基于弹道弯曲角速度单矢量的制导炮弹滚转角空中粗对准方法

In-flight Alignment Method of Guided Projectile Roll Angle Based on Trajectory Bending Angular Velocity Single Vector

制导炮弹内弹道呈现高转速、大过载的特点,其导航坐标系统滚转通道无法进行初始对准。针对以上难点问题,根据无控段飞行特性,提出一种基于弹道弯曲角速度矢量的滚转角空中粗对准方法。在无需卫星、机动辅助的条件下,利用重力引起的弹道弯曲角速度矢量作为基准,通过单矢量定姿实现滚转角对准。为消除低精度陀螺仪的零偏、轴偏角等误差的影响,分析了弹体姿态运动测量信息的频域特性,利用FIR带通滤波器提取角速率陀螺信息中弹体滚转频点处的有用分量,并采取对准起始时刻冻结弹体坐标系下的积分策略,平滑随机测量噪声,从而提高对准精度。通过数学仿真手段,探究了惯性陀螺误差对对准精度的影响。数学仿真结果表明:该方法仅利用低精度角速率陀螺即可实现在无控段快速粗对准滚转角,误差在1°左右;在飞行搭载试验中,滚转角对准误差可控制在2°以内。

As the interior ballistics of guided projectiles feature high rotational speed and high overload, the initial alignment of roll angle can only be achieved in air. To solve this problem, a coarse roll angle alignment method based on trajectory bending angular velocity in free flight phase is proposed. Without satellite and maneuver assistance, using the trajectory bending angular velocity induced by gravity as reference, the roll angle is obtained by single vector attitude determination. Then, the frequency domain characteristics of the projectile attitude motion measurement is analyzed to reduce the impact of the zero bias, misalignment and other errors of the low accuracy gyroscope. A FIR bandpass filter is utilized to extract desired component of the angular rate measurement at the rolling frequency point. An integration strategy under the frozen projectile system at the beginning of alignment is adopted to suppress the random noise, thereby improving the performance of the alignment. The influence of inertial gyroscope error on alignment accuracy is explored by mathematical simulation. The simulation results show that through this method, fast coarse alignment of roll angle in free flight can be realized only using low precision angular rate gyroscope, and the error is about 1°. In the flight test, the roll angle alignment error can be controlled within 2°.