To address uncertainties in satellite orbit error prediction,this study proposes a novel ensemble learning-based orbit prediction method specifically designed for the BeiDou navigation satellite system(BDS).Building o...To address uncertainties in satellite orbit error prediction,this study proposes a novel ensemble learning-based orbit prediction method specifically designed for the BeiDou navigation satellite system(BDS).Building on ephemeris data and perturbation corrections,two new models are proposed:attention-enhanced BPNN(AEBP)and Transformer-ResNet-BiLSTM(TR-BiLSTM).These models effectively capture both local and global dependencies in satellite orbit data.To further enhance prediction accuracy and stability,the outputs of these two models were integrated using the gradient boosting decision tree(GBDT)ensemble learning method,which was optimized through a grid search.The main contribution of this approach is the synergistic combination of deep learning models and GBDT,which significantly improves both the accuracy and robustness of satellite orbit predictions.This model was validated using broadcast ephemeris data from the BDS-3 MEO and inclined geosynchronous orbit(IGSO)satellites.The results show that the proposed method achieves an error correction rate of 65.4%.This ensemble learning-based approach offers a highly effective solution for high-precision and stable satellite orbit predictions.展开更多
Decimeter-level service is provided by the BeiDou satellite navigation system wide area differential service(BDS WADS)for users who collect carrier phase measurements.However,the fluctuations in Geostationary Earth Or...Decimeter-level service is provided by the BeiDou satellite navigation system wide area differential service(BDS WADS)for users who collect carrier phase measurements.However,the fluctuations in Geostationary Earth Orbit(GEO)satellite orbit errors reduce the spatial correlation of orbit errors.These fluctuations not only decrease the accuracy and stability of zone correction service provided by BDS WADS,but also shorten its effective range.In this paper,we proposed an algorithm to weaken the influence of GEO satellite orbit error fluctuations and verified the method using data from eight sparsely distributed zones.The results show that orbit errors can be stabilized using orbit fluctuation corrections,and the positioning precision and stability of the BDS WADS can be improved simultaneously.Under normal circumstances,the horizontal and vertical positioning accuracy of users within 1000 km from the center of the zone can reach 0.19 m and 0.34 m.Furthermore,the effective range is increased.The positioning performance within 1800 km could reach 0.24 m and 0.38 m for the horizontal and vertical components,respectively.展开更多
Global Positioning System (GPS) is a satellite-based navigation system that provides a three-dimensional user position (x,y,z), velocity and time anywhere on or above the earth surface. The satellite-based position ac...Global Positioning System (GPS) is a satellite-based navigation system that provides a three-dimensional user position (x,y,z), velocity and time anywhere on or above the earth surface. The satellite-based position accuracy is affected by several factors such as satellite clock error, propagation path delays and receiver noise due to which the GPS does not meet the requirements of critical navigation applications such as missile navigation and category I/II/III aircraft landings. This paper emphasizes on modelling the satellite clock error and orbital solution (satellite position) error considering the signal emission time. The transmission time sent by each satellite in broadcast ephemerides is not accurate. This has to be corrected in order to obtain correct satellite position and in turn a precise receiver position. Signal transmission time or broadcast time from satellite antenna phase center is computed at the receiver using several parameters such as signal reception time, propagation time, pseudorange observed and satellite clock error correction parameters. This corrected time of transmission and broadcast orbital parameters are used for estimation of the orbital solution. The estimated orbital solution was validated with the precise ephemerides which are estimated by Jet Propulsion Laboratory (JPL), USA. The errors are estimated for a typical day data collected on 11th March 2011 from dual frequency GPS receiver located at Department of Electronics and Communication Engineering, Andhra University College of Engineering, Visakhapatnam (17.73°N/83.319°E).展开更多
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
实时轨道、钟差产品的精度和完好性是实现全球卫星导航系统精准可信定位服务的重要前提。以2022年中国科学院(Chinese Academy of Sciences,CAS)实时轨道、钟差产品为例,从产品精度及精密单点定位精度两个方面评估实时轨道、钟差产品性...实时轨道、钟差产品的精度和完好性是实现全球卫星导航系统精准可信定位服务的重要前提。以2022年中国科学院(Chinese Academy of Sciences,CAS)实时轨道、钟差产品为例,从产品精度及精密单点定位精度两个方面评估实时轨道、钟差产品性能,并根据全球均匀分布的100个虚拟测站计算得到的瞬时空间信号用户测距误差(instantaneous signal-in-space user range error,IURE),分析实时轨道、钟差产品的空间信号用户测距误差分布特性,计算CAS实时轨道、钟差产品的完好性支持信息。试验结果表明,以德国地学研究中心提供的事后精密产品为参考,GPS和Galileo的轨道精度优于5 cm,钟差标准差(standard deviation,STD)优于0.08 ns,BDS和GLONASS的轨道精度优于15 cm,STD优于0.3 ns;选取全球分布测站以静态仿动态方式进行精密单点定位测试,四系统组合定位的3D方向精度均方根(root mean square,RMS)优于4 cm,收敛时间优于11 min。GPS和Galileo的IURE RMS优于4 cm,同时IURE分布峰度基本在10以内,偏度绝对值基本在0.5以内,可接受为高斯分布;GLONASS的IURE RMS在10 cm以内,但是各卫星IURE的偏度和峰度之间差异较大,尖峰厚尾情况较为严重;BDS的IURE RMS优于11 cm,但是不同类型卫星的IURE分布不同,且BDS-3上海微小卫星工程中心的卫星具有较为明显的双峰特性。对于星座故障和卫星故障先验概率,GPS星座故障先验概率最小为5.2×10^(-5),除BDS-2外,其他系统星座故障先验概率小于1.0×10^(-3);GLONASS卫星故障先验概率达到2.7×10^(-3),Galileo卫星故障先验概率最小为8.7×10^(-4)。对于空间信号用户测距误差的包络标准差和标准差,GPS和Galileo卫星的两种标准差差异均在4 cm以内;GLONASS卫星的两种标准差差异基本大于5 cm;相较于标准差,BDS-2和BDS-3的包络标准差差异较大。展开更多
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28040300)Project for Guangxi Science and Technology Base,and Talents(Grant No.GK AD22035957)+1 种基金the Informatization Plan of the Chinese Academy of Sciences(Grant No.CAS-WX2021SF-0304)the West Light Foundation of the ChineseAcademy of Sciences(Grant No.XAB2021YN19).
文摘To address uncertainties in satellite orbit error prediction,this study proposes a novel ensemble learning-based orbit prediction method specifically designed for the BeiDou navigation satellite system(BDS).Building on ephemeris data and perturbation corrections,two new models are proposed:attention-enhanced BPNN(AEBP)and Transformer-ResNet-BiLSTM(TR-BiLSTM).These models effectively capture both local and global dependencies in satellite orbit data.To further enhance prediction accuracy and stability,the outputs of these two models were integrated using the gradient boosting decision tree(GBDT)ensemble learning method,which was optimized through a grid search.The main contribution of this approach is the synergistic combination of deep learning models and GBDT,which significantly improves both the accuracy and robustness of satellite orbit predictions.This model was validated using broadcast ephemeris data from the BDS-3 MEO and inclined geosynchronous orbit(IGSO)satellites.The results show that the proposed method achieves an error correction rate of 65.4%.This ensemble learning-based approach offers a highly effective solution for high-precision and stable satellite orbit predictions.
基金the National Natural Science Funds of China(Grant No.41604032).
文摘Decimeter-level service is provided by the BeiDou satellite navigation system wide area differential service(BDS WADS)for users who collect carrier phase measurements.However,the fluctuations in Geostationary Earth Orbit(GEO)satellite orbit errors reduce the spatial correlation of orbit errors.These fluctuations not only decrease the accuracy and stability of zone correction service provided by BDS WADS,but also shorten its effective range.In this paper,we proposed an algorithm to weaken the influence of GEO satellite orbit error fluctuations and verified the method using data from eight sparsely distributed zones.The results show that orbit errors can be stabilized using orbit fluctuation corrections,and the positioning precision and stability of the BDS WADS can be improved simultaneously.Under normal circumstances,the horizontal and vertical positioning accuracy of users within 1000 km from the center of the zone can reach 0.19 m and 0.34 m.Furthermore,the effective range is increased.The positioning performance within 1800 km could reach 0.24 m and 0.38 m for the horizontal and vertical components,respectively.
文摘Global Positioning System (GPS) is a satellite-based navigation system that provides a three-dimensional user position (x,y,z), velocity and time anywhere on or above the earth surface. The satellite-based position accuracy is affected by several factors such as satellite clock error, propagation path delays and receiver noise due to which the GPS does not meet the requirements of critical navigation applications such as missile navigation and category I/II/III aircraft landings. This paper emphasizes on modelling the satellite clock error and orbital solution (satellite position) error considering the signal emission time. The transmission time sent by each satellite in broadcast ephemerides is not accurate. This has to be corrected in order to obtain correct satellite position and in turn a precise receiver position. Signal transmission time or broadcast time from satellite antenna phase center is computed at the receiver using several parameters such as signal reception time, propagation time, pseudorange observed and satellite clock error correction parameters. This corrected time of transmission and broadcast orbital parameters are used for estimation of the orbital solution. The estimated orbital solution was validated with the precise ephemerides which are estimated by Jet Propulsion Laboratory (JPL), USA. The errors are estimated for a typical day data collected on 11th March 2011 from dual frequency GPS receiver located at Department of Electronics and Communication Engineering, Andhra University College of Engineering, Visakhapatnam (17.73°N/83.319°E).
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
文摘实时轨道、钟差产品的精度和完好性是实现全球卫星导航系统精准可信定位服务的重要前提。以2022年中国科学院(Chinese Academy of Sciences,CAS)实时轨道、钟差产品为例,从产品精度及精密单点定位精度两个方面评估实时轨道、钟差产品性能,并根据全球均匀分布的100个虚拟测站计算得到的瞬时空间信号用户测距误差(instantaneous signal-in-space user range error,IURE),分析实时轨道、钟差产品的空间信号用户测距误差分布特性,计算CAS实时轨道、钟差产品的完好性支持信息。试验结果表明,以德国地学研究中心提供的事后精密产品为参考,GPS和Galileo的轨道精度优于5 cm,钟差标准差(standard deviation,STD)优于0.08 ns,BDS和GLONASS的轨道精度优于15 cm,STD优于0.3 ns;选取全球分布测站以静态仿动态方式进行精密单点定位测试,四系统组合定位的3D方向精度均方根(root mean square,RMS)优于4 cm,收敛时间优于11 min。GPS和Galileo的IURE RMS优于4 cm,同时IURE分布峰度基本在10以内,偏度绝对值基本在0.5以内,可接受为高斯分布;GLONASS的IURE RMS在10 cm以内,但是各卫星IURE的偏度和峰度之间差异较大,尖峰厚尾情况较为严重;BDS的IURE RMS优于11 cm,但是不同类型卫星的IURE分布不同,且BDS-3上海微小卫星工程中心的卫星具有较为明显的双峰特性。对于星座故障和卫星故障先验概率,GPS星座故障先验概率最小为5.2×10^(-5),除BDS-2外,其他系统星座故障先验概率小于1.0×10^(-3);GLONASS卫星故障先验概率达到2.7×10^(-3),Galileo卫星故障先验概率最小为8.7×10^(-4)。对于空间信号用户测距误差的包络标准差和标准差,GPS和Galileo卫星的两种标准差差异均在4 cm以内;GLONASS卫星的两种标准差差异基本大于5 cm;相较于标准差,BDS-2和BDS-3的包络标准差差异较大。
