基于可满足性问题求解器的星上FPGA永久损伤容错技术研究

摘要

现代卫星广泛使用的FPGA在空间高能粒子的影响下,会产生门电路的永久性损伤.而传统的三模冗余等容错方法不但成倍增加了系统硬件开销,还存在因冗余器件耗尽而失效的风险.因此,提出一种利用FPGA自身冗余资源,修复永久性损伤的容错方案.该方案通过建立FPGA内部资源的功能模型,将容错问题转化为数学上的可满足性问题.并且利用经过改进的GSAT算法对该问题求解,可以获得在功能上与损伤前完全相同的电路结构,及其所对应的FPGA配置文件.将该文件重新下载到FPGA中,可以屏蔽损伤带来的影响,从而达到利用FPGA自身冗余资源容错的目的.通过实验和分析可以看出,本文方案具有对损伤修复成功率高、计算量小和需要内存空间少的特点,因此符合星上计算能力和硬件资源十分有限的实际情况.%FPGA is a kind of semiconductor device and it could be damaged by extern high energy cosmic ray jn space.The permanent failure of reconfigurable SRAM based FPGA can not be cleared. Therefore a multiple redundancy technique is adopted to enhance system' s reliability. However, it doubles or even triples the hardware consumption of eleccronic system. In this paper a method for repairing FPGA' s permanent failure is proposed. by using FPGA ' s own redundancy resource. This method transforms FPGA' s inner model into a satisfiability problem ( SAT) and solves it by a modified SAT solver. And then an alternative circuit with the function equivalent to original circuit on the damaged FPGA can be obtained. Compared with genetic algorithm, the new method requirea less computational effort and smaller memory, is more suitable for space applications.