NASA Goddard developed a compact, lightweight, low-frequency (25~100 MHz), wideband (75 MHz), subsurface imaging Inverse Synthetic Aperture Radar (ISAR) and associated post-processing software. The software processes data received by the ISAR radar to extract down- and cross-range images of the target object.

Use of low frequencies allows the electromagnetic energy to penetrate to a greater depth, enabling observation of the interior of a solid object to a higher resolution than can be achieved with alternate technologies. Higher bandwidth has been used in earlier ISAR systems; however, these require expensive high-bandwidth RF components and higher-speed data processing units.

The new ISAR system uses a novel step frequency technique that eliminates both these requirements. The step frequency approach keeps the local bandwidth very small, enabling data processing at much lower speed. By stepping through the frequencies, the ISAR achieves much higher overall bandwidth and consequently very high range resolution.

The system enables scientists and geologists to image 3D interior structure of a solid object to a depth of up to tens of meters. The system also features wide bandwidth, providing higher resolution than previous technologies, such as conventional pulse ground penetrating radar, for analysis of thin-layer pavements and geological subsurface structures.

NASA is actively seeking licensees to commercialize this technology. Please contact NASA's Licensing Concierge at This email address is being protected from spambots. You need JavaScript enabled to view it. or call us at 202-358-7432 to initiate licensing discussions. Follow this link  for more information.