Initial alignment consideration for underwater robot´s strapdown inertial navigation system

This paper considers the initial alignment problem for underwater robot´s strapdown inertial navigation system. In general, initial alignment can be roughly divided into three types; coarse alignment, gyro compassing, and aided alignment. For underwater robot, gyro compassing is not suitable for its initialization, since it is difficult to accurately rotate the robot platform in the water. In this paper, we evaluate and compare the other two methods - coarse alignment and aided method, and investigate which one is more suitable in practice for a given IMU device.