US Patent 7671890 Roving camera security system

A covert all-weather roving camera security system includes a monorail track, at least one self-propelled trolley able to move itself back and forth continuously along the monorail track, and a plurality of surveillance cameras attached to the trolley. A housing completely encloses the monorail track and the trolley and has a sunshield on its top to protect the cameras from overheating and a filtered window on its sides and bottom to prevent human eyes from seeing in the housing while permitting the cameras to see out.