A radar system, originally developed by the National Nuclear Security Administration's Sandia National Laboratories for military surveillance and reconnaissance applications, is helping a volunteer search-and-rescue group in New Mexico save lives.

Rapid Terrain Visualization precision-mapping synthetic aperture radar data were used for the first time in November 2003 by the Albuquerque Mountain Rescue Council to help find and rescue a hiker stranded in the dark in the stark Sandia Mountains.

SAR experts at Sandia say the same technology could map other mountainous terrain around the country and be used in search-and-rescue missions.

“What this system improves is the precision, the resolution, of the elevation representation that we get,” said Dale Dubbert of Sandia's SAR Sensor Technologies Department. While a standard topographic map renders relatively large features such as ridges and canyons, RTV radar provides detail down to the size of a car or individual rock formation.

“The reason that's important to search-and-rescue operations in rugged terrain is that it helps to plan the rescue attack, saving time and potentially saving lives, as well as reducing the risk to the rescuers by providing them unprecedented mapping detail,” Dubbert said.

The RTV mapping system uses interferometric synthetic aperture radar, or IFSAR. Two antennae offset in elevation aboard a moving aircraft allow the measurement of target height, as well as east-west and north-south position like conventional SAR. This produces a 3-D map that shows terrain details never before possible.

The IFSAR maps have an absolute height accuracy of less than two meters and a relative accuracy of less than one meter.

No other mapping system in the world achieves this level of accuracy combined with a high area coverage rate and real-time processing, Dubbert said. The IFSAR can map day or night and through cloud cover.