Unambiguous Radial Velocity Estimation Based on Delay-Interferometry in Range Frequency Domain

Abstract To solve the problem that the estimated radial velocity of fast moving target is ambiguity in synthetic aperture radar/ground moving target indication (SAR/GMTI), an approach is proposed to estimate the radial velocity unambiguously in the paper. The method utilizes the processing of delay and interferometry in range frequency domain. After range compression and delay, the dual-channel data possess the same Doppler chirp rate. Then, interferometric processing is done in range frequency domain, obtaining the linear relationship between the interferometric phase and range frequency, with the slope containing the information of radial velocity. Since the slope is no ambiguity, radial velocity is estimated unambiguously. The maximum unambiguous radial velocity of the proposed method is also analyzed. Numerical simulations demonstrate the validity of the proposed method with high accuracy of estimation.