船用极区格网惯性导航系统综合校正方法

Comprehensive calibration method of shipborne grid inertial navigation system

摘要:

为抑制适用于极区的船用格网惯性导航系统随时间积累的导航误差,提出一种基于格网坐标系的综合校正方法对陀螺常值漂移进行估计和补偿. 该方法首先基于格网坐标系推导了P方程,该方程建立起位置误差、格网航向误差与平台漂移角ψ的关系；其次推导了ψ方程,该方程建立起陀螺常值漂移与平台漂移角的关系；最后基于P方程与ψ方程设计了一种两点式综合校正方案,该方案通过建立观测量误差与载体坐标系下陀螺常值漂移之间的关系完成对陀螺常值漂移的估计和补偿.系统在外水平阻尼条件下间断地获取两次外部位置和航向信息后对陀螺常值漂移进行估计,进而对位置和格网航向误差重调并补偿陀螺常值漂移即可完成船用格网惯导系统的综合校正. 仿真结果表明:在两次间断的外部位置和航向信息辅助下,所设计的两点校综合校正算法可以准确地估计出载体坐标系下的陀螺常值漂移,补偿陀螺常值漂移并进行系统重调可有效抑制船用格网惯导系统随时间积累的导航误差,从而有效地保证了船舶在极区航行时的导航精度.

Abstract:

To restrain the accumulated navigation error of shipborne grid inertial navigation system (INS), the paper proposed a comprehensive calibration method based on grid frame to estimate and compensate the gyroscope constant drift. First, the P equation was derived based on grid frame, and the P equation established the relationship among the position errors, the grid yaw error, and the platform drift angles ψ. Then the ψ equation was derived to establish the relationship between the gyroscope constant drifts and the platform drift angles ψ. Finally, on the basis of P equation and ψ equation, a two-point comprehensive calibration scheme was designed, and the gyroscope constant drifts in body frame were estimated and compensated by establishing the relationship between the gyroscope constant drifts and observation errors. Under external level damping state, the gyroscope constant drifts were estimated after obtaining two intermittent external position and azimuth information, then the comprehensive calibration of shipborne grid INS was realized by resetting the position errors and grid yaw error and compensating the gyroscope constant drifts. Simulation results demonstrate that with the aid of two intermittent external position and yaw information, the proposed two-point comprehensive calibration method can estimate the gyroscope constant drifts accurately. Conducting the gyroscope error compensation and the system reset can efficiently restrain the accumulated errors of shipborne grid INS, thus significantly improve the navigation accuracy of ships navigating in polar regions.