egos workshop 2005
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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EGOS Workshop 2005
GDSS - Ground Data System Services:a Service Oriented Architecture for Mission OperationsRoger Thompson, Nestor Peccia, Stewart Hall, Oliver Page
Presented by:Roger Thompson
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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
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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
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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
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Integrated Systems vs. Modular Components
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Service-Oriented Architecture:Plug-in Components
Components
Services
Infrastructure
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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
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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
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Mission Operations Functions
MES: Mission Exploitation
MCS: Mission Operations
GSTS: Ground Station Network
Spacecraft
StationM&C
GSUS: Ground Support System
EGSE
On-boardAutomation
GroundAutomation
Tracking &Ranging
AOCS
FlightDynamics
SpacecraftM&C
OperatorInteraction
Analysis &Reporting
MissionData Processing
MissionData Acquisition
MissionProduct
Distribution
ExternalData
Distribution
OperationsPlanning
StationScheduling
MissionPlanning
On-boardSoftware
OB SoftwareDevelopment &
Validation
OB SoftwareManagement
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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
Information Object Y
Information Object X
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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
Object Object View
Events
Service Object
Operations
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OtherGSUSMES
Spacecraft
GSTS
MCS
OB Data ProductStorage
Spacecraft M&COB Procedure
ExecutionOB Schedule
ExecutionOB Software
Tracking &Ranging
MissionPlanning
MissionData
Processing
ExternalUser
OperationsPlanning
FlightDynamics
OperationsAutomation
OperatorInteraction
StationM&C
StationScheduling
ExternalData User
Analysis &Reporting
OB SoftwareDevelopment
OB SoftwareManagement
Spacecraft M&CProxy
OB ScheduleProxy
OB ProcedureProxy
OB Data ProductProxy
OB SoftwareProxy
Mission Operations [MO] Services
GDD
LOC
PEXSEX
DPM
AUTOPI
OSM
SRI
FDSREP
MC
SLE-Man
PRQ
TIM
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GDSS Mission Operations ServicesID Name Description
MC Core Monitoring & Control Parameters: publish status; setActions [Commands]: publish status; invoke/sendAlerts [Events]: notify; raise
AUT Automation Specialisation of MC for automation of proxy functions
DPM Data Product Management Data Product [Payload Data File]: directory; transfer
FDS Flight Dynamics Orbit/Attitude: determination, propagation, manoeuvre preparation
GDD Generic Data Dissemination Product: catalogue; order; deliver
LOC Location Position: tracking, ranging, onboard positioning
OPI Operator Interaction Message/Alarm/Query: notify; operator response
OSM OB Software Management On-board Software: load; dump
PEX Procedure Execution Procedure/Function: control; progress reporting
PRQ Planning Request Planning Request: request; response
RBM Remote Buffer Management Buffer: catalogue; retrieve; clear
REP Report Reports: publish; catalogue; retrieve; generate
SEX Schedule Execution Schedule: distribute; edit; control; progress reporting
SRI Software Reference Image On-board Software Image/Patch: distribute
TIM Time Time: report; set; correlate; notify
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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.
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The Service Model and Generic Structure
Service Versions Capability Sets
Service Consumer Service Provider
Service Directory
Invoke
Lookup Publish
Service Layer
Service Provider
Service ConsumerHCI Displays
Other Applications
ServiceConfiguration
Database
ServiceHistoryArchive
Service EditorOperationsPreparation
Invo
ke
Archive
History
ServiceDirectory
Publish
Lookup
Configure
Configure
Edit
Active Service Interface
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Events and Operations: Parameter Example
Service Layer
Service Provider
Service ConsumerHCI Displays
Other Applications
ServiceConfiguration
Database
ServiceHistoryArchiveO
bse
rve C
on
tro
l Man
ag
e
Archive
Replay, Retrieve
Access
Access
Parameter Class
Parameter Object Definitions
Parameter History
Parameter Events
Set Parameter Action
Disable/Enable Monitoring Checks
Dynamic History Replay:Observer view
Block Retrieval
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Operations ExecutionService Status Data
Object Identity1 1
Object Definition
Concurrent Sessions(Live + Simulated + Replay)
1 1Object Status
UpdateE
Operation
O
1 nObject Instance
InstantiateO
Generic Service Object Information Model
Pre
sen
t
Operations AnalysisService History
Historical Sessions
Object Identity1 n 1 n
Object Definition Object Status
Past
Status UpdateEvent
Definition UpdateEvent
EE
1 nObject Instance
InstantiationEvent
E
Replay
E
Replay
E
Replay
E
Operations PreparationService Configuration Data
Object Identity1 n 1
Object Definition Version
Version Series
Install
EditSaveValidate
Fu
ture
1
Retrieve
EEE
Retrieve
EEE
Retrieve
EEE
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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
?!!
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Service Layering
Application Level Services
Common Services
MO DomainServiceFramework
ConsumerApplication
ProviderApplication
MO DomainSpecificApplications
TechnologyAdaptors
SAP: Service Access PointPlug-inApplications
Infrastructure Services
Message Exchange; File Transfer; Mail
TechnologySpecificInfrastructure
Communications Services
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Service Layering
Application Level Services
Common Services
ConsumerApplication
ProviderApplication
SAP: Service Access Point
Infrastructure Services
Message Exchange; File Transfer; Mail
Communications Services
Technology Adapters
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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
Service Layer
Service Provider
Service Consumer
Ob
ser
ve Co
ntr
ol
Man
ag
e
Archive
ServiceHistoryArchive
RetrieveReplay Control
Replay (Observe)
ServiceConfiguration
Database
MC
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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
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Recommendations
1. Build a Prototype of the basic MC service over the Common service as soon as possible
2. Embark on a study to develop the Event Archive (EARC) and produce a prototype implementation
3. Develop more service definitions, integrated with the service framework UML model
4. Continue to participate in / lead the CCSDS equivalent activities
5. Widely circulate the GDSS Study and encourage wide community review of subsequent work