YUMA PROVING GROUND, Ariz.-- The element of surprise can be a critical weapon, and nothing removes it from the playbook of enemy forces quite like radar.

Radar units send out pulses of high-frequency electromagnetic waves that reflect off objects, and modern radar systems are sophisticated enough to track even small, rapidly moving objects like rockets and mortar and artillery shells.

U.S. Army Yuma Proving Ground (YPG) has long experience testing these systems. Currently, the proving ground is hosting an operational test of the Marine Corps' AN/TPS-80 Ground/Air Task Oriented Radar (G/ATOR). Specifically under evaluation is the Block 2 version of the system, which searches for ground-based weapons fire. The version of the G/ATOR under test now uses Gallium Arsenide (GaAs) for its semiconductor in the transmit/receive modules: a system coming for test at YPG later this year uses more efficient Gallium Nitride (GaN).

"This operational assessment is set up to make a fielding decision on four GaAs systems," said Maj. Peter Young, operational test project officer. "We have these initial four systems that will be delivered to the Marines this fall, and this test is to evaluate their operational readiness."

The portable unit's upright rectangular face weighs in at a relatively light 3,000 pounds, significantly less than that of comparably sized radars. Much of the weight savings comes from the system being cooled by ambient air, even in torrid desert heat.

"This is an expeditionary radar--it will go anywhere the Marines go," said John Karlovich, program manager. "It is a pretty capable system that has legs to pace the threat for decades to come."

About 40 Marines from various installations across the country participate in the testing, broken down into two radar teams and a target processing center that feeds information from the radar into a fire direction center to coordinate counter-fire against the location from which the 'hostile' round or rocket originated.

"They're emplacing and displacing the radar based on tactical scenarios," said Chief Warrant Officer 4 Abraxas Patton, G/ATOR Block II project officer. "We're using YPG as our 'enemy,' having them fire on a pretend friendly force. The radars are set up to detect these incoming rockets, artillery, and mortars so we can counter-fire on them to protect friendly forces."

Two YPG weapons operation crews supporting the test move frequently throughout a typical day to test the radar's ability to track fires from different locations, requiring careful coordination. The diverse expertise of YPG's weapons operators mean the G/ATOR can be readily put through its paces against all types of indirect fire, from mortars and rockets to artillery shells. In some test scenarios, the system was exposed to all of these simultaneously, or in close succession from multiple locations over the course of the day. Hundreds of rounds were fired.

"YPG can shoot everything I want to shoot," said Young.

The operational test was originally slated to be part of a large operational exercise at a Marine Corps installation. When the exercise was significantly scaled back in scope, the testers chose YPG, which had been home to developmental testing of the system for nearly a year, as a backup location. The testers appreciated YPG's flexibility, vast range space, and expertise and capability in firing every kind of threat the radars are expected to guard against in a combat situation.

"We've been to several other test centers, and YPG is by far the best," said Patton. "The professionalism and responsiveness of the personnel supporting us are phenomenal."

"This is a culmination of a long, challenging development program," added Karlovich. "It really is a quantum leap in capability for any radar that isn't an active array. It's pretty exciting."