A novel EM-Log aided gyrocompass alignment for in-motion marine SINS

An EM-Log (Electromagnetic Log) aided in-motion gyrocompass alignment algorithm is proposed to accomplish the fine alignment for marine SINS (strapdown inertial navigation system) on sailing vessel. The EM-Log is used to track the maneuver velocity of the vessel and remove the earth rotation angular velocity and the angular velocity of the navigation frame relative to the earth frame from accelerometer measurements. In terms of SINS damping technology, we change the structure of gyrocompass alignment loop and employ EM-Log measurements to reduce the negative effects of vessel accelerations. The simulation and experiment results show that our proposed method could accomplish fine alignment of in-motion marine SINS, while the conventional one failed.