With a combination of new software, rugged palmtop computers and
handheld radios, Marine engineers and aviators have developed a
close-air support system that could help lower the risk of friendly
The system, called ACASS (advanced close-air support), automates
the process by which a forward air-controller on the ground transmits
the location of a target to a pilot in the cockpit, thus minimizing
the chances of human error.
The program is in development at the Marine Corps Warfighting Lab,
in Quantico, Va.
ACASS currently only works with the AV-8B Harrier jump-jet, but
it could be installed on most Navy strike aircraft in the future,
said Marine Maj. Brian McKinney, who runs the program at the lab.
The forward air-controller (FAC) uses a rugged handheld computer
with a built-in GPS receiver, which turns the PC into a moving map.
He illuminates the target with a laser rangefinder and the location
of the target automatically appears on the PC screen’s digital
map. He communicates with the cockpit using a 2.5-pound multi-band
handheld radio. The $5,000 device, called Multiband Inter/Intra
Team radio, replaces 44 pounds and $45,000 worth of older radios.
“When you lase a target, a box pops up on the map, with a
10-digit military grid,” he explained. The grid is computed
based on the target’s latitude, longitude and elevation. The
FAC then lets the computer compile the so-called nine-line brief.
The nine-line brief includes the nine pieces of standard information
that a forward air controller needs to send to the pilot who will
strike the target. It’s used by all U.S. military services
and NATO. The nine-line brief also tells the pilot the position
of friendly forces in the area.
The FAC then can transmit the nine-line brief to the aircraft,
and the information appears on the pilot’s cockpit display.
The biggest advantage of ACASS, McKinney said, is that it minimizes
the likelihood of human error.
The process by which the geo-coordinates of a target are communicated
in close-air support operations has not changed much since World
War II. Today, the FAC uses a map to find a target, he copies down
the grid coordinates and radios the pilot to “stand by for
a nine-line.” The pilot, meanwhile, has to grab his pen and
write down the 10-digit grid on his kneeboard — at the same
time he is flying the airplane and watching out for enemy fire.
After he’s copied down the information, the pilot has to manually
punch in the grid coordinates into his mission computer. “See
how that creates possibilities for errors?” McKinney asked.
With ACASS, the information goes straight to the pilot’s
display. He only has to push one of two buttons: to accept or deny
the target coordinates. If he accepts them, the information is dumped
into his mission computer, which feeds data to the bomb’s
guidance system. On his heads-up display, he sees an icon representing
the target. “He never has to fat-finger anything,” said
McKinney. “It eliminates the errors of transcribing.”
The Marine Corps has been testing ACASS since August 2000. Eventually,
said McKinney, it will be combined with the current ground-to-air
technology, called the target location, designation handoff system
The weak link in the ACASS today is the laser rangefinder, he noted.
“It’s not as accurate as it needs to be.” Experienced
FACs are able to compensate for the rangefinder’s inaccuracy
by relying on their own map-reading skills and expertise to verify
a target location.
Even though the system only works with the Harrier, McKinney expects
that it will be installed on all Navy F/A-18s, Joint Strike Fighters
and on the upgraded Cobra gunships. To be ACASS-compatible, an aircraft
must have a digital communications system.
The Warfighting Lab loaned five ACASS systems to the Spanish and
Italian air forces, which fly Harriers. The lab has received inquiries
from the other U.S. military services regarding ACASS, said McKinney,
but he added that it’s still too early in the program to know
whether it would have utility for the U.S. Air Force or Air National