A dual-channel airborne SAR imaging approach is proposed to acquire well focused images of ground moving targets after compensating the platform trajectory deviation. The phase error attributed to either platform trajectory deviation or target motion is given by a polynomial of slow time. The SAR image before motion compensation is segmented into multiple sub-images, and a compressive-sensing (CS) technique is applied on each sub-image to estimate the polynomial coefficients featuring platform trajectory deviation. A range-frequency reversal transform (RFRT) and fractional Fourier transform (FrFT) are combined to estimate the motion parameters and position of each moving target. The proposed approach is verified with real data and simulated data, respectively, and the moving targets in the acquired image are well recognized.