Inverse Synthetic Aperture Radar (ISAR) Imaging in the Presence of Electronic Attack (EA)

TECHNOLOGY AREA(S): Air Platform, Battlespace, Weapons
OBJECTIVE: Develop a maritime Inverse Synthetic Aperture Radar (ISAR) imaging algorithm that is robust to electronic attack (EA).
DESCRIPTION: For maritime ISAR applications, high-resolution ISAR imagery is usually essential to characterize target features. Conventionally, the cross-range resolution of an ISAR image is obtained from the diversity of the radar-viewing angle to the target and the high down-range resolution is achieved by increasing the radar system bandwidth. However, current operational ISAR imaging achieves the wide synthetic bandwidth at the cost of long observation time and has a normally shorter functional range than that of a conventional wideband radar. The longer observation time can seriously distort the coherence of the radar sub-pulses and degrade the image quality while also increasing the probability of incurring interference from EA in contested environments. For time critical operations dictated by a missile application, the observation time for each target is usually extremely limited. The need exists to develop an innovative new ISAR imaging approach that functions in the presence of EA and its detrimental impacts to the radar receiver and detection capability to form ISAR images capable of performing Autonomous Target Recognition (ATR) of maritime targets in weapon and airborne radar systems.
Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by DoD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Security Service (DSS). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this project as set forth by DSS and NAVAIR in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advanced phases of this contract.
PHASE I: Develop an innovative maritime ISAR imaging algorithm that is robust to EA for operation in highly contested environment. Develop a novel ISAR framework and imaging algorithm that leverages the physics of radar backscattering theory of targets to greatly reduce the amount of data and acquisition time required to precisely reconstruct the ISAR images as compared to the traditional ISAR imaging approach. Develop a toolkit approach with variable EA inputs to assess the robustness of the ISAR image algorithm and to assess the algorithm performance in terms of image quality against EA using simulated radar data of maritime targets. The Phase I effort will include prototype plans to be developed under Phases II.
PHASE II: Assess the Phase I algorithm performance in terms of image quality and automatic target recognition against electronic attack using simulated and experimental radar data of maritime targets. Complete the EA toolkit as a product that is compatible with the application radars to assess the ISAR image formation robustness and quality.
Work in Phase II may become classified. Please see Description for details.
PHASE III: The EA robust ISAR image formation algorithm developed in Phase II will be optimized to replace existing traditional ISAR algorithms in Navy applications such as Triton, MH-60R, and possible weapons applications. Although EA is considered a military environment, a successful technology could assist with heavy electronic interference in busy ports and waterways that have some level of electromagnetic interference.
REFERENCES: 1. Candes, E. and Tao, T. Near-Optimal Signal Recovery from Random Projections: Universal Encoding Strategies. IEEE Transactions on Information Theory, 2006, pp. 5406-5425. https://statweb.stanford.edu/~candes/papers/OptimalRecovery.pdf; 2. Zhang, L., Xing, M., Qui, C., Li, J. and Bao, Z. Achieving Higher Resolution ISAR Imaging with Limited Pulses via Compressed Sampling. IEEE Geoscience and Remote Sensing Letters, 2009, pp. 567-571. https://ieeexplore.ieee.org/document/5061612/KEYWORDS: ISAR; Electronic Attack ISAR; Robust ISAR; ISAR Imagery; Backscattering ISAR; Inverse Synthetic Aperture Radar