Selecting the optimal reference satellite is an important component of high-precision relat/ve positioning because the reference satellite directly influences the strength of the normal equation. The reference satelli...Selecting the optimal reference satellite is an important component of high-precision relat/ve positioning because the reference satellite directly influences the strength of the normal equation. The reference satellite selection methods based on elevation and positional dilution of precision （PDOP） value were compared. Results show that all the above methods cannot select the optimal reference satellite. We introduce condition number of the design matrix in the reference satellite selection method to improve structure of the normal equation, because condition number can indicate the ill condition of the normal equation. The experimental results show that the new method can improve positioning accuracy and reliability in precise relative positioning.展开更多
In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and pr...In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and proposed the concept of using a frequency dilution of precision to describe the quantitative effect of different frequency combinations on the positioning precision. To this end, we computed and plotted the global spatial distribution map of the relative positioning dilution of precision for single-day solution, half-hour solution, and single-epoch solution of the global positioning system(GPS), regional Beidou navigation satellite system(BDS2), future global Beidou navigation satellite system(BDS3), and their fusion systems.Using processing software with autonomous intellectual property rights(GCN and VENUS/ARSNet), we solved the measurement data and examined the positioning precision of the single-day solution and single-epoch solution of GPS and BDS2.The analysis demonstrated that the B1/B2 frequency positioning precision of BDS2 was better than that of L1/L2 frequency positioning of GPS, but the positioning precision of the BDS2 is worse than that of GPS over most of the service region of the BDS2. Further, the positioning precision of BDS3 is better than that of GPS in the Asia-Pacific region, while it is the opposite in other regions. Based on these conclusions, we put forth some optimization recommendations regarding the signal frequency of the navigation system and GPS measurement standards to serve as references for optimizing the system performance and formulating standards.展开更多
Low-Earth-Orbit（LEO） formation-flying satellites have been widely applied in many kinds of space geodesy. Precise Relative Orbit Determination（PROD） is an essential prerequisite for the LEO formation-flying satell...Low-Earth-Orbit（LEO） formation-flying satellites have been widely applied in many kinds of space geodesy. Precise Relative Orbit Determination（PROD） is an essential prerequisite for the LEO formation-flying satellites to complete their mission in space. The contribution of the BeiDou Navigation Satellite System（BDS） to the accuracy and reliability of PROD of LEO formation-flying satellites based on a Global Positioning System（GPS） is studied using a simulation method. Firstly, when BDS is added to GPS, the mean number of visible satellites increases from9.71 to 21.58. Secondly, the results show that the 3-Dimensional（3 D） accuracy of PROD, based on BDS-only, GPS-only and BDS ＋ GPS, is 0.74 mm, 0.66 mm and 0.52 mm, respectively. When BDS co-works with GPS, the accuracy increases by 29.73%. Geostationary-Earth-Orbit（GEO） satellites and Inclined Geosynchronous-Orbit（IGSO） satellites are only distributed over the Asia-Pacific region; however, they could provide a global improvement to PROD. The difference in PROD results between the Asia-Pacific region and the non-Asia-Pacific region is not apparent. Furthermore, the value of the Ambiguity Dilution Of Precision（ADOP）, based on BDS ＋ GPS, decreases by 7.50% and 8.26%, respectively, compared with BDS-only and GPS-only. Finally, if the relative position between satellites is only a few kilometres, the effect of ephemeris errors on PROD could be ignored. However, for a several-hundred-kilometre separation of the LEO satellites, the SingleDifference（SD） ephemeris errors of GEO satellites would be on the order of centimetres. The experimental results show that when IGSO satellites and Medium-Earth-Orbit（MEO） satellites co-work with GEO satellites, the accuracy decreases by 17.02%.展开更多
基金partially sponsored by the National 973 Project of China(2013CB733303)partially supported by the postgraduate independent exploration project of Central South University(2014zzts249)
文摘Selecting the optimal reference satellite is an important component of high-precision relat/ve positioning because the reference satellite directly influences the strength of the normal equation. The reference satellite selection methods based on elevation and positional dilution of precision （PDOP） value were compared. Results show that all the above methods cannot select the optimal reference satellite. We introduce condition number of the design matrix in the reference satellite selection method to improve structure of the normal equation, because condition number can indicate the ill condition of the normal equation. The experimental results show that the new method can improve positioning accuracy and reliability in precise relative positioning.
基金supported by National Key Research Program of China(Grant No.2016YFB0501900)National Natural Science Foundation of China(Grant Nos.41874008,41374032)The University Grants Committee of HongKong Research Grants Council Project(Grant No.PolyU 152023/14E)
文摘In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and proposed the concept of using a frequency dilution of precision to describe the quantitative effect of different frequency combinations on the positioning precision. To this end, we computed and plotted the global spatial distribution map of the relative positioning dilution of precision for single-day solution, half-hour solution, and single-epoch solution of the global positioning system(GPS), regional Beidou navigation satellite system(BDS2), future global Beidou navigation satellite system(BDS3), and their fusion systems.Using processing software with autonomous intellectual property rights(GCN and VENUS/ARSNet), we solved the measurement data and examined the positioning precision of the single-day solution and single-epoch solution of GPS and BDS2.The analysis demonstrated that the B1/B2 frequency positioning precision of BDS2 was better than that of L1/L2 frequency positioning of GPS, but the positioning precision of the BDS2 is worse than that of GPS over most of the service region of the BDS2. Further, the positioning precision of BDS3 is better than that of GPS in the Asia-Pacific region, while it is the opposite in other regions. Based on these conclusions, we put forth some optimization recommendations regarding the signal frequency of the navigation system and GPS measurement standards to serve as references for optimizing the system performance and formulating standards.
基金supported by the National Natural Science Foundation of China (Nos. 91438202, 61370013)
文摘Low-Earth-Orbit（LEO） formation-flying satellites have been widely applied in many kinds of space geodesy. Precise Relative Orbit Determination（PROD） is an essential prerequisite for the LEO formation-flying satellites to complete their mission in space. The contribution of the BeiDou Navigation Satellite System（BDS） to the accuracy and reliability of PROD of LEO formation-flying satellites based on a Global Positioning System（GPS） is studied using a simulation method. Firstly, when BDS is added to GPS, the mean number of visible satellites increases from9.71 to 21.58. Secondly, the results show that the 3-Dimensional（3 D） accuracy of PROD, based on BDS-only, GPS-only and BDS ＋ GPS, is 0.74 mm, 0.66 mm and 0.52 mm, respectively. When BDS co-works with GPS, the accuracy increases by 29.73%. Geostationary-Earth-Orbit（GEO） satellites and Inclined Geosynchronous-Orbit（IGSO） satellites are only distributed over the Asia-Pacific region; however, they could provide a global improvement to PROD. The difference in PROD results between the Asia-Pacific region and the non-Asia-Pacific region is not apparent. Furthermore, the value of the Ambiguity Dilution Of Precision（ADOP）, based on BDS ＋ GPS, decreases by 7.50% and 8.26%, respectively, compared with BDS-only and GPS-only. Finally, if the relative position between satellites is only a few kilometres, the effect of ephemeris errors on PROD could be ignored. However, for a several-hundred-kilometre separation of the LEO satellites, the SingleDifference（SD） ephemeris errors of GEO satellites would be on the order of centimetres. The experimental results show that when IGSO satellites and Medium-Earth-Orbit（MEO） satellites co-work with GEO satellites, the accuracy decreases by 17.02%.
