Achieving higher accuracy positioning results in urban environments at a lower cost has been an important pursuit in areas such as autonomous driving and intelligent transportation.Lowcost Inertial Navigation System a...Achieving higher accuracy positioning results in urban environments at a lower cost has been an important pursuit in areas such as autonomous driving and intelligent transportation.Lowcost Inertial Navigation System and Global Navigation Satellite System(INS/GNSS)integrated navigation systems have been an important means of fulfilling the above quest due to the complementary error characteristics between INS and GNSS.The complex urban driving environment requires the system sufficiently adaptive to keep up with the time-varying measurement noise and sufficiently robust to cope with measurement outliers and prior uncertainties.However,many efforts lack a balance between adaptability and robustness.In this paper,a novel positioning method with both adaptability and robustness is proposed by coupling the Mahalanobis distance method,the Variational Bayesian method and the student’s t-distribution in one process(M-VBt method).This method is robust against non-Gaussian noise and priori uncertainties,plus adaptive against measurement noise uncertainty and time-varying noise.The field test results show that the M-VBt method(especially the Mahalanobis distance part)has significantly improved the system performance in the complex urban driving environment.展开更多
Urban public infrastructure is an important basis for urban development.It is of great significance to deepen the research on intelligent management and control of urban public infrastructure.Spatio-temporal informati...Urban public infrastructure is an important basis for urban development.It is of great significance to deepen the research on intelligent management and control of urban public infrastructure.Spatio-temporal information contains the law of state evolution of urban public infrastructure,which is the information base of intelligent control of infrastructure.Due to the needs of operation management and emergency response,efficient sharing and visualization of spatio-temporal information are important research contents of comprehensive management and control of urban public infrastructure.On the basis of summarizing the theoretical research and application in recent years,the basic methods and current situation of the acquisition and analysis of spatio-temporal information,the forecast and early warning,and the intelligent control of urban public infrastructure are reviewed in this paper.展开更多
提出了采用单频精密单点定位(precise point positioning,PPP)技术实现基于u-blox的城市区域亚米级导航定位技术服务模式,该模式完全取代精度相对较低的标准单点定位(standard point positioning,SPP)技术,同时相比于网络RTK(real-time ...提出了采用单频精密单点定位(precise point positioning,PPP)技术实现基于u-blox的城市区域亚米级导航定位技术服务模式,该模式完全取代精度相对较低的标准单点定位(standard point positioning,SPP)技术,同时相比于网络RTK(real-time kinematic)技术具有占用资源更少、不受用户数量限制等优点。单频PPP技术实现包括数据的接收与解码,位置解算和实时位置信息地图显示功能。通过城市密集区域车载实验,E、N、U 3方向定位精度分别为0.54 m、0.61 m和1.95 m,说明单频PPP技术在可以稳定提供亚米级导航定位服务。展开更多
针对城市公园可达性受多种环境因素影响,以及在时间上存在动态变化特征的问题,通过建立公园吸引力评价模型和引入时间序列实时导航数据,提出了一种顾及公园自身吸引力的城市公园时空可达性研究方法(Spatial-Temporal Accessibility of A...针对城市公园可达性受多种环境因素影响,以及在时间上存在动态变化特征的问题,通过建立公园吸引力评价模型和引入时间序列实时导航数据,提出了一种顾及公园自身吸引力的城市公园时空可达性研究方法(Spatial-Temporal Accessibility of Attraction-Oriented Urban Parks,STAAOP):首先,基于众源地理信息数据,采用熵权法从多种角度构建公园吸引力评价模型;然后,基于吸引力评价结果与时间序列实时导航数据,运用两步移动搜索法构建可达性度量模型;最后,计算可达性变化结果的标准差,并运用局部空间自相关分析法识别可达性变化的聚类区域和异常区域,从整体和典型区域的角度分析可达性变化强度.以济南市为例,采用STAAOP方法进行实验,结果表明:STAAOP方法及其所包含的模型可以更好地捕捉城市公园可达性的时间动态变化特征,在整体和区域上都能取得较好的实验结果,该方法为更准确、真实评价城市公园可达性提供了一种新的思路和参考.展开更多
In this paper,I present B-DRIVE—a blockchain-based distributed IoT(Internet of Things)network for smart urban transportation.The network is designed to connect a large fleet of IoT devices,installed on various vehicl...In this paper,I present B-DRIVE—a blockchain-based distributed IoT(Internet of Things)network for smart urban transportation.The network is designed to connect a large fleet of IoT devices,installed on various vehicles and roadside infrastructures,to distributed data storage centers,called as Full-Nodes,to log and disseminate sensor generated data.It connects devices from around the city to multiple Full-Nodes to log timestamped data into the blockchain.These sensors vary from GPS(Global Positioning System),air quality meter,gyrometer to speed cameras in order to facilitate efficient urban mobility.The three identified hardware layers that comprise the network are the IoT layer,Storage layer,and User layer.They consist of Moving/Static-Nodes,Full-Nodes,and Smart devices,respectively.The Moving/Static-Nodes are primarily made up of moving vehicles and road-side infrastructures,respectively,thus acting as various data sources.Whereas,Full-Nodes and Smart devices are institutions and mobile phones,acting as data handler/disseminator and navigator/data visualizer,respectively.The data,or data blocks,received by Full-Nodes get appended into Full and Running-Blockchain,meant for specific purposes.The network is designed to be free from any block mining activity.It provides open access to anonymous sensor data to end-users,especially scientists,policy-makers and entrepreneurs,to develop innovative urban transportation solutions.It is believed that a system like B-DRIVE,along with existing VANETs(Vehicular Ad-hoc NETworks),is capable of answering some of the current urban transportation issues around traffic congestion,navigation,and vehicle parking.Other applications of blockchain data could vary from user activity mapping to VGI(volunteered geographic information)data quality assessment.Two identified limitations of the presented architecture are the low processing power of current IoT devices and the lack of urban IoT infrastructure.展开更多
Non-line-of-sight(NLOS)multipath effect is the main factor that restricts the application of global navigation satellite system(GNSS)in complex environments,especially in urban canyon.The effective avoidance of NLOS s...Non-line-of-sight(NLOS)multipath effect is the main factor that restricts the application of global navigation satellite system(GNSS)in complex environments,especially in urban canyon.The effective avoidance of NLOS signals can significantly improve the positioning performance of GNSS receiver.In this paper,an NLOS/LOS classification model based on recurrent neural network is proposed to classify satellite signals received in urban canyon environments.The accuracy of classification is 91%,and the recognition rate of NLOS is 89%;the classification performance is better than that of traditional machine learning classification models such as support vector machine.For BeiDou navigation satellite system/global positioning system(BDS/GPS)fusion system,the least square algorithm and extended Kalman filter are used to estimate the position.The experimental results show that the three-dimensional positioning accuracy after NLOS recognition is improved about 60%on average compared with the traditional methods,and the positioning stability is also improved significantly.展开更多
Urban road pricing schemes are becoming increasingly popular among researchers and politicians as they promise a handle on increasing inner city traffic and economy as well as sustainable improvements for cities facin...Urban road pricing schemes are becoming increasingly popular among researchers and politicians as they promise a handle on increasing inner city traffic and economy as well as sustainable improvements for cities facing huge congestion and pollution problems. As in the cases of London and Stockholm, many European cities are going to implement such toll systems, especially as also the European Commission is voting for such pricing schemes in the recent white book on transportation and traffic, This research therefore provides a description of different urban road pricing schemes, their cost implications for city （last mile） transport as well as the decision and management options derived from these schemes for logistics companies. These options are furthermore checked regarding their advantages and disadvantages under the described toll schemes.展开更多
基金funded by National Natural Science Foundation of China(No.61901015)。
文摘Achieving higher accuracy positioning results in urban environments at a lower cost has been an important pursuit in areas such as autonomous driving and intelligent transportation.Lowcost Inertial Navigation System and Global Navigation Satellite System(INS/GNSS)integrated navigation systems have been an important means of fulfilling the above quest due to the complementary error characteristics between INS and GNSS.The complex urban driving environment requires the system sufficiently adaptive to keep up with the time-varying measurement noise and sufficiently robust to cope with measurement outliers and prior uncertainties.However,many efforts lack a balance between adaptability and robustness.In this paper,a novel positioning method with both adaptability and robustness is proposed by coupling the Mahalanobis distance method,the Variational Bayesian method and the student’s t-distribution in one process(M-VBt method).This method is robust against non-Gaussian noise and priori uncertainties,plus adaptive against measurement noise uncertainty and time-varying noise.The field test results show that the M-VBt method(especially the Mahalanobis distance part)has significantly improved the system performance in the complex urban driving environment.
基金Jinqiao Project Seed Fund of Beijing Association for Science and Technology(No.ZZ19018)。
文摘Urban public infrastructure is an important basis for urban development.It is of great significance to deepen the research on intelligent management and control of urban public infrastructure.Spatio-temporal information contains the law of state evolution of urban public infrastructure,which is the information base of intelligent control of infrastructure.Due to the needs of operation management and emergency response,efficient sharing and visualization of spatio-temporal information are important research contents of comprehensive management and control of urban public infrastructure.On the basis of summarizing the theoretical research and application in recent years,the basic methods and current situation of the acquisition and analysis of spatio-temporal information,the forecast and early warning,and the intelligent control of urban public infrastructure are reviewed in this paper.
文摘提出了采用单频精密单点定位(precise point positioning,PPP)技术实现基于u-blox的城市区域亚米级导航定位技术服务模式,该模式完全取代精度相对较低的标准单点定位(standard point positioning,SPP)技术,同时相比于网络RTK(real-time kinematic)技术具有占用资源更少、不受用户数量限制等优点。单频PPP技术实现包括数据的接收与解码,位置解算和实时位置信息地图显示功能。通过城市密集区域车载实验,E、N、U 3方向定位精度分别为0.54 m、0.61 m和1.95 m,说明单频PPP技术在可以稳定提供亚米级导航定位服务。
文摘In this paper,I present B-DRIVE—a blockchain-based distributed IoT(Internet of Things)network for smart urban transportation.The network is designed to connect a large fleet of IoT devices,installed on various vehicles and roadside infrastructures,to distributed data storage centers,called as Full-Nodes,to log and disseminate sensor generated data.It connects devices from around the city to multiple Full-Nodes to log timestamped data into the blockchain.These sensors vary from GPS(Global Positioning System),air quality meter,gyrometer to speed cameras in order to facilitate efficient urban mobility.The three identified hardware layers that comprise the network are the IoT layer,Storage layer,and User layer.They consist of Moving/Static-Nodes,Full-Nodes,and Smart devices,respectively.The Moving/Static-Nodes are primarily made up of moving vehicles and road-side infrastructures,respectively,thus acting as various data sources.Whereas,Full-Nodes and Smart devices are institutions and mobile phones,acting as data handler/disseminator and navigator/data visualizer,respectively.The data,or data blocks,received by Full-Nodes get appended into Full and Running-Blockchain,meant for specific purposes.The network is designed to be free from any block mining activity.It provides open access to anonymous sensor data to end-users,especially scientists,policy-makers and entrepreneurs,to develop innovative urban transportation solutions.It is believed that a system like B-DRIVE,along with existing VANETs(Vehicular Ad-hoc NETworks),is capable of answering some of the current urban transportation issues around traffic congestion,navigation,and vehicle parking.Other applications of blockchain data could vary from user activity mapping to VGI(volunteered geographic information)data quality assessment.Two identified limitations of the presented architecture are the low processing power of current IoT devices and the lack of urban IoT infrastructure.
文摘Non-line-of-sight(NLOS)multipath effect is the main factor that restricts the application of global navigation satellite system(GNSS)in complex environments,especially in urban canyon.The effective avoidance of NLOS signals can significantly improve the positioning performance of GNSS receiver.In this paper,an NLOS/LOS classification model based on recurrent neural network is proposed to classify satellite signals received in urban canyon environments.The accuracy of classification is 91%,and the recognition rate of NLOS is 89%;the classification performance is better than that of traditional machine learning classification models such as support vector machine.For BeiDou navigation satellite system/global positioning system(BDS/GPS)fusion system,the least square algorithm and extended Kalman filter are used to estimate the position.The experimental results show that the three-dimensional positioning accuracy after NLOS recognition is improved about 60%on average compared with the traditional methods,and the positioning stability is also improved significantly.
文摘Urban road pricing schemes are becoming increasingly popular among researchers and politicians as they promise a handle on increasing inner city traffic and economy as well as sustainable improvements for cities facing huge congestion and pollution problems. As in the cases of London and Stockholm, many European cities are going to implement such toll systems, especially as also the European Commission is voting for such pricing schemes in the recent white book on transportation and traffic, This research therefore provides a description of different urban road pricing schemes, their cost implications for city （last mile） transport as well as the decision and management options derived from these schemes for logistics companies. These options are furthermore checked regarding their advantages and disadvantages under the described toll schemes.
