Research On Sliding Spotlight And TOPS SAR Variable PRF Imaging Technology

Because the traditional single-based spaceborne synthetic aperture radar (SAR) cannot receive signals while transmitting signals, there is a defect that high azimuth resolution and wide swath imaging cannot be achieved at the same time. In response to this problem, researchers have proposed the use of variable pulse repetition frequency (PRF) technology to achieve high-resolution wide swath imaging. However, the echo data of the variable PRF SAR will have the problem of sampling at different intervals in the azimuth direction. Using traditional frequency domain algorithms to process the data will cause serious deterioration of the imaging quality, or even imaging; the time domain algorithm can directly focus on the data of the variable PRF, but the amount of calculation is huge. In this paper, we deduced the change rule of PRF and proposed a variable PRF imaging algorithm based on time-frequency scale scaling. A new interpolation method is used to perform uniform sampling of the unambiguous signal in the time domain. Then use the Omega-K algorithm to achieve range cell migration correction (RCMC), and finally focuses the signal in the azimuth frequency domain. The proposed SAR working system with variable PRF is verified by simulation experiments.