Range-doppler algorithm of multireceiver synthetic aperture sonar using nonuniform signal

When the structures of multireceiver synthetic aperture sonar (SAS) are applied, imaging techniques are not always able to acquire images with outstanding resolution in nonuniform situations. In order to cope with this issue, we present a robust imaging algorithm in this paper. Based on our method, the receivers adopted by imaging algorithms are firstly determined. Then, we model the multireceiver SAS spectrum made up of the monostatic one and bistatic one. The bistatic portion is resolved via the application of sub-block filtering in the spectral domain. In the range-Doppler domain, the spectrums of determined receivers are coherently added. In the spectral domain, the compression in the range direction relying on multiplications is handled. With the help of interpolations, the coupling between both directions is removed in the range-Doppler domain, where the subsequent step is to do the compression in the azimuth direction. Our method can well focus the SAS datasets with the slight nonuniform case and redundant receiver case. However, traditional method just works well with the slight nonuniform case. In comparison with traditional method, our method can get high-resolution image all the time. The results based on simulations and experiments fully validate our method.