Time synchronization method based on hybrid bus of RS485 and Ethernet

Abstract

The invention discloses a time synchronization method based on a hybrid bus of an RS485 and the Ethernet. A star topology network is formed among Ethernet nodes, an RS485 node forms a chain topology network with the Ethernet nodes, and after time synchronization is completed in the star topology network, the RS485 node synchronizes with the Ethernet nodes by the following steps of: 1, transmittinga delay request information packet including record transmission time to the Ethernet nodes; 2, receiving a returned delay response packet and recording reception time, wherein the delay response packet includes the time when the Ethernet nodes receive the delay request information packet and the time when the delay response packet is transmitted; 3 calculating network delay time; 4, and receiving synchronization information packets transmitted by the Ethernet nodes at a fixed time interval, and performing clock correction according to local timestamps included in the synchronization information packets. The time synchronization method realizes the transmission of time information between different topologies, and effectively solves the clock synchronization problem of the hybrid bus.

Description

technical field [0001] The invention is applicable to the civil aviation airborne test system based on the hybrid bus structure of RS485 and Ethernet, and provides a time synchronization method for it. The synchronous timing of the airborne test system under the hybrid bus architecture is realized, and the accuracy of the time stamp of the test data is guaranteed. [0002] The present invention relates to the field of flight test. Flight test is an indispensable and important link in the development process of aviation equipment and civil aircraft. It is a process of testing aircraft, airborne equipment or equipment in a real flight environment, which has high risk, The flight test is characterized by long period, large investment and strong exploratory nature. The purpose of the flight test is to verify the theory and the results of the ground test, and to identify the design indicators, airworthiness and performance of the aircraft. Background technique [0003] With the ...

AI Technical Summary

Problems solved by technology

The commonly used synchronization method for RS485 serial bus is the hard-line synchronization method based on the frame synchronization signal or the command synchronization method based on the synchronization message. The disadvantage is that it does not contain time information and cannot be compatible with other timing networks. The synchronization accuracy cannot be further improved and the efficiency is very low.

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