Study on the Accuracy of the Quadratic-Approximated Range Equation for SAR Ground Moving Target Imaging

Inhalt:
Many of the existing synthetic aperture radar (SAR) ground moving target imaging methods are based on the quadratic approximation of a target’s range equation. However, the phase error caused by this approximation may degrade the imaging quality severely. In this paper, a study on the accuracy of this approximation is presented. An approximate analytical expression for the phase error is derived, which clearly reveals the relationships between the phase error and the parameters of the SAR system and the target. Moreover, simulations are performed to find out in which cases a quadratic approximation can be made to the range equation.