Research And Implementation Of Synchronization Technology For Ground-based Wireless Positioning System

With the development of modern technology,the application of positioning and navigation technology is becoming more and more widespread.Both in the civilian and military fields,reliable positioning and navigation methods are needed to meet people's needs for obtaining accurate location information.However,even the most widely used Global Navigation Satellite System(GNSS)cannot be applied to all application scenarios.In order to overcome the inherent shortcomings of satellite positioning mode,groundbased positioning navigation system with high accuracy,high efficiency and flexible application range has emerged.At present,the research of ground-based positioning system is developing toward independent positioning,fast networking,and improving positioning accuracy,etc.These characteristics determine that the ground-based positioning system can be flexibly applied to complex scenarios such as smart factories,cities,canyons,and unmanned aircraft start-stop in the area.It has high research value.In this thesis,specific research on the networking scheme,signal system and synchronization scheme of the ground-based positioning system are conducted.Based on this design,a hardware platform that conforms to the system mechanism is built,and verify the system communication function and synchronization scheme on the hardware platform.The main contents are as follows.Firstly,by reading the literature,the development and current situation of groundbased positioning system at home and abroad are investigated.its features and limitations are analyzed.And in-depth research and analysis for the synchronization technology which is the core of the system are conducted.Secondly,based on the existing positioning and navigation principles,the networking scheme,signal system and positioning scheme of the ground-based positioning system are studied,and a carrier synchronization-based clock synchronization scheme is proposed for the base station networking and forwarding positioning system based on TDMA signal system.Again,according to the system functional requirements and performance indexes,an integrated multi-mode switching hardware platform including transceiver,synchronization loop,signal processing and control unit,and communication unit is designed and implemented.Combined with the actual test conditions,the system networking was carried out by using optical terminals and fiber optic network to simulate the positioning distance,and the construction of the ground-based positioning system was completed.Finally,the functional verification of the system modulation transmitting,receiving and demodulating,signal processing and external communication as well as the performance test were completed on the hardware platform.On this basis,the verification of the system carrier synchronization and clock synchronization scheme was completed.The foundation for the high-precision positioning results of the ground-based navigation system is laid.