Channel Phase Error Estimation and Compensation for Ultrahigh-Resolution Airborne SAR System Based on Echo Data

For a new kind of ultrahigh-resolution airborne synthetic aperture radar system, a novel two-step approach to estimate and compensate channel phase error based on echo data is presented in this letter. According to the relationship between phase error and pulse compression, the residual channel phase error after internal calibration is modeled as frequency-domain polynomials and divided into two parts. By establishing an optimization estimation model, two parts of the channel phase error can be estimated and compensated successively from a small amount of echo data, which result in the advantage of few storage consumption and fast convergence speed while making up for the insufficiency of system calibration method. Actual eight-channel raw data have been processed, the result of which demonstrates the validity of the presented approach.