This paper analyzes how the trajectory deviations in the airborne synthetic aperture radar (SAR) can affect the received data. It shows that the range error can be separated into space invariant and variant contributions, which can be compensated by the first-order and second-order motion compensation processing. To realize high resolution SAR image, this paper represents a motion compensation method integrated in range-doppler (RD) algorithm. Finally, the analysis and scheme are validated by the results on simulated data.