Research On Optimization Of SDS-TWR And Fusion Of Location Algorithm In Indoor Position Based On UWB

Global Navigation Satellite Systems (GNSS) is one of the most popular location systems. But this technology still has its limitation in indoor positioning. With the development of Wireless Sensor Network (WSN), people show increasing interest in Wireless Location Technology based on UWB, infrared ray, blue tooth, ultrasound wave, RFID, etc. Considering the properties of low transmitted power, anti-interference capability, penetrability, secrecy performance and localizing precision, UWB-tech has much more promising application prospect.In this Thesis, the technical feature of UWB-tech and its channel characteristics are discussed. Accounting the distance-measuring strategy of UWB, we used a better arithmetic to decrease the long delaying time in the SDS-TWR ranging protocol, also we prove the validity of our arithmetic mathematically. As the Taylor algorithm needs precise initial input, we used the Least Squares method and the Taylor algorithm together to improve.... Then we perform a UWB positioning system, and some performances are r tested. The structure of this essay is followed as below.Firstly, we discusse some common UWB positioning techniques, e.g. RSS, TOA. And their Cramer-Rao lower bounds are compared. It is proved that TOA is the most effective techniques for UWB ranging. Moreover, we studied TOA’s ranging protocol, e.g. OWR, TWR, SDS-TWR, and calculated their error caused by clock drift. We could see that SDS-TWR sacrifices more measuring time to reduce the error.Secondly, we made some research on localizing technologies, e.g. The Least Squares, The Chan, The Taylor-algorithm, etc. We proposed an inproved algorithm that the Taylor-algorith is combined with the Least Squares. Once the measured nodes moved during positioning, the results would fluctuate. So we use the UKF filtering algorithm in positioning. The simulated results show that the UKF can effectively trace the movement of the nodes.At last, we propose the frame of UWB positioning system by using DaceWave’s DW1000, including optimized SDS-TWR ranging algorithm and the fusion of Taylor and LS, which can save a lot of measuring time and offer possibility to real-time ranging. And we used the UWB positioning system to do some indoor tests, which turned out that the precision of positioning is under 40cm.