Abstract: A coherent sidelobe canceller configured as a linear array antenna system having a digital open-loop configuration comprising signal receiver means having (N+1) channels (N is an integer more than one) comprising a main antenna, N auxiliary antennas, and (N+1) signal receiver circuits connected to (N+1) antennas including said main antenna with a one-to-one relationship, to produce radar video signals; analog-to-digital converter means, each channel being connected to corresponding one of said signal receiving means to convert said radar video signals to digital signals; memory means connected to said analog-to-digital converting means to store said digital signals therein; weighting coefficient calculating means connected to all (N+1) channels of said analog-to-digital converting means to perform statistical calculation processing with respect to time series digital signals, thus calculating weighting coefficients based on statistical characteristic of an input signal; multiplier means having (N+1) channels,