Study On Wave-base Initial Alignment Method Of Strapdown Inertial Navigation System

Initial alignment is one of the key Inertial Navigation System technologies. How to improve the anti-disturbing ability and quick response of the carriers is worth of deep research.This paper builds a dynamic error mathematics model through the principle of the Strapdown Inertial Navigation System (SINS), and deduces dynamic error equations in detail, and then analysis on the characteristics of errors in motion states is illustrated. Three kinds of periodic systematic errors are given and their periods are affected by the vehicle motion.Coarse alignment of the SINS has little limit on precision, and is designed to get an initial coarse attitude matrix. In this paper, analytic coarse alignment and horizon leveling plus azimuth estimation coarse alignment and the inertial coarse alignment are compared, and simulation results are given too.Fine alignment of the SINS aims at getting the more accurate attitude matrix through estimating the small error angles between direction cosine matrix after coarse alignment and true matrix. Feedback control method and self-alignment filter can be used to reduce the small error angles. This paper focuses on the classical compass alignment method. The arithmetic and control flow following the auto control theory and the choose of proper control parameters are given. In addition, affections of external disturbing velocity is discussed, and compensation method of velocity on the inertial instruments is presented. At last, simulation result on conditions of different circumstances confirms the validity of this method.Common alignment process needs a long time, which is not good for the quick response. To improve the mobility performance, this paper discusses the quick inertial alignment method, using the gravity information at the start moment position and settle moment position. The whole process needs the output of gyroscope and accelerometers, having no special demands on the moving route. It SINS; error model; gyrocompass loop; self alignment; inertial alignment...