基于伪测量法的直链式N体空间绳系系统约束状态估计

Constrained State Estimation of Linear N-body Space Tethered System Based on the Pseudo Measurement Method

  • 摘要: 针对直链式N体空间绳系系统(STS),将系绳绳长作为先验信息,在仅使用2个GPS(全球定位系统)传感器的条件下,提出了一种基于伪测量法的约束状态估计方法。首先,基于Udwadia-Kalaba方法建立了一种新颖的直链式N体STS通用动力学模型。然后,针对GPS传感器更新频率低和非线性系统模型线性化过程中雅可比矩阵计算复杂的问题,开发了一种改进的平方根无迹卡尔曼滤波(IUKF)算法。同时,基于李导数的局部弱可观的秩判据方法严格证明了本文估计方法的可观性。最后,仿真验证了本文方法的有效性。仿真结果表明所提方法能够保证系统状态估计精度和跟踪实时性。

     

    Abstract: A constrained state estimation scheme based on the pseudo measurement method is proposed for the linear N-body space tethered system (STS), which takes the tether length as prior information and uses only two GPS (global positioning system) sensors. Firstly, a novel general dynamic model of linear N-body STS is established based on UdwadiaKalaba method. Then, an improved square root unscented Kalman filter (IUKF) is developed considering the low update frequency of GPS sensors and the high complexity of Jacobian matrix calculation in the linearization of the nonlinear system model. Furthermore, the rank criterion based on the local weak observability of Lie derivatives is utilized to prove that the proposed estimation scheme is observable. Finally, extensive simulation results are presented to verify the effectiveness of the proposed scheme. The simulation results show that the proposed scheme can guarantee the precise state estimation and real-time tracking.

     

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