| With the rapid development of information technology,location services have become an important part of network information services.Currently,location services have slowly penetrated into enterprise services,government and public services and so on,which have gained attention in a variety of industries,such as smart cities,smart warehousing and logistics,Internet of vehicles,and shared industries,all of which rely on location information to provide corresponding location services.Considering the important role of location services in vertical industry applications,the 5G Release 17 standard requires positioning accuracy better than 0.2m for industrial IoT applications and 0.1m for vehicle networking positioning.Therefore,it is important to study high-precision wireless positioning technology.The main research work in this paper are as follows.(1)Inspired by the high-precision characteristics of carrier phase,this paper investigates high-precision positioning algorithms in a mobile cellular communication environment,and proposes a high-precision carrier phase positioning algorithm based on the mobile feature.The algorithm uses the time difference carrier phase to estimate the mobile feature of the target to be located without introducing additional sensors.By combining instantaneous carrier phase measurements and distance measurements,with the mobile feature,the posterior probability of the target to be located based on Bayesian theory can be obtained.In turn,the position estimation of the target to be located can be realized by using the factor graph and sum-product algorithm.Simulation results show that the proposed algorithm can achieve centimeter-level accuracy.(2)This paper uses the smart software defined radio(SMART SDR)development board to build a positioning system,uses the development board to transmit and receive signals respectively,and verifies the location solution performance of the mobile terminal based on this.In this paper,a multipath signal processing module,a carrier phase measurement module,a signal transmission delay estimation module and a location solving module are designed.The received signal is firstly identified by frame synchronisation to identify the starting position of each frame,and then the multipath interference is suppressed by the signal processing process.The anti-multipath processed signal is transmitted to the carrier phase measurement module and the time delay estimation module to achieve carrier phase estimation and time delay estimation.Finally,the location solution is achieved by the algorithm proposed in this paper.The positioning system can be tested in a practical environment and is able to achieve initial positioning at the decimetre level. |
