Research On Mobile Sensing For Urban Environment

Through the collection,integration and sharing of urban environmental information,the intercommunication between city and people,people and people can be realized,and then a city that can remember,correlate,and anticipate could be constructed to realize the intelligent operation of the city and improve the happiness level of the citizens.To achieve this goal,we should make full use of information technology to perceive,analysis and integrate various kinds of information in cities.A large number of terminal sensors are needed to perceive and acquire urban information for urban sensing.With the continuous development of mobile Internet and micro sensor technology,wearable devices such as smart-phones and smart watches have gradually become an indispensable part of people’s life.Based on the ubiquitous computing power and universal perception ability of smart-phones and wearable smart devices,this paper attempts to link the position,environment and people seamlessly to build a urban nervous system and realize the Omni-directional stereoscopic perception of urban information.The main research work includes the following aspects:(1)This paper analyzes the information elements that mobile devices need to perceive in urban life,and proposes the idea of specific perception scenario.This scenario includes three aspects,namely,"Where","What is around",Individual state".The entire perceptual information elements are divided into corresponding three categories: location perception,environmental perception and personal state perception from the perception of different sensors carried by the smart-phones.Under the guidance of the reference frame,this paper builds a basic mobile sensing platform,and the platform is an exploration and attempt of the reference frame.This paper try to solve three key problems: 1)how to organize all kinds of perceptual information data;2)how to deal with the perceived data of a large number of users in the perception platform;3)how to ensure effective perception and not interfere with the normal life of the user.In order to verify the effectiveness of this platform,this paper has carried out a verification study from two aspects:(1)Through the study of multi-sensor based indoor positioning to guarantee the benchmark of the framework;(2)Through the research if noise perception and noise mapping to verify the unity of individual micro perception to the macroscopic perception of swarm intelligence,so as to provide experience for the comprehensive construction of the reference framework of mobile sensing platform for urban sensing.(2)Location perception is the primary perception element,which is the benchmark of the framework platform perception information.For outdoor location,there are mature location technologies,such as GPS,Beidou and so on,and there is no mature unified solution for indoor positioning yet.In this paper,we analyzed the existing indoor positioning techniques,such as WiFi,Bluetooth,UWB,RFID and some commonly used positioning algorithms,such as proximity,geometric positioning,scene analysis and pedestrian dead reckoning,This paper proposes an indoor positioning method for indoor navigation applications,in which a particle filter combines PDR and RSSI data using the built-in sensors of smartphones.Map constraints are taken into account,to reflect the interior layout of buildings.The major features of the method are that it leverages and fuses the advantages of two different indoor positioning methods(pedestrian dead reckoning and received-signal-strength-indicator-based indoor positioning),and considers the influence on positioning of the indoor spatial map.This allows an improvement of the positioning accuracy by excluding locations in inaccessible regions and reducing through-the-wall trajectories.The use of particle filter therefore helps to improve the user experience.In the actual continuous loop route test,the RMSE location error of this method is 1.48 m.(3)Environmental perception is the main part of mobile sensing,and it verifies the unity of individual micro perception to the macroscopic perception of swarm intelligence.With the development of society and economy,noise pollution has become a new challenge for sustainable development in urban areas and it have attracted widespread attention nowadays.Therefore,this paper takes noise as the research object and studies it as a typical representative of environmental perception.In this paper,the traditional noise monitoring methods,such as sound propagation model or fixed observation stations,are analyzed in this paper,however,there are still some deficiencies in update frequency or accuracy.A low-cost and easy noise-mapping method using smartphones needs to be found.This paper presents a low cost and feasible noise monitoring and noise map generation method based on smart-phone.This method focuses on three aspects,namely,calibration,convenient carrying and fast drawing of noise map.The experiment proves that the method can quickly and conveniently realize monitoring of the environmental factors by the power of the crowd sensing.At the same time,it is proved that the perception platform can effectively handle the macroscopic perception data,and gives the visualized analysis results.