Multi-Channel SAR Research at the Naval Research Laboratory

This paper describes research at the Naval Research Laboratory (NRL) into Multi Channel Synthetic Aperture Radar (MSAR) and features data collected with the NRL MSAR system. The NRL MSAR is an airborne test bed designed to investigate remote sensing and surveillance applications that exploit multiple along-track phase centers, in particular, applications that require measurement of scene motion. The system operates at X-band and supports 32 along-track phase centers through the use of two transmit horns and 16 receive antennas. As illustrated in this paper, SAR images generated with these phase centers can be coherently combined to directly measure scene motion using the Velocity SAR (VSAR) algorithm, and these measurements can then be used to correct the image distortion that the motion causes. This unique radar was deployed in 2014 and 2015, and this paper presents a description of the system and representative results. Also included is a discussion of ongoing efforts to improve the magnitude and phase balance across the 32 channels, as this is essential to effective VSAR processing.