Subjects: Astronomy >> Astrophysical processes submitted time 2022-07-29 Cooperative journals: 《天文研究与技术》
Abstract： In order to solve the problem of non-uniform temperature thermal deformation caused by antenna alidade under solar radiation, environmental parameters, solar irradiation parameters and the geometric model of the alidade structure are derived, and the thermodynamic simulation of antenna alidade structure under multiply operating conditions is realized, and Based on the integrated model, the temperature characteristics of antenna alidade are analyzed. 24 fiber Bragg grating temperature sensors are installed on the antenna alidade structure, and the relative accuracy of the measured temperature and the simulated temperature field is higher than 85%, which verifies the correctness of the simulation method. Combined with the geometric relationship between the shift field of the antenna structure and the data of the deviation of the antenna azimuth axis and the measured temperature characteristic data, the rapid calculation of the deformation from measured temperature to the alidade structure is realized, and the causes of the deviation of the antenna alidade shaft are analyzed.
Subjects: Astronomy >> Astrophysical processes submitted time 2022-06-28 Cooperative journals: 《天文研究与技术》
Abstract：我国探月工程嫦娥七号将构建由中继星上4.1m口径抛物面天线及地基射电望远镜组成的首个月地空间甚长基线干涉测量（Very Long Baseline Interferometry, VLBI)试验系统。不同于地基甚长基线干涉测量望远镜，受中继星轨道扰动和设备时延影响，射电源预报时延模型和实际时延有时可能会有较大差异，导致无法引导VLBI相关处理机正常工作，需要通过射电源条纹搜索方法寻找实际时延模型才能解决这一问题。由于4.1m空间天线口径较小，接收信号能力弱。为提高信噪比，需要长时间积分，而线性时延模型无法保证长时间的时延精度。针对这一问题，提出了一种用于空间甚长基线干涉测量的射电源条纹搜索算法，首先通过建立时延和时延率的二维搜索网格，使用每个网格点对应的先验时延和时延率构建线性时延模型；再使用该线性时延模型对原始数据分时段相关处理；然后采用二维傅里叶变换搜索残余时延和时延率，确定最大的相关幅度值对应的网格点；最后使用该网格点的先验时延和时延率以及残余时延和时延率重构二次项时延模型。通过对RadioAstron空间甚长基线干涉测量的地空基线实际数据处理，验证了该射电源条纹搜索算法的正确性。
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