The Ground/Air Task-Oriented Radar will perform air surveillance, provide cues to air defense systems, perform counterfire target acquisition, and provide data to air traffic controllers, performing the functions of five different legacy radars.
The radar will perform air surveillance, cue air defense weapons,
perform counter-fire target acquisition (of enemy artillery
and mortar firing locations), and provide data to air traffic controllers.
Consolidating these functions into a single multi-role
radar will dramatically reduce Marine Corps logistics, operating,
and training costs.
The G/ATOR program is currently in the engineering and manufacturing
development phase; Northrop Grumman Electronic
Systems in Baltimore, Md., is the prime contractor.
The entire G/ATOR system is transported by only two uparmored
vehicles – a six-wheel, 7-ton Medium Tactical Vehicle
Replacement (MTVR) all-terrain truck built by Oshkosh, and a
single Humvee. In a G/ATOR’s operational configuration, its large
radar antenna array is mounted on a trailer towed by the MTVR
vehicle, and is folded down flat during movement. The antenna
array remains on the trailer during all operations, and is elevated
for use hydraulically. The trailer has hydraulically controlled
leveling legs. The MTVR truck carries a pallet with a generator
and the Humvee carries the radar system’s Communications-
Electronic Group (CEG) on a pallet. Both pallets may be lifted off
the vehicles during radar set-up.
G/ATOR will be fielded over time in increments. Increment I,
scheduled for an initial operational capability (IOC) and a fullrate
production decision in 2016, is the air surveillance and
short-range air defense radar, which will replace the TPS-63,
MPQ-62, and UPS-3 radars. Increment I will provide all the basic
hardware for future increments, which will add new capabilities
through mission-specific software packages.
Increment II, slated for an IOC in 2017, will
add the enemy artillery and mortar targetlocating
capability, replacing the existing
TPQ-46 radar. Increment IV, scheduled for an
IOC in 2018, will add military air traffic control
functionality, replacing the Marine Corps’ TPS-73 radar and the Airport Surveillance Radar
portion of the TPN-31A Air Traffic Navigation,
Integration, and Coordination System.
Lee Bond, the G/ATOR program manager
within the Program Executive Office for Land
Systems, said that Increment III, which previously
encompassed tactical enhancements
to the other increments, has essentially been
deferred until the other three increments are
well in hand.
The incremental program will allow the Marine
Corps to “neck down” over time to only
two radars – the expeditionary short-to-medium-range G/ATOR and the large, transportable
TPS-59(V)3 long-range air surveillance radar.
G/ATOR Increment I also will serve as a gapfiller
radar, covering areas out of view of the
TPS-59(V)3 due to line-of-sight limitations.
The TPS-59(V)3 is optimized to track tactical
ballistic missiles out to 400 nautical miles
and cruise missiles and aircraft out to 300
nautical miles.
With the exception of the MTVR vehicle, the
major G/ATOR system components – the trailer
with antenna array, the Humvee with the
CEG pallet, and the generator pallet – will be
transportable in external sling loads by Marine
Corps heavy-lift helicopters and MV-22 Osprey
tilt-rotor aircraft.
The key to achieving G/ATOR’s multi-role capabilities
within a highly mobile expeditionary
system is active electronically scanned array
(AESA) radar technology. Unlike mechanically
scanned radars with curved-dish antennas,
an active phased-array radar can steer its agile
beams electronically. G/ATOR’s antenna array
is made up of 2,600 highly reliable small
solid-state transmit-receive modules, each a
small radar in itself that can alternate between
transmitting and receiving. AESA radars can
operate in multiple modes simultaneously and
can track significantly more targets than older
systems.
G/ATOR has a planar, or flat-face, phasedarray
antenna that is 12 feet tall and 7 feet
wide. The antenna rotates on the trailer at 30
revolutions per minute to provide 360-degree
coverage against airborne threats, mechanically
scanning in azimuth and electronically
scanning in elevation. For some missions, the
antenna will be stationary and will scan a sector
of the airspace it is facing electronically in
two dimensions – azimuth and elevation.
Bond said the need to keep weight down
to allow the radar system to be air lifted with
rotary-wing aircraft “drove us to an air-cooled
array instead of a more common but much
heavier closed-loop liquid cooling system.”
The array has to be kept at a constant temperature
across all of its 2,600 transmit-receive
modules for peak performance, he said,
and the air cooling has proven to be very effective.
“Despite the fact that G/ATOR has a
larger array and sees literally twice as far as
the legacy systems it will replace,” Bond said,
“it’s much lighter, primarily due to the AESA
active elements on the array and the air cooling
system.”
In March 2009, Northrop Grumman successfully
completed the G/ATOR program’s Critical
Design Review, the final hurdle before the company
began building the first Increment I engineering
development model (EDM) prototype
system. That EDM is now undergoing contractor
integration and testing, Bond said. Northrop
Grumman began building a second EDM 2-3
months after the first.
Marine Corps Program Executive Officer for
Land Systems Bill Taylor noted, “There’s been
strong technical progress on this program this
past year, and we’re beginning to see real operating
hardware.”
Milestone C approval for low-rate initial production
of the G/ATOR Increment I radar system
is scheduled in 2013. The Marine Corps’ Approved
Acquisition Objective is a total of 69 G/ATOR systems – 17 Increment I radars, 38 Increment
IIs, and 14 Increment IVs.
In February 2009, then-Under Secretary of
Defense for Acquisition, Technology, and Logistics
John Young designated G/ATOR, also referred
to as the Multi-Role Radar System, a Department
of Defense Special Interest Program
that could potentially meet the ground-based
radar requirements of the other services. As a
result, the Office of the Secretary of Defense
conducts periodic reviews of the services’ radar
programs to ensure commonality as each
program is authorized to proceed to its next
acquisition milestone.