Interrupted Synthetic Aperture Radar (SAR)

Modern antenna technology makes possible the deployment of systems able to perform radar, communications, and electronic warfare functions with a single aperture. Such systems, due to demanding mission requirements and constraints, must switch among numerous modes while maintaining essential functions (e.g. air-to-air situational awareness). Therefore, radar functions that normally require extended dedicated aperture time and bandwidth must be interrupted so that other vital missions functions are not compromised. This proposal addresses Synthetic Aperture Radar (SAR) imaging in the presence of temporal and spectral interruptions. In addition to interruptions due to competing mission tasks, interruptions may also be caused by spontaneous friendly and hostile radio frequency interference. The proposed work will address the quality and utility of imagery formed from interrupted SAR data as a function of interruption metrics. C & P Technologies proposes to study the functional dependence of image quality factors on interruption metrics such as: mean-interrupt rate, interruption duty-cycle, higher-order interruption statistics and minimum inter-interupt time. The proposed methods build upon recent developments in signal processing and applied mathematics, namely, sparsity-regularized inverse problems and algorithms for low-rank matrix completion. The proposed work will compare the image quality and utility of several SAR algorithms. BENEFIT: C & P plans to commercialize the results of this research in multiple commercial application areas of SAR such as commercial surveillance, satellite imaging applications including monitoring ocean waves, winds, currents, and seismic activity. The main emphasis will be data recovery for improved image quality and resolution. C & P plans to build a commercial toolbox for data recovery using the techniques developed as part of the proposed effort. C & P plans to address several of these application issues during the Phase I effort and plans to collaborate with primes during the Phase II period.