Bipartite graph-based control flow checking for COTS-based small satellites

Single event upset (SEU) effect, caused by highly energized particles in aerospace, threatens the reliability and security of small satellites composed of commercial-off-the-shelves (COTS). SEU-induced control flow errors (CFEs) may cause unpredictable behavior or crashes of COTS-based small satellites. This paper proposes a generic software-based control flow checking technique (CFC) and bipartite graph-based control flow checking (BGCFC). To simplify the types of illegal branches, it transforms the conventional control flow graph into the equivalent bipartite graph. It checks the legality of control flow at runtime by comparing a global signature with the expected value and introduces consecutive IDs and bitmaps to reduce the time and memory overhead. Theoretical analysis shows that BGCFC can detect all types of inter-node CFEs with constant time and memory overhead. Practical tests verify the result of theoretical analysis. Compared with previous techniques, BGCFC achieves the highest error detection rate, lower time and memory overhead; the composite result in evaluation factor shows that BGCFC is the most effective one among all these techniques. The results in both theory and practice verify the applicability of BGCFC for COTS-based small satellites.