Time-Delay And Doppler Range Model For Synthetic Aperture Radar

Synthetic aperture radar (SAR) owns a lot of advantages such as high-resolution imaging, day-and-night working and so on, which has been widely applied in military and civilian areas. In this paper, we propose a time-delay and Doppler range model (TDRM) for SAR, which achieves very high accuracy, and is easy to use because it is two-dimensional linear with respect to time-delay and Doppler frequency. First, by establishing a polar coordinate system, the range history of SAR in the new coordinate system is obtained. Then, by combining round-trip time-delay and Doppler frequency with TDRM, we derive the range model in time-delay and Doppler domain. Finally, the analytical expression of TDRM is obtained by first-order Taylor approximation. We simulate TDRM with a specific SAR system. The simulation results verify the validity of the model. Specifically, for all targets in 2km×2km scene, the relative errors and the quadratic phase errors of TDRM are less than 7×10
^-9
and π/4, respectively.