DARPA explores next-generation imaging radar

Researchers are looking to develop a system that can make 3D images without the platform or target motion that is traditionally required by SAR.

Military researchers are looking to develop a next-generation imaging radar that doesn’t rely on movement, while producing 3D images regardless of bad weather, tree cover or other obstructions.

In a posting to the FedBizOps site, the Defense Advanced Research Projects Agency announced that the agency is looking for proposals for its Advanced Scanning Technology for Imaging Radars (ASTIR) program. The program is looking to develop technologies to demonstrate new imaging radar architecture.

Imaging radars provide several capabilities for the military, including reconnaissance, surveillance and targeting applications. Because of their ability to operate under inclement weather conditions and differing times of day, they are sometimes used for treaty verification and navigation.

The high-resolution images created by radar imaging allows the military to distinguish between terrain and manmade targets and is capable of detecting and analyzing the location, speed, size and radar cross section of on-the-move targets. Because they rely on radar rather than infrared or optical wavelengths, imaging radars can also detect targets hidden by foliage as well as some underground targets.

Synthetic Aperture Radar, which is typically used to create radar images, works by sending out radar pulses over an area as the platform moves around the area. The reflected radar pulses are then recorded and compiled into a high-resolution image. Inverse Synthetic Aperture Radar works similarly—instead of utilizing the movement of platform, ISAR is dependent on target movement.  

The ASTIR program ultimately is looking to produce a more cost-effective radar imaging solution that would not require target or platform movement, meaning that the radar would have to achieve imaging/beam-steering.

To do so, DARPA envisions the use of an electronic sub-reflector and a single transmit/receive chain. One possible approach includes the use of a planar electronically reflecting surface rather than an electro-mechanically displaced mirror. Other possible techniques include putting phase shifters onto the sub-reflector itself, or digitally modulating each element on the sub-reflector, according to the announcement.

Overall, the agency wants the imaging radar to be able to provide high-resolution 3D images without the motion required by SAR and ISAR. Even if there is motion, the radar should be able to produce video frame rates to provide images, according to DARPA.

Multiple awards will be available for the program. The final proposal due date is Oct. 10.

The BAA is following an announcement for a Proposers’ Day for the ASTIR program that is to be held on Aug. 18. The last day to register for the event is Aug. 15.

Next-generation SAR, such as the Air Force’s Gotcha wide-area SAR, often requires supercomputers to process radar information into data products. Earlier this year, the Air Force Research Lab ordered a 20 teraflop super computer equipped with advanced neuromorphic architectures to help develop the Gotcha system.