Simulation of the Effects of Radiation on a Satellite Memory and Improving Its Fault-Tolerant Ability, Using SIHFT

Abstract

This chapter describes a software environment based on VirSim tool to simulate the effect of radiation on COTS (commercial off-the-shelf) memories and shows the efficiency of the software EDAC (error detection and correction). As a case study, a sample student LEO (low Earth orbit) satellite with 8-MB (megabytes) RAM (random access memory) is considered and software EDAC for detecting and correcting the faults in the memory is implemented. The software EDAC is responsible for reliability of data in this 8-MB RAM. One separated task in VirSim tool has been developed for injection SEUs (single event upset) to the 8-MB memory of the satellite. The SEUs have been generated based on the ARGOS satellite reports. According to these reports the average of SEUs is about 5.5 SEU/MB per day, where it generates about 5 MBU (multiple bit upset) out of any 100 SEU. About four of these MBUs are double events (2-bit upset in one word) and one of them is triple. The software EDAC detects and corrects all 1-bit SEUs and detects double MBUs but it does not guarantee the detection of triple MBUs. This kind of simulation is very simple, accessible, and very close to the real environment and one can use it for checking effectiveness of the approach. The simulation results demonstrate efficacy of the approach in terms of fault detection and correction capabilities.