As news reports have described,United States military convoysin Iraq havecomeunder attack from insurgent forces who are utilizing unconventional warfare techniques. A variety of methods have been proposed to increase the safety of these convoys, including constant airborne surveillance of the convoy and convoy route using unmanned aerial vehicles.

In response to this need, MLB has developed and tested a new convoy-following mode of operation for the Bat mini-UAV. A GPS signal from a vehicle in the convoy is uplinked to the Bat, which coordinates its flight with the convoy while automatically aiming its gimbaled camera. The focus point of the camera can be on the vehicle itself or a point of interest at anoffset distance. The Bat updates its flight path continuously to keep its sensor aimed at this focus point. No a priori information of the convoy route is required as the Bat adjusts its path in real-time to the position and speed of the convoy.

For example, when the convoy stops, the UAV automatically enters an orbiting mode and keeps its camera fixed on the stopped vehicles. When traveling at speed, the Bat moves into fixed formation but aims its camera at a desired location relative to the convoy. Video from the Bat is received in the convoy vehicles and may also be sent back to a stationary base.

MLB has conducted numerous test flights of this new convoy-following mode. A typical test consists of forty minutes of flight while the observed vehicle travels in urban and highway conditions. Speeds of the vehicle have ranged from zero to sixty miles per hour. These initial tests have shown that the Bat keeps the focus point in the image frame more than 97% of the flight time. The Bat is capable of conducting this flight technique for up to six continuous hours.