Extension of Unambiguous Doppler in High-Frequency Surface Wave Radar Based on Poisson Disk Sampling

In marine remote sensing, the phenomena of Doppler ambiguity widely exist in the velocity measurements of fast-moving targets in high-frequency surface wave radar (HFSWR) with frequency-modulated interrupted continuous waveform. The maximum Doppler that can be unambiguously measured for targets in HFSWR is restricted by the chirp repetition frequency. In this article, an approach for the extension of unambiguous Doppler in HFSWR is proposed based on Poisson disk sampling and sparse reconstruction. The start instants of adjacent chirps are set to be Poisson disk sampled. Taking advantage of the spectral antialiasing performance of the proposed nonuniform sampling strategy, the maximum unambiguous Doppler of HFSWR can be enlarged without decreasing the maximum aliasing-free range. The range-Doppler spectrum can be correctly reconstructed by utilizing a sparse reconstruction algorithm. Compared with the existing methods for resolving the Doppler ambiguity of HFSWR, the proposed method is able to monitor multitarget scenarios without introducing false alarms. The effectiveness of the proposed method is demonstrated by simulations and experiments based on measured HFSWR data.