A multi-static radar system for providing surveillance, the radar system comprising: a plurality of radar receivers (RX1, RX2) and a plurality of radar transmitters (TX1, TX2) arranged in a multi-static configuration to form at least one radar cell (112, 212, 812) to provide an area of radar coverage within said at least one radar cell (112, 212, 812); wherein each radar transmitter (TX1, TX2) is a static transmitter (TX1, TX2) operable to persistently illuminate a respective radar cell (112, 212, 812) with a radar signal comprising a sequence of radar pulses; wherein, in operation, each radar cell (112, 212, 812) is illuminated by at least two radar transmitters (TX1, TX2); wherein each radar transmitter (TX1, TX2) is operable to transmit radar pulses of radio waves having the same respective transmission frequency; wherein each transmitter (TX1, TX2) is synchronised as a part of the radar system; wherein each radar receiver (RX1, RX2) is a static receiver (RX1, RX2) operable to receive radar signals from within a respective radar cell (112, 212, 812), including radar return signals echoed from any object within said respective radar cell (112, 212, 812), as a result of illumination of said radar cell (112, 212, 812) by at least one corresponding radar transmitter (TX1, TX2) located remotely from that radar receiver (RX1, RX2); and means for processing the respective radar signals received at each radar receiver (RX1, RX2) to determine information relating to at least one of position and motion of said object. a plurality of radar receivers (RX1, RX2) and a plurality of radar transmitters (TX1, TX2) arranged in a multi-static configuration to form at least one radar cell (112, 212, 812) to provide an area of radar coverage within said at least one radar cell (112, 212, 812); wherein each radar transmitter (TX1, TX2) is a static transmitter (TX1, TX2) operable to persistently illuminate a respective radar cell (112, 212, 812) with a radar signal comprising a sequence of radar pulses; wherein, in operation, each radar cell (112, 212, 812) is illuminated by at least two radar transmitters (TX1, TX2); wherein each radar transmitter (TX1, TX2) is operable to transmit radar pulses of radio waves having the same respective transmission frequency; wherein each transmitter (TX1, TX2) is synchronised as a part of the radar system; wherein each radar receiver (RX1, RX2) is a static receiver (RX1, RX2) operable to receive radar signals from within a respective radar cell (112, 212, 812), including radar return signals echoed from any object within said respective radar cell (112, 212, 812), as a result of illumination of said radar cell (112, 212, 812) by at least one corresponding radar transmitter (TX1, TX2) located remotely from that radar receiver (RX1, RX2); and wherein each radar transmitter (TX1, TX2) is a static transmitter (TX1, TX2) operable to persistently illuminate a respective radar cell (112, 212, 812) with a radar signal comprising a sequence of radar pulses; wherein, in operation, each radar cell (112, 212, 812) is illuminated by at least two radar transmitters (TX1, TX2); wherein each radar transmitter (TX1, TX2) is operable to transmit radar pulses of radio waves having the same respective transmission frequency; wherein each transmitter (TX1, TX2) is synchronised as a part of the radar system; wherein each radar receiver (RX1, RX2) is a static receiver (RX1, RX2) operable to receive radar signals from within a respective radar cell (112, 212, 812), including radar return signals echoed from any object within said respective radar cell (112, 212, 812), as a result of illumination of said radar cell (112, 212, 812) by at least one corresponding radar transmitter (TX1, TX2) located remotely from that radar receiver (RX1, RX2); and means for processing the respective radar signals received at each radar receiver (RX1, RX2) to determine information relating to at least one of position and motion of said object.