Enhancing Reliability Using Radiation Hardening: Approach, and Reliability Impacts

With the growing importance of embedded systems in aerospace field, it is necessary to address the radiation effects to which they are especially sensitive. Particularly, the embedded aerospace systems must take into account... [ view full abstract ]

With the growing importance of embedded systems in aerospace field, it is necessary to address the radiation effects to which they are especially sensitive. Particularly, the embedded aerospace systems must take into account the disruptive and sometimes destructive effects of heavy ions. 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.

Once an existing module for the mentioned application is selected, it is necessary to enhance its reliability. 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. This trade-off depends also on the safety and reliability analysis performed beforehand as well as the components that are concerned and on which the mechanisms are to be applied.

Once the most critical components are identified, logical radiation hardening is performed by selecting the optimal mechanism studied beforehand for each component. Trading-off at this level is necessary to meet the requirements while minimizing an expected increase in cost as well as in physical volume and in computing time. Seven types of components have been identified and the corresponding hardening mechanisms defined.

Once selected, the hardening mechanisms are integrated in the architecture and a new reliability analysis is performed to measure the impact of the “robustification” and verify that reliability has been indeed enhanced. 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.