关键词: 多传感器融合, 连续时间状态估计, 均匀B样条, 运动轨迹参数化, 位姿估计

Abstract:

Multi-sensor fusion effectively mitigates the limitations of individual navigation techniques, significantly enhancing the availability and reliability of navigation systems in complex environments. Conventional approaches for navigation parameter estimation, such as Kalman filtering and least-squares optimization, are predominantly based on discrete-time state models. These methods exhibit inherent limitations when dealing with asynchronous, multi-rate, and high-frequency sensor data. This paper proposes a continuous-time state estimation framework that employs uniform B-splines to parameterize the motion trajectory of the vehicle. By doing so, the original discrete pose estimation problem is transformed into the estimation of B-spline control points. The continuous-time analytical expression of the trajectory enables direct derivation to establish observation models that relate inertial measurement unit (IMU) outputs (i.e., acceleration and angular velocity) to the spline control points, thereby avoiding the precision degradation and noise property alterations associated with traditional inertial navigation system (INS) integration. Similarly, measurements from other sensors, such as position and velocity from GNSS, are also formulated as observation equations with respect to the spline control points, leading to a unified optimization problem. Simulation experiments demonstrate that the proposed method yields pose estimates with reduced high-frequency noise influence and improved smoothness. Specifically, it achieves a 41.4% improvement in positioning accuracy and a 35.0% improvement in attitude determination accuracy. During GNSS signal outages, the new approach shows slower error growth, reducing the maximum horizontal positioning error from 17.4 cm to 7.29 cm. In segments with missing IMU data, the method eliminates the need for data interpolation, enhancing positional accuracy by nearly twice and attitude accuracy by nearly fourfold. Experiments using real-world datasets further validate the effectiveness of the proposed method, showing that it maintains high performance even in complex environments, with positioning accuracy improved by 30.0% and attitude accuracy improved by 69.6%.

Key words: multi-sensor fusion, continuous-time state estimation, uniform B-splines, motion trajectory parameterization, pose estimation