A single dwell velocity estimation method for pulse Doppler radar using multicarrier signals

For pulse Doppler radars, targets become undetectable for Doppler frequencies in the detection-blind range occupied by the clutter Doppler spectrum. To overcome this problem, different Pulse Repetition Frequencies (PRFs) are used to search for targets with Doppler ambiguity and estimate their velocity, which is required for target tracking. Owing to the different PRFs used for velocity estimation, many beam dwells are required for illuminating the targets, Doppler compensation cannot be realized in a short time. In this paper, we propose a novel velocity estimation method that uses multicarrier signals in a single dwell. First, we obtain separated subcarrier signals from the echo signal and multiply some separated subcarrier signals by other separated subcarrier signals in a conjugate manner, obtaining Frequency-Converted Subcarrier (FCS) signals. We derive the potential ambiguous and unambiguous Doppler frequencies for the separated subcarrier and FCS signals, respectively, using a slow-time Discrete Fourier Transformation (DFT). Subsequently, the actual Doppler ambiguity number is derived from the results. Finally, the unambiguous Doppler frequency and target velocity are inferred. The effectiveness and superiority of the proposed method are validated by performing simulation studies.