Tasking Framework: Parallelization of Computations in Onboard Control Systems

For the next generation of onboard computer in space application a high demand on processing power exists. Currently used onboard system didn't provide the necessary computing power. The in the paper describe tasking frame work is the core processing model for the OBC-NG (On Board Computer - Next Generation) operating system with an reactive computing model

A Component-Based Middleware for a Reliable Distributed and Reconfigurable Spacecraft Onboard Computer

Emerging applications for space missions require increasing processing performance from the onboard computers. DLR's project “Onboard Computer - Next Generation” (OBC-NG) develops a distributed, reconfigurable computer architecture to provide increased performance while maintaining the high reliability of classical spacecraft computer architectures. Growing system complexity requires an advanced onboard middleware, handling distributed (realtime) applications and error mitigation by reconfiguration. The OBC-NG middleware follows the Component-Based Software Engineering (CBSE) approach. Using composite components, applications and management tasks can easily be distributed and relocated on the processing nodes of the network. Additionally, reuse of components for future missions is facilitated. This paper presents the flexible middleware architecture, the composite component framework, the middleware services and the model-driven Application Programming Interface (API) design of OBC-NG. Tests are conducted to validate the middleware concept and to investigate the reconfiguration efficiency as well as the reliability of the system. A relevant use case shows the advantages of CBSE for the development of distributed reconfigurable onboard software

PaTaS - Quality Assurance in Model-Driven Software Engineering for Spacecraft

Within PATAS (Product Assurance with TASTE Study), a product quality model with software and model metrics is developed and implemented in an end-to-end model-driven software engineering (MDSE) lifecycle demonstrator, based on TASTE. The goal of this study is to find applicable concepts to maintain quality and dependability levels, when MDSE is applied. This requires the definition of connected model and software quality indicators. These indicators are identified and integrated with ESA's reference software product quality model (ECSS-Q-HB-80-04A). The resulting quality model is integrated in a model-based software development lifecycle demonstrator, based on TASTE. To evaluate this demonstrator and the integrated quality indicators, mission-critical parts of the command and data handling subsystem of a satellite mission are modelled and subsequently coded, simulating a realistic development scenario as use case. The aim of the activity is to demonstrate the effect of the end-to-end lifecycle in combination with the developed quality model on the final onboard software product. The final results will set the baseline for recommendations to improve Quality Assurance in MDSE at ESA. In this talk, we present the on-going study and its latest results

Tasking Modeling Language: A toolset for model-based engineering of data-driven software systems

The interdisciplinary process of space systems engineering poses challenges for the development of the on-board software. The software integrates components from different domains and organizations and has to fulfill requirements, such as robustness, reliability, and real-time capability. Model-based methods not only help to give a comprehensive overview, but also improve productivity by allowing artifacts to be generated from the model automatically. However, general-purpose modeling languages, such as the Systems Modeling Language~(SysML), are not always adequate because of their ambiguity resulting from their generic nature. Furthermore, sensor data handling, analysis, and processing of data in on-board software requires focus on the system’s data flow and event mechanism. To achieve this, we developed the Tasking Modeling Language~(TML) which allows system engineers to model complex event-driven software systems in a simplified way and to generate software from the model. Type and consistency checks on the formal level help to reduce errors early in the engineering process. TML is focused on data-driven systems and its models are designed to be extended and customized to specific mission requirements. This paper describes the architecture of TML in detail, explains the base technology, the methodology, and the developed domain specific languages~(DSLs). It evaluates the design approach of the software via a case study and presents advantages as well as challenges faced

Einsatz von Simulationen bei der Softwareentwicklung in Raumfahrtprojekten

An Systeme in der Raumfahrt werden hohe Anforderung hinsichtlich der funktionalen Korrektheit und der Einhaltung von Sicherheitsrichtlinien gestellt. Um diese Anforderungen zu gewährleisten ist der Entwicklungsprozess durch die ECSS-Norm vorgeschrieben, der alle europäischen Unternehmen und Institution in der Raumfahrt verpflichtet sind. Wie in den einzelnen Phasen Simulationen zur Verifikation eingesetzt werden, wird in diesem Paper beschrieben

Test von adaptiven Softwaremechanismen zur Fehlerkompensation

Der Beitrag stellt den im Verbundvorhaben SiLEST (Software in the Loop for Embedded Software Test) verfolgten Ansatz des durch eine Umgebungssimulation unterstützten Softwaretests vor. Besonderes Ziel des Testansatzes ist es, hinsichtlich der Umgebungssimulation einen hohen Grad der Wiederverwendbarkeit von Simulationsmodulen und eine weitgehende Testautomatisierung zu gewährleisten. Von besonderem Interesse bei dem Testansatz ist dabei der Test des Softwareverhaltens unter gestörten Betriebsbedingungen, wie es beispielsweise in einem gealterten System oder bei beschädigter Sensorik bzw. Aktuatorik der Fall ist