"Gotcha" is the cute name for an experimental system that collects vast amounts of synthetic-aperture radar data from an aircraft circling an urban area and processes it into 3D video for real-time surveillance and forensic analysis. Now the US Air Force Research Laboratory is looking to identify potential sources for a Gotcha Spiral 2, a dual-band (X/UHF) radar system capable of staring at a city-sized area 10-20km in diameter and downlinking the data for ground processing.
The key behind Gotcha is that data are collected in a single radar mode, then processed in a supercomputer to produce a range of products, including "super-resolution" 2D imagery, 3D video, ground moving-target indication and coherent change detection. Imagery can be viewed in near real-time, or an analyst can backtrack through the store of radar data to find out what led up to an event.
Gotcha was first tested by AFRL in 2006, looking at a 1km-sized city section and processing the X-band SAR data into real-time 3D video. Now the laboratory has installed a dedicated supercomputer, called Desch, which will allow the radar to stare at a circle of about 5km and convert the data into a 400-megapixel image once a second.
Gotcha Spiral 2 would take another step, both in the size of the area being scanned and in the use of high/low-band radar, which AFRL's solicitation says will improve the systems' change-detection and foliage-penetration capabilities.