The 419th Flight Test Squadron at Edwards AFB recently executed ground laser testing on the B-52H aircraft.
The B-52 bomber is integrating the LITENING targeting pod (TGP) under the right wing.
Operational B-52 aircrews have requested additional targeting pod resources to maintain precision weapon delivery and to provide air support for troops on the ground. The test program at the 419th will provide results to support fielding recommendations.
The LITENING TGP will provide the field with additional military utility.
The targeting pod provides Infrared and TV imagery along with three different lasers. It’s a gimbaled sensor that can look about the ground while using lasers. The lasers may help generate precise ground coordinates or point out items for ground troops.
The LITENING system is a self-contained, multi-sensor targeting and surveillance system, which has been fielded in other aircraft types across the U.S. Military. LITENING enables aircrews to detect, acquire, auto-track and identify targets at extremely long ranges for weapon delivery or nontraditional intelligence, surveillance and reconnaissance missions. LITENING’s laser imaging sensors, advanced image processing and digital video output provide superior imagery, allowing aircrews to identify and engage targets under a wide range of battlefield conditions.
While the LITENING TGP can provide a much needed and improved capability, it cannot be fielded until laser safety is complete. The lasers cannot be allowed to strike the aircraft for both safety reasons and accuracy.
“We needed to create what is called a MASK curve that stops the lasers when the targeting pod looks at B-52 aircraft structure. Essentially, the aircraft may get in the way of the laser, so we have to stop the laser from firing,” said Perry Choate, 419th FLTS Electro Optics lead.
“The importance of this laser mask zone test was to assure the lasers would not touch any aircraft structure. The most important reason to keep the lasers from hitting the aircraft was to guarantee a correct laser range measurement to the intended ground point of interest. If the laser hit the aircraft, the laser range measurement would be in error.”
Two other reasons for keeping the laser from touching the B-52 is the sensitivity of the internal laser range receiver, which can be affected by such a close reflection to the targeting pod from the aircraft itself. There is also a nominal ocular hazard distance from where the laser hits the aircraft surface that could possibly affect the cockpit area and aircrew.
In order to integrate the lasers, the 419th test team had to find the angles where each of the lasers just begin to touch aircraft structure, which was labor intensive. This entailed measuring each of the lasers as test personnel moved around the aircraft structure.
“We had to climb on the engines and wing areas to measure where the lasers were in relation to the aircraft structure. Once we determined the angles, a safety buffer was added to that initial two-dimensional curve. I assured extra margin about the B-52 cockpit area since our aircrew has windows that allow viewing the targeting pod,” said Choate.
The result was a list of angles that masked out the B-52 aircraft structure to prevent laser striking aircraft structure with added safety margins.
What made the test challenging is that all three lasers are invisible to the eye. A special camera that sees the invisible lasers, along with a phosphorescent card that glowed when struck by laser energy, was used to pinpoint the laser spots.
“We were efficient and kept the test safe for all participants,” Choate said.
In the end, the team designed and verified the MASK curve.
“The next step is to take our MASK curve to flight and run another airborne test just to be sure we have the all the angles correct,” said Choate.
That flight test is planned for early 2016.
“The B-52H operational fleet is anticipating use of the LITENING TGP to continue their role in air dominance and to support ground troops while deployed in hostile areas.”