Research And Implementation Of Avionics-Ethernet Clock Synchronization System Based On IEEE 1588

With the development of avionics system, much attention has been paid to the study and application of TTEthernet technology. TTEthernet is Ethernet-based communication network, which establishes a unified, high-precision clock synchronization system to synchronize the devices of avionics system. On this background, the thesis designs and implements an Ethernet clock synchronization system prototype according to the IEEE 1588 protocol (PTP).Main contents of this thesis are as follows:First, clock synchronization error analysis and compensation based on the IEEE 1588 protocol. This thesis studies the clock model, message type and synchronization principle defined by IEEE 1588 protocol, and the factors affect the accuracy of clock synchronization are summarized in this thesis. To further improve the synchronization accuracy, IEEE 1588 based error compensation measures are put forward, including PTP message’s time-stamp error compensation, exchange equipment time-delay measurement and the slave clock adjustment strategy.Next, the design and implementation of IEEE 1588 based PTP clock node. As the core part of the Ethernet clock synchronization system, PTP clock node is based on the open source PTPd code package written in C and it runs on Linux system. Especially the PHY chip DP83640 is adopted as hardware to support the IEEE 1588 protocol. Hardware combined with PTPd code immensely improves the synchronous accuracy and keep the integrity of the agreement.Finally, the test of IEEE 1588 based Ethernet clock synchronization prototype system. A test environment is established and the clock synchronization prototype system is composed of master-slave PTP nodes via Ethernet connection. The test mainly focuses on the accuracy of the clock synchronization by contrasting master-slave clock nodes’ 1PPS signal. The results show that the accuracy of clock synchronization can reach microsecond-level and the hardware time-stamp accuracy is 3 orders of magnitude higher than the soft time-stamp.The research achievements in this thesis provide a feasible reference for high precision clock synchronization of Ethernet-based avionics system.