Search radar apparatus

Search radar apparatus including an MTI video processing unit having a canceller for generating video signals of moving targets, a zero-velocity filter for generating clutter video signals, and clutter level indication means for determining a standard clutter level per range-azimuth clutter cell of the radar range with the application of clutter video signals, the improvement therein comprising a conditional circuit connected to the canceller and the zero-velocity filter for generating per range quant of each radar scan a clutter switching signal when for the range quant the signal value obtained with the zero-velocity filter is greater than the signal value obtained with the canceller, and further comprising a combination circuit connected to the zero-velocity filter and the conditional circuit for selecting the clutter video signals present with the clutter switching signals and for determining from said selected clutter video signals a temporary clutter level in each clutter cell and in each antenna revolution period for application to the clutter level indication means to produce a standard clutter level.