Motion compensation is the key step of SAR imaging

especially for high resolution SAR imaging.The motion parameter can be measured by navigational instrument

and also can be estimated from data.These two methods usually need to be combined.Although there are many studies about motion parameter estimation

and many estimation and compensation methods have been proposed

how to select a proper method according to real situation is still problem.This paper proposes algorithms for estimating the motion parameter and SAR imaging for a given radar and motion state

which can obtain a good SAR image with reduced computation load.