A floodlight radar system includes a transmitter arranged to generate output waveforms at first and second centre frequencies, and at least one transmit antenna configured to illuminate a search volume constantly at the first and second centre frequencies. A sparse array of receive antennas is arranged in a common plane and configured to monitor the search volume constantly. The system includes a receive circuit arranged to extract target position information from return signals received by each antenna, and a signal processor circuit which is arranged to resolve ambiguity in the position information using a known relationship between calculated Doppler spectra, wavelengths and phase differences at the first and second frequencies, to calculate azimuth, elevation, range and velocity of a target identified in the search volume. The system is able to rapidly detect and locate multiple fast moving targets in three dimensions.