Study On Initial Alignment Method Of Strapdown Inertial Navigation System

One of the key technologies of Strapdown Inertial Navigation System(SINS) is the initial alignment,whose accuracy affects the precision of SINS and whose speed effects the response rapidity of the weapon.The aim at alignment accuracy and time and the complicated environment made the initial alignment of SINS difficulty.Terefore the initial alignment is becoming a key technology of SINS,and lots of scholars and experts pay extensive concern to it.Concern the initial alignment of SINS,the following crucial technologies were investigated in this paper:(1)It is carried on the model for the MEMS(Micro Electro Mechanical Systems) gyroscope and the accelerometer. In order to improve the output of inertial measurement precision, it gives the circuit of error compensation for gyroscope (CRS-0304) and accelerometer (M1221).(2)In the establishment of SINS's attitude matrix, the Euler angle, the direction cosine,the Quaternion and the Equivalent rotating vector are deducted. the Quaternion has a small amount of calculation,a amount of high-precision, avoiding singularity and other advantages.(3)It analyses the basic principle of initial alignment on the static base of SINS.The method of optimal multi-location is used to the static base. The two and three positions is simulated by Matlab. From the chart of the three positions'simulation,it is better effective around the pitch axis than the roll axis.(4) It uses the transfer alignment on moving base. Mechanics equation of the veloeity matehing,the attitude matching and the veloeity and attitude matching transfer alignment are deducted. The three matching methods are studied by simulation. Seen from the chart of the simulation, the veloeity and attitude matching can be more successful to resolve this problem at initial alignment on the moving base of SINS.