BeiDou navigation satellite system(the BeiDou system) is the only PNT(Positioning, Navigation and Tim-ing) resource in China that has coverage of the globe and near-Earth space and provides continuous high-precision,l...BeiDou navigation satellite system(the BeiDou system) is the only PNT(Positioning, Navigation and Tim-ing) resource in China that has coverage of the globe and near-Earth space and provides continuous high-precision,low-cost positioning, navigation and timing solutions for users in a unified spatio-temporal benchmark. As an importantspatio-temporal benchmark transmission system, the BeiDou system is the most important resource for the nationalPNT system to provide a PNT capability under a unified spatial-temporal benchmark. This paper proposes the con-cept, composition and development model of the space-based PNT system design based on the BeiDou system withall its space characteristics, as well as the advantages of the system. It opens up a new direction for the construction ofChina's PNT system and expands a new horizon in the research of a PNT system in China.展开更多
为了克服有限数据对城市快速路网规划建模的影响,并实现面向规划方案的系统客观的评价方法,本研究以河南省安阳市城市快速路网规划为算例,首先,在人口信息和居民出行(Orientation and Destination,OD)数据不可达的情境下,引入多路径OD...为了克服有限数据对城市快速路网规划建模的影响,并实现面向规划方案的系统客观的评价方法,本研究以河南省安阳市城市快速路网规划为算例,首先,在人口信息和居民出行(Orientation and Destination,OD)数据不可达的情境下,引入多路径OD矩阵反推算法(Multiple Path Matrix Estimation,MPME)以明确现状中心城区内居民出行OD分布矩阵,采用Python集计人口栅格数据中每个单元的数值大小并赋予给相应的交通小区;进而,基于交通需求分析的结果,给出城市快速路网规划方案,并于系统工程决策层面对各方案进行比选;最后,分别从技术评估(静态)和服务评估(动态)对规划方案实施效果进行了评价.结果显示,规划方案3的密切值为0.212,在3个方案中表现最好;规划方案实施后,中心城区负荷度较高的道路都降为1.0以下甚至更低.结论表明,本研究提出的方法可有效解决数据有限条件下的城市快速路网规划工作,研究方案具有可操作性,可作为专项交通规划工作中行之有效的1种方法.展开更多
文摘BeiDou navigation satellite system(the BeiDou system) is the only PNT(Positioning, Navigation and Tim-ing) resource in China that has coverage of the globe and near-Earth space and provides continuous high-precision,low-cost positioning, navigation and timing solutions for users in a unified spatio-temporal benchmark. As an importantspatio-temporal benchmark transmission system, the BeiDou system is the most important resource for the nationalPNT system to provide a PNT capability under a unified spatial-temporal benchmark. This paper proposes the con-cept, composition and development model of the space-based PNT system design based on the BeiDou system withall its space characteristics, as well as the advantages of the system. It opens up a new direction for the construction ofChina's PNT system and expands a new horizon in the research of a PNT system in China.
