Double (multiple) Base Of Synthetic Aperture Radar Imaging Algorithms

Bi-/multistatic Synthetic Aperture Radar (SAR) is one of the hotspots in the SAR research field nowdays. Transmitter(s) and receiver(s) of bi-multistatic SAR are mounted on separated platforms, so the imaging algorithms of bi-/multistatic SAR are more complicated than the traditional SAR. Multistatic SAR can be divided into several bistatic SARs, and multistatic SAR image of tagets can be obtained by combining the bistatic SAR images. Therefore, the key point and majority of this paper is the image formation algorithms of bistatic SAR.There are two ways to form a bistatic SAR image:one is to deduce the two dimensional frequency spectrum of the bistatic SAR based on its geometric pattern and extend/improve the conventional image formation algorithms to form the bi-static SAR image; the other is to use thought of equivalent, transform the bistatic geometric pattern to its equivalent monostatic pattern, and then use the tranditional imaging algorithms to form a bistatic SAR image. As for the azimuth-invariant bistatic SAR, in the former way, the Range Doppler algorithm based on the MSR (Method of Series Revision) two-dimensional frequency spectrum of the bistatic SAR is discussed; In the latter way, the advanced baseline-center equivalent algorithm and the range hyperbolical equivalent Range Doppler algorithm are obtained. Good simulation results based on these algorithms for parallel equal-velocity bistatic SARs are obtainedThe multistatic SAR imaging algorithms are based on those of the bistatic SAR. An imaging algorithm is proposed for the azimuth-invariant airborne multistatic SAR which is composed of one transmitter and several receivers and has great military application importance. First of all, it is divided into several bistatic SARs. The bistatic SARs use the baseline-center monostatic-equivalent algorithm to form the images of the target respectively, and then conduct the registration of the two images’pixels, and interpolate the image data into the same position of the common image plane, then the multistatic SAR image formation result can be obtained finally. The simulation results are given according to the algorithm steps. The multistatic SAR’s ability to collect scattering energy of different angles is proved and multistatic SAR’s image quality is better than that of bistatic SAR’s.