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基于特征锚点跟踪的小行星着陆导航方法研究

Feature Anchor Point Tracking-Based Navigation for Asteroid Landing

  • 摘要: 针对小行星探测器在下降着陆段对高精度实时自主导航的任务需求,综合考虑星载计算资源受限与小行星复杂地表环境因素等,提出了一种基于特征锚点跟踪的小行星着陆自主导航方法。利用3DSIFT算法从小行星三维点云数据中提取初始特征点,并通过空间分布特征筛选机制选取具有高辨识度的特征锚点,为后续视觉跟踪提供精确的三维定位参考基准;采用轻量级卷积神经网络直接检测并跟踪特征锚点在图像序列中的二维投影,避免了传统方法中计算密集的特征匹配步骤,在保证导航精度的同时显著降低了计算复杂度;基于建立的2D-3D点对应关系,基于EPnP方法实现探测器位姿参数的精准估计。通过软件仿真和半物理试验验证,该方法在保证位姿估计精度的同时,可有效降低导航系统的许用算力,为小行星探测下降着陆段的自主导航提供了一种高效可靠的解决方案。

     

    Abstract: In response to the task requirements of high-precision real-time autonomous navigation for the asteroid probe during the descent and landing phase, considering the limited onboard computing resources and the complex terrain environment of the asteroid, this paper proposes a feature anchor point tracking-based autonomous landing navigation method. Firstly, the 3DSIFT algorithm is used to extract initial feature points from the three-dimensional point cloud data of the asteroid, and the spatial distribution feature selection mechanism is adopted to select feature anchors with high recognition degree, providing an accurate three-dimensional reference benchmark for subsequent visual tracking. On this basis, a lightweight convolutional neural network is used to directly detect and track the two-dimensional projections of the feature anchors in the image sequence, avoiding the computationally intensive feature matching steps in traditional methods, while ensuring navigation accuracy and significantly reducing computational complexity. Finally, based on the established 2D-3D point correspondence relationship, the asteroid lander’s pose parameters are accurately estimated using the EPnP method. Through software simulation and semi-physical experiments, it is verified that this method can effectively reduce the allowable computing power of the navigation system while ensuring the accuracy of pose estimation, providing an efficient and reliable solution for the autonomous navigation of the probe during the descent and landing phase of asteroid exploration.

     

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