A Study On RTLS-UWB System Based On DW1000 Precision Location

Real-time positioning system(RTLS)is a system that can acquire the location information of people or objects at any time.For example,the global positioning system(GPS)which we often use,Beidou positioning system belongs to the real-time positioning system based on satellite signals.Wi-Fi and iBeacon positioning systems are used in indoor environment,but the positioning errors of these positioning systems are very large.Ultra-wideband(UWB)technology used in this paper can achieve centimeter-level distance measurement,which is very suitable for indoor and outdoor precise positioning system applications.The DW1000 chip used in this paper meets the physical layer standard of IEEE802.15.4-2011.It integrates a timer with high precision picosecond time resolution and can directly measure the flight time of the signal.The main work of this paper is to develop the circuit design and positioning software of DW1000 module,and realize the real-time positioning system based on UWB technology.Firstly,the paper describes the technical background and development trend of UWB-based precise positioning system.The research of this topic has very good practical value.The common methods of wireless ranging,such as received signal strength,signal arrival angle and signal flight time,are studied.The advantages and disadvantages of TDOA,TWR and SDS-TWR ranging methods are emphatically analyzed,and the error analysis is carried out.By studying the physical layer of the IEEE 802.15.4-2011 UWB standard,the channel bandwidth,signal modulation and data frame structure defined by the physical layer of UWB are analyzed.In the part of hardware design,the working principle of DW1000 chip is analyzed,and the minimum system hardware circuit is designed.At the same time,a practical location tag with small size,low power consumption and low cost is designed.The problems needing attention in the process of hardware design of DW1000 are described in detail.The hardware circuit of anchor node is designed by using high performance 32-bit ARM processor STM32F405 chip and hardware Ethernet chip.The software part of the system is designed with emphasis on the distance measurement program design of the DW1000 chip.The embedded real-time operating system ChibiOS/RT and ChibiOS/HAL are used to drive the underlying hardware efficiently,which simplifies the difficulty of driving the underlying hardware.An improved ADS-TWR ranging method and TDMA technology are used to complete the application of multi-label positioning system.Based on the QT language,a visual positioning engine software is designed,which can display the positioning results intuitively.Finally,the production test of the hardware is completed,and the test results of RF parameters are given.The hardware performance meets the design requirements.We have set up the actual test environment,through the analysis of the test data,it is concluded that the ranging error of the system is±15cm and positioning error ±30cm.Compared with the traditional positioning technology,this system can achieve centimeter positioning accuracy,and has a good market prospect.