High Dynamic Range (HDR) Improvements for Synthetic Aperature Radar (SAR)/Ground Moving Target Indicator (GMTI) and Passive/Bistatic Radar

SPEC is proposing a fast range cell adaptive AGC, expanding the front end dynamic range to 140 dB or more. Modern wideband SAR imaging and GMTI radars require very high dynamic ranges to detect objects in ground clutter and especially in the presence of strong reflectors. Today’s wideband ADCs have only 12-14 bits, giving a SFDR of 60-75 dB. SPEC is currently delivering TRL8/9 radar transceivers with adaptive AGC giving an overall 110 dB dynamic range. SPEC proposes to use a new class of wideband ADC with built-in Fast Detection Bit that can immediately signal an FPGA and create range cell amplitude tracks. These range cell amplitude predictions directly feed to the AGC algorithm and control the variable attenuator on a range cell basis, providing the anticipated 140 dB or more of overall dynamic range. During Phase I, SPEC will integrate a wideband RF front end using demonstration boards, and will implement the fast range cell adaptive AGC algorithm. SPEC will generate synthetic and dynamic SAR or GMTI scenes, input these through the RF front end, and optimize the AGC and overall dynamic range to maximize STAP detection, image quality, and range performance metrics.