Polynomial Phase Adjustment by Contrast Enhancement Algorithm for SAR

Abstract:
Phase Adjustment by Contrast Enhancement (PACE) is an autofocus algorithm that is capable of performance unattainable by conventional techniques. It is a nonparametric method that requires no constraints on the type of phase error to be measured. The algorithm does not require special data culling techniques or the presence of isolated scatterers. However, the drawback of the PACE algorithm is that the number of estimated variables is very large, this leads to a long computational time. This paper presented a polynomial PACE algorithm, it constrain the phase error as a polynomial expression with respect to the azimuth frequency. It can correct high order phase error and the number of variables can be reduced since the variables are the coefficients of the polynomial expression. The polynomial PACE algorithm can significantly reduce the computational time while the accuracy is sufficient. This paper derived the details of the polynomial PACE and the results of experiments using real SAR data are presented to show the validity of the proposed algorithm.