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CERTI is an HLA RTI developed since 1996 by ONERA, the French Aerospace Lab. The initial purpose of CERTI was to develop a home made RTI in order to: learn HLA usage and HLA RTI internals (e.g. time management), have total control over source code in order to use this particular RTI with specific modifications in several research projects (security mechanism, multi-resolution, high performance distributed simulation...). CERTI became open source in 2002: https://savannah.nongnu.org/projects/certi. Since then, Open Source CERTI project has had variable activity periods, mostly driven by research project needs and funds. CERTI development has started again since the end of 2006, with an increased interest from the open source user community. After a brief status survey of CERTI, this presentation will focus on the Open Source objectives of CERTI and explain why this is not a product but a project driven OSS initiative, pushed by a Public establishment like ONERA. We will further explain how open sourceness CERTI stimulates its development and the community itself and why every stakeholder benefits from this.

This paper presents some experiments and some results to enforce real time distributed simulations in accordance with the High Level Architecture (HLA). Simulations were run by using CERTI, an open source middleware, as the Run Time Infrastructure (RTI). Models were distributed over computers under various available versions of the 2.6 Linux kernel. Studies and experiments relied on a real case study. The chosen case study was the simulation of an "in formation" flight of observation satellites. This case study brings up some real applicative needs in real time distributed simulations and real configurations of simulators and models. Two simulations of "in formation" flight of satellites were studied. The study consisted in modeling the behaviour of the simulators and in running these models by using various kernel or middleware operating mechanisms and services. Time measurements were performed at each test giving some results on the ability of the simulation to meet its real time requirements.