动力学模型自适应滤波算法研究

Adaptive Filtering Algorithms of Dynamic Model

  • 摘要: 在全球导航卫星系统(global navigation satellite system,GNSS)动态测量中,常采用Kalman滤波进行导航解算。但是,载体运动的不规则性经常会导致动力学模型偏差增大,从而出现定位精度下降的问题。针对此,在实时估计协同转弯模型(coordinated turn,CT)转弯率的基础上提出了两种减弱动力学模型偏差影响的自适应滤波算法。一种是实时估计转弯率的CT模型与改进的椭球约束方程相结合的滤波算法;另一种是通过对载体运动规律的分析,推导了实时估计转弯率的三维转弯模型,提出了一种三维转弯模型与新息向量构造的自适应因子相结合的自适应滤波算法。实验结果表明,这两种算法在不同的机动情况下都能较好地控制动力学模型误差的影响,其精度明显优于标准Kalman滤波和CT模型与常速度模型相结合的滤波算法。尤其是第二种算法,不仅通过自适应估计提高了动力学模型的精确性,还通过自适应因子进一步控制了动力学模型扰动的影响,显著提高了动态导航解的精度和可靠性。

     

    Abstract:
      Objectives  Kalman filter is frequently used in global navigation satellite system kinematic positioning applications. However, due to the irregularity of carriers' movement, the dynamic model is often deviated and the positioning accuracy is decreased.
      Methods  To solve this problem, two adaptive filtering algorithms are proposed to weaken the effects of dynamic model bias based on the estimated turning rate of coordinated turn (CT) model. One is the filtering algorithm that combines CT model with an improved ellipsoid constraint equation. The other is a 3D turning model for real-time estimation of the turning rate through the analysis of the carriers' movement. An adaptive filtering algorithm that combines 3D turning model and the adaptive factor constructed by the innovation vector is proposed.
      Results  The experimental results illustrate that the two algorithms can control the influence of the dynamic model errors well under different maneuvering conditions, and their accuracy is significantly better than that of standard Kalman filter and the filtering algorithm combining CT model with constant velocity model.
      Conclusions  In particular, the second algorithm not only improves the accuracy of dynamic model by adaptive estimation, but also further controls the disturbance influence of dynamic model by adaptive factor, which significantly enhances the accuracy and reliability of the navigation solutions.

     

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