Paris Air Show

Paris 2011: Raytheon develops missile for small UAVs

 - June 19, 2011, 9:30 AM

Raytheon’s growing portfolio of precision munitions is to expand with the development of a new smart missile to arm small UAVs that are current unable to carry weapons. Initial flight tests have produced good results, and the small tactical missile (STM) is gearing up for more advanced testing in the coming weeks.

STM development was spurred on by the experience of operators of small UAVs such as the U.S. Army’s RQ-7 Shadow. “Operators of these UAVs can see guys planting IEDs, but they have nothing to shoot,” explained Cody Tretschok, Raytheon’s STM capture manager, referring to operations in locations such as Afghanistan against insurgents armed with improvised explosive devices. “They can call in airstrikes but that might take 30 to 60 minutes, by which time the enemy has gotten away. The challenge is, what can we do for these small systems? How can we dramatically reduce the kill chain?”

Arming the UAVs themselves is the obvious answer, but the size and payload capacity of the vehicles demands a very small weapon. There are advantages as a small warhead significantly reduces the level of collateral damage, an important consideration when operating in populated areas. “But you can go too far,” warned Tretschok. “It doesn’t make sense to make a weapon that doesn’t have a large enough warhead to be effective.”

Answering this conundrum is a seven-pound warhead developed by Nammo Talley. The small size of the warhead has allowed Raytheon to devise a missile that weighs just 13 pounds yet still delivers an effective blast.

The STM is unpowered, but its wings give it a range of around four to seven kilometers when launched from a typical 8,000- to 12,000-foot altitude. Guidance is by semi-active laser and/or GPS.

Flexibility of operation was an important driver in its design, and it incorporates a range of advanced features drawn from Raytheon’s extensive munitions range, including off-boresight launch, impact angle control, fuzing options (point, delay and airburst) and high agility to engage moving targets. The weapon is fully interfaced with the UAV operator’s station.

Development of STM began around three years ago, and in 2010 flight tests were undertaken at the Yuma Proving Ground in the U.S. Three drops were undertaken from the Cobra autonomous UAV platform, which was developed by Raytheon as a testbed for unmanned systems and sensors. All three drops used inert weapons, one being guided by GPS alone and two using both GPS and laser.

While ground tests of the warhead continue, more flight tests are planned for the end of the summer with fuzing options added. STM drops from a tactical platform are planned for later in the year, or early next.

Further developments of the STM are being worked on, including a common launch tube for two missiles for carriage by larger platforms. Although these platforms can carry larger weapons such as the Hellfire, the STM can be carried in larger numbers and offers a useful low collateral damage option.

The provision of a motor to extend range is also being examined, although the weapon’s current glide range is well matched to the way in which small UAVs are typically employed. Helicopter- and ground-launched concepts for the STM are also under review.

The STM becomes the smallest member of a family of smart weapons from Raytheon that ranges from the Paveway laser and dual-mode bombs, down through the SDB II, JAGM and Griffin. The latter is a 33-pound weapon that has been integrated with the U.S. Air Force’s A/MC-130W Dragon Spear Hercules used by the U.S. Special Operations Command and has also been linked with larger UAVs and helicopters.