| Modern science and technology have higher and higher requirements for time and frequency.Research on high-precision time synchronization methods plays a fundamental role in national defense construction and the development of national science and technology.In the aviation field,aircraft and aircraft,aircraft and ground stations all need to maintain high-precision time synchronization,and the time synchronization system must have dynamic adaptability,maneuverability,and autonomous operation capabilities.Among many time synchronization technologies,the microwave two-way time synchronization technology has the characteristics of high comparison accuracy and independent of satellites.At the same time,this method can also meet the requirements of the above scenarios and is suitable for highprecision time synchronization of moving targets.To achieve nanosecond time synchronization accuracy,it is necessary to analyze the error sources in the microwave two-way time synchronization system to eliminate or reduce the impact of time delay errors.The main research contents and results of this paper are as follows:(1)According to the requirements of the subject,the composition framework of the microwave two-way ranging and time synchronization system is designed,and the system functions are briefly described in modules;4 typical networking modes in the system application scenarios are described.(2)In view of the multi-target networking requirements,the baseband part of the system adopts a design mode of one transmitting channel and multiple receiving channels.The transmitting part is used to realize the synchronous generation of spreading code,modulation data and carrier signal;the receiving part is compatible with BPSK and The capture and tracking of BOC two modulation methods signal.(3)The influence of frequency source on time synchronization under dynamic environment is studied.According to the related theory of receiver tracking loop error,the vibration phase noise and Alan deviation phase noise of crystal oscillator are analyzed,which provides a theoretical reference for crystal oscillator selection.(4)The moving time delay error in the microwave two-way time synchronization process of the moving target is studied.A mathematical model of the aircraft motion delay error is established,and the simulation results of the motion delay error in different scenarios are obtained;the motion delay error correction model is derived using dynamics and geometric methods,and the air-ground time synchronization motion delay with the aircraft as the moving target is derived.Make corrections;use the UAV model to analyze the dynamic time delay error caused by the random shaking of the body;finally analyze the influence of the Doppler effect on time synchronization;the simulation results meet the requirements of nanosecond time synchronization accuracy for moving targets. |
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