Chinese Area Positioning System (CAPS) is a transmitted satellite navigation system moved by the Chinese Academy of Sciences. Three basic modes of navigation and positioning with CAPS are given, and then a comparative...Chinese Area Positioning System (CAPS) is a transmitted satellite navigation system moved by the Chinese Academy of Sciences. Three basic modes of navigation and positioning with CAPS are given, and then a comparative analysis is made in this paper. In terms of the principle that the ionospheric delay is at an inverse ratio to the frequency square, a new ionospheric-free positioning method based on a double-antenna CAPS receiver is put forward. Then the hybrid differential observations and the solving equations and algorithms for one epoch and multi epochs are deduced according to the basic principle of the method. The method may remove the global errors in signal emission, propagation, transmission and receiving (e.g., ionospheric delay, hardware delay, and clock error). So it is very convenient for the single-epoch solution and multi-epoch navigation and positioning, and may efficiently improve the precision of real time CAPS navigation. Furthermore, the method can be used not only for the geometric orbit determination of CAPS GEO and IGSO satellites and the navigation and positioning, but also for the estimation of the tropospheric zenith delay, which is useful for the study of water vapor changes in the atmosphere. Polynomials are used in this method to express the tropospheric zenith delay and CAPS satellite orbits within the limited time interval, which reduces the num- ber of unknown parameters and thus speeds the computation.展开更多
There is increasing concern about the uncombined(UC)observation model in the field of global navigation satellite system(GNSS).Based on the global positioning system(GPS)and the third-generation BeiDou navigation sate...There is increasing concern about the uncombined(UC)observation model in the field of global navigation satellite system(GNSS).Based on the global positioning system(GPS)and the third-generation BeiDou navigation satellite system(BDS-3),this study processed the UC precision orbit determination(POD)for single and dual systems.First,a UC observation model suitable for multi-GNSS POD was derived,and the ionospheric-free(IF)combination observation model was presented.Although the ambiguity parameters of UC and IF strategies were different after reparameterization,the difference could be removed when processing ambiguity resolution,and the equivalence was proved theoretically.To demonstrate the accuracy of BDS-3 orbits fully,the observation data of approximately 1 month were selected for determining the precise orbit for global positioning system(GPS)only,BDS-3 only,and GPS/BDS-3 systems based on the UC and IF models.The orbit precision of BDS-3 satellites was validated by using metrics,including comparison with precision products released by Wuhan University,orbit boundary discontinuity,and satellite laser ranging(SLR)residuals.The results show that the orbit accuracies of the IF and UC models are almost the same,the difference in orbits is approximately several millimeters,and the clock difference is within 0.01 ns.The GPS/BDS-3 combined solution shows better accuracy compared to other solutions.The average accuracies in the R and 3D directions are approximately 4 and 15 cm,and the clock standard deviation is approximately 0.2 ns compared to external orbit product.The root mean square of SLR residuals is approximately 4 cm.展开更多
使用2011-10-10全球随纬度均匀分布的10个IGS测站的观测数据,分别采用非组合、组合PPP(precise point positioning)模型进行定位解算,详细对比分析了两种PPP模型的静态和动态定位精度和收敛速度,以及ZPD估计精度。实验结果表明,两种PPP...使用2011-10-10全球随纬度均匀分布的10个IGS测站的观测数据,分别采用非组合、组合PPP(precise point positioning)模型进行定位解算,详细对比分析了两种PPP模型的静态和动态定位精度和收敛速度,以及ZPD估计精度。实验结果表明,两种PPP模型均可实现水平方向mm～cm级,高程1～3cm的静态定位精度;水平方向1～3cm,高程方向4cm左右的模拟动态定位精度,非组合L1和L2载波相位观测值残差只有传统模型中组合相位观测值残差的1/3～1/5,内符合精度更高。对于30s采样率的观测数据,组合PPP静态定位平均收敛时间为23min,动态为38min;非组合PPP静态定位平均收敛时间为29min,动态为71min,后者的收敛时间均普遍长于前者。在ZPD估计方面,两种模型的估计精度相当,均可达6mm左右。展开更多
The mining area deformation monitoring theory and method using precise point positioning （PPP） ambi- guity resolution （AR） were studied, and an ambiguity fixing model with satellite and receiver combina- tion phas...The mining area deformation monitoring theory and method using precise point positioning （PPP） ambi- guity resolution （AR） were studied, and an ambiguity fixing model with satellite and receiver combina- tion phase delay （CPD） was proposed for zero-differenced PPP ambiguity fixing and its corresponding formula derivation was given. The data processing results for I h at six IGS stations in China show that 93% of ambiguities can be fixed within 10 min and all ambiguities can be fixed within 15 min. After ambi- guity fixing, the positioning accuracy is improved by more than 85% in the E and N directions, with abso- lute positioning accuracy reaching millimeter level, and it was improved by 70% in the U direction, reaching centimeter level; the proposed zero-differenced ambiguity fixing model can effectively improve the convergence rate and positioning accuracy in PPP. Data monitoring continuously conducted for half a year at four COPS stations of Shanxi China Coal Pingshuo Group validated the feasibility of using PPP in mining area deformation monitoring.展开更多
Dual-Frequency Ground-Based Augmentation Systems(GBAS)can be affected by receiver Inter-Frequency Bias(IFB)when Ionosphere-Free(Ifree)smoothing is applied.In the framework of the proposed GBAS Approach Service Type F(...Dual-Frequency Ground-Based Augmentation Systems(GBAS)can be affected by receiver Inter-Frequency Bias(IFB)when Ionosphere-Free(Ifree)smoothing is applied.In the framework of the proposed GBAS Approach Service Type F(GAST-F),the IFB in the Ifree smoothed pseudorange can be corrected.However,IFB residual uncertainty still exists,which may threaten the integrity of the system.This paper presents an improved algorithm for the airborne protection level considering the residual uncertainty of IFBs to protect the integrity of dual-frequency GBAS.The IFB residual uncertainty multiplied by a frequency factor is included in the Ifree protection level together with the uncertainty of other error sources.To verify the proposed protection level algorithm,we calculate the IFB residual uncertainties of ground reference receivers and user receiver based on BDS B1I and B3I dual-frequency observation data and carry out a test at the Dongying Airport GBAS station.The results show that the proposed Ifree protection level with IFB residual uncertainty is 1.48 times the current protection level on average.The probability of Misleading Information(MI)during the test is reduced from 3.2×10^(-4)to the required value.It is proven that the proposed protection level can significantly reduce the integrity risk brought by IFB residual uncertainty and protect the integrity of dual-frequency GBAS.展开更多
基金Supported by the Knowledge Innovation Project of the Chinese Academy of Sci-ences (Grant No. KGCX1-21)the National Basic Research Program of China (Grant No. 2007CB815500)+2 种基金the National High Technology Research and Development Program of China (Grant No. 2006AA12z303)the National Natural Science Foun-dation of China (Grant No. 40774009)the Special Project of Taishan Scholars of Shandong Province of China (Grant No. TSXZ0502)
文摘Chinese Area Positioning System (CAPS) is a transmitted satellite navigation system moved by the Chinese Academy of Sciences. Three basic modes of navigation and positioning with CAPS are given, and then a comparative analysis is made in this paper. In terms of the principle that the ionospheric delay is at an inverse ratio to the frequency square, a new ionospheric-free positioning method based on a double-antenna CAPS receiver is put forward. Then the hybrid differential observations and the solving equations and algorithms for one epoch and multi epochs are deduced according to the basic principle of the method. The method may remove the global errors in signal emission, propagation, transmission and receiving (e.g., ionospheric delay, hardware delay, and clock error). So it is very convenient for the single-epoch solution and multi-epoch navigation and positioning, and may efficiently improve the precision of real time CAPS navigation. Furthermore, the method can be used not only for the geometric orbit determination of CAPS GEO and IGSO satellites and the navigation and positioning, but also for the estimation of the tropospheric zenith delay, which is useful for the study of water vapor changes in the atmosphere. Polynomials are used in this method to express the tropospheric zenith delay and CAPS satellite orbits within the limited time interval, which reduces the num- ber of unknown parameters and thus speeds the computation.
基金National Natural Science Foundation of China(Grant Nos.41674016,41874041,41704035,41904039)by State Key Laboratory of Geo-Information Engineering,NO.SKLGIE2018-M-2-1.
文摘There is increasing concern about the uncombined(UC)observation model in the field of global navigation satellite system(GNSS).Based on the global positioning system(GPS)and the third-generation BeiDou navigation satellite system(BDS-3),this study processed the UC precision orbit determination(POD)for single and dual systems.First,a UC observation model suitable for multi-GNSS POD was derived,and the ionospheric-free(IF)combination observation model was presented.Although the ambiguity parameters of UC and IF strategies were different after reparameterization,the difference could be removed when processing ambiguity resolution,and the equivalence was proved theoretically.To demonstrate the accuracy of BDS-3 orbits fully,the observation data of approximately 1 month were selected for determining the precise orbit for global positioning system(GPS)only,BDS-3 only,and GPS/BDS-3 systems based on the UC and IF models.The orbit precision of BDS-3 satellites was validated by using metrics,including comparison with precision products released by Wuhan University,orbit boundary discontinuity,and satellite laser ranging(SLR)residuals.The results show that the orbit accuracies of the IF and UC models are almost the same,the difference in orbits is approximately several millimeters,and the clock difference is within 0.01 ns.The GPS/BDS-3 combined solution shows better accuracy compared to other solutions.The average accuracies in the R and 3D directions are approximately 4 and 15 cm,and the clock standard deviation is approximately 0.2 ns compared to external orbit product.The root mean square of SLR residuals is approximately 4 cm.
文摘使用2011-10-10全球随纬度均匀分布的10个IGS测站的观测数据,分别采用非组合、组合PPP(precise point positioning)模型进行定位解算,详细对比分析了两种PPP模型的静态和动态定位精度和收敛速度,以及ZPD估计精度。实验结果表明,两种PPP模型均可实现水平方向mm～cm级,高程1～3cm的静态定位精度;水平方向1～3cm,高程方向4cm左右的模拟动态定位精度,非组合L1和L2载波相位观测值残差只有传统模型中组合相位观测值残差的1/3～1/5,内符合精度更高。对于30s采样率的观测数据,组合PPP静态定位平均收敛时间为23min,动态为38min;非组合PPP静态定位平均收敛时间为29min,动态为71min,后者的收敛时间均普遍长于前者。在ZPD估计方面,两种模型的估计精度相当,均可达6mm左右。
基金Financial support from the National Natural Science Foundation of China (No. 41074010)the Jiangsu Innovation Works Fund of Postgraduate (No. CXZZ11-0299)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘The mining area deformation monitoring theory and method using precise point positioning （PPP） ambi- guity resolution （AR） were studied, and an ambiguity fixing model with satellite and receiver combina- tion phase delay （CPD） was proposed for zero-differenced PPP ambiguity fixing and its corresponding formula derivation was given. The data processing results for I h at six IGS stations in China show that 93% of ambiguities can be fixed within 10 min and all ambiguities can be fixed within 15 min. After ambi- guity fixing, the positioning accuracy is improved by more than 85% in the E and N directions, with abso- lute positioning accuracy reaching millimeter level, and it was improved by 70% in the U direction, reaching centimeter level; the proposed zero-differenced ambiguity fixing model can effectively improve the convergence rate and positioning accuracy in PPP. Data monitoring continuously conducted for half a year at four COPS stations of Shanxi China Coal Pingshuo Group validated the feasibility of using PPP in mining area deformation monitoring.
基金financial support from the National Natural Science Foundation of China(Nos.61871012,62022012,U1833125,U2033215)the National Key Research and Development Program of China(Nos.2020YFB0505602,2018YFB0505105)+2 种基金the Civil Aviation Security Capacity Building Fund Project,China(Nos.CAAC Contract 2020(123),CAAC Contract 2021(77))Open Fund Project of Intelligent Operation Key Laboratory of Civil Aviation Airport Group,China(No.KLAGIO20180405)the Beijing Nova Program of Science and Technology,China(No.Z191100001119134)。
文摘Dual-Frequency Ground-Based Augmentation Systems(GBAS)can be affected by receiver Inter-Frequency Bias(IFB)when Ionosphere-Free(Ifree)smoothing is applied.In the framework of the proposed GBAS Approach Service Type F(GAST-F),the IFB in the Ifree smoothed pseudorange can be corrected.However,IFB residual uncertainty still exists,which may threaten the integrity of the system.This paper presents an improved algorithm for the airborne protection level considering the residual uncertainty of IFBs to protect the integrity of dual-frequency GBAS.The IFB residual uncertainty multiplied by a frequency factor is included in the Ifree protection level together with the uncertainty of other error sources.To verify the proposed protection level algorithm,we calculate the IFB residual uncertainties of ground reference receivers and user receiver based on BDS B1I and B3I dual-frequency observation data and carry out a test at the Dongying Airport GBAS station.The results show that the proposed Ifree protection level with IFB residual uncertainty is 1.48 times the current protection level on average.The probability of Misleading Information(MI)during the test is reduced from 3.2×10^(-4)to the required value.It is proven that the proposed protection level can significantly reduce the integrity risk brought by IFB residual uncertainty and protect the integrity of dual-frequency GBAS.
