The multi-channel SAR image domain STAP methods

with a long coherent processing time

can achieve very high performance of clutter restrain and moving target detection. However

the array distortion and non-homogeneity environments have not been taken into consideration in the existing image domain STAP methods. This paper studies their influence on the performance of the image domain STAP

and then proposes a new multi-channel SAR image domain STAP method that can cope with array distortion and non-homogeneity environments. The introduced method first applies the Power Selection and Training （PST） method to select the training data

and then proposes a new Improved Sample Matrix Inversion （ISMI） method to remove the moving targets in the training data. With the training data eliminating the moving targets

the covariance matrix of the clutter is estimated. Afterwards the array distortion is estimated based on the covariance matrix

and the array distortion is calibrated later during the image domain STAP processing. The experiments based on real clutter data prove the validity of the introduced method.