论文标题
Beidou-G2:过去和现在
BeiDou-G2: Past and Present
论文作者
论文摘要
储层计算是预测湍流的有力工具,其简单的架构具有处理大型系统的计算效率。然而,其实现通常需要完整的状态向量测量和系统非线性知识。我们使用非线性投影函数将系统测量扩展到高维空间,然后将其输入到储层中以获得预测。我们展示了这种储层计算网络在时空混沌系统上的应用,该系统模拟了湍流的若干特征。我们表明,使用径向基函数作为非线性投影器,即使只有部分观测并且不知道控制方程,也能稳健地捕捉复杂的系统非线性。最后,我们表明,当测量稀疏、不完整且带有噪声,甚至控制方程变得不准确时,我们的网络仍然可以产生相当准确的预测,从而为实际湍流系统的无模型预测铺平了道路。
In January 2022, the defunct satellite BeiDou-G2 was pulled out of geostationary orbit by Shijian-21 to a graveyard orbit. For safe docking and operation, it was necessary to determine the rotation state in advance. In this paper, we show the evolution of the rotation of the BeiDou-G2 satellite based on the photometry observation data for the past 10 years. The rotational speed of BeiDou-G2 was found to be annual oscillation, mainly due to the solar radiation. Based on the evolution of BeiDou-G2's rotation speed and its orbit, we confirmed that in the last 10 years, the satellite had six abnormal events. These abnormal events were mainly due to the increase in the rotation speed caused by suspected fuel leakages. Additionally, the abnormal events included one collision in 2012, which was inferred to be the trigger of the fuel leakages in the following years. No rotational speed abnormalities occurred again after 2017, probably due to the complete release of the residual fuel. The parameters and the propagating models after one incidence of solar panel damage in 2014 and one fragment in 2016, with the standard errors for propagating over 1 year of the rotational axis less than 3° and rotational speed being 0.11°/s, were believed to be able to satisfy the accuracy requirements of the rotation state well at the moment of docking.