Evaluation of a Kalman filter for SAR motion compensation

A synthetic aperture radar motion compensation system (SARMCS) is being developed at the Defence Research Establishment Ottawa to compensate an airborne SAR for spurious motions of the radar antenna that may be caused by air turbulence of aircraft maneuvers. A Kalman filter has been developed as part of this SAR motion compensation system which uses a low-cost strapdown IMU (inertial measurement unit), to measure antenna motion. The function of the Kalman filter is to control misalignments of the strapdown analytical platform, since analysis has indicated that these errors are dominant contributors to motion compensation error. Representative results from processing raw recorded flight data have verified the proper operation of all aspects of the Kalman filter and have indicated that the filter performance is consistent with the motion compensation requirements. Some examples of actual SAR strip-map imagery are shown in order to demonstrate the enhancement provided by the SARMCS