Signal Modeling and Imaging of Frequency-Modulated Continuous Wave Sliding Spotlight Synthetic Aperture Ladar

Frequency-modulated continuous wave synthetic aperture ladar (FMCW-SAL) is an important remote sensing observation method. Sliding spotlight FMCW-SAL can obtain high resolution and wide observation coverage in azimuth simultaneously. This work models and simulates sliding spotlight FMCW-SAL signal. FMCW-SAL beam scanning leads to spectrum aliasing in the azimuth direction, and the linear and second-order position offset errors are introduced in the range direction. Compared with sliding spotlight FMCW synthetic aperture radar (SAR), the linear position offset error is more serious and must be corrected. However, there is no linear position offset correction in previous research studies in sliding spotlight FMCW-SAR. An improved sliding spotlight FMCW-SAL imaging algorithm is proposed for the above problems here. This algorithm includes two new phase compensation factors, which can remove Doppler ambiguity and correct first-order, second-order position offset errors in range simultaneously. Simulation experiments verify the effectiveness of the signal model and the imaging algorithm.