Research On Time Synchronization Method For Ad Hoc Networked Wide-area Test System

In the future,Attack and Defense System Operations will put forward higher requirements for the cooperative control technology in ad hoc network.It can be specifically manifested in space-time unification and energy support issues for Attack and Defense System Operations of bee colony,wide-area,intelligence.However,the current time synchronization can hardly guarantee the wide-area time accuracy of ad hoc networked testing in actual combat.Therefore,the time synchronization method of ad hoc wide-area test has been studied in this thesis,which has solved the problem of coordination and energy conservation in networked test system.The thesis studies the time synchronization method of low-power and high-precision for ad hoc networked wide-area test system based on the precise clock synchronization protocol of IEEE 1588.And it designs and implements a time synchronization mechanism based on LEACH-R and time division multiple access with distributed energy aware node activation protocol.The time synchronization accuracy of simulation test is less than 1μs,which provides comprehensive technical support for the guarantee technology for the new generation of military test and automatic test system.The thesis studies from the following four parts for ad hoc networked wide-area test system.Firstly,a time synchronization method of low-power and high-precision for ad hoc networked wide-area test system is proposed in the thesis.Under the analysis of the bee colony combat system,a distributed energy-aware time division multiple access synchronization method based on LEACH-R is proposed,which is aimed to solve the problem of complex synchronization hierarchy and limited energy of the nodes in global network.It is proved that the network lifetime is greatly prolonged and the synchronous message packet can be transmitted efficiently and orderly.Secondly,a compensation algorithm is proposed there for asymmetric link delay in forward and backward wireless communication link based on transparent clock.The problem of inconsistent delay caused by different forward and backward data rates in messages that are transmitted by transparent clock is solved by dynamically estimating the asymmetric delay of forward and backward communication links.Experiments show that real-time dynamic asymmetric rate estimation algorithm can effectively promote the time synchronization accuracy of ad hoc networks.Thirdly,study on frequency drift compensation algorithm based on Kalman filter:A estimation algorithm based on Kalman filter is used to solve the accumulation of synchronization errors caused by frequency drift and frequency drift change rate in synchronization holding phase.The experimental results show that the estimation compensation algorithm based on Kalman filter has higher synchronization accuracy and more stable synchronization process than the instantaneous adjustment synchronization method.Finally,test verification in OPNET network simulation:In the thesis,OPNET network simulation software is used to simulate the ad hoc networked wide-area test system.Based on the test and optimization of wide-area network,the simulation results are collected by changing the number of network nodes and modifying network simulation parameters.The thesis has modeled and simulated the time synchronization of the ad hoc networked wide-area test system.The results show that the design has achieved the expected goal.The time synchronization accuracy is less than 1μs.And the network energy consumption speed,network end-to-end delay and network packet loss rate are improved,which can effectively solve the problem in coordination,effective data transmission and network packet loss rate in accurate space-time unification among test nodes of networked test system.