PRECISE ESTIMATION OF FLIGHT PATH FOR AIRBORNE SAR MOTION COMPENSATION

Airborne synthetic aperture radar (SAR) systems are very sensible to deviations of the aircraft to the reference flight path. The trajectory errors can be divided into along-azimuth errors and the line-of-sight (LOS) displacement, while the latter one is the main source of motion errors. The LOS displacement can be obtained from the navigation data in which an ideal flight path should be assumed first. However, the accuracy of the assumed nominal trajectory is limited especially in high resolution SAR systems. To improve the precision of the estimation of LOS displacement, we present a novel method to acquire a precise flight path in the imaging intervals. This method can estimate trajectory deviation precisely by making full use of the navigation data.