A technique is provided for measuring attitude of an aerial vehicle without using a highly accurate IMU. A total station (TS) for tracking a UAV includes a laser scanner. The laser scanner is made to emit laser scanning light to the UAV that is flying. The UAV has four identifiable targets, and identification and locating of the four targets are performed by means of laser scanning. The attitude of the UAV is calculated on the basis of the locations of the four targets.