WCET analysis of on-board space software system by RapiTime

RapiTime, the on-target timing analysis, verification and optimization tool for critical real-time embedded systems, was recently used to analyse the worst-case execution time (WCET) of code on an experimental micro-satellite. UPMSat-2 features the Attitude Determination and Control System (ADCS), a subsystem which computes the orientation (attitude) of the satellite with respect to the Earth, and takes corrective actions in order to keep it within specified values. Software standards for on-board spacecraft software require schedulability analysis for the verification process. This analysis requires the WCET of each task to be known. RapiTime analyses the structure of source code and adds instrumentation points at relevant places. These execution traces are then collected to generate time measurement statistics, including the WCET measurements required for schedulability analysis. Partly funded by the Spanish Ministry of Economy and Competitiveness (MINECO), UPMSat-2 is scheduled to be launched in 2013. More information and results are available at http://www.rapitasystems.com/publications.html (Analysis of WCET in an experimental satellite software development). Visit Rapita Systems and the Solar Orbiter for more details of our recent space work.