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针对卫星实时系统中关键数据一次容错问题,首先,针对关键数据与非关键数据混合传输场景,建立系统模型,对系统的容错传输能力进行分析,得出混合数据一次容错传输条件;其次提出NP-PEDF-FT调度算法,通过在非抢占式EDF容错算法的基础上,利用截止期容错系数λ调整出错任务的截止期,实现全部关键数据的1次容错传输;同时加入数据传输队列监测功能,以保证关键数据在其截止期之前优先传输;最后对算法进行了仿真分析,比较NPPEDF-FT、NP-EDF-FT、NP-DP-FT三种非抢占式容错调度策略,分析结果表明,NP-PEDF-FT算法关键数据丢包率较NP-EDF-FT算法平均降低31.6%,较NP-DP-FT算法平均降低86.4%。
Aiming at the primary fault tolerance of the key data in the satellite real-time system, aiming at the scenario of mixed transmission of key data and non-critical data, a system model is established to analyze the fault-tolerant transmission capacity of the system. Based on the non-preemptive EDF fault-tolerant algorithm, the PEDF-FT scheduling algorithm is used to adjust the deadline of the fault task by the deadline fault tolerance λ to achieve a fault tolerant transmission of all the key data. At the same time, the data transmission queue monitoring function is added to NP-EDF-FT and NP-DP-FT are compared. The analysis results show that NP-EDF-FT and NP-DP-FT are non-preemptive fault-tolerant scheduling strategies. Compared with the NP-EDF-FT algorithm, the PEDF-FT algorithm reduces the packet loss rate by an average of 31.6%, which is 86.4% lower than the NP-DP-FT algorithm.