Distance Measurement For Ultra-wide Band WSN Nodes Using Time Reversal Method

In wireless sensor network,due to the multipath environment existence,node location have a great impact on the distance,which lead to a significant reduction in positioning accuracy. The ultra-wideband technology with strong multipath resolution capability and penetration capability,time reversal technique with ability of optimized channel and suppression multi-channel.Therefor this paper combine ultra-wideband with time reversal for ranging study of wireless sensor network.This paper aim to improve the shortcomings with poor accuracy of positioning, large amount of calculation for the existing ranging method indoor.this paper mainly combine with time reversal and traditional wireless network sensor network to made a comprehensive research.Firstly,given the ranging method which based on window time reversal, It bring together the time reversal theory,UWB technology and TOA method which can effectively use multipath compensation to eliminate the impact from environment on range.Secondly, introduce the ranging process of window time reversal in the indoor environment,analyzes the ranging impact on the obstacle in LOS environment.It also propose that how to reduce the impact of obstacles on the ranging.through 40 groups experiment which can obtain ranging errors are less than 1%.Finally,given the method to reduce the influence of obstacles on ranging.In NLOS environment,it can obtain the direct path and focused energy by the spatial and temporal focusing of test pulse with UWB.After that comprehensive analysis of the amplitude and energy coefficient to perception in LOS environment or NLOS environment.Further study obstacles affecting factors,we analyzed the influence regular of obstacles’ length,width,and position,and combined with focusing peak power ratio and additional time delay of them to deduce the estimation expression of error.Finally the paper by multigroup experiments to process the ranging experimental data.Under the NLOS environment, through use of the relationship between focusing peak power ratio and additional time delay to restore the real distance,which can obtain the ranging error.