基于虚拟里程计强化模型的自适应INS/NHC定位方法

Adaptive INS/NHC positioning method based on virtual odometer enhanced model

  • 摘要: 虚拟里程计(virtual odometer, VODO)和非完整性约束(non-holonomic constraint, NHC)是GNSS中断时抑制惯性导航系统(inertial navigation system, INS)误差发散的重要手段,但现有VODO的预测精度和运行效率仍存在限制,且常规NHC噪声模型难以准确刻画车辆侧滑等复杂的运动状态. 本文提出了基于卷积神经网络(convolutional neural network,CNN)/Transformer的VODO强化模型的自适应INS/NHC定位方法. 该方法采用多层CNN提取IMU原始数据中的局部特征,借助Transformer编码层捕捉全局时序依赖,通过多头注意力机制实现高效并行计算,从而实现高性能前向速度预测;结合预测前向速度和车辆运动状态构建NHC噪声自适应模型,实现约束参数的动态调整. 实验结果表明,强化模型前向速度的预测精度达0.56 m/s,相较于经典网络,预测精度提高了13.3%,且训练效率提高了8.1%. 在GNSS中断135 s且车辆连续转弯的情况下,本文方法的平面定位精度相较于传统约束方法提升了18.85%,进一步抑制了系统误差发散.

     

    Abstract: Virtual odometer(VODO) and non-holonomic constraint (NHC) can effectively suppress the inertial navigation system (INS) error dispersion during GNSS outage. In recent years, virtual odometer based on machine learning has been widely used in in-vehicle localization, but there are still many limitations on the prediction accuracy and operational efficiency of the existing models. Meanwhile, the fixed noise NHC is difficult to accurately portray complex motion states such as vehicle sideslip. In this paper, we proposes an adaptive INS/NHC localisation method based on the convolutional neuravl network (CNN)/Transformer virtual odometry reinforcement model. The method adopts multi-layer CNN to extract local features in the IMU raw data, captures global timing dependencies with the help of Transformer coding layer, and realises high-performance forward speed budget by efficient parallel computation through multi-attention mechanism; and constructs an adaptive model of NHC noise by combining the predicted forward speed and the vehicle motion state to realise the dynamic adjustment of constraint parameters. The experimental results show that the prediction accuracy of forward speed of the hybrid network reaches 0.56 m/s, and the prediction accuracy and training efficiency are improved by 13.3% and 8.1% respectively compared with the classical network. In the case of 135 seconds of GNSS outages and continuous vehicle turning, the planar positioning accuracy of this paper’s method is improved by 18.85% compared with the traditional constraint method, which effectively suppresses the system error dispersion.

     

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