Patent ID: 7714993

Claim:
A method for guiding a machine carrying a tool for movement along a predetermined path at a worksite, said method comprising: placing a fan-type laser transmitter at the worksite remote from the machine, said laser transmitter having an arbitrary reference direction and generating two fan-shaped laser beams; sensing the two fan-shaped beams with at least five individual interconnected photodetectors fixed arbitrarily at known positions in a detector support array having a three-dimensional shape generally configured as a pyramid such that at least one of the at least five individual interconnected photodetectors will always be unblocked in all orientations of the detector support array, said detector support array being placed at a known position on the machine said at least five photodetectors being geometrically arranged and spaced apart to reduce eclipsing of one detector by another; setting a reference azimuth angle from said arbitrary reference direction into a control unit provided on the machine, said reference azimuth angle points in a direction parallel to the predetermined path; computing a measured azimuth angle using information provided to the control unit by the detector array sensing the two fan-shaped beams; determining position of the machine relative to the predetermined path via said control unit comparing the measured azimuth angle to the reference azimuth angle; and generating signals which help guide the machine along the predetermined path.