April 14, 2012:
The U.S. Army now has a new sensor package for its Raven (RQ-11B) UAV. The new sensor system includes a gimbaled camera and laser designator. A day vidcam or a night vision one can quickly be mounted on a Raven. The only change needed for the new gimbaled controller is a software upgrade. With the gimbaled camera the operator can quickly move the field-of-view around without having to move the aircraft. What's impressive about the new sensor package is that it weighs less than 450 gm (one pound). The progress people see in their cell phone cameras is also showing up in UAVs, especially the micro (under 6 kg/11 pound) class ones.
Introduced nine years ago, the current Raven weighs two kilograms (4.4 pounds). This is about ten percent heavier than the original model but much more capable in terms of performance. Over 6,000 Ravens have been built so far and this UAV dominates the micro-UAV market.
The big advantage with Raven is that it’s simple, reliable, and it works. A complete system (controller, spare parts, and three UAVs) costs $250,000. The UAV can be quickly taken apart and put into a backpack. It takes off by having the operator start the motor and then throwing it. This can be done from a moving vehicle, and the Raven is a popular recon tool for convoys. It lands by coming in low and then turning the motor off. Special Forces troops like to use it at night because the enemy can’t see it and often can’t hear it as well.
The controller allows the operator to capture video, or still pictures, and transmit them to other units or a headquarters. The operator often does this while the Raven is flying a pre-programmed pattern (using GPS). The operator can have the UAV stop and circle, in effect keeping the camera on the same piece of ground below. The operator can also fly the Raven, which is often used when pursuing hostile gunmen.
Raven can stay in the air for 80 minutes at a time. The Raven is battery powered and thus very quiet. Raven broadcasts real time video back to the operator, who controls the Raven via a laptop computer or hand-held controller. The Raven can go as fast as 90 kilometers an hour but usually cruises at between 40 and 50. It can also go as far as 15 kilometers from its controller and usually flies a preprogrammed route, using GPS for navigation. The Raven is made of Kevlar, the same material used in helmets and protective vests. On average, Raven can survive about 200 landings before it breaks something. While some Ravens have been shot down, the most common cause of loss is losing the communications link (as the aircraft flies out of range) or a software/hardware failure on the aircraft. The flight control software has a “failsafe” mode so that when the radio link between aircraft and operator is lost, the aircraft will immediately head for home (where it was launched from).