面向容错的对地观测卫星实时任务调度研究

提出一种面向容错的对地观测卫星任务调度模型,该模型采用主版本/副版本技术可以实现对任意时刻一颗卫星失效时的容错.在容错调度模型的基础上,提出了一种卫星容错调度算法FTSS.FTSS采用重叠技术,有效提高了卫星资源利用率.此外,FTSS采用了任务合成策略可以有效减少实际执行任务的个数从而进一步提高系统的可调度性.为了验证FTSS算法的性能,本文通过模拟实验对FTSS与其它3个基准算法进行了比较分析.实验结果表明FTSS优于其它算法,适合卫星实时任务容错调度.

FauIt-ToIerance Oriented ReaI-Time Task ScheduIing on MuItipIe Earth-Observing SateIIites

This paper presents a novel dynamic fault-tolerant scheduling model for real-time tasks on multiple observation satellites.In this model, the primary/backup policy is employed to tolerate one satellite's permanent failure at one time instant.On the basis of the fault-tolerant model, we propose a novel fault-tolerant satellite scheduling algorithm called FTSS.To improve the resource utilization, the overlapping technology is adopted.According to the satellite feature with time windows, we analyze the overlapping mechanism on satellites and combine them into FTSS.In addition, the FTSS employs the task merging strategies that are used to decrease the task count needed to execute and thus further enhance the schedulability.To demonstrate the superiority of our FTSS, we conduct simulation experiments to compare FTSS with three baseline algorithms.The experimental results indicate that FTSS efficiently improves the scheduling quality of others and is suitable for satellite fault-tolerant scheduling.