Abstract: A phased array radar system, such as may be used in a low-angle tracking radar or direction finding equipment, includes a multi-channel digital filter to remove unwanted multipath signals. The R.F. signals from the array are first converted to zero I.F. and digitized. After n-channel Doppler filtering (13) the digital signals are subjected to filtering (14) either to effect band-pass spatial filtering, thereby attenuating generally all signals arriving outside preset angular limits, or notch filtering which heavily attenuates signals arriving from one particular angle. In one embodiment spatial filtering is followed by notch filtering. The filtered signals are then beam-formed (15) before being applied to further digital processing, such as beam peak tracking (16).