Patent ID: 7148958
Filing Date: 2006-12-12
Classification: G01C,G01S

Abstract:
1. A method for measuring a height or a relative position in an axial direction, said method comprising the steps of: vertically arranging a pair of rotary laser devices, aligning respective axes of said pair of rotary laser devices into a single axis and keeping said rotary laser devices away from each other in an axial direction thereof by a predetermined interval; arranging a light-receiving sensor, keeping said sensor radially away from said single axis; emitting a plurality of fan-shaped laser beams from each of the rotary laser devices while rotating said laser beams, said laser beams comprising at least one fan-shaped laser beam inclined to a plane containing said single axis; receiving and detecting the laser beams with the light-receiving sensor; determining inclinations of the rotary laser devices relative to the light-receiving sensor, respectively, based on time intervals of said detection of the laser beams; and detecting the position of the sensor relative to said pair of rotary laser devices in the axial direction.