Trade-off in logical radiation hardening: Approach, mechanisms, and reliability impacts

In aerospace field, it is necessary to address the radiation effects to which embedded systems are especially sensitive. Besides, the reuse of existing components implies that a modification of the architecture is sometimes expected to meet the safety requirements for such critical applications. To achieve such safety level, physical radiation hardening is usually used despite its cost. However, by performing a logical radiation hardening, it is possible to achieve the expected results while decreasing the expected cost of such an evolution. As a first step, a state of the art of existing mechanisms for logical radiation hardening is performed. These mechanisms are evaluated according a set of parameters: the type of errors they address, whether it is for purpose of detection or correction, the performance, the necessary additional physical volume, the computing time. To select the mechanisms to be used, a trade-off is performed, which depends also on the reliability analysis performed as well as the components that are concerned and on which the mechanisms are to be applied. A use case is presented and a comparison between the unprotected module and the protected module is performed. The results obtained show that the optimized selection of hardening mechanisms yields to an improvement in reliability.