Taku Izumiyama, IHI Corporation; Takashi Imaoku, IHI Corporation; Yuichiro Kogi, Fukuoka Institute of Technology; Atsushi Mase, Masehira Co.Ltd; Toshiya Hanada, Kyushu University; Yasuhiro Yoshimura, Kyushu University
https://doi.org/10.64861/DRWC5640
Keywords: Inverse Synthetic Aperture Laser Radar, High-resolution imaging, space debris, Active imaging sensor, Laser applications, Orbital debris characterization, Optical systems, Satellite characterization
Abstract:
In recent years, resident space objects (RSOs) such as satellites, rocket upper stages, and fragments of debris have been increasing rapidly, and in particular uncatalogued objects in the 1–10 cm size range have become a serious risk to the safe use of the space environment. Current microwave radars and ground‑based/on‑orbit optical telescopes are primarily used to obtain position and orbital information, but it is difficult for them to characterize, with high spatial resolution, the shape, attitude, and size of small debris below 10 cm or satellites exhibiting anomalous behavior. This study presents the concept of an inverse synthetic aperture laser radar (ISAL) that superimposes microwave chirp signals onto near‑infrared laser light and achieves sub-10-cm spatial resolutions at long standoff ranges through inverse synthetic aperture processing. With support from the Japan Aerospace Exploration Agency (JAXA) Space Strategic Fund, we aim to use an ISAL system to image sub‑10‑cm structures and to perform precise tracking of on‑orbit objects at ranges exceeding 50 km. First, the paper describes the operating principles of ISAL and compares its characteristics with those of conventional space situational awareness (SSA)/space domain awareness (SDA) sensors. Based on initial simulations, we then evaluate the fundamental performance of ISAL, including range and cross‑range resolution, required transmit power, and required repetition count. Next, we explicitly state the assumptions and constraints used in the simulations and present a phased demonstration roadmap to validate them, consisting of component‑level tests, short‑range outdoor tests, long‑range ground demonstrations, and on‑orbit demonstrations. At the present stage, this work is primarily based on parametric studies and simulation results. In planned future demonstration experiments, we will validate the proposed models and advance the quantitative assessment of SDA performance metrics.
Date of Conference: September 15-18, 2026
Track: SDA Systems & Instrumentation