrature" signals are produced for each one of a series of range sweeps, such signals being phase compared with a reference signal to produce a pair of signals and wherein such pair of signals is converted into a series of complex digital words, each one of such words corresponding to a different one of a number of range cells in each one of the series of sweeps, the improvement comprising: a. means for combining a portion of the series of complex digital words of one of the series of range sweeps with a portion of the series of complex digital words of another one of such range sweeps to produce a series of correction complex digital words, each one thereof being representative of the average Doppler velocity of returns at a different one of the range cells; b. canceller means including: means for modifying each one of the input complex digital words of one of the range sweeps with a corresponding one of the correction complex digital words to produce a series of modified complex digital words; and means for combining each one of the modified complex digital words with a different one of the input complex digital words of another one of the range sweeps to reject moving clutter returns and to pass moving target returns.