An Approach to Azimuth Spectrum Reconstruction for Bistatic Multichannel SAR

Spaceborne bistatic synthetic aperture radar (SAR) system employed different locations for transmitter and receiver could provide additional interference information compared to monostatic SAR. The spaceborne bistatic multichannel SAR system can lift the restrictions between high-resolution and wide-swath. Multichannel SAR system utilize pulse-repetition frequencies less than Doppler bandwidth at the cost of ambiguous Doppler spectrum. This represents that the radar echoes received by each channel are under-sampling. Unambiguously reconstruct the Doppler spectrum is necessary for SAR image focusing. However, Conventional azimuth reconstruction method in the Doppler spectrum for bistatic multichannel SAR result in failure because of the variety of expression for round-trip slant range of the bistatic SAR echoes. To address this problem, an improved approach to azimuth spectrum reconstruction for bistatic multichannel SAR is proposed in this paper. Application of matrix filter method can realize the recovery for signals of all channels. The effectiveness of the proposed approach in this paper is demonstrated with simulation experimental results.