空间科学学报

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Occultation Distribution and Collaborative Observations of Fengyun Meteorological Satellites and Commercial Satellites

LU Wenqiang, XU Na, CHEN Ran, MENG Xiangguang, LIAO Mi, LIU Yan, TANG Qi, CHENG Yan, YANG Guanglin, HU Xiuqing, ZHAO Xiangang, SUN Yueqiang

, Available online , doi: 10.11728/cjss2026.03.2025-0123

Abstract(384) FullText HTML (173) PDF 26924KB(24)

Abstract:
GNSS Radio Occultation (RO) serves as a key technique for constructing a global high-precision atmospheric and ionospheric sounding capability. China’s operational Fengyun-3 (FY-3) RO system produces data of exceptional quality, characterized by high accuracy, stability, and standardization, making it the current accuracy benchmark in RO sounding. However, due to its orbital configuration, the FY-3 system alone still exhibits coverage gaps in equatorial and polar regions. In recent years, the rapid development of commercial constellations such as Tianmu and Yunyao has enabled multi-source RO cooperative observations, offering a promising approach to enhance the spatiotemporal density of RO data. Based on RO measurements from the FY-3, Tianmu, and Yunyao constellations, this study systematically evaluates the spatial distribution characteristics and joint observation benefits of the three systems. Results demonstrate that integrating commercial constellations significantly increases the number of global RO events and improves coverage at low and high latitudes. Local time coverage is also enhanced from segmented intervals to nearly continuous throughout the day. Despite the considerable improvement in observational density, data overconcentration in certain mid-latitude areas and small-scale gaps under high-resolution analysis remain, indicating that orbital configurations and constellation coordination require further optimization. This study provides quantitative references for the future collaborative development of China’s FY-3 and commercial RO constellations.

Design of Finite Frequency Domain Disturbance Rejection Controller for the Drag-free Spacecraft in Space-borne Gravitational Wave Detection

XU Qianjiao, CUI Bing, WANG Pengcheng, XIA Yuanqing, ZHANG Yonghe

, Available online , doi: 10.11728/cjss2024.05.2024-0022

Abstract(1840) FullText HTML (922) PDF 5881KB(86)

Abstract:
In space-borne gravitational wave detection, there are technical challenges in designing the controller for the drag-free spacecraft with dual test masses. These difficulties arise from constraints within the limited measurement frequency domain and the necessity for a high-precision control index. In this paper, a design method of disturbance rejection controller in the finite frequency domain based on the generalized Kalman-Yakubovich-Popov (GKYP) lemma is proposed. Firstly, to address the performance constraints within the designated frequency band of the detection mission, a finite frequency domain control performance index in the form of a frequency response function is constructed. This index is meticulously developed by amalgamating the sensitivity and complementary sensitivity control indexes. Then, a control structure with fixed-order characteristics for output feedback is proposed, and a method for selecting controller parameters based on the GKYP lemma is established. By this, a finite frequency domain disturbance-resistant controller design method is constructed. In contrast to current drag-free controller design methods, the proposed approach significantly diminishes the conservatism in the control index. This realizes the precise design of the controller in the specified frequency band, ultimately resulting in a reduction in the order of the controller. Finally, numerical simulations demonstrate that the proposed method successfully meets the control performance index for each loop of the drag-free system even in the presence of complex disturbances and noises.