US Patent 7398946 Power line sentry charging

A rechargeable battery energized unmanned aerial vehicle having surveillance capability and an ability to clandestinely collect propulsion and other energy needs from a conveniently located and possibly enemy owned energy transmission line. Energy collection is by way of a parked vehicle engagement with the transmission line in a current flow dependent, magnetic field determined, rather than shunt, voltage dependent, conductor coupling. Surveillance during both a parked or docked condition and during aerial vehicle movement is contemplated.