Research On Location Technology Based On Wireless Network

In recent years,research on wireless network positioning technology has become one of the hotspots with the increasing demand for applications such as situational awareness and environmental intelligence and acquiring location information of mobile objects.ZigBee technology is widely used due to its low power consumption,low cost and high coverage area.UWB technology is considered to be potential due to its advantages of multipath fading resistance,strong penetrating power and high positioning accuracy.This paper first gives a brief introduction to the mainstream positioning technology,and compares the advantages and disadvantages of several common positioning technologies.Then the three kinds of radio signal propagation model such as logarithmic attenuation model,DOI(Degree of Irregularity)model and RIM model(Radio Irregularity Model)are expounded and simulated in MATLAB platform.The irregularity increases gradually with the increase of parameters doi in DOI and RIM model.In positioning systems,algorithm is the determining part of the positioning performance.Choosing the RSSI(Received Signal Strength Indication)algorithm based on measuring distance directly and DV-Hop(Distance Vector-hop)and Amorphous algorithms based on measuring distance indirectly to compare in MATLAB simulation platform,discussing the relationship between the normalized positioning accuracy and the number of nodes at the different algorithms?different radio propagation models and different node densities.The simulation results show that the logarithmic decay model and the RSSI localization algorithm have better performance.Therefore,this model and algorithm are chosen as the basis for algorithm improvement.Aiming at the problem that the traditional fingerprint localization algorithm with huge workload and the signal strength RSSI is inaccurate,this paper proposes to use ray tracing technology to collect the offline data part and generate the signal strength RSSI database of each grid point.This database is used as the database for fingerprint identification.At last the K-nearest neighbor method is used to calculate the final position.Finally,ZigBee and UWB(Ultra-Wide Band)positioning system platform was built,designing hardware and software of the network node and the positioning process of the system.In the ZigBee positioning system,the reference node transmits the information to the blind node for calculation.In the UWB positioning system,the label transmits the information to the base station for calculation.Testing the positioning effect and communication range of the two positioning systems indoors and outdoors.The availability of the two positioning systems designed in this paper is verified,which not only improves the traditional ZigBee wireless positioning performance,but also provides the UWB technology for feasibility plan.