Research On Local Positioning Based On Typical Signals Of Opportunity

With the rapid development of information era and increasing travel requirements of people's life,people want to know the location information themselves urgently,and the requirement for location service is also increasing.The quality of location service not only depends on the accuracy of the location information,but also depends on the size of location service area,but the conventional positioning technology was restricted to the development of social urbanization such as the application of GNSS,it unable to meet the requirements of the location in the complex area for people live in city center.In this context,people founded a new method for local positioning based on the typical signals of opportunity,and it is WiFi.Without extra setting special navigation and positioning equipment,the method of local positioning can acquire location information just rely on the existing basis of surrounding wireless network equipment.But there are some problems like interference signal volatility,localization algorithm integrity,WLAN receiving equipment diversity for the application of WLAN positioning in some situation.1.According to the signal transmission characteristics of WLAN,it designed two kinds of indoor experiments,with the result of experiments,to analysis the RSSI of WLAN wireless signal time-varying characteristic and relationship between RSSI and receiving distance,to discuss the fluctuation characteristics in different RSSI and the influence of multipath effect for RSSI sampling.Based on another filtering algorithm,it proposed a new method for RSSI signal filtering preprocessing that named critical gaussian filtering algorithm,and it made up the inadequacy of single signal filtering pre-processing.2.Using NDIS network driver interface specification of Windows network system,with the micro port network card driver Miniport Driver,to extract the WLAN wireless RSSI signal.Design and establish the fingerprint database and fingerprint database index,to extract the characteristic quantity of the fingerprint database.It introduce the weights of Euclidean distance for calculating the coordinates of the point,to realize the WKNN algorithm of multidimensional weighted Euclidean distance for matching positioning,and set up a formula that location positioning of fingerprint database based on typical signals of opportunity.3.Testing the formula of fingerprint database positioning in actual scenario.It contain static single point positioning,dynamic moving track positioning and location positioning with different wireless cards.Static single point positioning,it is discussed point position error with different K to select,to provide the reference for location positioning of the edge of the area.Dynamic moving track positioning,with the form of track positioning shows the change of the WLAN local positioning.According to the fingerprint position test with different wireless network cards,to verify the feasibility of the position fingerprint localization algorithm with different receiving terminals swap.The result show that the formula of local positioning based on typical signals of opportunity is useful for local positioning in actual scenario,to achieve the static positioning and dynamic positioning in indoor environment,and it can get high positioning accuracy,it can meet the requirement of most location service of indoor environment with the location accuracy,to provide the reference for department of local positioning.