A new method of improving the accuracy of the hyperbolic range equation

The range equation employed in the current low earth orbital Synthetic Aperture Radar (Leo-SAR) systems is the hyperbolic range equation (HRE). The key parameters of it are effective velocity and effective squint angle. Traditionally the calculation method of the two values may lead to large errors, and it is only fit for Leo-SAR with moderate space resolution. To get the azimuth resolution on the order of one meter or even higher, an improved method based on the accurate second-order Doppler parameters is used in this paper to decrease the errors of the two parameters above. Then we can get the improved hyperbolic range equation (IHRE). The theory is validated by the parameters of TerraSAR-X, and the image with the space resolution around 0.35m is focused perfectly.