| Wireless sensor network has been widely used in real life because of its low power consumption and low cost.Positioning technology applied in wireless sensor network,which has a good application in the fields of military,medical,disaster relief and so on,has attracted many researchers in recent years.In the outdoor environment,the Global Positioning System(GPS)can be used to locate some targets to obtain the information.But in the indoor environment,due to the impact of many factors,such as obstacles,one's walking and walls,energy and direction of the wireless signal will change in different levels in the process of communication and therefore it will produce a low positioning accuracy or error if outdoor positioning technology were applied in the indoor environment.The purpose of this paper is to improve the positioning accuracy of indoor positioning technology.Two interference factors,environment parameter and burst interference,are investigated in detail.In order to reduce the ranging error caused by the imprecise environment parameters and the replacement of local environmental parameters by the global,firstly the indoor location area is divided into many different sub areas.All the sub areas are linearly fitted for obtaining precise local environmental parameters to accurately position each area,which results in small ranging error.Secondly Gauss model is used to filter the RSSI values measured by the network node and then average the filtered values.The average RSSI value is not burst interfered and used as the final measurement value of RSSI to improve the accuracy of RSSI value.Trilateral positioning method is analyzed in the actual environment.Because the traditional trilateral positioning method with weights can not distinguish the primary and secondary status of different weight values,an improved trilateral positioning method with weights is proposed and simulated on MATLAB.The simulated results show that the improved method can enhance the positioning accuracy. |
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