Precision aided inertial navigation using SAR and digital map data

The authors describe a novel scheme for obtaining position update information for an inertial navigation system through the use of imagery from a synthetic aperture radar (SAR) sensor and an onboard digital map database. Updated information is obtained through comparison of the locations of terrain features extracted from the SAR imagery with locations predicted using the digital map and current navigation estimates. The authors also discuss the overall system concept along with experimental and analytical results obtained to date. Analytical results include a preliminary error analysis which treats SAR image distortions introduced through navigation errors and the consequent effects on update accuracies. A description of the terrain feature extraction Algorithms is presented along with experimental results