Research And Application Of High Precision Positioning Method In Indoor Based On UWB

In recent years, along with the mobile communication and the wireless sensor network (WSN) constant develop. Location based services (LBS) in the indoor environment has been paid more and more attention. Traditional indoor position technology such as infrared, RFID, Bluetooth and so on, in the cost of the system, positioning accuracy, complexity, stability and other aspects can not meet the needs of users. In this context, Ultra Wide Band (UWB) positioning technology has caused people to pay attention. UWB technology has high ability of communication, the advantages of anti multi path, strong penetrability, high time resolution, high precision positioning, which is a good choice in the indoor environment.This paper focuses on how to improve the UWB indoor positioning accuracy, the main work:Analysis of the advantages and disadvantages of the commonly indoor positioning technology and demonstrates theoretically the techniques suitable for UWB positioning. The analysis shows that based on the received signal strength (RSS) positioning technology is vulnerable to external disturbances, so it has poor positioning accuracy; Based on the angle of arrival (AOA) positioning technology need the antenna array and is not suitable for application in multi path dense environment; Based on signal arrival time positioning technology can make full use of UWB signal strong penetrating ability, anti multi path and a high time resolution advantages, which has a very high positioning accuracy.Based on the time difference of arrival (TDOA) ranging method is determined by the analysis of ranging method and experimentally tests under different indoor environment UWB ranging precision. Then it analyses the multi path, system deviation, error rate, abnormal value, non line of sight (NLOS) impact on the accuracy of fault location. Test results show that multi path has little effect on UWB ranging accuracy in the indoor LOS; the process of eliminating ranging outliers can improve the ranging accuracy of 3mm. the ranging accuracy is significantly reduced in the indoor NLOS, which showes that the main factors affecting measurement accuracy is NLOS.Aiming at the problem of NLOS in the analysis of location error has some common identification methods. Focusing on how to restrain and eliminate gross errors on location in NLOS error, then the Kalman filtering method based on the autoregressive of UWB ranging pretreatment is proposed. Experimental results show that the self regression Kalman filtering method for UWB ranging can effectively improve the positioning accuracy and the positioning precision can reach sub decimeter level.UWB positioning system is applied to the scene of the fire rescue. Through the simulation experiment showed that the design of indoor positioning system can be accurate positioning and tracking to the scene of the fire fighters position.