Design Of Real Time LAN For Airborne Test Based On IEEE1588Clock Synchronization

Modern large aircraft flight test with the parameter has the characteristics of multi-type, large number and wide destribution, which require the data acquisition system to have the capability of high performance acquisition, large capacity communication, distributed connection. The interconnection between data acquisition system in traditional distributed system was PCM structure, which has been existed as the standard of IRIG-106for over40years, has the advantages of high reliability, durability, perfect time determinacy. However, its disadvantages of narrow connection bandwidth、short transmission distance, Limited DAU connection numbers and not flexble Topology, made it difficult to meet the need of flight test for large aircrafts.The paper is to meet the engineering requirement of flight test for large aircrafts. The test system adopts the latest new networked architecture, proposes the design of real time LAN for airborne test based on IEEE1588Clock synchronization. The network design based on the standard of IEEE802.32005, in physical layer and data link layer using the wired transmission media and network switches to realize interconnection, in internet layer is based on IPV4technology, in transmission layer adopts UDP protocol, and the test data encapsulation in application layer using IENA protocol.The quality assurance of real-time communication relys on the connectionless UDP protocol and technology of full duplex network switches with static routing; the clock synchronization of test instrument network relys on the IEEE1588PTPV1protocol and transparent clock technology; the networked test system equipment configuration and management based on SNMP protocol, programming based on TFTP protocol; the network data storage and recording by PCAP format.The IEEE1588clock synchronization technology and FTI network switch technology are the key techniques to realize the real time LAN for airborne test. The paper is mainly on the technical principles and the designing scheme of IEEE1588clock synchronization and FTI network switches.In the end, through the network test, proof the design of real time LAN for airborne test based on IEEE1588Clock synchronization can meet the requirement of networked test system in system clock synchronization precision, data transmission delay and reliability of data communication three aspects.