To realize the function of the synthetic aperture radar (SAR) image and ground moving target indication (GMTI)

the along-track array is the best configuration for the distributed small satellites.However

array errors significantly degrade the performances.An estimation method based on the data in compressed range time and azimuth Doppler domain is given.In the proposed method

the range pulse compression is used to improve the signal to noise ratio.And the gain error is corrected before the other error estimations which avoids the interaction between the gain error and the along-track position error.Computer simulations show that the convergence rate of the proposed method is quickened with the estimate accuracy improved

compared with the conventional method.