Enhanced Radar Imaging of Rotating Objects for Space Domain Awareness (SDA)

Inverse synthetic aperture radar (ISAR) imaging plays a vital role in space domain awareness (SDA) by providing high-resolution images of moving targets. However, the resolution of ISAR images is inherently limited by factors such as transmit waveform bandwidth, target motion and observation time. This study investigates these constraints and proposes a method to enhance ISAR image resolution. Specifically, we focus on coherent backprojection ISAR imaging and apply 2D bandwidth extrapolation techniques, which simultaneously enhances both range and cross-range resolution to improve the final image quality. The range is improved by extrapolating the bandwidth of the transmitted radar signal, while cross-range is enhanced through extrapolation of the observation time.To demonstrate the effectiveness of these enhancements, we applied the proposed method to data collected from a resident space objects (RSOs) using a Long Baseline Bistatic Radar (LBBR) system. The results demonstrate a significant enhancement in ISAR image resolution, leading to improved measurement metrics. This improvement is crucial for object feature identification, such as the projected target dimensions, highlighting the practical implications of our findings.