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EGOS Workshop 2005

EGOS Workshop 2005. GDSS - Ground Data System Services: a Service Oriented Architecture for Mission Operations Roger Thompson, Nestor Peccia, Stewart Hall, Oliver Page. Presented by: Roger Thompson. GDSS Study Context. Definition of Standardised G round D ata S ystem S ervices

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EGOS Workshop 2005

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  1. EGOS Workshop 2005 GDSS - Ground Data System Services:a Service Oriented Architecture for Mission Operations Roger Thompson, Nestor Peccia, Stewart Hall, Oliver Page Presented by: Roger Thompson

  2. GDSS Study Context Definition of Standardised Ground Data System Services • Study for ESA/ESOC commenced in 2004: • Considering Service Architecture for EGOS Infrastructure • Builds on Reference Architecture developed in context of European GS Technology Harmonisation • Builds on Mission Operations Service Framework being developed by CCSDS Spacecraft M&C Working Group • Study Outputs • GDSS Service Framework document • Draft Specifications produced for: • GDSS-C Common Service • GDSS-MO Core M&C Service • GDSS-MO Schedule Execution Service EGOS Workshop 2005

  3. GDSS Objectives • Definition of a Service Oriented Architecture for the Mission Operations domain • Focussed on Ground Segment, but capable of extension to Check-out and Space Segment • Compatible with evolving CCSDS SM&C Standards • Standardised Services enable: • Open Interfaces between Major Components • Development of Re-usable [and Replaceable]Plug-in Components • Rapid Mission Specific Deployment • Isolation of Domain Software from Deployment Technology • Legacy Software to be wrapped for Re-use EGOS Workshop 2005

  4. CCSDS Context • See Presentation by Mario Merri • CCSDS Spacecraft M&C Working Group • MOIMS Area WG, Established October 2003 • Active Participation from ESA, BNSC, CNES, CSA, DLR, JAXA and NASA (JPL, GSFC) • Mission Operations Services: end-to-end Application level services for spacecraft operations interactions • Current Status • Mission Operations Service Framework available • High Priority Service Specifications in production • SM&C Core, Common and Protocol Layers • Early work on other Service Specifications • Prototyping of High Priority Services about to start EGOS Workshop 2005

  5. Integrated Systems vs. Modular Components EGOS Workshop 2005

  6. Service-Oriented Architecture:Plug-in Components Services Components Infrastructure EGOS Workshop 2005

  7. Benefits of the SOA Approach • Components exchangeable for others supporting same Service Interfaces • Plug-and-play interoperability of MCS components • Common Service Framework • Re-use of common infrastructure across multiple systems • Independence of mission configuration data and history from system implementation • Infrastructure Implementation can be changed without change to core Applications • Independence of core application software from underlying implementation technology – platform and communications • Components rapidly deployable in different combinations • Reduced mission-specific deployment costs • Extensible: easy to add new components • Scope to evolve a system, by replacing components or changing underlying technologies • Success is dependent on the Granularity of the service architecture selected EGOS Workshop 2005

  8. Identification and Modelling of Services • UML-2 Model with different “Views” (cf. RM-ODP) • Functional View • Information View • Service View • [Multiple] Deployment Views: Physical Architectures • Functional View • Application Level Mission Operations Functions • Initial Selection based on ECSS and Ground Segment Harmonisation • Separation of Functions at Potential Distribution Boundaries:Space-Ground; Geographical Sites; Client-ServerDifferences in Cardinality (Scalability) • End-to-End Interfaces • Omits Data Transfer and Storage Functions • Point-to-Point; Defined by Interfaced Functions; Wire Protocols EGOS Workshop 2005

  9. OperationsPlanning EGSE OB SoftwareDevelopment &Validation Analysis &Reporting MissionPlanning MissionProductDistribution MissionData Processing OperatorInteraction FlightDynamics OB SoftwareManagement GroundAutomation ExternalDataDistribution StationM&C StationScheduling Tracking &Ranging Spacecraft SpacecraftM&C On-boardAutomation AOCS MissionData Acquisition On-boardSoftware Mission Operations Functions GSUS: Ground Support System MES: Mission Exploitation MCS: Mission Operations GSTS: Ground Station Network EGOS Workshop 2005

  10. Information Object X Information Object Y Information View • Same Information Type flows on Multiple Interfaces • Identify Fundamental Information Types for Domain • M&C: Parameters; Actions [Commands]; Alerts [Events] • Operator Interactions • Automation: Activities [Procedures]; Tasks ; Schedules • Planning Requests • Time; Position; Orbit & Attitude Vectors; Predicted Events • Software Images • Data Products; Reports • Identify Operations [Use Cases] that can be performed on these Information Types Function A Function B Data Flow: Message A Data Flow: Message B EGOS Workshop 2005

  11. Service Object Object Object View Service View • Interfaces: Point to Point, Data Flow Oriented, Full Protocol Stack • Services: Many to Many, Information Oriented, One Layer of Stack • Service Objects: represent Domain Specific Information • Event Messages synchronise the Consumer’s View • Control Messages allow the Consumer to invoke Operations • Each Domain Service has its own specialised Information Model • Generic Common Service: publish Events and invoke Operations ServiceProvider ServiceConsumer Events Operations EGOS Workshop 2005

  12. OB SoftwareDevelopment MissionPlanning MissionDataProcessing ExternalUser SRI GDD PRQ FDS REP OB SoftwareManagement Analysis &Reporting OperationsPlanning FlightDynamics ExternalData User OSM OperatorInteraction OperationsAutomation SLE-Man DPM MC PEX SEX TIM OPI AUT OB SoftwareProxy Spacecraft M&CProxy OB ProcedureProxy OB ScheduleProxy OB Data ProductProxy LOC StationScheduling Tracking &Ranging StationM&C OB Software Spacecraft M&C OB ProcedureExecution OB ScheduleExecution OB Data ProductStorage Mission Operations [MO] Services GSUS Other MES MCS GSTS Spacecraft EGOS Workshop 2005

  13. GDSS Mission Operations Services EGOS Workshop 2005

  14. Service Definition • Platform Independent UML Model [Model Driven Architecture] • Includes: • Information View:defines Domain Level information common to Service Providers and Consumers • Service Configuration Data (e.g. for a specific Spacecraft) allows customisation of a Service Instance • Configuration Data is Open, not specific to Implementation • Service View:messages exchanged between Service Providers and Consumers • Service History/Logging allows for recording, retrieval and even replay of past Service Messages sequencing of messages • Expected Service Interaction, Error Conditions, etc. • Relationships: to other Objects in other Domain Services • Other Characteristics:Security, Quality of Service, Parallelism, etc. EGOS Workshop 2005

  15. Lookup Service Directory Service ConsumerHCI DisplaysOther Applications Configure History ServiceLayer Active Service Interface Invoke Edit Service EditorOperationsPreparation ServiceConfigurationDatabase ServiceHistoryArchive ServiceDirectory Lookup Publish Configure Archive Service Consumer Service Provider Service Provider Invoke Publish The Service Model and Generic Structure • Service Versions • Capability Sets EGOS Workshop 2005

  16. Parameter Class Disable/Enable Monitoring Checks Replay, Retrieve Access Observe Manage Control Archive Access Events and Operations: Parameter Example Set Parameter Action Dynamic History Replay:Observer view Service ConsumerHCI DisplaysOther Applications Block Retrieval ServiceLayer ServiceConfigurationDatabase ServiceHistoryArchive Service Provider Parameter History Parameter Object Definitions Parameter Events EGOS Workshop 2005

  17. Edit SaveValidate Version Series Operations PreparationService Configuration Data 1 n 1 1 Future Object Identity Object Definition Version Install InstantiationEvent Definition UpdateEvent Replay Replay Status UpdateEvent Replay E E E Historical Sessions Operations AnalysisService History E E E Past 1 1 n n 1 n Object Instance Object Status Object Identity Object Definition Retrieve E E E E Retrieve E E E Retrieve E E Generic Service Object Information Model O E O Instantiate Update Concurrent Sessions(Live + Simulated + Replay) Operation Operations ExecutionService Status Data Present 1 1 n 1 1 1 Object Instance Object Status Object Identity Object Definition EGOS Workshop 2005

  18. Kali mera ?!! Service Layering • Stack of Layered Services or Protocols • Stack must match on both sides for Interoperability • Low-level Communication does not ensure Compatibility at the Application Level EGOS Workshop 2005

  19. MO DomainSpecificApplications ConsumerApplication ProviderApplication Plug-inApplications SAP: Service Access Point Application Level Services MO DomainServiceFramework Common Services Infrastructure Services Message Exchange; File Transfer; Mail TechnologyAdaptors TechnologySpecificInfrastructure Communications Services Service Layering EGOS Workshop 2005

  20. ConsumerApplication ProviderApplication SAP: Service Access Point Application Level Services Common Services Technology Adapters Infrastructure Services Message Exchange; File Transfer; Mail Communications Services Service Layering EGOS Workshop 2005

  21. Replay Control Retrieve Service Consumer Replay (Observe) Service Layer C M Observe Manage Control ServiceConfigurationDatabase ServiceHistoryArchive Service Provider Archive Common Interaction Patterns • Common to multiple MO Services • Generic Service Elements implemented in Common Layer • MO Services “specialise” Generic Objects:define Attributes, Operations and Events • 2 Principal Patterns: Operations and Product Distribution • Generic Infrastructure to Support all Services EGOS Workshop 2005

  22. Conclusions • Benefits of SOA • Flexibility / re-usability in mission architecture • Common Layer • Independence from technology • Granularity of Services • Achievable standardisation • SOA Modelling Guidelines • Guidance for future development • Community Review • Benefit of wide review by space system experts • Relationship to CCSDS Spacecraft M&C WG • Continue to track parallel work • Prototyping • Needed to prove / improve the service definitions • Extending the model • Management of future service definition work EGOS Workshop 2005

  23. Recommendations • Build a Prototype of the basic MC service over the Common service as soon as possible • Embark on a study to develop the Event Archive (EARC) and produce a prototype implementation • Develop more service definitions, integrated with the service framework UML model • Continue to participate in / lead the CCSDS equivalent activities • Widely circulate the GDSS Study and encourage wide community review of subsequent work EGOS Workshop 2005

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