Research On Disaster Area Rescue And Positioning Method Based On Intelligent Antenna

Natural disasters often happen in the blink of an eye.Because the most efficient rescue time is noticeably short,the importance of rapid and accurate positioning technology in disaster areas is gradually increasing.However,the disaster area environment is extremely complex,communication facilities may be damaged,and temporary base stations need to be deployed.The multipath effect and signal attenuation are serious,and the line-of-sight(LOS)path between the base station and the mobile terminal is blocked,which leads to the poor performance of the existing LOS path based positioning methods.In the face of these challenges,this paper proposes a single-anchor disaster area positioning method based on intelligent antenna(IA).IA can control the reflection direction of incident waves.Using the control function of IA to electromagnetic wave,the positioning method proposed in this paper can actively construct the optimal millimeter wave(mm-wave)multiple-input multiple-output(MIMO)signal propagation path between the base station and the mobile terminal to achieve high-precision positioning.In this paper,the positioning application of intelligent antenna in non-line-of-sight(NLOS)environment in disaster area is studied.Main works of this paper are concluded as follow:1.Existing IA-aided channel models are usually modeled as the sum of the paths from the base station transmitter through the IA to the receiver,and a complex gain is introduced into each element of the IA.These models only consider the number of elements and ignores the physical characteristics of IA,such as radiation direction and path loss.Therefore,based on the physical characteristics of IA,this paper establishes a new path loss model which is closer to the reality,taking the size of IA,the number of elements and the radiation characteristics of the antenna system into account.Simulation results show that at the rate of 8bit/s/Hz,an IA with 400 elements can reduce the power by 14.7%compared with the active relay device under the same circumstance.2.Traditional location models are based on LOS propagation situation,which has large system error when dealing with complex problems such as NLOS propagation and multipath effect.Meanwhile,compared with traditional microwave transmission,mm-wave has fewer effective scatterers in the channel due to its propagation characteristics,and the multipath part shows strong sparsity.The short wave length of mm-wave signal makes larger scale MIMO systems possible,which leads to narrower beamforming.In view of the above problems and the characteristics of mm-wave MIMO system,this paper proposes an IA-aided NLOS positioning model combined with the proposed path loss model,derives the expression of the received signal,uses the distributed compressed sensing theory to recover original signals,and obtains the reconstructed channel and location parameters.Simulation results show that the proposed algorithm has higher reconstruction accuracy than other algorithms.3.Some NLOS optimization models only consider the Snell’s law of reflection,and do not consider the positioning method when the propagation path of electromagnetic wave is controllable.IA makes electromagnetic wave have controllable propagation path,that is,the positioning system can control the propagation path of electromagnetic wave according to needs,so that the propagation process and measurement process(such as ranging,angle measurement)of electromagnetic wave are unified into the framework of positioning system.According to the above requirements,this paper designs an IA-aided three-stage positioning method,which combines the reflection characteristics of IA.The idea of "scanning-positioning-optimization" is adopted to improve the signal-to-noise ratio(SNR)of received signal and achieve higher positioning accuracy.Simulation results indicate that the positioning accuracy after optimization is improved by 57.9%with unknown rotation angle and 38.6%with known rotation angle.Compared with the existing NLOS positioning methods,the proposed method can obtain higher positioning accuracy.