Towards the definition of ESA s future OBCP building block

Transcription

1 Towards the definition of ESA s future OBCP building block M. Ferraguto, J. Johansson, K. Jurva (SSF) A. Oganessian, M. Prochazka (ESA) A.I. Rodríguez, T. Schoofs (GMV) M. Barrenscheen (IDA), M. Muñoz (SA), M. Cupak (ESC)

2 2 Agenda Motivation and objectives Review of existing OBCP implementations Assessment of the ECSS OBCP standard Assessment of potential innovations Requirements and interfaces of the OBCP building block OBCP building block prototype Conclusions

3 3 What is an On-Board Control Procedure (OBCP)? Definition: A procedure to be executed on-board which can easily be loaded, executed, and replaced without modifying the remainder of the on-board SW Main use cases: Satellite operations Implementation of system/mission functionality Testing

4 4 What is an On-Board Control Procedure (OBCP)? It is like having an automatic operator on-board: Send sequences of commands Optionally including: Execution logic Checking command results Perform (complex) monitoring tasks React on events Different implementations on several ESA missions over the last 25 years

5 5 Motivation and objectives Starting points: New ECSS standard on OBCP ECSS-E-ST-70-01C OBCP system Development lifecycle for OBCPs Relationship to spacecraft on-board software lifecycle SAVOIR-FAIRE: on-board SW reference architecture Objective: Based on building blocks Define the requirements and interfaces for a reusable and standard flight-qualified OBCP SW system building block.

6 6 Two parallel activities: objectives Define the OBCP building block, including Provided and required interfaces Its position within the ESA OBSW reference architecture defined in SAVOIR-FAIRE Provide a vision of the future use of OBCPs Set of use cases and to consider options for further steps in the standardisation of OBCPs, such us updating the current OBCP standard or standardising the OBCP language. The two parallel activities are currently on-going and they are planned to conclude in 2012

7 7 Two parallel activities lead by ESA

8 8 Agenda Motivation and objectives Review of existing OBCP implementations Assessment of the ECSS OBCP standard Assessment of potential innovations Requirements and interfaces of the OBCP building block OBCP building block prototype Conclusions

9 9 Review of Existing OBCP Implementations The available documentation for a number of different OBCP implementations has been reviewed Herschel-Planck, GOCE, Sentinel-1, Cryosat-1, Rosetta, Venus Express, BepiColombo, Columbus and the NASA VML system The level of detail of the available documentation varies greatly

10 10 Two broad classes of OBCP systems exist Command sequences An OBCP is a sequence of telecommands on a relative time-line Limited (if any) execution logic Similar to ground operations, but permanently resident on-board More suitable for the implementation of fixed operations sequences Script-like Written using a high-level language, possibly compiled, and executed on-board by an on-board interpreter More suitable to implement complex control logic Requires a more complex OBCP engine

11 11 Existing Implementations: main aspects assessed Language capabilities E.g. fixed TC tokens vs general-purpose language + library OBCP preparation environment capabilities E.g. compiler, debugger, link to system DB, etc. OBCP execution environment capabilities E.g. commandability, observability, scheduling, etc. OBCP management capabilities E.g. relationship with the OBSW lifecycle

12 12 Agenda Motivation and objectives Review of existing OBCP implementations Assessment of the ECSS OBCP standard Assessment of potential innovations Requirements and interfaces of the OBCP building block OBCP building block prototype Conclusions

13 13 Assessment of the ECSS OBCP standard Goals: Considerations of further standardisation steps Propose a possible update of the current standard Improve understanding of the standard and trigger a discussion leading to the definition of the OBCP building block Approach: Look at use cases, existing and future missions Analyse the standard Find inconsistencies and ambiguities Propose improvements

14 14 Assessment of the ECSS OBCP standard The standard introduces a number of concepts like OBAP (On-Board Application Procedures) vs. OBOP (On-Board Operations Procedures) and covers all the main aspects of OBCPs, including: Use cases Language capabilities Preparation environment capabilities Execution environment capabilities Engineering process, taking into account the distinction of OBOPs vs. OBAPs

15 15 Identified possible improvements of the standard Prioritisation of the requirements, taking into account: The needs of the various users OBCP execution environment as a black box to be integrated into the host OBSW Mandatory vs optional requirements Standardisation of the language, not only of the language features Some requirements could be removed: e.g. the ones on the OBCP viewer Better characterisation of OBOP vs OBAP

16 16 Agenda Motivation and objectives Review of existing OBCP implementations Assessment of the ECSS OBCP standard Assessment of potential innovations Requirements and interfaces of the OBCP building block OBCP building block prototype Conclusions

17 17 Assessment of potential innovations Started from taking the best of Additional concepts like: Explicit support of state machines Standardisation of the target object code language Source language improvement to better support the users, e.g. support of at least basic forms of objectorientation Standardised interface towards the system database Integration with the SAVOIR-FAIRE standard on-board SW architecture

18 18 Further innovations related to OBSW trends Time and Space Partitioning [TSP] SOIS architecture [SOIS] Component-oriented frameworks [CBSE] Relation to FDIR (Fault Detection Isolation and Recovery)

19 19 Agenda Motivation and objectives Review of existing OBCP implementations Assessment of the ECSS OBCP standard Assessment of potential innovations Requirements and interfaces of the OBCP building block OBCP building block prototype Conclusions

20 20 Requirements and interfaces of the OBCP building block Requirements definition Based on the OBCP ECSS standard Accompanied with use cases to demonstrate their purpose Compatible with the ESA OBSW reference architecture Taking into account the current OBCP implementations Provided and required interfaces and interaction to flight software and spacecraft operations

21 21 Agenda Motivation and objectives Review of existing OBCP implementations Assessment of the ECSS OBCP standard Assessment of potential innovations Requirements and interfaces of the OBCP building block OBCP building block prototype Conclusions

22 22 OBCP building block prototype The prototype activity is on-going Demonstration of main: Requirements Interfaces Innovations

23 23 SSF building block prototype experience Starting from the very advanced OBCP system used for the Herschel-Planck Focuses on implementation and demonstrations of new concepts like: Explicit support for state machines to facilitate OBCP design and implementation Use of a priority system avoiding starvation of lowerpriority OBCPs in a way that is transparent for the higher-priority ones Basic forms of object-orientation

24 24 GMV building block prototype experience (i) At present, the specification of requirements and interfaces is progressing considering current ECSS-E-ST standard specification. Assessment of ECSS-E-ST requirements in categories: core an optional requirements Proposal for new requirements coming from our research in future use of OBCPs The high level architecture that is proposed is in line with the COrDeT OBSW Reference architecture, [COrDeT]

25 25 GMV building block prototype experience (ii) Some core functionalitis are selected to be prototyped and modelled by using COrDeT toolset framework OBCP-BB Interaction Layer Une of TASTE framework Prototyping a Lua interpreter implementing the OBCP-Engine

26 26 Agenda Motivation and objectives Review of existing OBCP implementations Assessment of the ECSS OBCP standard Assessment of potential innovations Requirements and interfaces of the OBCP building block OBCP building block prototype Conclusions

27 27 Conclusions Proposed a number of improvement and innovations in the OBCP domain Requirements and interfaces for a future standard on-board SW OBCP building block Two prototype implementations (on-going) Future work: Consolidation of results (requirements and interfaces), focusing on OBOPs (reflecting operator's needs) and OBAPs (reflecting software system needs) In the long term: implementation of a pre-qualified building block, to be made available for future space missions

28 28 Thanks for your attention Any question? Contact: