The U.S. Navy plans to upgrade 1,000 of its existing high-speed
anti-radar missiles under a program also funded by the German and
Italian governments. The improvements will provide more accurate
navigation and targeting capabilities, officials said.
The high-speed anti-radar missile (HARM) is a supersonic, long-range
weapon that has been used by the U.S. Navy and Air Force for two
decades. Its primary mission is the suppression or destruction of
enemy surface-to-air missile radar, early-warning radar and radar-directed
air-defense artillery systems. More than 2,000 HARMs have been fired
The tri-national project is for the engineering and manufacturing
development of a kit—called precision navigation upgrade (PNU)—that
will be attached to existing missiles. The PNU combines a global
positioning (GPS) guidance system and an inertial measurement unit.
The satellite capability allows HARM to reach the correct target,
even if it loses the enemy’s radar signal.
Each PNU kit will cost approximately $40,000. There are three contractors:
Raytheon Systems Co., in Tucson, Ariz., BGT Missiles Division, of
Germany and Alenia Marconi, of Italy.
Making HARM more precise means fewer missiles will have to be fired,
said Capt. Christopher Powers, U.S. Navy program manager for defense
suppression systems. “We can’t continue to lob HARMs
out there by the hundreds,” he said during a conference of
the Precision Strike Association, in Fort Belvoir, Va.
HARM was due for a hardware-based improvement, because its software
upgrades had gone “as far as you can go,” said Powers.
The Navy’s long-term plan is not just to improve the accuracy
of HARM, but also to boost its performance against targets that
shut down the radar after the HARM is launched.
The PNU development program with Italy and Germany should be completed
by 2004, Powers said. It is not clear how many missiles these two
nations plan to upgrade. The U.S. Air Force is not participating
in the project, but Powers expects that, if the Navy’s efforts
are successful, the Air Force will join the program at a later stage.
The improved missiles are intended to be launched from F/A-18 Hornet
multi-role warplanes, E/A-6B radar-jamming Prowlers and Tornado
fighters. HARM is 13.7 feet long, 10 inches in diameter, has a wing
span of 44 inches and weighs 800 pounds.
In the future, Powers said, HARM could be equipped with an advanced
multi-mode seeker, to address the so-called counter-shutdown problem.
The anti-radiation homing seeker would be changed to a more modern
millimeter-wave seeker, for example, so that HARM would find the
target even after the enemy shut down the emitting radar.
The multi-mode seeker is not part of the PNU program. The Navy
is funding a technology demonstration called advanced anti-radiation
guided missile (AARGM). The AARGM is a seeker upgrade of the existing
HARM airframe. The projected unit cost of this upgrade is $295,000.
About 1,800 HARM weapons will be upgraded to the AARGM configuration.
“At Raytheon, internally, we are looking at ways to solve
the emitter shutdown problem,” said Russ Haas, the company’s
business development manager for defense suppression systems.
Some of the options being studied at Raytheon include a multi-mode
seeker and the possibility of coupling the HARM PNU with the newest
version of the HARM targeting system, which currently is in development
at the company. This 8-foot long, 90-pound pod autonomously detects
and identifies radar-guided threats at long ranges. It was designed
originally for the Air Force F-16C/D block 50D aircraft.
The combination of the PNU and the targeting pod may solve the
shutdown problem, said Haas in an interview. He speculated that
the Navy may not need a new multi-mode seeker. “If they are
going to solve the shutdown problem in the most affordable manner,
they are going to have to look at on-board targeting as part of
that solution,” he said.
Raytheon was the original developer of HARM, a program that began
in the early 1970s. The versions of the missile currently in the
Air Force and Navy inventories are the AGM-88B and C. The B missiles
with the PNU kit will be called AGM-88 B+. The C version with the
PNU kit will be called AGM-88D.