RT Journal Article SR Electronic T1 GPS-Denied Navigation Aided by Synthetic Aperture Radar Using the Range-Doppler Algorithm JF NAVIGATION: Journal of the Institute of Navigation JO NAVIGATION FD Institute of Navigation SP navi.533 DO 10.33012/navi.533 VO 69 IS 3 A1 Lindstrom, Colton A1 Christensen, Randall A1 Gunther,, Jacob A1 Jenkins, Scott YR 2022 UL https://navi.ion.org/content/69/3/navi.533.abstract AB The need to successfully navigate in the absence of GNSS has grown in recent years. In particular, light aircraft such as UAVs are growing in popularity for a variety of applications vulnerable to GPS denial. The research presented here develops a GPS-denied navigation scheme for light aircraft employing images formed from a synthetic aperture radar system. Past research has explored the utility of radar telemetry in GPS-denied systems. This research advances previous work by exploiting radar images to obtain range and cross-range position measurements. Images are formed using the Range-Doppler Algorithm, an efficient image formation algorithm ideal for the sometimes limited processing packages available to light aircraft. An inertial navigation and radar processing system is implemented using both real and simulated radar images to aid in estimating an aircraft’s state in a GPS-denied environment. The results show that navigation in the absence of GPS using synthetic aperture radar is feasible with converging and bounded estimation errors.