The US Naval Research Laboratory (NRL) Radar Division has partnered with San Diego-based General Atomics Aeronautical Systems (GA-ASI) to improve joint intelligence, surveillance and reconnaissance (ISR) missions.
Under the partnership, NRL intends to integrate maritime mode inverse synthetic aperture radar (maritime-ISAR) imaging capability with GA-ASI’s Lynx Multi-Mode Radar, deployed on the USAF MQ-9 Reaper and Predator XP unmanned aerial systems (UAS).
NRL Radar Analysis Branch head Thomas Pizzillo said: "Because ships and small watercraft at sea are usually in motion, having both forward velocity and other linear and angular motions, for example, pitch and roll and heave and sway, this creates a problem for typical ISAR platforms.
"The addition of a maritime-ISAR mode to the General Atomics Lynx radar, as a software-only upgrade, is the most cost-effective alternative to introduce this capability to the MQ-9 fleet."
The Synthetic Aperture Radar (SAR) is a radar imaging method that combines multiple pulses transmitted from a moving platform to form a high-quality two-dimensional (2D) image of the ground-terrain of interest.
Traditional SAR algorithms assume the target scene (background) is stationary and any motion in the scene shows up as a smear or streak in the image.
However, ISAR algorithms assume the target itself is moving, and the net effect is to focus the image of a moving target without smearing.
Pizzilo added: "NRL has successfully adapted the necessary changes to ISAR image formation in which the rotational motion of the target is not known beforehand. This provides the end-user with an imaging software tool that can produce high-quality imagery in conditions with significantly complex target motion."
Image: GA-ASI and NRL partner to expand the USAF MQ-9 UAVs mission and improve joint-service ISR capability. Photo: courtesy of US Air Force/Lt Col Leslie Pratt.