晃动基座捷联惯导系统初始对准迭代方法

由于受风力或发动机启动等因素的影响，惯导系统载体(如导弹、飞机、舰船和车辆)经常遇到低频晃动的情况。晃动干扰使得陀螺测量到的地球自转角速度信噪比大幅下降，从而导致常用的对准方法无法满足高精度初始对准要求。针对这一问题，提出了一种基于晃动基座的捷联惯导系统迭代初始对准方法。本方法由惯性导航计算出水平速度误差，利用最小二乘法估算出水平角速度误差、姿态误差和航向误差，然后进行迭代计算，从而算出导航初始时刻的姿态和航向。车载(发动机启动)试验结果表明，该算法既提高了晃动基座条件下的初始对准精度，航向角误差的方差采用静态对准时为0.39244°，摇摆对准为0.03331°，本文采用的迭代对准为0.00883°，缩短了对准时间，迭代对准2min的航向角精度等效于静态对准和摇摆对准5min的精度。

Iterative Method of Initial Alignment for SINS on Swaying Bases

Influenced by wind or starting-up of the engine, carriers of strapdown inertial navigation system, such as missile, plane, ships and vehicles etc., often experience low frequency swaying. The noise-signal ratio was significantly decreased when the gyroscope measuring the earth rotation angular velocity, due to the above mentioned swaying, which leaded to unsatisfactory results in high precision initial alignment when conventional alignment methods were used. To solve this problem, an initial iterative alignment method for swaying bases strapdown inertial navigation system was established. In this method, horizontal velocity error was calculated by SINS. Errors of Horizontal angular velocity, attitude errors and azimuth errors were estimated by least square procedure. Then iterative calculation was carried out, and the initial attitude and azimuth were obtained. Experimental results of vehicle start-up showed that the precision of azimuth was enhanced. The variance of azimuth error of static state alignment, swaying alignment and iterative alignment was 0.39244°, 0.03331°, 0.00883° respectively. Initial alignment time was shorten, the precision of azimuth of iterative alignment in 2min equivalent to conventional static state or swaying alignment methods in 5min.