BeiDou regional navigation satellite system （BDS） also called BeiDou-2 has been in full operation since December 27, 2012. It consists of 14 satellites, including 5 satellites in Geostationary Orbit （GEO）, 5 satel...BeiDou regional navigation satellite system （BDS） also called BeiDou-2 has been in full operation since December 27, 2012. It consists of 14 satellites, including 5 satellites in Geostationary Orbit （GEO）, 5 satellites in Inclined Geosynchronous Orbit （IGSO）, and 4 satellites in Medium Earth Orbit （MEO）. In this paper, its basic navigation and positioning performance are evaluated preliminarily by the real data collected in Beijing, including satellite visibility, Position Dilution of Precision （PDOP） value, the precision of code and carrier phase measurements, the accuracy of single point positioning and differential position- ing and ambiguity resolution （AR） performance, which are also compared with those of GPS. It is shown that the precision of BDS code and carrier phase measurements are about 33 cm and 2 mm, respectively, which are comparable to those of GPS, and the accuracy of BDS single point positioning has satisfied the design requirement. The real-time kinematic positioning is also feasible by BDS alolae in the opening condition, since its fixed rate and reliability of single-epoch dual-frequency AR is comparable to those of GPS. The accuracy of BDS carrier phase differential positioning is better than 1 cm for a very short baseline of 4.2 m and 3 cm for a short baseline of 8.2 km, which is on the same level with that of GPS. For the combined BDS and GPS, the fixed rate and reliability of single-epoch AR and the positioning accuracy are improved significantly. The accu- racy of BDS/GPS carrier phase differential positioning is about 35 and 20 % better than that of GPS for two short baseline tests in this study. The accuracy of BDS code differential positioning is better than 2.5 m. However it is worse than that of GPS, which may result from large code multipath errors of BDS GEO satellite measurements.展开更多
An investigation has been made on the models and characteristics of triple-frequency carrier-phase linear combinations for the Bei Dou Navigation Satellite System(BDS). Based on the three frequencies of the BDS, three...An investigation has been made on the models and characteristics of triple-frequency carrier-phase linear combinations for the Bei Dou Navigation Satellite System(BDS). Based on the three frequencies of the BDS, three categories of combinations are developed: ionosphere-free combinations(i.e., those that eliminate the ionospheric effect), minimum-noise combinations(those that mitigate the effects of thermal noise and multiple paths), and troposphere-free combinations(those that mitigate tropospheric effects). Both the ionosphere-free and troposphere-free combinations can be expressed as planes, whereas the minimum-noise combinations can be expressed as a line. The relationships between these three categories of linear combinations are investigated from the perspective of geometry. The angle between the troposphere-free plane and ionosphere-free plane is small, while the angles between the troposphere-free plane and the minimum-noise line, and between the ionosphere-free plane and the minimum-noise line, are large. Specifically, the troposphere-free plane is orthogonal to the minimum-noise line. By introducing the concepts of lane number and integer ionosphere number, the characteristics of the long-wavelength integer combinations and ionosphere-free integer combinations are investigated. The analysis indicates that the longest wavelength that can be formed for integer combinations is 146.53 m, and the ionosphere-free integer combinations all have large noise amplification factors. The ionosphere-free integer combination with minimum noise amplification factor is(0, 62, 59). According to the lane number, integer ionosphere number, and noise amplification factor, optimal integer combinations with different characteristics are presented. For general short baselines and long baselines, three independent integer combinations are suggested.展开更多
Several noteworthy breakthroughs have been made with the BeiDou Navigation Satellite System(BDS)and other global navigation satellite systems as well as the associated augmentation systems,such as the commissioning of...Several noteworthy breakthroughs have been made with the BeiDou Navigation Satellite System(BDS)and other global navigation satellite systems as well as the associated augmentation systems,such as the commissioning of the BDS-3 preliminary system and the successful launch of the first BDS-3 GEO satellite which carries the satellite-based augmentation payload.Presently,BDS can provide basic services globally,and its augmentation system is also being tested.This paper gives an overview of BDS and satellite navigation augmentation technologies.This overview is divided into four parts,which include the system segment technologies,satellite segment technologies,propagation segment technologies,and user segment technologies.In each part,these technologies are described from the perspectives of preliminary information,research progress,and summary.Moreover,the significance and progress of the BeiDou Satellite-based Augmentation System(BDSBAS),low earth orbit augmentation,and the national BeiDou ground-based augmentation system are presented,along with the airborne-based augmentation system.Furthermore,the conclusions and discussions covering popular topics for research,frontiers in research and development,achievements,and suggestions are listed for future research.展开更多
针对北斗Ⅱ卫星导航星座中卫星位置不确定问题,改进并完善了正在筹建中的北斗Ⅱ卫星导航星座布局,在此基础上仿真分析了我国区域性导航系统以及北斗Ⅱ卫星导航星座的多星覆盖、位置精度衰减因子(position dilution of preci-sion,PDOP)...针对北斗Ⅱ卫星导航星座中卫星位置不确定问题,改进并完善了正在筹建中的北斗Ⅱ卫星导航星座布局,在此基础上仿真分析了我国区域性导航系统以及北斗Ⅱ卫星导航星座的多星覆盖、位置精度衰减因子(position dilution of preci-sion,PDOP),给出了覆盖性能、导航定位精度等导航星座系统性能。仿真结果表明,北斗Ⅱ卫星导航系统多星覆盖及PDOP性能相对优于GPS导航星座,尤其适用于我国及周边地区。通过对不同最低仰角下北斗II导航星座及GPS星座多星覆盖变化分析,确定了各星座多星覆盖与仰角的关系以及变化特征,为北斗II导航系统组建工作以及应用终端设计提供了依据。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
基金sponsored by the National Natural Science Foundation of China(Grant Nos.41020144004,41374019,41104022)the National High Technology Research and Development Program of China(Grant No.2013AA122501)
文摘BeiDou regional navigation satellite system （BDS） also called BeiDou-2 has been in full operation since December 27, 2012. It consists of 14 satellites, including 5 satellites in Geostationary Orbit （GEO）, 5 satellites in Inclined Geosynchronous Orbit （IGSO）, and 4 satellites in Medium Earth Orbit （MEO）. In this paper, its basic navigation and positioning performance are evaluated preliminarily by the real data collected in Beijing, including satellite visibility, Position Dilution of Precision （PDOP） value, the precision of code and carrier phase measurements, the accuracy of single point positioning and differential position- ing and ambiguity resolution （AR） performance, which are also compared with those of GPS. It is shown that the precision of BDS code and carrier phase measurements are about 33 cm and 2 mm, respectively, which are comparable to those of GPS, and the accuracy of BDS single point positioning has satisfied the design requirement. The real-time kinematic positioning is also feasible by BDS alolae in the opening condition, since its fixed rate and reliability of single-epoch dual-frequency AR is comparable to those of GPS. The accuracy of BDS carrier phase differential positioning is better than 1 cm for a very short baseline of 4.2 m and 3 cm for a short baseline of 8.2 km, which is on the same level with that of GPS. For the combined BDS and GPS, the fixed rate and reliability of single-epoch AR and the positioning accuracy are improved significantly. The accu- racy of BDS/GPS carrier phase differential positioning is about 35 and 20 % better than that of GPS for two short baseline tests in this study. The accuracy of BDS code differential positioning is better than 2.5 m. However it is worse than that of GPS, which may result from large code multipath errors of BDS GEO satellite measurements.
基金sponsored by the National Natural Science Foundation of China(Grant Nos.41074024,41204030)the National Basic Research Program of China(Grant No.2013CB733301)
文摘An investigation has been made on the models and characteristics of triple-frequency carrier-phase linear combinations for the Bei Dou Navigation Satellite System(BDS). Based on the three frequencies of the BDS, three categories of combinations are developed: ionosphere-free combinations(i.e., those that eliminate the ionospheric effect), minimum-noise combinations(those that mitigate the effects of thermal noise and multiple paths), and troposphere-free combinations(those that mitigate tropospheric effects). Both the ionosphere-free and troposphere-free combinations can be expressed as planes, whereas the minimum-noise combinations can be expressed as a line. The relationships between these three categories of linear combinations are investigated from the perspective of geometry. The angle between the troposphere-free plane and ionosphere-free plane is small, while the angles between the troposphere-free plane and the minimum-noise line, and between the ionosphere-free plane and the minimum-noise line, are large. Specifically, the troposphere-free plane is orthogonal to the minimum-noise line. By introducing the concepts of lane number and integer ionosphere number, the characteristics of the long-wavelength integer combinations and ionosphere-free integer combinations are investigated. The analysis indicates that the longest wavelength that can be formed for integer combinations is 146.53 m, and the ionosphere-free integer combinations all have large noise amplification factors. The ionosphere-free integer combination with minimum noise amplification factor is(0, 62, 59). According to the lane number, integer ionosphere number, and noise amplification factor, optimal integer combinations with different characteristics are presented. For general short baselines and long baselines, three independent integer combinations are suggested.
基金the National Natural Science Foundation of China(No.61571309)Talent Project of Revitalization Liaoning(No.XLYC1907022)+1 种基金Natural Science Foundation of Liaoning Province(No.2019-MS-251)High-Level Innovation Talent Project of Shenyang(No.RC190030).
文摘Several noteworthy breakthroughs have been made with the BeiDou Navigation Satellite System(BDS)and other global navigation satellite systems as well as the associated augmentation systems,such as the commissioning of the BDS-3 preliminary system and the successful launch of the first BDS-3 GEO satellite which carries the satellite-based augmentation payload.Presently,BDS can provide basic services globally,and its augmentation system is also being tested.This paper gives an overview of BDS and satellite navigation augmentation technologies.This overview is divided into four parts,which include the system segment technologies,satellite segment technologies,propagation segment technologies,and user segment technologies.In each part,these technologies are described from the perspectives of preliminary information,research progress,and summary.Moreover,the significance and progress of the BeiDou Satellite-based Augmentation System(BDSBAS),low earth orbit augmentation,and the national BeiDou ground-based augmentation system are presented,along with the airborne-based augmentation system.Furthermore,the conclusions and discussions covering popular topics for research,frontiers in research and development,achievements,and suggestions are listed for future research.
文摘针对北斗Ⅱ卫星导航星座中卫星位置不确定问题,改进并完善了正在筹建中的北斗Ⅱ卫星导航星座布局,在此基础上仿真分析了我国区域性导航系统以及北斗Ⅱ卫星导航星座的多星覆盖、位置精度衰减因子(position dilution of preci-sion,PDOP),给出了覆盖性能、导航定位精度等导航星座系统性能。仿真结果表明,北斗Ⅱ卫星导航系统多星覆盖及PDOP性能相对优于GPS导航星座,尤其适用于我国及周边地区。通过对不同最低仰角下北斗II导航星座及GPS星座多星覆盖变化分析,确定了各星座多星覆盖与仰角的关系以及变化特征,为北斗II导航系统组建工作以及应用终端设计提供了依据。
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.
