Patent attributes
A first surveying unit comprises a frame in a horizontally rotatable manner, a telescope unit in a vertically rotatable manner, a first angle measuring unit and a first distance measuring unit which measure a prism, wherein the second surveying unit comprises a scanning mirror which rotatably irradiates a laser beam and a second angle measuring unit which detects a rotation angle of the scanning mirror, wherein a target instrument comprises a pole installed at a measuring point, the prism has a known positional relationship with a lower end of the pole, and a target plate mounted on the pole, wherein an arithmetic control module scans a laser beam, calculates a measuring point direction vector based on point cloud data of the target plate, and calculates a three-dimensional coordinate of the measuring point based on an optical center of the prism, the measuring point direction vector, and the positional relationship.