Inertia device comprising inertia sensors with different levels of precision

The device has a control unit (3) connected to inertial sensors i.e. angular sensors e.g. rate gyroscopes (2x-2z), where each sensor has a sensitive axis. The sensitive axes are respectively aligned on axes (X-Z) of reference mark. Each sensor has a predetermined precision class, where the accuracy classes of the sensors are different from each other. The sensor with low accuracy class is mounted on a vertical axis of mark. Two of the sensors are positioned on a same axis, where the accuracy class of one of the sensors is less than that of another sensor.