US Patent 8395665 Automatic tracking method and surveying device

A method of automatic tracking of a target is disclosed. This method includes a light spot detecting step of detecting a light spot from a target supported on a moving object, a step of taking a moving image of the target and the moving object, a step of target tracking based on the detection of the light spot, a step of performing image tracking based on the moving image in parallel to the target tracking, a step of comparing a position of the target obtained by the target tracking with a position of the image obtained by the image tracking, and a step of tracking the target based on a result of the target tracking in case where the target position and the image position are within a predetermined range.