1. A method for a measuring instrument comprising a position calculating circuit including a tracker and a servo system, an angle measuring system and a distance measuring system for sending out measuring beams for distance and angle measurements and for receiving reflected beams during measurement sessions, said angle measuring system being adapted to calculate position data including at least horizontal and vertical angle between said measuring instrument and a target using said measuring beams and reflecting beams, comprising the steps of: obtaining sets of target position data including at least horizontal and vertical angle between said measuring instrument and said at least one target in consecutive measurements during a measurement session; calculating a model describing a path of and/or a distance to said target based on at least one data set obtained at a preceding measurement, said model predicting positions of said target; estimating at least a present position of said target and/or at least a present distance to said target using said calculated model; and at initiation of a new measurement session, using said estimated position of said target when searching for said target.