Sequential-Based Range-Doppler Estimation With Fast and Slow Time Sub-Nyquist Sampling

Range-Doppler detection with pulse sequences exists widely in Radar, sonar, ultrasound imaging, and many other engineering applications. However, the classic methods require a high sampling rate for wideband pulses, and the Doppler estimation with slow time sub-Nyquist sampling may suffer from the phase wrapping. In this brief, a sequential-based range-Doppler estimation method with fast and slow time sub-Nyquist sampling is proposed. Utilizing the finite rate of innovation (FRI) theory, the range parameters can be estimated from several Fourier coefficients. The fast time sampling rate is determined by the number of the unknown parameters, instead of the signal bandwidth. Then, the aliasing-free Doppler parameters are estimated by the subspace method and the Chinese remainder theorem (CRT). The sequential-based method enables to estimate each Doppler parameter separately, and the Doppler estimation is transformed into a robust CRT problem, which enhances the robustness of the Doppler estimation. Simulation and hardware results demonstrate the effectiveness of the proposed method.