Abstract
With the rapid development of social informatization and the deepening of the complexity of interior architecture,people's demand for accurate and efficient indoor positioning services has increased dramatically.The WiFi positioning technology has become a popular research hotspot with its advantages of wide distribution,fast transmission and low cost.However,at present,researches on WiFi indoor positioning mostly focus on indoor two-dimensional positioning.However,there are relatively few researches on WiFi indoor three-dimensional positioning,which results in the lack of efficiency and accuracy of indoor positioning services.Therefore,this dissertation studies the indoor three-dimensional positioning technology and method based on WiFi.By studying the RSSI value preprocessing method and distance measurement model,the error of WiFi three-dimensional positioning ranging stage is reduced,and based on this,a new method is proposed.WiFi-based three-dimensional space intersection centroid improved algorithm to achieve higher precision three-dimensional positioning of WiFi indoor.The WiFi-based indoor three-dimensional positioning method improves the indoor three-dimensional positioning accuracy and provides new ideas for accurate and efficient indoor positioning services.This article specifically studied the following aspects:
(1)The principle of WiFi three-dimensional positioning and its key technical methods are analyzed.The main research content based on WiFi three-dimensional positioning and the relationship between them are determined,and the key issues that need to be solved in WiFi three-dimensional positioning research and corresponding solutions are clarified.The WiFi positioning ranging method,RSSI ranging path loss model and traditional3D positioning algorithm are deeply studied,which provides theoretical and technical support for the research of WiFi three-dimensional positioning.
(2)The preprocessing method of RSSI data and the method of determining the optimal ranging model are studied.First,the RSSI data preprocessing method is studied,and the RSSI data collected is subjected to singular value processing and Gaussian filter processing to obtain the RSSI value used for ranging.Secondly,on this basis,the distance measurement
model is evaluated and analyzed to determine the optimal distance measurement model in the indoor space environment.Finally,a parameter optimization method for the distance measurement model is proposed,which is based on WiFi while reducing the ranging error. The implementation of indoor three-dimensional positioning algorithms and the implementation of higher-precision three-dimensional positioning provide ranging support.
(3)An improved indoor3D location algorithm based on WiFi is proposed.The algorithm combines3D centroid algorithm on the basis of traditional RSSI-based location algorithm.It uses the AP reference node and distance measurement results to build a location space model to make intersections.The intersection point of the solution of the center of mass,so as to achieve the final position of the node to be measured,while improving the accuracy of indoor three-dimensional space to a certain extent.
(4)Built and implemented a WiFi-based indoor three-dimensional positioning system.In order to meet the needs of WiFi-based indoor three-dimensional positioning system,the system framework is designed,and the core functions of the system in the mobile terminal, server and database are analyzed.At the same time,the data acquisition and position coordinate display of the system are implemented on the Android platform.Features.Finally, the actual performance of the system's positioning performance is tested,and the feasibility and effectiveness of the WiFi indoor three-dimensional positioning method are verified by analyzing the experimental results.
The WiFi-based indoor three-dimensional positioning method can compensate for the lack of positioning service accuracy caused by ignoring the user's three-dimensional position information,and can significantly improve the accuracy of the positioning service.Studying WiFi-based indoor3D positioning methods provides a new idea for more accurate indoor positioning services.
Key words:WiFi,Three-dimensional positioning,RSSI,Optimal ranging model,Intersection centroid