SURVEYING SYSTEM

A surveying system has a total station and a target instrument, wherein the target instrument has an illuminating lamp, wherein a total station has an optical axis deflector capable of deflecting a distance measuring optical axis, a projecting direction detecting module for performing an angle measurement of the distance measuring optical axis, an image pickup unit, and an arithmetic control module for controlling a deflecting action of the optical axis deflector and a distance measuring action of a distance measuring unit, wherein the arithmetic control module is configured to detect an illumination light from an image acquired by the image pickup unit, to acquire a direction of the illuminating lamp based on a detection result, to make the optical axis deflector to scan with a distance measuring light around the acquired direction and to perform a distance measurement and an angle measurement along a scanning path, wherein the target instrument has a retro-reflector of a reflection sheet and has a reference point of the target instrument at a known position with respect to the illuminating lamp, wherein the arithmetic control module is configured to make the optical axis deflector to execute a two-dimensional scanning pattern, to detect the reflected distance measuring light at the time when the scanning pattern crosses the retro-reflector and to track the target instrument based on the detection result.