The north finder based on fiber optic gyroscope is an instrument to realize autonomous north seeking based on the principle of inertial navigation. It is an important part in the field of inertial technology. It can realize all-weather, omni-directional, independent and rapid direction measurement without being restricted by natural conditions. At the same time, it also has many advantages, such as high precision, long continuous working time and so on. Gyroscope is the core component of the north finder. Among them, fiber optic gyroscope is a very new angular rate sensor that uses fiber optic sensing technology to measure the spatial inertial rotation rate. It is an all solid-state optical gyroscope. It has no rotating and friction components. Compared with the traditional mechanical gyroscope, fiber optic gyroscope has the advantages of small size, light weight, short start-up time It has many advantages, such as high sensitivity and resolution, long service life, strong impact and vibration resistance and so on.
Because of the advantages of fiber optic gyroscope, it can meet the requirements of small size, high precision and fast orientation in many aspects. Therefore, the research of north seeking system based on fiber optic gyroscope has attracted extensive attention. In foreign countries, since the 1990s, fiber optic gyroscope has been applied to the research of developing north seeking device. Patent US5778543 discloses a north seeking instrument using fiber optic gyroscope. One fiber optic gyroscope and two accelerometers are installed on a rotating platform, and the sensitive axes of the two accelerometers are orthogonal to each other to measure the inclination angle of the rotating platform. The sensitive axis of the fiber optic gyro is equal to the table of the rotating platform, which is used to measure the rotation speed of the earth. The gyro north finder method disclosed in patents EP2026036 and US8151475 can be realized not only by fiber optic gyroscope, but also by micromechanical gyroscope. In addition, research institutions in the United States, Japan, South Korea, France and other countries have successively published research results on fog north seeking technology, and have successively developed fog north finder or navigation system with north seeking function.