To measure the position of an object with high accuracy by measuring the relative distance between a specified known point and a mobile using a laser radar thereby locating the mobile.

A helicopter (referred to heli) 8 irradiates a laser light 14 and receives a reflected wave thereof thus determining the distance to a wire 9, or the like, on the ground. The distance is recorded, as a laser radar data, on a sequentially memory along with a gyro data, i.e., an acceleration or the like, sampled by means of a gyro mounted on the heli and a GPS data, i.e., the position of heli 8, measured by GPS and then inputted to a measuring unit on the ground. The measuring unit derives the equation of motor of the heli 8 based on the initial position thereof determined from the laser radar data, gyro data, etc., and then determines the absolute position of heli 8 by solving the equation. Furthermore, the absolute position of wire 9 or the like is determined through calculation using the absolute position thus determined and the laser radar data.