SAR image feedback for improved inertial measurement unit alignment

High-performance Synthetic Aperture Radar (SAR) requires high fidelity motion measurement, both translational motion for the synthetic aperture and angular motion for antenna pointing. In particular, gyro drift about the vertical (yaw) axis is particularly problematic to keep aligned adequately, especially for tactical-grade instruments. A method has been developed to measure antenna pointing error accurately from general SAR images, with the error fed back to the motion measurement Kalman filter to correct for gyro drift errors.