To improve the positioning accuracy in GPS point positioning, the geometric dilution of precision （GDOP） including HDOP, VDOP, TDOP, PDOP is commonly considered. The properties of the DOP for the GPS satellite navig...To improve the positioning accuracy in GPS point positioning, the geometric dilution of precision （GDOP） including HDOP, VDOP, TDOP, PDOP is commonly considered. The properties of the DOP for the GPS satellite navigation system are studied and the coordinate system is improved in order to decrease the amount of variables. In the end, by simulation and discussing the results, the corresponding conclusions are presented.展开更多
Along with the planning and implementation of the COMPASS satellite navigation system, first as a regional then a global system, there is a need to probe into the positioning performance of the mixed constellation in ...Along with the planning and implementation of the COMPASS satellite navigation system, first as a regional then a global system, there is a need to probe into the positioning performance of the mixed constellation in the stepwise deployment scheme. Both the increase in the number of the MEO satellites in the constellation and the decrease in the user equivalent ranging error of the GEO satellites will improve the overall positioning performance of the system. Using the weighted dilution of precision as the evaluation criterion, we study the theoretical relationship between the internal parameters and the positioning precision during the evolution of the system. On one hand, the influence of each factor on the positioning performance is quantitatively analyzed under the circumstances of various constellation deployment schemes and user types. On the other hand, for given positioning performance indices, simulations are carried out to present the inversion of parameters. Our conclusions provide useful suggestions to the system design and stepwise deployment scheme of satellites.展开更多
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
针对现有基于测距的集群UAV协同导航方法普遍忽略了空间构型对定位定能的影响,难以获得精确的导航定位结果,提出一种基于空间构型优选的5G集群UAV协同导航方法。构建了复杂环境下基于5G信号的UAV相对测距误差模型,基于最小几何精度因子(...针对现有基于测距的集群UAV协同导航方法普遍忽略了空间构型对定位定能的影响,难以获得精确的导航定位结果,提出一种基于空间构型优选的5G集群UAV协同导航方法。构建了复杂环境下基于5G信号的UAV相对测距误差模型,基于最小几何精度因子(geometric dilution of precision,GDOP)准则建立了协同导航节点寻优策略,实现了协同导航空间构型的实时优选;设计了基于5G测距网络的协同导航滤波器,对UAV导航信息进行在线估计和实时补偿,提高集群UAV的协同定位精度。仿真结果表明:该方法从机定位精度平均提升了约42.05%,为集群UAV实现在卫星不可用条件下的自主导航提供了一种有效的新方法。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
传统的选星方法通常以遍历为手段,在可见星较多的情形下往往计算量很大。常规的遗传算法通常固定交叉和变异概率,产生不必要的时间消耗。针对这些问题,提出了引入成熟因子映射交叉概率和变异概率的双系统遗传选星算法,目的在于快速地找...传统的选星方法通常以遍历为手段,在可见星较多的情形下往往计算量很大。常规的遗传算法通常固定交叉和变异概率,产生不必要的时间消耗。针对这些问题,提出了引入成熟因子映射交叉概率和变异概率的双系统遗传选星算法,目的在于快速地找到最优解或可接受的次优解。该方法以几何精度因子(Geometric Dilution of Precision,GDOP)为适应度,构造单染色体种群,定义成熟度来指导交叉变异操作,再经过每代精英保留策略和隔代种群数量控制,最终搜索得到符合门限的可接受解。实验结果表明,在进化200代的条件下,成熟因子映射遗传算法比常规遗传算法的搜索时间平均节省约24.75%,引入种群数量控制机制后搜索时间进一步节省了约55.32%。该方法可以快速获得稳定数学期望的可用选星集合。展开更多
针对传统的遍历法无法满足多全球卫星导航系统(global navigation satellite system,GNSS)组合导航选星的实时性需求,提出了一种基于灰狼优化(grey wolf optimization,GWO)算法的快速选星方法。该算法利用自适应收敛因子和信息反馈机制...针对传统的遍历法无法满足多全球卫星导航系统(global navigation satellite system,GNSS)组合导航选星的实时性需求,提出了一种基于灰狼优化(grey wolf optimization,GWO)算法的快速选星方法。该算法利用自适应收敛因子和信息反馈机制,在局部寻优与全局搜索之间实现平衡,表现出良好的求解性能,即可以保证在获得理想几何构型的同时大幅减少接收机运算量。经过仿真实验,分析了参数选取对GWO快速选星算法结果的影响。利用实测数据对所提算法进行验证,结果表明,所提算法在四系统组合下,从49颗可见星中选择7颗进行定位时,与遍历法相比,几何精度因子(geometric dilution of precision,GDOP)误差仅为1.8%,而计算效率提高了71.7%。该算法适用于多GNSS组合导航定位不同选星数目的情况,还可以拓展至区域导航卫星系统。展开更多
超宽带室内定位精度受非视距传播(Non-Line Of Sight,NLOS)、多径效应、基站布设等因素影响,而这些因素均与基站的布设阵型有关.因此,本文提出一种基于位置精度稀释因子(Positioning Dilution Of Precision,PDOP)、到达时间差(Time Diff...超宽带室内定位精度受非视距传播(Non-Line Of Sight,NLOS)、多径效应、基站布设等因素影响,而这些因素均与基站的布设阵型有关.因此,本文提出一种基于位置精度稀释因子(Positioning Dilution Of Precision,PDOP)、到达时间差(Time Difference Of Arrival,TDOA)测量误差和克拉美劳界的基站布设优化数学模型,可用遗传算法和萤火虫算法等智能算法求解.理论推导和仿真测试表明优化后的基站布设阵型相较于传统的立方体8基站阵型具有更好的平均误差和方差.14.5 m×7.6 m×3 m展厅的实测实验结果表明,经过优化后的基站布设阵型定位精度提高了0.7132 cm,且方差减小了50.6496 cm^(2)具有较高的稳定性.展开更多
基金a grant from Science and Technology Commission of Shanghai Municipality (05dz15006)
文摘To improve the positioning accuracy in GPS point positioning, the geometric dilution of precision （GDOP） including HDOP, VDOP, TDOP, PDOP is commonly considered. The properties of the DOP for the GPS satellite navigation system are studied and the coordinate system is improved in order to decrease the amount of variables. In the end, by simulation and discussing the results, the corresponding conclusions are presented.
文摘Along with the planning and implementation of the COMPASS satellite navigation system, first as a regional then a global system, there is a need to probe into the positioning performance of the mixed constellation in the stepwise deployment scheme. Both the increase in the number of the MEO satellites in the constellation and the decrease in the user equivalent ranging error of the GEO satellites will improve the overall positioning performance of the system. Using the weighted dilution of precision as the evaluation criterion, we study the theoretical relationship between the internal parameters and the positioning precision during the evolution of the system. On one hand, the influence of each factor on the positioning performance is quantitatively analyzed under the circumstances of various constellation deployment schemes and user types. On the other hand, for given positioning performance indices, simulations are carried out to present the inversion of parameters. Our conclusions provide useful suggestions to the system design and stepwise deployment scheme of satellites.
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.
文摘针对现有基于测距的集群UAV协同导航方法普遍忽略了空间构型对定位定能的影响,难以获得精确的导航定位结果,提出一种基于空间构型优选的5G集群UAV协同导航方法。构建了复杂环境下基于5G信号的UAV相对测距误差模型,基于最小几何精度因子(geometric dilution of precision,GDOP)准则建立了协同导航节点寻优策略,实现了协同导航空间构型的实时优选;设计了基于5G测距网络的协同导航滤波器,对UAV导航信息进行在线估计和实时补偿,提高集群UAV的协同定位精度。仿真结果表明:该方法从机定位精度平均提升了约42.05%,为集群UAV实现在卫星不可用条件下的自主导航提供了一种有效的新方法。
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%。
文摘传统的选星方法通常以遍历为手段,在可见星较多的情形下往往计算量很大。常规的遗传算法通常固定交叉和变异概率,产生不必要的时间消耗。针对这些问题,提出了引入成熟因子映射交叉概率和变异概率的双系统遗传选星算法,目的在于快速地找到最优解或可接受的次优解。该方法以几何精度因子(Geometric Dilution of Precision,GDOP)为适应度,构造单染色体种群,定义成熟度来指导交叉变异操作,再经过每代精英保留策略和隔代种群数量控制,最终搜索得到符合门限的可接受解。实验结果表明,在进化200代的条件下,成熟因子映射遗传算法比常规遗传算法的搜索时间平均节省约24.75%,引入种群数量控制机制后搜索时间进一步节省了约55.32%。该方法可以快速获得稳定数学期望的可用选星集合。
文摘针对传统的遍历法无法满足多全球卫星导航系统(global navigation satellite system,GNSS)组合导航选星的实时性需求,提出了一种基于灰狼优化(grey wolf optimization,GWO)算法的快速选星方法。该算法利用自适应收敛因子和信息反馈机制,在局部寻优与全局搜索之间实现平衡,表现出良好的求解性能,即可以保证在获得理想几何构型的同时大幅减少接收机运算量。经过仿真实验,分析了参数选取对GWO快速选星算法结果的影响。利用实测数据对所提算法进行验证,结果表明,所提算法在四系统组合下,从49颗可见星中选择7颗进行定位时,与遍历法相比,几何精度因子(geometric dilution of precision,GDOP)误差仅为1.8%,而计算效率提高了71.7%。该算法适用于多GNSS组合导航定位不同选星数目的情况,还可以拓展至区域导航卫星系统。
文摘超宽带室内定位精度受非视距传播(Non-Line Of Sight,NLOS)、多径效应、基站布设等因素影响,而这些因素均与基站的布设阵型有关.因此,本文提出一种基于位置精度稀释因子(Positioning Dilution Of Precision,PDOP)、到达时间差(Time Difference Of Arrival,TDOA)测量误差和克拉美劳界的基站布设优化数学模型,可用遗传算法和萤火虫算法等智能算法求解.理论推导和仿真测试表明优化后的基站布设阵型相较于传统的立方体8基站阵型具有更好的平均误差和方差.14.5 m×7.6 m×3 m展厅的实测实验结果表明,经过优化后的基站布设阵型定位精度提高了0.7132 cm,且方差减小了50.6496 cm^(2)具有较高的稳定性.
