Tools for Describing Space Data Systems Reference Architecture

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1 CCSDS Architecture Working Group Tools for Describing Space Data Systems Reference Architecture 16 March 2005 Peter Shames, NASA/JPL, Takahiro Yamada, JAXA/ISAS

2 Agenda Introduce the Reference Architecture for Space Data Systems (RASDS) Show some examples of how it can be used to model space data systems Define the RASDS requirements on formal methodologies & tools Describe our analysis of using SysML to provide the means to formally describe RASDS models 3/10/2005 CCSDS Architecture WG 2

3 A Physical View of a Space Data System One or More Instruments One or More Spacecraft A Space Tracking Network Commodity Space Communication s Systems Commodity Space Navigation Systems A Spacecraft Control Center An Instrument Control Center Source: A. Hooke, NASA/JPL A Ground Tracking Network A Science Facility 3/10/2005 CCSDS Architecture WG 3

4 Reference Architecture Purpose Establish an overall CCSDS approach to architecting and to developing domain specific architectures Define common language and representation so that challenges, requirements, and solutions in the area of space data systems can be readily communicated Provide a kit of architect s tools that domain experts will use to construct many different complex space system architectures Facilitate development of standards in a consistent way so that any standard can be used with other appropriate standards in a system Present the standards developed by CCSDS in a systematic way so that their functionality, applicability, and interoperability may be clearly understood 3/10/2005 CCSDS Architecture WG 4

5 Technical Approach Develop a methodology for describing systems, and systems of systems from several viewpoints Initial focus was CCSDS, but it is more generally applicable to space data systems Derived from Reference Model of Open Distributed processing (RM-ODP), which is ISO Adapted to meet requirements and constraints of space data systems Define the needed viewpoints for space data system architecture description Does not specifically include all elements of RM-ODP engineering and technology views, assume use of RM-ODP for these Does not encompass all aspects of Space Systems, i.e. power, propulsion, thermal, structure, does not preclude them either Define a representational methodology Applicable throughout design & development lifecycle Capture architecture & design artifacts in a machinable form, able to support analysis and even simulation of performance Validate methodology by applying it to several existing CCSDS reference models and existing systems Identify relevant existing commercial methodologies Evaluate UML 2.0 and SysML, now in progress Explore applicability of selected methodology & tools to RASDS 3/10/2005 CCSDS Architecture WG 5

Space Data System Several Architectural Viewpoints Enterprise Connectivity Functional Business Concerns Organizational perspective Physical Concerns Node & Link perspective Computational Concerns

6 Space Data System Several Architectural Viewpoints Enterprise Connectivity Functional Business Concerns Organizational perspective Physical Concerns Node & Link perspective Computational Concerns Functional composition Information Communications Data Concerns Relationships and transformations Protocol Concerns Communications stack perspective Derived from: RM-ODP 3/10/2005 CCSDS Architecture WG 6

7 RASDS Top Level Object Ontology Composed Of Organization Mission Requirements FulfilledBy Objectives Goals ComposedOf Fulfills Scenarios Owns/Operates Calls Function Produces Information Structure Behavior Interfaces Constraints ProvidesService Uses Communication Protocol stack Standards Consumes IsAllocatedTo ComposedOf ContainsInstances ImplementedOn AssociatedWith Node Component Performance s Environment ConnectVia ConnectTo Data Metadata Rules Characteristics 3/10/2005 CCSDS Architecture WG 7 Type Link

8 Space Data System Architectural Notation Object Object with Interface Object Encapsulation Management Node (physical location) Node Encapsulation (physical aggregation) Service External Concerns Logical Link Physical Link Space Link (rf or optical) 3/10/2005 CCSDS Architecture WG 8

9 Unified Object Representation Management Interfaces: How objects are configured controlled, and reported upon Object Service Interfaces: How services are requested & supplied Core Functions What the object does External Interfaces: How external elements are controlled Concerns: Issues Resources Policies 3/10/2005 CCSDS Architecture WG 9

10 Enterprise View Federated Enterprises with Enterprise Objects Cross- Support Agreement Agency QRS Agency ABC Mission A Mars Exploration Program Federation Mission Q Proj R GTN B Prog C Enterprise Objects Prog Instr S Instrument Integration Mission AX Enterprise Concerns: Objectives Roles Policies Activities Configuration Contracts Lifecycle / Phases Proj X GTN Y Service Z Company XYZ Mission BFD Development & Operations Domain Operations Contract Mission BFD Organization PDQ 3/10/2005 CCSDS Architecture WG 10

11 Functional View Example Functional Objects & Interactions Monitor & Control Mission Planning Directive Generation Directive Management Directive Execution Mission Analysis Data Repository Data Acquisition Functional Concerns: Behaviors Interactions Interfaces Constraints Spacecraft Analysis LT Data Repository Tracking Orbit Determ Radiometric Data Collect 3/10/2005 CCSDS Architecture WG 11

12 Connectivity View Nodes & Links SPACECRAFT Mission Planning Computer Internet Space Link Spacecraft Transceiver Command & Data Handling Computer S/C Bus Spacecraft Control Computer Ground Tracking Station ACS Computer Science Instrument Connectivity Concerns: Distribution Communication Physical Environment Behaviors Constraints Configuration 3/10/2005 CCSDS Architecture WG 12

13 Connectivity & Functional View Mapping Functions to Nodes Science Spacecraft Monitor & Control Data Acquisition Directive Execution Data Repository Comm Mgmt Attitude Control Radiometric Data Collect Tracking Science Institute Mission Planning Directive Generation LT Data Repository (Archive) Data Repository Comm Tracking Mgmt Radiometric Data Collect Spacecraft Analysis Monitor & Directive Directive Data Control Management Generation Repository Mission Analysis Orbit Determ Traj Design Tracking Station S/C Control Center Combined View: End to End Behavior Performance Throughput Trade studies 3/10/2005 CCSDS Architecture WG 13

14 Information Objects Relationship to Functional View S/C Event Plans Observation Plans Directive Generation Directive Execution Command Execution Actual Data Objects Operation Plans Commands Data Models Operations Plan Schema & Structure Definition Realization Command Schema & Structure Definition Realization S/C Commands Instrument Commands Information Objects are exchanged among Functional Objects Instantiation Instantiation Abstract Data Architecture Meta-models Data Object 1..n Information Object Semantic Information Representation Information Structure Information Data Object 1..n Information Object Semantic Information Representation Information Structure Information Information Concerns: Structure Semantics Relationships Permanence Rules

15 Communications Viewpoint Protocol Objects End-To-End Command Processing GROUND SYSTEM Command Generation Commands SPACECRAFT C&DH Payload Command Execution Packet Packet Tracking Station Packet (Relay) Packet TC Space Data Link TC Space Data Link (Relay) Frame TC Space Data Link SLE CLTU SLE CLTU TCP/ IP PPP TCP/ IP PPP RF Generation TCP/ IP RF Onboard GenerationPhysical TCP/ IP Onboard Physical Communications Concerns: Standards Interfaces Protocols Technology Interoperability Suitability 3/10/2005 CCSDS Architecture WG 15

16 Security Analyses Multiple Viewpoints & Relationships Ground Tracking Network B Mission A Spacecraft Spacecraft Control Center C Mission A Instrument Control Center Trust relationships Policies Privacy / proprietary issues Enterprise Security Domains Monitor & Control Directive Execution Attitude Control Radiometric Data Collect Access control Authentication Data Acquisition Data Management Comm Mgmt Tracking Functional Allocations Science Spacecraft Science Institute Firewalls Encryption Boundary access points Combined View: Connectivity & Relationships Tracking S/C Control Station Communications Center Allocations Performance 3/10/2005 CCSDS Architecture WG Trade studies 16

17 High Level RASDS Methodology / Tool Requirements Meta-model and model language that is independent of specific tool environments and implementations Models can be exchanged and imported into other tool suites Tool suite with a graphical interface that enables creation, manipulation, display, archiving, and versioning of meta-models, component and connector type templates, and instance models Support development of machine readable, portable architecture meta-model for RASDS Support development of instance models for specific space systems deployments Provide a framework that supports coarse grained simulation of behavior and performance characteristics instance models 3/10/2005 CCSDS Architecture WG 17

18 Formal Method Evaluation Studied UML 2.0, SysML, xadl Unified Modeling Language (UML 2.0) Too focused on software systems Includes elements that are not needed for RASDS Some commercial tool support now System Modeling Language (SysML) Has most of the required features (and more) Needs some extensions for RASDS viewpoints and details Commercial tools support expected late 2004 / early 2005 xadl Extensible approach that can accommodate RASDS xadl needs to be customized, not interoperable w/ XMI Tool support from UCI and USC, academic quality 3/10/2005 CCSDS Architecture WG 18

19 SysML Background Informal partnership of modeling tool users, vendors, etc. Organized in May 2003 to respond to UML for Systems Engineering RFP Includes many aerospace companies and major UML tool vendors Charter The SysML Partners are collaborating to define a modeling language for systems engineering applications, called Systems Modeling Language (SysML ). SysML will customize UML 2 to support the specification, analysis, design, verification and validation of complex systems that may include hardware, software, data, personnel, procedures, and facilities. References: SysML Partners Web Site See also SysML Specification Draft v0.9 on this web site Source: SysML Partners 3/10/2005 CCSDS Architecture WG 19

20 SysML Language Architecture Source: SysML Partners 3/10/2005 CCSDS Architecture WG 20

21 Mapping RASDS into SysML No simple one for one mapping RASDS uses Viewpoints to expose different concerns of a single system SysML uses specific diagrams to capture system structure, behavior, parameters and requirements Several SysML diagrams, focused on different object classes, may be usefully applied to any given RASDS Viewpoint Extended SysML Views may be used to define the relationships between Viewpoints and Diagrams SysML will support more accurate fine grained modeling of structure, relationships and behavior than was expected of RASDS 3/10/2005 CCSDS Architecture WG 21

22 Mapping RASDS into SysML Enterprise Organizational component & collaboration diagrams Use case, interaction overview diagrams Requirements & constraints for rules, policies & agreements Connectivity Physical component, composition, collaboration & class diagrams Parametric diagram for physical link characterization Functional Logical component, collaboration & class diagrams Activity, state chart, parametric, & timing diagrams Informational Information class & parametric diagrams Communication Protocol component & collaboration diagrams State machine, sequence, activity & timing diagrams 3/10/2005 CCSDS Architecture WG 22

23 Enterprise View Using SysML Use Case Diagram <<usage>> Enterprise: Use Case Mars Exploration Program Federation Science Team <<primary>> Mission Operations Team <<Primary>> Agency ABC <<includes>> Relay Service A Operations Contract Mission A <<extends>> TT&C Service B <<includes>> <<extends>> <<includes>> GTN B <<extends>> Cross Support Agreement Service Operations Team <<Secondary>> <<includes>> <<extends>> <<includes>> Instr C Agency QRS Mission Q <<includes>> Instrument Integration Science Team <<primary>> Instrument Team <<Secondary>> 3/10/2005 CCSDS Architecture WG 23

24 Connectivity View (Nodes & Links) Using SysML Components (Spacecraft) Spacecraft CDH : CmdDataHandlingSystem sciinstr : scienceinstrument dm : DataManager SensorData s : Sensor ap: Mechanical CmndIn InstrCmnd ecu : Execution Control Unit DataDone ObsFin ap : Aperture oc : ObsControl TakeObs ic : InstrControl TeleCmnd Telem ul : UpLink dl : DownLink Derived from: SysML Partners RFAntenna 3/10/2005 CCSDS Architecture WG 24

25 Connectivity View (Nodes & Links) Using SysML Components (MOS & TT&C Systems) MOS : MissionOpsSystem TT&C : TrackTelemCommand ObsReq dm : DataManager MOP : Mission OpsPlanning Telem TelemDone TelemData CmndData Tele Cmnd TM : Telemetry Re Trans TC : Telecommand DL UL dl : DownLink ul : UpLink RF Ant Cmnd SC : SendCmnd PointingData Pt : Pointing Ant: Mechanical 3/10/2005 CCSDS Architecture WG 25

26 Connectivity View (Composition) Using SysML Components Spacecraft CDH : CmdDataHandlingSystem sciinstr : scienceinstrument MOS : MissionOpsSystem Telem dm : DataManager TelemDone ObsReq MOP : Mission OpsPlanning TelemData CmndData TT&C : TrackTelemCommand DL TM : Telemetry dl : DownLink Tele Cmnd Re Trans UL TC : Telecommand ul : UpLink RF Ant RF: link [X-band] dm : DataManager DataDone Cmndin ecu : Execution Control Unit InstrCmnd oc : ObsControl ObsFin TeleCmnd Sensor Data Take Obs Telem ul : UpLink S : Sensor IC : InstrControl dl : DownLink RF: link [KaBand] AP: Mechanical Ap : Aperture RFAnt Cmnd SC : SendCmnd Pointing Data Pt : Pointing Ant: Mechanical Global structure inherited by each kind of Spacecraft and constrained for each kind 3/10/2005 CCSDS Architecture WG 26

27 Functional View Using SysML Activity Diagram Showing component allocations (optional) Spacecraft Ground System Instrument S/C Control TT&C Network Mission Ops Plan ObsSeq Recv Cmnd plannedobs Xmit Cmnd Execute Cmnd retransreq Prepare Cmnd Instr Cmnd readycmnd retransdatareq Take Obs Store Data Recv Data Accept Data Transmit Data obscomplete Finish ObsSeq 3/10/2005 CCSDS Architecture WG 27

28 Informational View Using SysML Class Diagram Reusable, refinable information structure: <<info obj>> InstrCmndFile <<data obj>> InstrCmndList describes 1..* 1 <<metadata obj>> InstrCmndMetaData <<data obj>> InstrCmnd 1..* <<metadata obj>> InstrCmndSemantics <<metadata obj>> InstrCmndStructure Derived from: SysML Partners Global representation inherited by each kind of Information Object 3/10/2005 CCSDS Architecture WG 28

29 Communication View (Protocol Objects) Using SysML Component Diagram MOS : MissionOpsSystem SC : SpaceCraft SC : SendCmnd Cmnd MOP : Mission OpsPlanning <<controls>> CmndIn ECU : Execution Control Unit TC : TeleCmnd <<protocol>> TP: TransportLayer <<protocol>> TP: TransportLayer <<protocol>> IP: InternetLayer <<protocol>> IP: InternetLayer <<protocol>> LL: LinkLayer <<protocol>> LL: LinkLayer <<protocol>> PL: PhysLayer <<protocol>> PL: PhysLayer RF: link [Xband] CmndData:RF Derived from: SysML Partners 3/10/2005 CCSDS Architecture WG 29

30 Communication View Using SysML State Machine Diagram <<protocol>> TP: TransportLayer evsend / transmitcount=0 Sending Idle evdonesend / ++transmitcount tm(wait Time) [transmitcount<limit] tm(wait Time) Throw( Unable to Send ) evack[isvalid] Waiting Protocol specifications inherited by each instance of Protocol Objects Derived from: SysML Partners 3/10/2005 CCSDS Architecture WG 30

31 Acknowledgements This task was carried out as part of the program of work of Consultative Committee for Space Data Systems (CCSDS). It was performed by the Architecture Working group (AWG), chaired by Takahiro Yamada, ISAS Other AWG members who actively participated are listed below: Fred Brosi, NASA/GST Dan Crichton, NASA/JPL Adrian Hooke, NASA/JPL Steve Hughes, NASA/JPL Niklas Lindman, ESA/ESOC Nestor Peccia, ESA/ESOC Lou Reich, NASA/CSC Don Sawyer, NASA/GSFC Peter Shames, NASA/JPL Anthony Walsh, ESA/Vega 3/10/2005 CCSDS Architecture WG 31

32 BACKUP SLIDES 3/10/2005 CCSDS Architecture WG 32

A Generic Method for Defining Viewpoints in SysML

A Generic Method for Defining Viewpoints in SysML Takahiro Yamada Japan Aerospace Exploration Agency/Institute for Space and Astronautical Science 3-1-1 Yoshinodai, Sagamihara 229-8510, JAPAN Copyright