Research On Radio Time Synchronization Technology In Distributed System

Precise time synchronization technology is more and more used in the field of engineering and military.In the military application scenarios of distributed nodes,precise time synchronization technology is needed to support the cooperative operations among or within various weapon platforms such as sea,land and air.At the same time,under the background of modern war,the autonomy,application flexibility and accuracy of time synchronization technology are required in various fields.Aiming at the synchronization requirement of distributed electronic system,based on bidirectional time transfer,this paper introduces the dual branch signal system and BOC modulation mode,designs the corresponding acquisition and tracking algorithm,and gives the real-time clock difference measurement method and synchronization accuracy of nodes in static and maneuvering scenarios.The main contents of the paper are summarized as follows:1.The technical scheme and parameter measurement method of dual one-way ranging measurement technology to achieve synchronization between nodes are studied,and the main errors in synchronization process and the corresponding means to improve the accuracy are analyzed.2.The design of synchronous signal system and mode has been completed.The double branch composite synchronous signal is designed for information transmission and pseudo distance measurement,BOC modulation mode is introduced in both branches;The narrow correlation peak and splitting spectral characteristics of BOC modulation and branch signal characteristics are used to improve the code tracking accuracy and anti-multipath performance of in-phase branch signal,and anti-interference performance of orthogonal branch signal,and the simulation results are verified.3.A receiver acquisition and tracking algorithm is designed for synchronous signals.In the acquisition stage,the coherent,noncoherent and differentially coherent joint acquisition algorithms are compared from the detection probability and other evaluation indicators,and the coherent acquisition algorithm with the highest detection probability and the shortest average acquisition time is selected.In the tracking phase,the tracking accuracy of “Bump-Jump”,ASPe CT and DET algorithm are compared,and a joint tracking algorithm of phase detector based on double loop estimation is proposed.The simulation results show that when the carrier to noise ratio reaches 45 d B-Hz,the synchronization accuracy between nodes is improved to 0.2ns by using the synchronization signal and acquisition tracking algorithm.4.Aiming at the synchronization problem in maneuvering scene,the maneuvering speed is introduced to improve the synchronization technology and increase the accuracy to 0.68 ns.Aiming at the synchronization problem in the case of strong multipath interference,an algorithm for smoothing satellite time-service data using dual one-way ranging measurement technology is proposed.The simulation results show that the synchronization accuracy can reach 1ns under strong multipath interference.