Research On Indoor Positioning Method Based On Single AP Access Environment

The personnel positioning system is an important part of the operation and maintenance management of the urban underground comprehensive management operation.From the perspective of safety,the inspectors of the underground pipe gallery not only overcome the complicated working conditions caused by the complicated environment,but also face a certain degree of danger.In the event of an emergency,the system of the integrated pipeline corridor operation and maintenance center needs to calibrate the specific location of the worker in time to initiate rescue.Since wireless APs are distributed in a single form in the long and narrow underground pipe gallery and are relatively sparse,the staff can only receive a single Wi Fi signal strength value during the travel process,so the positioning method can only be proposed based on the single AP access environment.And due to the narrow and long geographical environment of the underground integrated pipe gallery,if the traditional location fingerprint positioning method is to be used,a complex and huge offline database needs to be established,which means that a large amount of offline fingerprint data needs to be collected,and a lot of labor costs are required.In addition,the Wi Fi indoor positioning system will be affected by multiple reasons such as multipath effects,human shadows,co-frequency interference,and equipment factors,making the strength of the Wi Fi received signal uncertain,which ultimately leads to low positioning accuracy.In summary,this research proposes an indoor positioning method based on a single AP access environment.This article had proposed an off-line location fingerprint database based on the adaptive simulated annealing(SA)particle swarm optimization algorithm(PSO)combined with kriging interpolation algorithm.Firstly,the received signal strength values of some points were collected,then the adaptive SA-PSO algorithm was used to optimize the parameters of the variation function of the theoretical spherical model,and the adaptive SA-PSO-Kriging interpolation model was established.Through the interpolation model,the RSSI of the prediction points were estimated,and a complete offline location fingerprint database was constructed together with the values of the collection points.Simulation and experiments show that the adaptive SA-PSO algorithm proposed in this paper has stronger optimization ability than the traditional PSO algorithm,can reduce the manual collection workload by 50%,the average positioning accuracy was improved by 5.8%,and the cumulative error probability of2 m and 4m was improved by 5%.This paper had proposed a Wi Fi/Geomagnetic combined positioning method.In this combination method,firstly,the collected Wi Fi strength data was filtered by outlier detection method.Then,the filtered Wi Fi signal intensity data value is used to construct the corresponding data fingerprint database.In the following positioning operation,the classical k-nearest neighbor algorithm was firstly used for preliminary positioning.Then,a standard circle was constructed based on the points obtained by the algorithm and the actual coordinate points.The diameter of the standard circle was the error,and the geomagnetic data were used for more accurate positioning in this circle.The method reduced the Wi Fi mismatch rate caused by multipath effects and improved positioning accuracy.Finally,a positioning accuracy experiment was performed in a single AP distribution environment that simulating a pipe corridor environment.The results show that the proposed Wi Fi/ geomagnetic combined location method has better positioning accuracy than the traditional single Wi Fi and geomagnetic matching location.At the same time,this paper also designed an indoor positioning system,which is based on the Android platform.The positioning system is based on C/S architecture,and the client is an Android application,which mainly provides location service for the staff of underground pipe corridor.The client mainly collects location fingerprint information in the surrounding environment to establish an offline location fingerprint database,and at the same time realizes the function of online positioning and display.The server is mainly on the PC of the main control center.Its main function is to receive and display location information,which is sent by the client.