SBIR-STTR Award

SAR target/feature detection can be divided into to separate aspects: 1) achieving sufficient energy on target for detection; and 2) discriminating the target from the clutter. Let's assume that there is sufficient target return to overcome the thermal noise floor. Then target detection is solely dependent upon separating the target from the forest clutter. VSAR offers significant benefits for enhanced imagery through clutter rejection, enhanced target definition. These enhancements enable improved detection of concealed targets, improved characterization of targets, true bare earth mapping under foliage, and characterization of foliage distribution. Essex has obtained results by coherently combining multiple SAR data collects. These collects were separated in elevation, azimuth, or both. VSAR algorithms have been incorporated into Essex SAR processing and visualization software packages, and have been demonstrated at UHF FOPEN frequencies. Extensions to other radar bands and platforms could provide new ways to recognize and characterize weak or partially concealed targets, or to profile scenes with large vertical relief. Essex has developed and integrated these VSAR capabilities into a platform-independent processing suite with a Java GUI running on Linux, Irix, and Windows. These techniques have been validated using data collected with the DARPA FOPEN ATD system at Camp Navajo (2001). The foliage penetration capabilities offered by the VSAR processing approach offers a significant benefit for several military ACTD programs as well as commercial terrain and infrastructure mapping appications. In addition, these techniques also relax the geometry constraints associated with the collection process for existing operational systems. Currently, the RadarSAT is constrained to collecting repeat pass pairs suitable for terrain mapping approximately every 21 days. The VSAR techniques proposed should improve that to every 2-3 days with better accuracy

Tomographic SAR is a data collection and processing technology that produces true 3-D volumetric imagery. This approach offers significant benefits for enhanced imagery through clutter rejection, enhanced target definition, and better resolution. Tomographic SAR has been demonstrated at UHF frequencies where it has shown benefits in concealed target detection, improved feature extraction and characterization, bare earth mapping under foliage, and foliage characterization. Essex has developed and integrated these capabilities into a platform-independent processing suite with a Java GUI running on Linux, Irix, and Windows. In addition, tomographic SAR has been successfully applied to a wide variety of synthetic aperture scenarios, and the theory permits fusion of data from multiple passes, multiple receiver antennas, or multiple platforms. The Phase II effort will focus on augmenting the tomographic algorithms resident at Essex with polarimetric classification techniques to enable expanded and enhanced feature extraction, terrain characterization, and target visualization. Extending these techniques to existing sensor systems provides many new opportunities for exploitation of mature, deployed SAR systems. One obvious benefit is the creation of true 3-D scenes with no layover

Keywords:
SYNTHETIC APERTURE RADAR SAR INTERFEROMETRIC SAR TOMOGRAPHIC SAR 3-DIMENSIONAL SAR TOMOGRAPHIC IMAGE FORMATION