随着卫星定位技术(Global Positioning System,GPS)在室外定位中的深入应用,人们在室外环境下对位置服务(Location Based Service,LBS)愈加依赖,而室内环境中的定位技术还有待发展。本文主要研究了目前室内环境下的主流定位技术及其解...随着卫星定位技术(Global Positioning System,GPS)在室外定位中的深入应用,人们在室外环境下对位置服务(Location Based Service,LBS)愈加依赖,而室内环境中的定位技术还有待发展。本文主要研究了目前室内环境下的主流定位技术及其解决方案,并将其优缺点进行了对比分析,最终给出选择超宽带定位技术的原因。同时,还分析了超宽带定位技术的基本原理及最终选择TDOA算法的原因,并给出求解其后续非线性方程组的建议。简述了在室内环境下影响移动目标精准定位的主要因素,其中,因为非视距传播最能影响信号传播,所以针对降低其对精度的影响力进行了相关算法介绍。展开更多
The adopted 2-D SSD （stopping sight distance） adequacy investigation in current design practice may lead to design deficiencies due to inaccurate calculation of the available sight distance. Although this concern ha...The adopted 2-D SSD （stopping sight distance） adequacy investigation in current design practice may lead to design deficiencies due to inaccurate calculation of the available sight distance. Although this concern has been identified by many research studies in the past, none of them suggested a comprehensive methodology to simulate from a 3-D perspective concurrently both the cross-section design and the vehicle dynamics in space during emergency braking conditions. The proposed methodology can accurately perform SSD adequacy investigation in any 3-D road environment where the ground, road and roadside elements are inserted by identifying areas of interrupted vision lines between driver and obstacle being less than the required distance necessary to bring the vehicle to a stop condition. The present approach provides flexibility among every road design and/or vehicle dynamic parameter inserted, as well as direct overview regarding design elements that restrict the driver＇s vision and create SSD inadequacies. As a result, precious guidance is provided to the designer for further alignment improvement but mostly an accurate aid to implement geometric design control criteria with respect to both existing as well as new road sections is delivered. The efficiency of the suggested methodology is demonstrated through a case study.展开更多
文摘随着卫星定位技术(Global Positioning System,GPS)在室外定位中的深入应用,人们在室外环境下对位置服务(Location Based Service,LBS)愈加依赖,而室内环境中的定位技术还有待发展。本文主要研究了目前室内环境下的主流定位技术及其解决方案,并将其优缺点进行了对比分析,最终给出选择超宽带定位技术的原因。同时,还分析了超宽带定位技术的基本原理及最终选择TDOA算法的原因,并给出求解其后续非线性方程组的建议。简述了在室内环境下影响移动目标精准定位的主要因素,其中,因为非视距传播最能影响信号传播,所以针对降低其对精度的影响力进行了相关算法介绍。
文摘The adopted 2-D SSD （stopping sight distance） adequacy investigation in current design practice may lead to design deficiencies due to inaccurate calculation of the available sight distance. Although this concern has been identified by many research studies in the past, none of them suggested a comprehensive methodology to simulate from a 3-D perspective concurrently both the cross-section design and the vehicle dynamics in space during emergency braking conditions. The proposed methodology can accurately perform SSD adequacy investigation in any 3-D road environment where the ground, road and roadside elements are inserted by identifying areas of interrupted vision lines between driver and obstacle being less than the required distance necessary to bring the vehicle to a stop condition. The present approach provides flexibility among every road design and/or vehicle dynamic parameter inserted, as well as direct overview regarding design elements that restrict the driver＇s vision and create SSD inadequacies. As a result, precious guidance is provided to the designer for further alignment improvement but mostly an accurate aid to implement geometric design control criteria with respect to both existing as well as new road sections is delivered. The efficiency of the suggested methodology is demonstrated through a case study.
