Sony Computer Entertainment America has filed a new U.S. patent describing a controller that employs "hybrid video capture and ultrasonic tracking" technology.
The patent states that the system senses the movement of "one or more" controllers in a 3D space.
From the patent's abstract: "The captured video information is used to identify a horizontal and vertical position for each controller within a capture area. The ultrasonic tracking system analyzes sound communications to determine the distances between the game system and each controller and to determine the distances among the controllers. The distances are then analyzed by the game interface to calculate the depths within the capture area for each controller."