Detecting improvised explosive devices in Afghanistan requires constant, intensive monitoring using rugged equipment. When researchers at Sandia National Laboratories first demonstrated a modified miniature synthetic aperture radar (MiniSAR) system to do just that, some experts didn’t believe it.
But now, it seems, those early doubts are long gone. Sandia’s Copperhead – a highly modified MiniSAR system mounted on unmanned aerial vehicles – has been uncovering IEDs in Afghanistan and Iraq since 2009. Sandia is now transferring the technology to the US Army to support combat military personnel, according to Sandia’s Jim Hudgens.
Although IED detonations have declined in Afghanistan since a peak of more than 2 000 in June 2012, US Department of Defence reports indicate that IEDs accounted for about 60 per cent of US casualties that year.
SAR and its descendent MiniSAR, the first system of its size to successfully transmit real-time images from UAVs in 2006, use small antennae that capture reflections of microwaves returned from objects on the ground, transmitting and receiving many radar pulses as the aircraft flies. The received pulses are integrated by signal-processing techniques to synthesise a fine-resolution image, hence the name “synthetic aperture”.
Copperhead uses a technology called coherent change detection, which compares a pair of extremely detailed SAR images taken of the same scene but at different times. The process allows analysts to detect minute physical changes on the surface.
Source: Sandia National Laboratories