Spaceborne squinted multichannel synthetic aperture radar data focusing

This study analyses echo properties of spaceborne squinted multichannel along the track synthetic aperture radar (SAR) data. The highly squint angle and the large transmitted pulse bandwidth lead to Doppler spectrum back folding in the spaceborne squinted case. The extended Doppler bandwidth in the squinted mode increases the processing difficulty of azimuth multichannel data reconstruction. According to echo properties of the spaceborne squinted mode, a new imaging approach for spaceborne squinted multichannel SAR data focusing is proposed. The key point of this imaging approach is azimuth multichannel data preprocessing to resolve the aliased Doppler spectrum caused by both azimuth sub-sampling in each azimuth channel and the highly squint angle. Afterwards, a modified range migration algorithm is taken for consequent equivalent monostatic spaceborne squinted SAR data focusing. Simulation results on point targets and distributed target are given to validate the proposed imaging approach.