SINS level alignment based on classic control principle

In initial alignment of strapdown inertial navigation system (SINS) mounted on launch vehicles, the SINS would sway because of the ground wind. The azimuth angle alignment is usually realized by other instruments for its importance. The SINS measurements are usually corrupted by different types of errors, such as disturbance due to the swaying, which makes it difficult to accomplish the level alignment. This paper investigates the lever-arm effect, establishes model of disturbance model on control principle, analyzes the influence of lever arm effect to level alignment accuracy, and by the proposed method the lever arm compensation accuracy could be derived reversely under expected alignment precision.