Research On Key Technology Of Time-Triggered Ethernet For Spacecraft

Time-triggered Ethernet is a real-time Ethernet,with good stability,scalability and high-bandwidth advantages,the time triggered Ethernet applied to the spacecraft,to meet the needs of modular spacecraft effectively.However,the space environment and data transmission diversity are the factors of those problems such as the time synchronization is not credible or unable to support packet diversity scheduling.Aiming at the application background of the time triggered Ethernet in the spacecraft,the main work of this paper is as follows:First of all,this paper analyzes the technical characteristics of time triggered Ethernet,and summarizes the system structure,communication mechanism and common scheduling algorithm of time triggered Ethernet.Secondly,aiming at the bad communication environment in space will cause the problems that the synchronous message transfer with jitter and the result of time synchronization is credible,this paper proposed a kind of time synchronization algorithm with high credibility.The algorithm analyzes the relationship between packet jitter and synchronization by using probability theory,and then,using the way to calculate the signal to noise ratio to quantify the synchronization policy of the different size jitter.Simulation results show that the algorithm can choose different synchronization strategies based on packet jitter,and can adapt to the poor communication environment in space.Thirdly,this paper analyzes the characteristics that the complex spacecraft has the data transmission diversity.Aiming at the time-triggered Ethernet is not meet the quality of service of non-real time data,this paper proposed an adaptive QoS scheduling algorithm.Through monitoring of the link state with realtime and adjusting packet control configuration for RC with dynamic,the algorithm controls RC packet in detail by priority.Simulation results show that this algorithm can not only ensures the control of message priority,but also allocates bandwidth to each priority message.Finally,this paper summarizes the related work and the prospect of the next step.