SBIR-STTR Award

Battle damage assessment (BDA) of ships is normally performed with optical sensors from airborne platforms and requires clear atmospheric conditions for safe standoff ranges. In addition, airspace restrictions in anti-access/area denial (A2/AD) scenarios can easily require safe standoff ranges for BDA to be beyond the capabilities of airborne optical sensors. Inverse synthetic aperture radar (ISAR) imaging is an attractive alternative capable of performing ship BDA at much longer ranges in day or night all-weather conditions. However, BDA with ISAR imagery is much more challenging because the ISAR image features available for human consumption do not enable the level of interpretation that is possible using optical imagery. The proposed effort will develop innovative automated approaches to performing BDA using ISAR imagery. The proposed effort will consider the development of possible operating concepts (CONOPS) that will include ISAR imaging the ship in anticipation of observing the missile strike event. This will require coordination with the shooter. Other possible CONOPS could involve image change detection. Image change detection would allow for imaging the target before and after the missile strike. Potential radar Doppler imaging modalities include both ISAR and spotlight mode synthetic aperture radar (spot-SAR) imaging. All of these approaches can indicate if a vessel is dead-in-the water when combined with tracker information. In addition, the ability to conclude whether or not a vessel has been hit by the missile will also be assessed for all CONOPS.

Benefit:
Long range radar based BDA with day/night all weather availability that can also overcome A2/AD scenarios.

Keywords:
ISAR, ISAR, SAR, ship BDA

The timeliness, accuracy, and completeness of battle damage assessments (BDA) is critical to the success of any military engagement. BDA have traditionally utilized relatively short-range optical sensors onboard aircraft operating in close proximity. However, the safe airspace access required to observe the target at close range is not possible in anti-access/area denial situations. BDA utilizing long-range radar tracking and imaging is an alternative. Radar does not provide the level of high resolution and high definition consistent with human visual characteristics. As a result, there is a need for innovative approaches to extract comparable information from radar returns for the BDA of ships at sea from ranges that may exceed 50 nautical miles (nmi). Gross changes such as the vessel going dead-in-the-water or rotating antennas ceasing operation are easily discernable with radar. More challenging is determining if the vessel is listing and what type of external structural damage has occurred. Advances are needed in single and multi-channel inverse synthetic aperture radar (ISAR) imaging techniques. Advantages of interferometric ISAR should be considered, as some fielded radar systems are capable of supporting that mode. Consideration should be given to scenarios that allow imaging to be underway immediately prior to weapon impact, at the time of the impact, and at various times after impact. Transition of this product is to be as an appliance within the Navy’s Minotaur control application.