查看文章

The obvious orbit curvature of Medium Earth Orbit (MEO) results in severe two-dimensional space variance in the received signals. Thus, the focusing of MEO SAR data is still a problem to be solved. Fourth-order polynomial is used to model the range history. Also, an azimuth two-step resampling method is proposed to address the azimuth variance. The azimuth resampling in the time domain can adjust the azimuth chirp rate to be the same, then CS/RMA algorithm can be used to handle the space variance of the RCM. The second-step azimuth resampling can correct the left space variance of the Doppler parameters, including range-azimuth coupled space variance of the azimuth chirp rate, and the higher-order focusing parameters. The proposed method can well address the azimuth space variance of the whole scene, make the conventional frequency-domain focusing algorithms applicable to large scene …