Unambiguous range extension for pulse‐Doppler radar via Poisson disk sampling

Since the maximum unambiguous range in the traditional single‐channel pulse‐Doppler (PD) radar is restricted by the pulse repetition interval (PRI), there is a trade‐off between the maximum unambiguous range and the maximum unambiguous velocity. As a result, conventional coherent processing used in PD radar systems can hardly provide large unambiguous range and large unambiguous velocity simultaneously. We propose a method of unambiguous range extension for PD radar via Poisson disk sampling. The method enables the PD radar to detect farther targets unambiguously without sacrificing the maximum unambiguous velocity. The Poisson disk sampling is adopted in the slow time domain to ensure the interval length between any two adjacent transmitted pulses to be larger than a desired value, which can be set longer than the Nyquist sampling interval to extend the maximum unambiguous range. Then, the Iterative Soft Thresholding like (IST‐like) algorithm is utilized on the non‐uniformly under‐sampled data to recover the range‐Doppler spectrum accurately. Compared to some of existing methods of unambiguous range extension based on stochastic sampling, the proposed method has better velocity estimation accuracy. Simulations and experiments on real PD radar data demonstrate the effectiveness of the proposed method.