Research and development of an optical gyrocompass using a three-axis FOG

We propose an optical gyrocompass using a three-axis Fiber Optic Gyroscope (FOG) that is the technological heart of the optical gyrocompass. The core of the optical gyrocompass is a compact strap-down Inertial Measurement Unit (IMU), which contains a three-axis FOG, three accelerometers, and a real-time computer that is responsible for computing all the necessary data for demanding navigation. Thermal design is performed to manage heat conduction and quickly balance inner temperature of the optical gyrocompass for suppressing the thermally induced error, and then the uniform temperature environment is obtained for three-axis FOG. The long-endurance sea trial experiment result proves that the dynamic accuracy of the optical gyrocompass is lower than +/- 0.25 degrees secant latitude, and it is capable of navigating in high latitude region. The optical gyrocompass is also certified to meet the requirements of the International Maritime Organization (IMO) for gyrocompasses.