XASTRO: A formalised framework for the modelling of space systems

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XASTROA formalised framework for the modelling
of space systems
N. Lindman1, A.Walsh2, P. Ellsiepen2, A.
Crowson3, M. Dyck31European Space Agency,
Darmstadt, Germany.2VEGA IT GmbH, Darmstadt,
Germany.3Anite Systems GmbH, Darmstadt, Germany
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Outline

• Background
• Overview
• Objectives
• Technical Solution
• Challenge
• Conclusion

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Background

• ESA/ESOC Study Contract
• Following on from XASTRO Phase 1 study
  (2002-2003)
• investigation of the use of UML/XML open standard
  technologies for space system and information
  modelling to improve data exchange
• Approach feasible but additional tools needed
• Focus of the XASTRO Phase 2 study is the
  modelling of ESAs Ground Segment
• Part of a wider ESA initiative concerned with the
  harmonisation of Ground System Software
• Project started in January 2004 and scheduled to
  run for approximately 1 year

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XASTRO Phase 1 Overview (1)

• ESA study to investigate the use of XML as the
  basis for a standard data exchange framework
  between customers, contractors and suppliers
  during the life-cycle of a space mission
• Objective Investigate if the open standard
  technologies ofUML XML can be used to model a
  space system and its data
• Context XASTRO was executed under ESAs
  Innovative Technology Programme
• Focus Primarily on space segment, although the
  same principles would be applicable to other
  segments.
• Outcome available at http//www.vega.de/xastro1/

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XASTRO Phase 1 Overview (2)

• A number of use cases for XASTRO was analysed,
  for example
• System Architecture Specification
• Simulation SMDL now under development as part
  of new Simulation Model Portability standard
  (http//groups.yahoo.com/group/smp_list)
• Concurrent Engineering study ongoing to use the
  SMDL in the CDF at ESTEC.
• Real-Time Data Exchange
• Documentation Production
• Space Mission Information Management

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Interfaces
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XASTRO Phase 2 Overview

• Same approach adopted as in Phase 1 i.e provide
  an information model of the applicable system
  from where different products can be derived.
• Focus of this phase is the modelling of ESAs
  Ground Segment.
• ESA TRP Study
• Schedule
• Kick-off Jan 2004
• Methods and Tools Analysis report delivery May
  2004
• Modelling Framework Delivery July 2004
• Ground System Information Model delivery Nov 2004
• Final Delivery Mars 2005

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Objectives

• Improve Interoperability between Ground Systems,
  both within ESA and with external organisations
• Formal definition of Information (i.e. Monitoring
  Control Data, Schedules, Flight Dynamics data
  etc.)
• Formal definition of services (based on European
  Ground Software Technology Harmonisation output)
• Formal definition of Ground Systems Reference
  Architecture (based on European Ground Software
  Technology Harmonisation output)
• Formal definition of Ground System requirements
• Ground Systems Architecture formalised
  specification
• Promote Automation in Ground Segment Operations
• Ground System Configuration
• Documentation Production

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Proposed Technical Solution
Modeling Framework
GOSIF
GSIM
MIM
(XML Schemas)
(Applications and open standards)
(XML Documents)
(Applications)

• Modelling Framework and Tools
• Modelling Language (Meta-model)
• Modelling Tools (Editors)
• GSIM Ground System Information Model
• Standard Types (Services and Data Models)
• MIM Mission Information Model
• CryoSat (prototype)
• GOSIF Ground Operations Systems Information
  Framework
• Model Storage
• Applications (Generators/Translators, Special
  Editors)

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Modelling Framework (1)

• Hierarchical Decomposition of components
• Service modelling
• Multi-Disciplinary Views (Information, Functional
  etc.)
• Cross View Relationships
• Properties / Units
• Requirements
• External References (documents, behaviour etc.)
• Grouping (logical packaging of components)
• Separation of Types Instances (re-use of
  building blocks)
• Extensible
• Behaviour not supported natively

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Modelling Framework (2)

• Currently performing an analysis of modelling
  frameworks
• The following modelling frameworks are being
  considered
• Model Driven Architecture (MDA)
• RM-ODP
• SysML (modified UML 2.0 meta-model)
• CCSDS RASDS (focus on space data systems and
  based on RM-ODP)
• Baseline is to take MDA approach and align with
  CCSDS RASDS based on concepts of RM-ODP

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Modelling Framework (3)
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Modelling Framework (4)
Standardised Data Models
Information Viewpoint

Standardised Services
XASTRO2 Framework
Functional Viewpoint
Enterprise Viewpoint
Physical Viewpoint
Communications Viewpoint
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Ground Systems Reference Architecture (1)

• Why?
• we need to formalise the services provided by the
  ground systems and the information (data types)
  exchanged internally and externally.
• Promote interoperability by formalised definition
  of services to allow software interface
  generation.
• Communicate the architecture unambiguously to all
  stakeholders.
• To understand the BIG picture!

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Ground Systems Reference Architecture (2)

• Systems to be considered
• MCS Kernel including Web-remote monitoring and
  Telemetry Data Retrieval System
• Network Interface System (NCTRS including SLE
  Services)
• Ground Station Back-end System (TMTCS, STC, MCM)
• Flight Dynamics System
• Simulator
• MCS Ancillary system Mission Planning System,
  Generic Data Distribution, Generic File Transfer,
  External Interfaces.

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Ground Systems Information Model (1)
A library of reusable ground system services,
components and information types constituting the
building blocks for a mission specific ground
system.
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Ground Systems Information Model (2)

• ECSS
• E70-31 Monitoring and Control Data
• E70-32 Operational Procedure Language (PLUTO)
• CCSDS
• Packet Standards (Ground to Space Link)
• SLE (Mission Control System to Ground Station
  Link)
• RASDS
• OMG
• XTCE Monitoring and Control Data
• .
• Purpose of XASTRO is to complement space
  standards and to promote interoperability.

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Mission Information Model

• Mission instance of the Ground Systems
  Information model.
• Cryosat Mission Information Model to be developed
  as a prototype model to validate the approach.
• Fairly simple mission good prototype candidate

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GOSIF

• Mission Information Model Storage (XML Server)
• Accessibility
• Availability
• Security
• Applications
• Monitoring and control data editor
• Document Generators for ADDs and ICDs
• Software Interfaces (IDL, Web services)
• Log viewer
• Telemetry file viewer
• Etc.

MIM
Product A
Product C
Product B
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Challenge

• This is a huge undertaking
• Large and complex systems
• Large number of different information types
  within a ground system
• Many different domains.
• Need to focus to a subset of systems and
  services.
• Need to find the right architecture granularity.
• We need to collaborate, in particular with the
  European Ground Software Technology Harmonisation
  and the CCSDS. Collaboration web site deployed at
  http//portal.vega.de/xastro

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Conclusion

• There is a need to harmonise ground systems from
  a development, maintenance, operations and
  configuration aspect.
• There is a need to standardize the ground systems
  services and data models.
• There is a need to improve the information
  exchange within the ground systems.
• This study tries to answer above needs by
  providing a ground systems reference architecture
  and information framework.

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Thanks for your attention!
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