DSMAC stands for Digital Scene Matching And Correlation. It is a terminal guidance system used by the Tomahawk cruise missile. A camera in the nose is activated once the missile is near its target, and the view from the camera is compared constantly to a set of 'correct' images of the target stored in the missile. When the scene matches, the missile refines its heading to place itself in the center of the 'stored' scene. This allows for precision unknown prior to its invention; it is said that Tomahawks can pick a window on the side of a building to hit if given the proper reconnaissance photo of the target.