An anti-disturbance initial alignment algorithm for swing-base strapdown inertia! Navigation system(SINS) is presented, and the essential of the proposed approach is attitude determination(AD) using vector observations. It is easy to show that the apparent gravity expressed within an Inertial Space forms a cone whose main axis is the rotational axis of the earth. So, by the examination of gravity movement, the true heading can be found. Employing the gravity vector projective relation with the initial attitude-quaternion, the linear pseudo-measurement equation is built up. The initial attitude-quaternion is a constant parameter and the quaternion kinematics equation is linear and precise. The above characteristics yield a linear KF that eliminates the usual linearization procedure and is less sensitive to initial estimation errors. The turntable rocking simulation experiments are carried out which demonstrates the efficiency of the quaternion filter.%针对晃动基座捷联惯导初始对准问题,研究了一种具有干扰抑制能力的初始对准算法.根据重力矢量在惯性空间投影构成一包含地球北向信息的旋转锥面的现象,利用坐标系惯性凝固假设将重力量测矢量和参考矢量分别投影到载体惯性坐标系和导航惯性坐标系,将晃动基座条件下的初始对准转化为基于重力量测矢量确定对准起始时刻的姿态问题.借鉴四元数线性伪量测方程的概念,利用重力投影矢量与初始姿态四元数的线性量测关系实现初始姿态四元数的直接滤波估计.初始姿态四元数在对准过程中为常值,以其作为待估计的状态可避免系统模型误差和初始误差的影响.利用转台模拟不同的摇摆对准环境,导航级惯导系统可在10 min内完成初始对准且方位误差小于3′.
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