CMC在航天领域的应用

论述了陶瓷基复合材料在航天领域的研究与应用,主要从陶瓷基复合材料的优势特点、制备方法、国内外研究进展以及CMC在航天型号产品上应用需要突破的难点和技术关键等五个方面进行了详细论述和介绍,提出了发展趋势和研究方向.     

星载双频GPS相位历元差缩减动力学定轨(英文)

研究了星载双频GPS相位历元差缩减动力学定轨方法,该方法既克服了相位历元差运动学方法在观测几何较差或数据不足情况下无法应用的缺点,又避免了相位非差动力学方法易受周跳和模糊度影响的缺点。历元差方法对相位周跳的影响不敏感,因此能够降低相位数据预处理中周跳探测的难度。在模型求解过程中,解决了高维矩阵的计算问题,将长弧段观测数据分成若干短弧段,相邻两个短弧段的连接处不做差分,仅在每个短弧段内部进行历元间差分处理。通过对GRACE卫星进行试算,并与GFZ事后科学轨道进行比较,结果表明相位历元差缩减动力学定轨精度在径向、沿迹方向和轨道法向分别可达1.92cm、3.83cm和3.80cm,三维位置精度可达5.76cm,该方法与相位非差缩减动力学定轨精度相当。     

Study of the seasonal ozone variations at European high latitudes

The geographic area at high latitudes beyond the polar circle is characterized with long darkness during the winter (polar night) and with a long summertime insolation (polar day). Consequentially, the polar vortex is formed and the surrounding strong polar jet is characterized by a strong potential vorticity gradient representing a horizontal transport barrier. The ozone dynamics of the lower and middle stratosphere is controlled both by chemical destruction processes and transport processes.     

基于MATLAB与ODTK的卫星轨道确定精度仿真分析方法

在航天器轨道确定中,观测数据处理是一项繁杂的工作。介绍了以MATLAB对轨道确定工具箱Orbit Determination Tool Kit(ODTK)进行脚本控制的方法和步骤,并以最小二乘法为例,进行卫星轨道确定精度仿真分析。通过仿真算例分析,表明利用MATLAB与ODTK进行联合仿真能够快速、有效地进行卫星轨道确定数据处理。     

基于盒粒子滤波的低成本皮纳卫星高效姿态确定算法

针对低成本皮纳卫星姿态确定系统在质量、体积、计算量以及能耗等方面的限制问题,本文基于区间分析理论提出了卫星姿态区间化描述方法并建立了运动学区间化方程,提出了基于盒粒子滤波(BPF)的皮纳卫星姿态确定算法。该算法首先采用双矢量算法对太阳敏感器和磁强计得到的量测进行姿态解算,并将解算出的姿态四元数作为伪量测值输入传递给BPF,从而降低敏感器噪声对估计精度的影响。仿真实验表明,相比于传统粒子滤波的姿态确定算法,本文所提出的BPF姿态确定算法能够在保证姿态确定精度的同时大幅缩短算法运行时间。     

采用简化滤波器思想的卫星姿态确定系统故障诊断

针对星上计算机运算资源有限的问题,为了降低卫星姿态确定系统故障诊断的运算量,提出一种基于卡尔曼滤波器的故障检测与分离方法。该方法首先基于卫星姿态运动方程设计了一种加性卡尔曼滤波器,然后将卡尔曼滤波器与简化观测器思想相结合,进一步提出一种采用简化滤波器思想的姿态敏感器故障诊断律。所提出的故障诊断方法既可以实现对陀螺故障的检测与分离,又能够诊断星敏感器的故障。此外,该方法只利用一个滤波器即可实现故障检测与分离,其计算量小,有利于在轨实施。最终采用一个由三正交一斜装陀螺组件和星敏感器构成的姿态确定系统对所提出的方法进行了仿真校验,仿真结果表明了所提方法的有效性。     

高超声速飞行器新型热防护机制研究进展

从气动热载荷的来源出发,介绍了基于流动控制、光辐射操控、原子重组、电子耗散等物理机制的新型热防护机制的原理和进展.分别从环境和材料两方面实现对流热、化学热和辐射热的主动调控,进一步分析了高超声速飞行器新型热防护机制发展的特点和不足,对该领域未来研究的重点方向提出了建议.     

Track-to-object association algorithm based on TLE filtering

This paper focuses on the track-to-object association problem based on the two-line elements (TLE) set. The TLE’s short-term propagation error characteristics are analyzed to capture its uncertainty. Further, a four-step track-to-object association algorithm is designed for the optical observation data. First, for too-short arc tracklets, a circular orbit determination algorithm is proposed to calculate the inclination and the right ascension of the ascending node. Second, the TLEs are filtered based on these results. Nearly 96% of the TLEs can be filtered, which significantly improves the association efficiency. The last two steps consist of two association processes. A first-order association process is implemented first to get candidate objects, with the angles root mean square error as the metric. Then a precise association process checks the candidate objects and gives the final association result. The proposed approach is tested with simulated and observed data, respectively. With simulated data, the true positive rate is 98.7%. With the observed data, the association results were validated using the precise orbit ephemerides.     

Attitude analysis of space debris using SLR and light curve data measured with single-photon detector

Attitude is the important parameter for active debris removal and collision avoidance. This paper deduced the spin axis orientation and spin period of the rocket body, CZ-3B R/B (NORAD ID 38253), using the satellite laser ranging and light curve data measured with single-photon detector at Graz station. The epoch method and LC & SLR residuals fitting were combined to determine these values. The derived right ascension angle was around 220°, the declination angle was near 64° and the sidereal period was calculated to be 117.724 s, for 2017-07-03. The results derived from the two distinct methods were mutually validated. Rocket bodies are a major contributor to space debris and this work provides a reference for attitude determination and attitude modelling.     

CE5T拓展试验轨道精度分析

针对嫦娥5T服务舱(CE5T)拓展试验中的绕地大椭圆轨道,分析了轨道动力学演化趋势,通过测轨数据类型组合策略分析了统一S频段测量(USB)和甚长基线干涉测量(VLBI)在定轨中的贡献,得到了百米级的精密定轨精度;针对地月第二平动点(L2)绕飞轨道,分析了地心和月心积分的轨道动力学差异,制定了精密定轨的参数求解策略,得到了百米级的精密定轨精度;针对月球交会对接轨道的特点,选取三种不同的重力场模型定轨,比较了三者在轨道预报和数据拟合的差异,并与嫦娥3号(CE3)环月轨道的定轨精度进行比对,验证了不同重力场的适用范围,从计算精度和效率两方面制定了优化的定轨策略。