Design And Implementation Of An Indoor Localization System Based On WLAN And PDR

In our daily life,we have great need for localization service.People need to know their own location or the localization of other people in large shopping malls,railway stations,bus station and other place,and then get the required service.GPS is the common technology.And GPS is widely used in outdoor environment,but GPS can produce large error in the indoor environment and the environment under some cover.Therefore,it is necessary to study the indoor localization algorithm.To get the location of the users in the indoor environment,we use wifi and the built-in inertial sensor in Android mobile phone.The absolute position of the pedestrians in the indoor environment can be got by using the wifi fingerprint algorithm.But the accuracy of WLAN location fingerprint can not meet the needs of actual use in the factory due to the instability of WLAN signals and the effects of multi path propagation.The sensor used in the inertial navigation system can get the data of the acceleration and gyroscope during the process of the pedestrian movement.But the inertial navigation method will produce error accumulation.And the error will become greater and greater by the increase of time.Therefore,we can use the position information obtained by the wifi positioning algorithm to calibrate the position information of the inertial navigation system,and the Gauss filter of AP wireless signal is used to get the strength of signal.The K-Means algorithm is used to classify the fingerprint information after getting the position of fingerprint information.The K weighted adjacent algorithm is used to calculate the location of the pedestrian.The initial position of the user is determined by the location of the wifi fingerprint algorithm.The step number and step length of the pedestrian is produced to calculate the distance in the pedestrian inertial navigation module.The direction of the pedestrian is calculated by the direction sensor and the gyroscope.And the position of the user is obtained by using this method.By combining these two methods,the positioning accuracy is improved.An indoor positioning system in an electric company is designed and built to help people get their localization and get the history data of the position of the people.Experimental results show that the method can be used to locate the indoor pedestrian more accurately by combining the wifi method with the sensor data.