Ground moving target imaging based on 2-D velocity search in high resolution SAR
A novel ground moving target imaging algorithm based on 2-D velocity search is proposed in high resolution synthetic aperture radar. In the range-Doppler domain, a range velocity with low accuracy is obtained via the response length along the range direction of the target's range migration. Then, an accurate range velocity is determined in the velocity search for the best range migration correction. As to the azimuth velocity, it is roughly acquired based on the road slope extracted from a SAR image. Next, an accurate azimuth velocity is searched to match the Doppler rate of the moving target in order to realize the azimuth focusing, which is measured by the contrast of target imaging result. After the 2-D velocity search, the range defocus and azimuth defocus of a moving target is eliminated, and the final focused imaging is fulfilled. Compared with some existing imaging approaches, the proposed algorithm solves the problem of Doppler spectrum split and has a relatively low computation burden. Finally, some numerical experiments are provided to demonstrate the effectiveness of the proposed algorithm.