用三个点位置及速度计算SINS姿态

Using position and velocity of three points to calculate attitude parameters of SINS

为利用外测数据计算捷联惯性导航系统(SINS)姿态参数,建立了利用飞行器上3个点的体坐标系位置参数和参考系外测位置、速度参数求解SINS姿态参数的2种方法。首先把点坐标参数转化基线;然后给出外测求解欧拉角定义,最后给出2种方法计算SINS欧拉角及其变化率、体坐标系相对参考系的角速率、坐标转换矩阵及其导数形式和陀螺仪测量的角速率。利用飞行数据建立仿真数据,验证了2种方法一致性并给出了算法逼近精度。仿真发现,方法一中滚动通道的计算逼近精度较差。误差传递公式和蒙特卡洛的仿真结果显示:姿态参数的标准差与基线比例系数间存在线性关系;当基线夹角为90°时,各个姿态参数的直线斜率和直线拟合残差标准差接近;基线夹角越接近90°,姿态标准差斜率越小。

For using the exterior measure to calculate attitude parameters of Strapdown Inertial Navigation System(SINS),this paper established two methods to calculate attitude parameters of SINS using position parameters in body frame,exterior position and velocity parameters in reference frame.It converted point parameters into baselines parameters first,then gave the definition of Euler angles for exterior measure,and finally gave two methods to calculate Euler angles and their rates,the angular velocity of body frame relative to reference frame,the coordinate transform matrix and its derivative,and the angular velocity measured by gyroscope.Using flight data to build artificial data,it verified the consistence of two methods,and gave the approximation accuracy;The approximation accuracy of rolling channel is worse in method one;Error transfer formula and Monte Carlo simulation indicated,the attitude standard deviation could be fitted a line of baseline scale factor.For each attitude parameter,the slope and standard deviation of residual in line fitting are estimated as the included angle between baselines is 90°in artificial test.The artificial test is designed to estimate the relationship between attitude parameter precision and included angle between baselines,as the included angle between baselines is closer to 90°,the slope of attitude standard deviation is smaller.