A main problem of air borne SAR-MTI system based on DPCA technique is the performance decline of clutter suppression and moving target detection caused by the dissatisfying of DPCA condition

which is conduced by the velocity variety of radar platform.On the ground of interpolation theory

a new calibration method for this problem is presented in this paper.Based on signal model

system error is analyzed and the calibration method is provided.The key issue for the calibration precision is the accurate estimation of the velocity of radar platform

which can be obtained by conventional movement parameter estimation methods.It is demonstrated by the simulation results that the system error can be successfully removed by this method.Since the requirement to hardware instruments is reduced

this method can be easily realized in engineering practive.