Two Sandia teams played key roles in separate tests that tracked moving ground vehicles and successfully targeted them with missiles.
The tests were part of the Affordable Moving Surface Target Engagement program (AMSTE), funded by the Defense Advanced Research Projects Agency (DARPA) and administered by the Air Force Research Laboratory.
As part of the program, Northrop Grumman and Raytheon competed to develop an inexpensive way to destroy moving ground vehicles from standoff ranges, using multiple radar systems with GMTI (ground moving target indicator) capabilities. These radar systems typically also have synthetic aperture radar (SAR) capability, which produces radar imagery of the terrain but is unable to detect moving targets.
A Sandia team from Synthetic Aperture Radar I Dept. 2348 supplied the Lab’s SAR/GMTI testbed radar for Raytheon. Another team from Signal and Image Process System Dept. 15352 is developing robust algorithms for feature-aided vehicle tracking for use by Northrop Grumman in future, more complex tests.
In August the two companies conducted separate tests, placing radars with GMTI on airplanes and tracking remotely controlled moving ground vehicles — Northrop Grumman’s was a step van and Raytheon’s was a dune buggy. The radar information identifying the location of the moving targets and the generated targeting solution was transmitted to missiles launched from fighter aircraft. The missiles continued receiving target location updates during flight, making bull’s eye hits in both cases.
Jim Redel (2348), project leader for Sandia’s efforts with Raytheon, says having GMTI capabilities on a single plane monitoring a mobile ground target doesn’t provide enough information to give precise target location information. But by triangulating radar data from two or three planes, the location of the moving target can be pinpointed.
"One plane equipped with radar by itself can’t tell where the target is," Jim says. "You need the information from the different platforms to accurately track the target."
Hitting moving targets at night and in all weather with predictability and accuracy has been a long-standing military problem. Since GMTI works only for moving targets and SAR for stationary targets, move-stop-move scenarios — like at intersections — pose significant challenges. Situations where there are many vehicles moving in close proximity are challenging as well.
Technology being developed as part of AMSTE could assure a perfect hit nearly every time.
The Raytheon team completed the first AMSTE test, Aug. 15, at China Lake, Calif. The test used three radar-equipped surveillance aircraft — a U-2 with advanced SAR/GMTI, a Global Hawk UAV radar flying on a manned A-3 testbed aircraft, and the Sandia testbed radar on a Twin Otter simulating an advanced fighter. The weapon was a modified, GPS-aided, Maverick missile launched from an F-16. The missile came very close to the remote-controlled dune buggy target. The customer considered the test a direct hit.
Northrop Grumman’s test came later in the month at Eglin Air Force Base in Florida and scored a direct hit on the target — a remote-controlled step van moving at 20 mph along a slightly twisting road — with the missile. SAR systems with GMTI were carried on two aircraft, a BAC1-11 and Joint-STARS E-8. An F-16 launched the missile, a Lockheed Martin GPS-guided munition.
Northrop Grumman was tapped by DARPA and the Air Force Research Laboratory to participate in the next phase of AMSTE.
Following the China Lake test, Stephen Welby, DARPA Program Manager for AMSTE, congratulated the team for a successful flight test.
"Yesterday’s flight test was the first of its kind . . . a real-time multi-laterated GMTI tracker directed precision weapon delivered against a moving target," he said. "This is a powerful transformational capability for US war fighters."