Diploma and Master Theses (authored and supervised):

M. Schütz:
"COTS FPGAs in Space -- From old Concerns to new Possibilities";
Supervisor: A. Steininger; 191-02, 2018.

English abstract:
The term NewSpace refers to the global entry of emerging commercial companies into
the space market. NewSpace opens new ways of thinking and employing workflows. Field
Programmable Gate Arrays (FPGAs) have a significant impact on the overall costs of
spacecrafts. Consequently, in order to be competitive in this new era, the utilization
of Commercial off-the-shelf (COTS) FPGAs is inevitable. However, these devices are
sensitive to radiation effects, as they occur in space.
On behalf of RUAG Space GmbH, this thesis investigates conventional fault mitigation
techniques and introduces a new fault correction method. The most commonly deployed
techniques are memory scrubbing and Triple Modular Redundancy (TMR).
Scrubbing refers to a technique that periodically checks a memory for errors and corrects
them if necessary. Therefore, an Error Detection and Correction (EDAC) code is applied
to the memory.
TMR triplicates a design and voters are used to generate a correct output. Depending on
the level of granularity on which the design is triplicated, different properties arise. Fine-
Grain TMR (FGTMR) allows safe recovery, but incurs prohibitive area and performance
penalties. In contrast, Coarse-Grain TMR (CGTMR) has little overhead, but cannot
safely provide recovery without roll-back or reset.
The new approach, proposed in the present work, uses the Partial Reconfiguration (PR)
feature of modern FPGAs to augment an initially CGTMR with the ability of temporarily
loading a FGTMR design for forward-state-recovery. Therefore, a correct (fully redundant)
operation can seamlessly be resumed in case of data- as well as configuration faults within
the FPGA.
A showcase design is implemented to evaluate conventional fault mitigation techniques
and as a proof of concept for the new method as well. In addition to this practical
demonstration, the reliability of selected techniques, including the new approach, is
investigated theoretically by modeling their behaviour with Markov chains.

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