Backprojection Operator-Based One-Stationary Bistatic SAR Sparse Imaging

Unlike monostatic synthetic aperture radar (SAR), the instantaneous slant range of one-stationary bistatic SAR (OS-BiSAR) is determined by the position of the receiver, transmitter, and target. Therefore, the echo data of OS-BiSAR have strong 2-D spatial variability, which increases the difficulty of high-precision OS-BiSAR imaging. At present, the frequency-domain algorithm and its improved methods are no longer applicable, and it is impossible to perform high-precision imaging of OS-BiSAR. To solve above problems, in this letter, we propose a novel backprojection (BP)-based OS-BiSAR sparse imaging method. In the proposed method, an echo simulation operator is first constructed based on BP algorithm to achieve azimuth-range decoupling of the collected echo. Then, the considered scene is recovered by solving an $L_{1}$ -norm regularization problem. Experimental results shows that compared with typical matched filtering (MF)-based OS-BiSAR imaging algorithm, the proposed method can obtain the SAR image with higher quality especially when the used data are downsampled and improves the image target-to-background ratio (TBR) at least 5 dB.