In the study, position and velocity values of a geostationary satellite are found. When performing this, a MATLAB algorithm is used for Runge-Kutta Fehlberg orbit integration method to solve spacecraft’s position and...In the study, position and velocity values of a geostationary satellite are found. When performing this, a MATLAB algorithm is used for Runge-Kutta Fehlberg orbit integration method to solve spacecraft’s position and velocity. Integrated method is the solution for the systems which mainly work with a single station. Method provides calculation of azimuth, elevation and range data by using the position simulation results found by RKF. Errors of orbit determination are analysed. Variances of orbit parameters are chosen as the accuracy criteria. Analysis results are the indicator of the method’s展开更多
The results of cross-correlation analysis between electrons fluxes (with energies of > 0.6 MeV,> 2.0MeV and > 4.0MeV), geomagnetic indices and solar wind parameters are shown in the paper. It is determined that the...The results of cross-correlation analysis between electrons fluxes (with energies of > 0.6 MeV,> 2.0MeV and > 4.0MeV), geomagnetic indices and solar wind parameters are shown in the paper. It is determined that the electron fluxes are controlled not only by the geomagnetic indices, but also by the solar wind parameters, and the solar wind velocity demonstrates the best relation with the electron fluxes.Numerical value of the relation efficiency of external parameters with the highly energetic electrons fluxes shows a periodicity. It is presented here the preliminary results of daily averaged electrons fluxes forecast for a day ahead on the basis of the model of neuron networks.展开更多
联合甚长基线干涉测量(very long baseline interferometry,VLBI)时延数据与转发式(orbit determination by transfer tracking,ODTT)测距数据能够有效提高地球静止轨道(geostationary earth orbit,GEO)卫星定轨精度。参照位置精度衰减...联合甚长基线干涉测量(very long baseline interferometry,VLBI)时延数据与转发式(orbit determination by transfer tracking,ODTT)测距数据能够有效提高地球静止轨道(geostationary earth orbit,GEO)卫星定轨精度。参照位置精度衰减因子(position dilution of precision,PDOP)的改变,研究不同VLBI基线时延数据与转发式测距数据的联合对GEO卫星定轨精度的改善,可为特定条件下联合观测时VLBI基线的最优选择提供参考。基于中国科学院国家授时中心宽带VLBI系统和转发式测轨系统的实测数据,开展中星12号GEO卫星的定轨试验。试验结果表明定轨精度的提高与PDOP的降低成正相关。相比于转发式单独定轨,联合VLBI系统中的喀什—三亚基线,PDOP降低了3.00,定轨精度提高了11.48%;联合VLBI系统中的吉林—喀什基线,PDOP降低了3.38,定轨精度提高了14.73%;联合VLBI系统中的吉林—三亚基线,PDOP降低了6.90,定轨精度提高了19.75%;联合VLBI系统中的吉林—三亚和吉林—喀什两条基线,PDOP降低了9.94,定轨精度提高了27.23%。展开更多
连线干涉测量(Connected Element Interferometry,CEI)是一种全天时全天候的被动测角技术,已用于空间目标的跟踪监视.地球静止轨道(Geostationary Earth Orbit,GEO)卫星需要频繁机动以保持轨位或完成其他任务,其机动后的快速轨道恢复能...连线干涉测量(Connected Element Interferometry,CEI)是一种全天时全天候的被动测角技术,已用于空间目标的跟踪监视.地球静止轨道(Geostationary Earth Orbit,GEO)卫星需要频繁机动以保持轨位或完成其他任务,其机动后的快速轨道恢复能力对于监视预警极为重要.针对基于CEI的GEO短弧定轨和预报,分析了定轨算法的形亏和数亏,在附加先验轨道约束的短弧定轨基础上,提出了轨道半长轴初值的自适应优化方法.利用亚太七号卫星的CEI仿真和实测数据进行了短弧定轨和预报,实验结果表明,采用优化后的半长轴初值,30min短弧定轨和10min预报的卫星位置分量精度均优于4km,能够满足非合作GEO目标机动后快速轨道恢复的需求.展开更多
In the past few decades, applications of geostationary orbit (GEO) satellites have attracted increasing attention, and with the development of optical technologies, GEO optical satellites have become popular worldwide...In the past few decades, applications of geostationary orbit (GEO) satellites have attracted increasing attention, and with the development of optical technologies, GEO optical satellites have become popular worldwide. This paper proposes a general working pattern for a GEO optical satellite, as well as a target observation mission planning model. After analyzing the requirements of users and satellite control agencies, two objectives are simultaneously considered: maximization of total profit and minimization of satellite attitude maneuver angle. An NSGA-II based multi-objective optimization algorithm is proposed, which contains some heuristic principles in the initialization phase and mutation operator, and is embedded with a traveling salesman problem (TSP) optimization. The validity and performance of the proposed method are verified by extensive numerical simulations that include several types of point target distributions.展开更多
This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary orbit.The Earth’s oblateness perturbation and shadow are taken into acco...This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary orbit.The Earth’s oblateness perturbation and shadow are taken into account.It is difficult for a Lyapunov-based or trajectory-tracking guidance method to possess multiple characteristics at the same time,including high guidance optimality,robustness,and onboard computational efficiency.In this work,a concise relationship between the minimum-time transfer problem with orbital averaging and its optimal solution is identified,which reveals that the five averaged initial costates that dominate the optimal thrust direction can be approximately determined by only four initial modified equinoctial orbit elements after a coordinate transformation.Based on this relationship,the optimal averaged trajectories constituting the training dataset are randomly generated around a nominal averaged trajectory.Five polynomial regression models are trained on the training dataset and are regarded as the costate estimators.In the transfer,the spacecraft can obtain the real-time approximate optimal thrust direction by combining the costate estimations provided by the estimators with the current state at any time.Moreover,all these computations onboard are analytical.The simulation results show that the proposed guidance scheme possesses extremely high guidance optimality,robustness,and onboard computational efficiency.展开更多
Global navigation satellite system occultation sounder (GNOS) Fengyun-3C was launched successfully on September 23, 2013, which carried GPS/BDS receiver for the first time. This provides the convenience to study the e...Global navigation satellite system occultation sounder (GNOS) Fengyun-3C was launched successfully on September 23, 2013, which carried GPS/BDS receiver for the first time. This provides the convenience to study the enhancement results of low earth orbiter satellite (LEO) to BDS precise orbit determination (POD). First the data characteristic and code observation noise of GNOS are analyzed. Then the enhancement experiments in the case of global and regional ground observation stations layout are processed with four POD schemes: BDS single system, GPS/BDS double system, BDS single system with GNOS observations, GPS/BDS double system with GNOS observations. The precision of BDS orbits and clocks are compared via overlapping arcs. Results show that in the case of global station layout the along directional precision of GEO satellite has the biggest improvement, with the improvement percentage 60%. Then the precision of cross direction and the along direction of remaining satellites shows the second biggest improvement. The orbit precision of BDS-only POD in part of observation arcs some satellite even suffers a slight decline. The root mean square (RMS) of overlapping clock difference of visible arcs in GPS/BDS POD experiments improves by 0.1 ns level. As to the experiments of regional station layout with 7 ground stations, the orbit and clock overlapping precision and orbit predicting precision are analyzed. Results show that the predicting precision of BDS GEO satellites in the along direction improves by 85%. The remaining also has a substantial improvement, with the average percentage 21.7%. RMS of overlapping clock difference of visible arcs improves by 0.5 ns level.展开更多
Positioning accuracy of the Global Navigation Satellite System(GNSS) can be analyzed by Positioning Dilution Of Precision(PDOP).In order to enhance the navigating performance of Asia and the Pacific areas,this paper a...Positioning accuracy of the Global Navigation Satellite System(GNSS) can be analyzed by Positioning Dilution Of Precision(PDOP).In order to enhance the navigating performance of Asia and the Pacific areas,this paper analyzes the next generation BeidouTM navigation satellite system(CompassTM) enhanced by Geostationary Earth Orbit(GEO) and Inclining GeoSynchronized Orbit(IGSO).As global navigation satellite system,CompassTM must be robust enough to avoid system layoff,when some nodes are not available.So,the CompassTM enhanced by GEO and IGSO constellation is proposed and analyzed its PDOP proformance,this paper shows some exciting results of performance of CompassTM enhanced by GEO and IGSO.From the simulation results,we can found that:when more than fifteen satellites are invalid,the enhanced system could be operating normally.展开更多
文摘In the study, position and velocity values of a geostationary satellite are found. When performing this, a MATLAB algorithm is used for Runge-Kutta Fehlberg orbit integration method to solve spacecraft’s position and velocity. Integrated method is the solution for the systems which mainly work with a single station. Method provides calculation of azimuth, elevation and range data by using the position simulation results found by RKF. Errors of orbit determination are analysed. Variances of orbit parameters are chosen as the accuracy criteria. Analysis results are the indicator of the method’s
基金Supported by the China-Russia Joint Research Center on Space Weather,Chinese Academy of Sciences
文摘The results of cross-correlation analysis between electrons fluxes (with energies of > 0.6 MeV,> 2.0MeV and > 4.0MeV), geomagnetic indices and solar wind parameters are shown in the paper. It is determined that the electron fluxes are controlled not only by the geomagnetic indices, but also by the solar wind parameters, and the solar wind velocity demonstrates the best relation with the electron fluxes.Numerical value of the relation efficiency of external parameters with the highly energetic electrons fluxes shows a periodicity. It is presented here the preliminary results of daily averaged electrons fluxes forecast for a day ahead on the basis of the model of neuron networks.
文摘联合甚长基线干涉测量(very long baseline interferometry,VLBI)时延数据与转发式(orbit determination by transfer tracking,ODTT)测距数据能够有效提高地球静止轨道(geostationary earth orbit,GEO)卫星定轨精度。参照位置精度衰减因子(position dilution of precision,PDOP)的改变,研究不同VLBI基线时延数据与转发式测距数据的联合对GEO卫星定轨精度的改善,可为特定条件下联合观测时VLBI基线的最优选择提供参考。基于中国科学院国家授时中心宽带VLBI系统和转发式测轨系统的实测数据,开展中星12号GEO卫星的定轨试验。试验结果表明定轨精度的提高与PDOP的降低成正相关。相比于转发式单独定轨,联合VLBI系统中的喀什—三亚基线,PDOP降低了3.00,定轨精度提高了11.48%;联合VLBI系统中的吉林—喀什基线,PDOP降低了3.38,定轨精度提高了14.73%;联合VLBI系统中的吉林—三亚基线,PDOP降低了6.90,定轨精度提高了19.75%;联合VLBI系统中的吉林—三亚和吉林—喀什两条基线,PDOP降低了9.94,定轨精度提高了27.23%。
文摘连线干涉测量(Connected Element Interferometry,CEI)是一种全天时全天候的被动测角技术,已用于空间目标的跟踪监视.地球静止轨道(Geostationary Earth Orbit,GEO)卫星需要频繁机动以保持轨位或完成其他任务,其机动后的快速轨道恢复能力对于监视预警极为重要.针对基于CEI的GEO短弧定轨和预报,分析了定轨算法的形亏和数亏,在附加先验轨道约束的短弧定轨基础上,提出了轨道半长轴初值的自适应优化方法.利用亚太七号卫星的CEI仿真和实测数据进行了短弧定轨和预报,实验结果表明,采用优化后的半长轴初值,30min短弧定轨和10min预报的卫星位置分量精度均优于4km,能够满足非合作GEO目标机动后快速轨道恢复的需求.
基金supported by the National Natural Science Foundation of China(7150118061473301)
文摘In the past few decades, applications of geostationary orbit (GEO) satellites have attracted increasing attention, and with the development of optical technologies, GEO optical satellites have become popular worldwide. This paper proposes a general working pattern for a GEO optical satellite, as well as a target observation mission planning model. After analyzing the requirements of users and satellite control agencies, two objectives are simultaneously considered: maximization of total profit and minimization of satellite attitude maneuver angle. An NSGA-II based multi-objective optimization algorithm is proposed, which contains some heuristic principles in the initialization phase and mutation operator, and is embedded with a traveling salesman problem (TSP) optimization. The validity and performance of the proposed method are verified by extensive numerical simulations that include several types of point target distributions.
基金supported by the National Natural Science Foundation of China(No.12022214)the National Key R&D Program of China(No.2020YFC2201200)。
文摘This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary orbit.The Earth’s oblateness perturbation and shadow are taken into account.It is difficult for a Lyapunov-based or trajectory-tracking guidance method to possess multiple characteristics at the same time,including high guidance optimality,robustness,and onboard computational efficiency.In this work,a concise relationship between the minimum-time transfer problem with orbital averaging and its optimal solution is identified,which reveals that the five averaged initial costates that dominate the optimal thrust direction can be approximately determined by only four initial modified equinoctial orbit elements after a coordinate transformation.Based on this relationship,the optimal averaged trajectories constituting the training dataset are randomly generated around a nominal averaged trajectory.Five polynomial regression models are trained on the training dataset and are regarded as the costate estimators.In the transfer,the spacecraft can obtain the real-time approximate optimal thrust direction by combining the costate estimations provided by the estimators with the current state at any time.Moreover,all these computations onboard are analytical.The simulation results show that the proposed guidance scheme possesses extremely high guidance optimality,robustness,and onboard computational efficiency.
基金The National Natural Science Foundation of China (41674016,41274016,41604024).
文摘Global navigation satellite system occultation sounder (GNOS) Fengyun-3C was launched successfully on September 23, 2013, which carried GPS/BDS receiver for the first time. This provides the convenience to study the enhancement results of low earth orbiter satellite (LEO) to BDS precise orbit determination (POD). First the data characteristic and code observation noise of GNOS are analyzed. Then the enhancement experiments in the case of global and regional ground observation stations layout are processed with four POD schemes: BDS single system, GPS/BDS double system, BDS single system with GNOS observations, GPS/BDS double system with GNOS observations. The precision of BDS orbits and clocks are compared via overlapping arcs. Results show that in the case of global station layout the along directional precision of GEO satellite has the biggest improvement, with the improvement percentage 60%. Then the precision of cross direction and the along direction of remaining satellites shows the second biggest improvement. The orbit precision of BDS-only POD in part of observation arcs some satellite even suffers a slight decline. The root mean square (RMS) of overlapping clock difference of visible arcs in GPS/BDS POD experiments improves by 0.1 ns level. As to the experiments of regional station layout with 7 ground stations, the orbit and clock overlapping precision and orbit predicting precision are analyzed. Results show that the predicting precision of BDS GEO satellites in the along direction improves by 85%. The remaining also has a substantial improvement, with the average percentage 21.7%. RMS of overlapping clock difference of visible arcs improves by 0.5 ns level.
文摘Positioning accuracy of the Global Navigation Satellite System(GNSS) can be analyzed by Positioning Dilution Of Precision(PDOP).In order to enhance the navigating performance of Asia and the Pacific areas,this paper analyzes the next generation BeidouTM navigation satellite system(CompassTM) enhanced by Geostationary Earth Orbit(GEO) and Inclining GeoSynchronized Orbit(IGSO).As global navigation satellite system,CompassTM must be robust enough to avoid system layoff,when some nodes are not available.So,the CompassTM enhanced by GEO and IGSO constellation is proposed and analyzed its PDOP proformance,this paper shows some exciting results of performance of CompassTM enhanced by GEO and IGSO.From the simulation results,we can found that:when more than fifteen satellites are invalid,the enhanced system could be operating normally.