strapdown inertial sensing unit rotation
1Inertial navigation system — An Inertial Navigation System (INS) is a navigation aid that uses a computer and motion sensors to continuously track the position, orientation, and velocity (direction and speed of movement) of a vehicle without the need for external references …
2Gimbal — A gimbal is a pivoted support that allows the rotation of an object about a single axis. A set of two gimbals, one mounted on the other with pivot axes orthogonal, may be used to allow an object mounted on the innermost gimbal to remain vertical… …
