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Search Results: 1 - 10 of 27593 matches for " HU Xiaogong "
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Mars Express tracking and orbit determination trials with Chinese VLBI network
JianFeng Cao,Yong Huang,XiaoGong Hu,MaoLi Ma,WeiMin Zheng
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-4170-8
Abstract: With strong support from European Space Agency (ESA), Shanghai Astronomical Observatory (SHAO) organized a tracking and orbit determination trails using Chinese VLBI Network (CVN) to track Mars Express, the first Mars probe launched by ESA. Using a high-resolution VLBI software correlator and Doppler measurement system developed in-house, two sets of tracking data, VLBI and Doppler, were acquired. The trials represent the first successful foray held in China to track a probe about 360 million kilometers away from the Earth. The tracking data are analyzed using a Mars satellite orbit determination software system developed at SHAO. The results show that the accuracy of 5 s integrated three-way-Doppler data is about 0.3 mm/s, or roughly the same accuracy as ESA’s tracking data. Position discrepancies between the Doppler-based orbit solution of 8 h arc-length (about 1 orbital revolution) and ESA’s reconstructed orbit are of the order of several hundred meters. In preparing for the Russia-China co-sponsored Mars exploration mission Phobos-Grunt-YingHuo, simulations were carried out to evaluate the achievable orbital accuracy levels and the contributions of VLBI and Doppler data respectively. Results show that Doppler data provide better orbit accuracy, so that for VLBI to be able to provide kilometer level orbit solutions, the accuracy of VLBI measurement needs to be improved by at least one order of magnitude.
Precise orbit determination for geostationary satellites with multiple tracking techniques
Rui Guo,XiaoGong Hu,Bo Tang,Yong Huang,Li Liu,LiuCheng Cheng,Feng He
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-0074-x
Abstract: A new precise orbit determination (POD) strategy based on the combination of satellite laser ranging (SLR) and C-band transfer ranging for geostationary satellites (GEO) is presented. Two approaches to calibrate ranging biases of the C-band ranging system are proposed, namely the two tracking system co-location comparison and the combined POD method, with calibration accuracies estimated to be 0.5 ns and 1 ns respectively. Using data from a C-band tracking network in China, POD experiments indicate that meter-level POD accuracy is achievable for GEO. Root-mean-square (RMS) of the post-fit C-band ranging data is about 0.205 m. The radial component errors of POD are evaluated with SLR data from a station in Beijing, with residual RMS of 0.133 m. Orbital overlapping experiments show the total orbit error is a few meters. Computations of SLR residuals also suggest that for 2-hour prediction, the predicted radial error is about 0.373 m.
Precise positioning of the Chang’E-3 lunar lander using a kinematic statistical method
Yong Huang,XiaoGong Hu,PeiJia Li,JianFeng Cao,DongRong Jiang,WeiMin Zheng,Min Fan
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5484-5
Abstract: A kinematic statistical method is proposed to determine the position for Chang’E-3 (CE-3) lunar lander. This method uses both ranging and VLBI measurements to the lander for a continuous arc, combing with precise knowledge about the motion of the moon as provided by planetary ephemeris, to estimate the lander’s position on the lunar surface with high accuracy. Accuracy analyses are carried out with simulation data using the software developed at Shanghai Astronomical Observatory in this study to show that measurement errors will dominate the position accuracy. Application of lunar digital elevation model (DEM) as constraints in the lander positioning is also analyzed. Simulations show that combing range/doppler and VLBI data, single epoch positioning accuracy is at several hundred meters level, but with ten minutes data accumulation positioning accuracy is able to be achieved with several meters. Analysis also shows that the information given by DEM can provide constraints in positioning, when DEM data reduce a 3-dimensional positioning problem to 2-dimensional. Considering the Sinus Iridum, CE-3 lander’s planned landing area, has been observed with dedicated details during the CE-1 and CE-2 missions, and its regional DEM model accuracy may be higher than global models, which will certainly support CE-3’s lander positioning.
Improvement of orbit determination for geostationary satellites with VLBI tracking
Yong Huang,XiaoGong Hu,XiuZhong Zhang,DongRong Jiang,Rui Guo,Hong Wang,ShanBin Shi
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4647-0
Abstract: China’s COMPASS satellite navigation system consists of five or more geostationary (GEO) satellites. The roles of GEO satellites are to improve the regional user’s positioning accuracy and provide the continuous Radio Determination Satellite Service. The motion of GEO satellites relative to a ground tracking station is almost fixed, and regular orbit maneuvers are necessary to maintain the satellites’ allocated positions above the equator. These features present difficulties in precise orbit determination (POD). C-band ranging via onboard transponders and the L-band pseudo-ranging technique have been used in the COMPASS system. This paper introduces VLBI tracking, which has been successfully employed in the Chinese lunar exploration programs Chang’E-1 and Chang’E-2, to the POD of GEO satellites. In contrast to ranging, which measures distances between a GEO satellite and an observer, VLBI is an angular measurement technique that constrains the satellite’s position errors perpendicular to the satellite-to-observer direction. As a demonstration, the Chinese VLBI Network organized a tracking and orbit-determination experiment for a GEO navigation satellite lasting 24 h. This paper uses the VLBI delay and delay-rate data, in combination with C-band ranging data, to determine the GEO satellite’s orbit. The accuracies of the VLBI delay and delay rate data are about 3.6 ns and 0.4 ps/s, respectively. Data analysis shows that the VLBI data are able to calibrate systematic errors of the C-band ranging data, and the combination of the two observations improves orbit prediction accuracy with short-arc data, which is important for orbital recovery after maneuvers of GEO satellites. With the implementation of VLBI2010, it is possible for VLBI to be applied in the COMPASS satellite navigation system.
Accuracy of dynamic orbit determination using rebuilt space-borne\nGPS pseudo-range measurements from real-time navigation solutions
星载GPS 伪距观测量重建及定轨精度分析

PENG Dongju,HU Xiaogong,WU Bin,

遥感学报 , 2010,
Abstract: The method to rebuild space-borne pseudo-range measurements from real-time position data is discussed first in this paper. And then, the accuracy of dynamic orbit determination using rebuilt pseudo-range measurements and precise GPS ephemeris is analyzed in detail. Data from GRACE-A satellite from March 1 to 14 in 2008 is processed for this purpose. Research results show that the accuracy of real-time single point positioning using C/A code pseudo-range measurements and GPS broadcast ephemeris is about 15m, and the accuracy of dynamic orbit determination in post-processing mode is about 2m. It is demonstrated that dynamic orbit determination using rebuilt pseudo-range measurements in post-processing mode can not only significantly improve the position accuracy of real-time navigation solutions, but also provide consecutive satellite orbits.
Precise orbit determination for geostationary satellites with multiple tracking techniques

GUO Rui,HU XiaoGong,TANG Bo,HUANG Yong,LIU Li,CHENG LiuCheng &,HE Feng,

科学通报(英文版) , 2010,
Abstract: A new precise orbit determination (POD) strategy based on the combination of satellite laser ranging (SLR) and C-band transfer ranging for geostationary satellites (GEO) is presented.Two approaches to calibrate ranging biases of the C-band ranging system are proposed,namely the two tracking system co-location comparison and the combined POD method,with calibration accuracies estimated to be 0.5 ns and 1 ns respectively.Using data from a C-band tracking network in China,POD experiments indicate that meter-le...
Analysis on Orbit Determination of CE-3 with Different Lunar Gravity Field Model

昌胜骐, 黄勇, 李培佳, 胡小工
CHANG Shengqi
, HUANG Yong, LI Peijia, HU Xiaogong

- , 2016, DOI: 10.13203/j.whugis20140332
Abstract: 利用最新的月球重力场模型GL0660b对嫦娥三号探测器定轨的影响进行分析,并与LP150Q和SGM150模型进行了比较。首先计算了三个重力场模型的功率谱,分析了系数阶方差和误差阶方差的性质,GL0660b大大提升了月球重力场模型的阶数和解算精度;然后讨论了各模型在月球外部空间不同高度处截断到不同阶次的重力异常分布。利用这三个重力场模型对嫦娥三号环月期间的轨道进行解算,计算结果表明,利用GL0660b模型截断至150阶次,100 km×100 km轨道重叠弧段精度约为22 m,和LP150Q,SGM150全阶次模型精度相当;对于100 km×15 km轨道,GL0660b模型截断至360阶次,重叠弧段精度约为21 m,优于LP150Q和SGM150计算结果
Sidereal Filtering Based on Sphere Multipath Stacking and Its Application in PPP

王琰, 张传定, 胡小工, 朱凌凤, 冯炜, 常志巧
, ZHANG Chuanding, HU Xiaogong, ZHU Lingfeng, FENG Wei, CHANG Zhiqiao

- , 2018, DOI: 10.13203/j.whugis20160454
Abstract: 针对传统的观测值域恒星日滤波在卫星精密单点定位(precise point positioning,PPP)应用中存在的问题,提出球面多路径格网的恒星日滤波算法并应用到静态PPP中,设计了确定格网大小的统计方法,给出了算法的实施步骤。利用全球分布的10个IGS监测站接收的GPS卫星实测数据进行了试验验证,结果表明,本文算法能够明显削弱地面连续运行监测站载波相位观测量的多路径误差;应用本文算法后,1~3 h的静态PPP定位精度得到明显提高,E、N、U三方向RMS分别提高41.59%、38.60%、36.96%
Geodesic and Contour Optimization Using Conformal Mapping
Ricky Fok,Aijun An,Xiaogong Wang
Statistics , 2015,
Abstract: We propose a novel optimization algorithm for continuous functions using geodesics and contours under conformal mapping.The algorithm can find multiple optima by first following a geodesic curve to a local optimum then traveling to the next search area by following a contour curve. To improve the efficiency, Newton-Raphson algorithm is also employed in local search steps. A proposed jumping mechanism based on realized geodesics enables the algorithm to jump to a nearby region and consequently avoid trapping in local optima. Conformal mapping is used to resolve numerical instability associated with solving the classical geodesic equations. Geodesic flows under conformal mapping are constructed numerically by using local quadratic approximation. The parameters in the algorithm are adaptively chosen to reflect local geometric features of the objective function. Comparisons with many commonly used optimization algorithms including gradient, trust region, genetic algorithm and global search methods have shown that the proposed algorithm outperforms most widely used methods in almost all test cases with only a couple of exceptions.
Modeling and Precision Analysis of Solar Radiation Pressure for BDS Hybrid Constellation

李冉, 胡小工, 唐成盼, 周善石, 潘军洋, 刘利, 李晓杰
LI Ran
, HU Xiaogong, TANG Chengpan, ZHOU Shanshi, PAN Junyang, LIU Li, LI Xiaojie

- , 2018, DOI: 10.13203/j.whugis20160380
Abstract: 卫星帆板及本体受照情况变化复杂,导致卫星光压摄动力的变化难以准确模制,既是动力学定轨的最大误差源,也是定轨预报精度降低的主要原因。针对此问题,采用北斗地面系统的区域监测网数据,详细比较了3种主要的经验模型(T20模型、ECOM5参数模型、ECOM9参数模型)对不同卫星的适用性情况。结果显示,在春秋分前后,地球同步轨道(geosynchronous earth orbit,GEO)卫星使用ECOM9参数模型最好,其解算的卫星钟差与星地双向钟差的互差标准差优于2 ns;对于倾斜地球同步轨道(inclined geosynchronous satellite orbit,IGSO)卫星和中地球轨道(medium earth orbit,MEO)卫星,无论是在动偏期间还是姿态模式转换期间,T20模型表现出更好的适用性。不同于此前国内外学者的相关研究,试验表明,对BDS混合星座的不同类型卫星、同一卫星的不同时段,应采用不同的经验太阳光压模型,以获得更高的定轨和预报精度
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