Radar camera to spot stealth weaknesses

[Anonymous <nobody@replay.com>]

Radar camera to spot stealth weaknesses

BRYAN BENDER JDW Bureau Chief

Washington DC

The USA has developed a hand-held camera it hopes will help ground crews verify the low-observability, or stealth characteristics, of military aircraft. It is now conducting tests on the US Air Force's (USAF'S) fleet of F-117A Nighthawks, according to officials.

Tests of the prototype Holographic 3-Dimensional Radar Camera come as the USAF appears to have lost its first F-117A stealth fighter to enemy fire.

An F-117A was downed over Yugoslavia during the first week of NATO's Operation 'Allied Force' in March, after the aircraft may have been detected by Serb radar and was targeted with anti-aircraft fire.

Since the apparent shoot-down, the F-117As participating in the airstrikes have been supplemented with additional EA-6B Prowler electronic jamming aircraft for enhanced protection.

The 3-D radar camera would give the US another tool to help prevent stealthy aircraft from being detected in the future by highlighting weaknesses in radar-absorbing materials.

The camera records images of an aircraft's radar reflection and translates that information into an image indicating where the radar-absorbing material is creating a larger reflection than desired, according to engineers at the Department of Energy's (DoE) Pacific Northwest National Laboratory, which developed the system for the air force.

Operators would 'shoot' the aircraft with low-power electromagnetic waves and receive the reflected energy via the radar camera's antenna.

Software algorithms then translate the level of reflection into a radar image projected into head-mounted 'virtual vision' glasses. The image displays the radar signature of a portion of the aircraft in green, yellow, or red, denoting 'pass', 'assess', or 'fail'.

"Ground crews want to verify that the aircraft's radar detectability is low," said Thomas Hall, an engineer working on the project. "By using the 3-D radar camera, ground crews can better determine if critical portions of an aircraft are in 'go' or 'no go' condition."

The stealth verification tool has a Ku-band radar camera that operates at 12 to 18 GHz.

Engineers are currently building an X-band camera to operate at 8 to 12 GHz. The intention is to use both cameras to inspect aircraft both pre- and post-repair, particularly when an aircraft has been damaged during flight.

Evaluation across a range of frequencies is important, officials say, to emulate both enemies' long-range surveillance radars, which operate at lower frequencies, and short-range missile and artillery fire-control radars, which operate at higher frequencies.

The prototype 3-D radar camera was delivered to the F-117 System Program Office at Wright-Patterson Air Force Base, Ohio, late last year and is now undergoing tests at the 49th Fighter Wing at Holloman Air Force Base, New Mexico, the home of the service's F-117A fleet.