Resolution of range and Doppler ambiguities in medium PRF radars in multiple-target environment

In medium pulse-repetition frequency (PRF) radars, ambiguities may arise in both range and Doppler measurements. Efficient techniques have been established [1,2] to resolve the range ambiguity of a single isolated target using multiple PRF´s. In this paper, we describe a simple algorithm to resolve the Doppler ambiguity using the discrete Fourier transform (DFT) output of two PRF´s. A condition on the relative values of the two PRF´s is derived to account for the errors due to the finite bandwidth of DFT filters. A third PRF is used to identify the declarations of a particular target in different PRF´s. Range ambiguities are then resolved in a straightforward manner. A fourth PRF is made use of to extract blind-speed targets. The proposed method is computationally efficient and can be used even when ambiguous returns from several targets are received.