Research On Multi-target Indoor Precise Positioning Based On UWB Communication

With the development of today's Internet,artificial intelligence and the Internet of Things technology,the demand for indoor positioning applications is increasing day by day.Because outdoor positioning technologies such as GPS are difficult to obtain effective applications in indoor environments,wireless devices such as Zig Bee,Wifi,Bluetooth,and infrared are currently used,but these methods have some problems in terms of positioning accuracy,stability,and applicability,which cannot meet the growing indoor positioning needs.Ultra Wide Band(UWB)technology can achieve positioning by transmitting narrow pulses at the nanosecond level.It has the advantages of high clock resolution,strong penetration,low power consumption,and anti-multipath.UWB has been widely used in various fields in recent years.This article focuses on the research of multi-target indoor accurate positioning based on ultra-wideband communication.The communication flow and solution algorithm of two positioning methods(Time of Arrival(TOA))and Time Difference of Arrival(TDOA))are studied and analyzed in this article,these methods are commonly used in the positioning field.In addition we propose a new positioning method CTT(Combination of TDOA and TOF).This method uses tags as synchronization sources to implement short-term clock synchronization between base stations participating in positioning within the communication range of tags.Symmetric double-sided two-way ranging(SDS-TWR)ranging process between the tag and the main base station is completed while measuring the time difference of TDOA,and the ranging value is used to suppress errors in the TDOA position calculation process.In order to achieve the purpose of improving the accuracy of TDOA,this article uses DW1000 as a UWB transceiver to complete the experimental comparison of TOA,TDOA and CTT methods in the two-dimensional case of three non-collinear positioning base stations.The experiments show that the positioning accuracy and stability of CTT are close to TOA and higher than TDOA,the single positioning time is only 42.08% of TOA.Because the number of single positioning communications of CTT is constant when the number of base stations increases,based on this feature,this paper proposes a UWB multi-target positioning protocol based on Time Division Multiple Access(TDMA).The DW1000 was used to measure the time parameters of the TDMA synchronization process,which illustrates the feasibility of the protocol.We use MATLAB to simulate the CTT method,TOA method,and TDOA method under multiple base stations in two dimensions.The simulation results show that the CTT positioning loss rate and accuracy are close to the TOA method under reasonable base station density and base station layout.Since CTT does not need to perform sub-nanosecond clock synchronization for base stations in the entire network,it is easier to expand a large range of base stations than TDOA.In addition,the protocol can be directly applied to 3D scenes.