Aviationweek.com
HPM, High-Energy Lasers To Arm U.S. Warships
Apr 12, 2011
By David A. Fulghum
Directed-energy weapons are being paired with traditional cannons to produce advanced shipboard defense against people, small arms, light boats and unmanned aircraft using non-lethal and low-power devices.
Future plans also include introducing high-power microwave (HPM) devices for counter-electronics attacks and high-energy lasers, say BAE Systems officials visiting Washington for the Navy League’s Sea-Air-Space Exposition. With high power outputs, the targets set for these directed-energy combinations include enemy air defense and anti-ship cruise missiles. Other options are to put HPM devices into unmanned aerial vehicles (UAVs) or small missiles that can be carried by unmanned helicopters like the Fire Scout to patrol ahead of and above ships. The team of BAE Systems as integrator and Boeing, which is supplying the beam director, contends that the technology and platforms for both air and sea are available and await only the miniaturization of some key components.
The current 15-month program puts a two-phase, 10-kw laser on a ship-mounted, Mk 83 25-mm cannon. The cannons are being installed on virtually every surface ship in the Navy. And the laser supplement program will wrap up with a land-based demonstration. No additional crew is needed to operate the one-man, remote-control, gun and laser system. The laser beam director is installed on the left side of the gun mount and a laser source is located below it. The laser has integrated power conversion and cooling.
The Mk 38’s current electro-optical/infrared fire-control system would be used for initial detection of small boats, for example, at ranges of about 10 km. Targeting would then shift to the optics within the laser beam director at about 8 km.
“That gives a high-resolution capability to determine how many crewmen there are on a small boat, if they have weapons and what kind of weapons they are,” says John Perry, BAE Systems’ manager of business development for advanced systems. “We then transition to a low-power, eye-safe, green-laser, visual interruption mode.”
If the threatening behavior continues, there are more options available to the defenders. “We can switch to the [10-kw] high-energy laser mode and start to engage at 3-4 kilometers,” Perry says. “For a non-lethal engagement, we can target a portion of the boat away from the crew. It could be a radar or a deck-mounted weapon.”
Escalating the engagement a bit more, “We could cook off the ammunition — machine gun rounds, small missiles or rocket-propelled grenades. If it’s [an inflatable] boat, we can certainly puncture [air] bladders.”
The amount of time to create effects depends on the target range and the material type and can vary from two to tens of seconds. The pointing system ensures that the laser beam stays within 3 mm of the aim point even with both ships moving in a rough sea.
“For a [10-kw] deck-mounted system like this, in the future we think we can [target] UAVs,” Perry says. “When you get to hundreds of kilowatts [of laser power], you can move into anti-ship, cruise missile defense. Our approach is to get an initial capability out to the fleet to give them a chance to figure out a concept of operations and how it complements kinetics.”
Another part of the future plan for air targets is to take external cues from the ship’s radar so the gun/laser system can pick up a track, slew the gun mount and start tracking with optics within the beam director. Another type of directed energy envisioned for the Mk.38 gun mount is a BAE Systems-developed HPM weapon with an anti-electronic-attack capability.
By choosing the correct frequency span, HPM “has counter-electronics specific to swarms of small boats where you can stop their engines at [long] range,” Perry says.
“Unlike lasers, HPM beams don’t need a lot of accuracy. With a fan [of HPM energy] you can target 10-30 small boats. If you can knock out 50-75% of the engines in a swarm, you can then concentrate on the remainder with lasers or kinetic [cannons].”
[Editor's note: The Mk 38 gun mount designation has been corrected.]
Photo: Northrop Grumman
