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 navigat...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 relative 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 relative 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
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
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supported by the National Key Research and Development Program of China(No.2022YFB3904300)Joint Funds of the National Natural Science Foundation of China(No.U2233215)。
文摘全球导航卫星系统(Global navigation satellite system,GNSS)是民航所需导航性能(Required navigation performance,RNP)程序的重要导航传感器。GNSS的定位精度决定了民用飞机是否能够满足RNP飞行要求。由于飞机上接收机的计算能力有限,计算延迟可能会降低定位精度。为了满足高精度要求,计算延迟引起的误差不能再被忽视。本文提出了一种基于位置精度因子(Position dilution of precision,PDOP)贡献的两步迭代卫星选星算法优化,可以有效减小计算延迟并提高RNP程序下的定位精度。仿真结果表明,该方法在实时性方面优于传统算法,对确保民用飞机飞行安全具有重要意义。
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 relative 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。
