航空电子AFDX与AVB传输实时性抗干扰对比

Comparison of real-time anti-jamming transmission for avionics AFDX and AVB

为满足未来航电系统音视频信息传输的需求,考虑车载嵌入式系统的候选实时多媒体网络AVB在航电环境中的应用,并对AVB与AFDX的传输进行了对比研究。首先构建AVB与AFDX标准对比;其次提出基于网络演算的AVB和AFDX端到端延迟计算方法;然后通过定义不同的消息传输场景,采用理论方法分析消息传输实时性的干扰要素;最后利用仿真方法予以验证。在典型1 000条虚拟链路的组网规模下,结果显示:AFDX高优先级流量的端到端延迟优于AVB,对于低优先级流量端到端延迟,则AVB和AFDX各有优劣;但受突发的流量影响,在增加50条各0.22 Mbit/s带宽的低优先级流量干扰情况下,高优先级流量平均端到端延迟的变化率在AVB中为0.25%,在AFDX中为0.38%;在增加50条各0.22 Mbit/s带宽的高优先级流量干扰情况下,低优先级流量平均端到端延迟的变化率在AVB中为5.17%,在AFDX中为10.25%。结果表明:时间敏感消息在AVB网络中传输实时性的抗干扰能力优于AFDX。

AVB is considered to meet the demands of audio video transmission in future avionics system,which is a real-time multimedia network and has become a candidate for in-vehicle embedded systems. Comparative study on AFDX and AVB is implemented. First,standards of AVB and AFDX are compared. Second,the method for end-to-end delay in AVB and AFDX is discussed by network calculus. Then the elements interfering real-time transmission are analyzed depending on different transmission scenarios. Conclusions are verified by simulation. In typical networking with 1 000 virtual links,the results show that the end-to-end delay of high priority traffic in AFDX is smaller than that in AVB; the advantage and disadvantage of end-to-end delay for low priority traffic exist in both AVB and AFDX. But influenced by the burst 50 low priority streams（ each with 0. 22 Mbit/s bandwidth）,the variation rate of average end-to-end delay for high priority traffic is0. 25% in AVB and 0. 38% in AFDX; influenced by the burst 50 high priority streams（ each with0. 22 Mbit/s bandwidth）,the variation rate of low priority traffic is 5. 17% in AVB and 10. 25% in AFDX.Real-time anti-jamming transmission of time-sensitive information in AVB is superior to AFDX.