Fault Detection, Isolation and Recovery : Analysis of two scheduling algorithms

Sammanfattning: Unmanned, as well as manned space missions have seen a high failure rate in the early era of space technology. However, this decreased a lot since technology advanced and engineers learnt from previous experiences and improved critical real time systems with fault detection mechanisms. Fault detection, isolation and recovery, nowadays, is generally available in every flying device. However, the cost of hardware can bottleneck the process of creating such a system that is both robust and responsive. This thesis analyses the possibility of implementing a fault detection, isolation and recovery system inside of a single-threaded, cooperative scheduling operating system. The thesis suggests a cooperative implementation of such a system, where every task is responsible for parts of the fault detection. The analysis is done from both the integration layer, across the operating system and its tasks, as well as from the inside of the detection system, where two key components are implemented and analyzed: debug telemetry and operation modes. Results show that it is possible to implement a fault detection system that is spread across all the components of the satellite and acts cooperatively. Furthermore, the comparison with a traditional, dedicated fault detection system proves that errors can be caught faster with a cooperative mechanism.