The gyroscope's bracket and body are connected together. When its rotor rotates at a high speed, the axis of rotation is perpendicular to the ground. A transverse indicator rod and the rotor shaft are vertically cross-connected. The aircraft can change its attitude of flight, but the rotor shaft will always point to the ground, and the horizontal bar will always be parallel to the horizon. It is called “artificial horizon” in the instrument. This instrument is called a ground plane, also called a posture guide. In actual flight, the driver should at any time believe in the flight attitude indicated by the horizon plane instead of believing in his own feelings, so as to avoid the misjudgment caused by the sharp tilting motion of the aircraft, so as to ensure the safe flight of the aircraft.