一种船舶漂浮状态下捷联惯导快速自对准方法

A fast self alignment method for strapdown INS on drifting watercraft

为解决无外部参考信息船舶SINS漂浮状态下捷联惯导快速自对准问题,提出了在粗对准阶段采用时变参数罗经法、精对准阶段采用卡尔曼滤波精对准的方案。传统方案中罗经对准方案常常被用于精对准,这里采用大方位失准角条件下时变参数的罗经法进行粗对准,代替目前成熟的凝固法粗对准方案,在大方位失准角条件下同时利用东向通道和北向通道的速度误差进行控制回路反馈,在方位对准初期采用较大的阻尼振荡频率使大方位角快速减小,随后逐渐减小阻尼振荡频率以提高收敛精度,在经历1.4个振荡周期之后,方位失准角收敛到较小范围后,此时切换到卡尔曼滤波精对准阶段。通过实测试验数据的仿真表明,在船舶漂浮状态下经过不到4 min的时变罗经方位对准,能达到凝固对准法5 min时的对准精度,从而节省了对准时间。

In order to solve the problem of fast initial alignment of SINS on drifting watercraft without external reference information,a plan is adopted with time-varying parameter gyrocompass in coarse alignment and Kalman filter in fine alignment.In the traditional plan,the compass alignment scheme is often used for fine alignment.The gyrocompass method with time-varying parameters under the condition of large azimuth misalignment angle is used for coarse alignment in the proposed plan instead of the current mature solidification coarse alignment plan.Under the condition of large azimuth misalignment angle,the velocity errors of the east channel and the north channel are used to feed back in the control loop.In the initial stage of azimuth alignment,a large damping oscillation frequency is used to reduce the large azimuth angle quickly,and then the damping oscillation frequency is gradually reduced to improve the convergence accuracy.After 1.5 oscillation cycles,the azimuth misalignment angle converges to a small range,and then the system is switched to Kalman filter fine alignment stage.The simulation results of the actual test data show that the alignment accuracy of the time-varying compass in less than 4 min under floating condition can reach that of the solidification alignment method in 5 min,so the alignment time is saved.