System Modelling and Simulation

1
System Modelling and Simulation

• Joachim.Fuchs_at_esa.int
• Juan.Miro_at_esa.int
• Software Systems Division
• System Software and Synthesis Department
• Technical and Quality Management Directorate

2
Presentation Outline

• Modelling and Simulation in the project
  life-cycle
• Enabling factors
• Specific examples
• Functional Engineering Simulator
• SVF
• AIT / EGSE
• Harmonisation activities / Standardisation
• Future The Virtual Spacecraft Design
• Conclusions

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Modelling and Simulation in the Lifecycle
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Main successes

• Verifying system feasibility and performance
• Allowing design trades during system (re)design
• Refining operability (including human-in-the-loop
  systems)
• Demonstrating capability otherwise impossible to
  show
• Early demonstration and testing before hardware
  is available (e.g. OBSW testing)
• Avoidance of building hardware prototypes
• (Sub-)System Verification and Training

5
Main challenges today

• Integration within the system engineering (SE)
  process
• Shorten development time to effectively support
  the space system design iterations
• Linkage with system engineering data to configure
  the simulation and allow simulation results to
  feed-back into the System Engineering process
• Integration of engineering models (e.g.
  thermo-structural models)
• Increasing reuse of models between programmes
• Distributed development of models by
  subcontractors and delivery to primes (requires
  model exchange and interoperability standards)

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Enabling Factors

• Clear separation between
• Run-time infrastructure (kernel)
• Models
• Modelling environment
• Reuse
• Of models
• Of architectures
• For both
• Along the life-cycle
• Between projects
• Standardisation of
• Process
• Architectures
• Interfaces
• Building blocks / components

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The Functional Engineering Simulator

• Support to early design, concept definitions,
  possibly to be used in a concurrent design
  environment by adding dynamic component to
  approaches like Concurrent Design Facility (CDF)
  and therefore contribute to the
• Support to mission trades and verification of the
  mission concept
• Verification of functional spacecraft design
• Support to system trade-off analysis
• Verification of the baseline Mission and
  Spacecraft Design
• Mission performance by end-to-end system
  simulators
• Enables preparation of the user community
• Supports the System Engineering function in
  assessing system-level trade-offs

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Functional Architecture
Generic simulator architecture
Model breakdown used in SimVis
9
Supporting tool SimVis

• quick (days!) and flexible set-up for new
  missions
• a growing level of detail from mission to S/C
  design

Microsoft Excel
Workbook
Project Wizard
OpenIGS
Simulation
Visualisation
Run-Time Environment
Designer
Output Data
Data Processor
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Simulation to support Software Validation

• Software is very close to the system functions
  and has therefore a key position in the overall
  design process.
• Validation of the on-board software needs to be
  performed in a context that is representative of
  the satellite system in space and with ground
  interfaces.
• The simulation represents the spacecraft hardware
  and its dynamic behaviour in space. Models
  integrated in the SVF have a high level of
  commonality with those used in the System Test
  Bench (in term of scope, functionality and
  performance).

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Different configurations of a SVF
SW only configuration
HW configuration
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AIT / EGSE
Simulation Infrastructure
Test Supervisor
EnvironmentModels
Spacecraft DynamicsModels
Missing Spacecraft Equipment Models
Interfaces Subject of harmonisation
Ground Models
Front-End Equipment / SCOE
Spacecraft Equipment
e.g. SCOS 2000, CGS,
MDB
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Re-use / Lessons learned from ATV

• Reuse was feasible
• Operational simulator was used to produce
  environment for a SVT-Lite
• Original HW centered solution presented problems
  of context saving
• SW / emulator solution helped to address large
  parts of the problem
• Synergies between simulation facilities are
  possible, BUT if not planned properly at the
  beginning, they are difficult to implement
  technically and contractually

14
Harmonisation / standardisation activities

• European Harmonisation
• Ground segment SW
• Aspect relevant for simulation is the definition
  of common interfaces between EGSE and Simulator
  components, to allow consistent operation / test
  supervisor interfaces
• Enabling conditions for tool diversity
• System Design and Verification Tools Modelling
  and Simulation
• Process started to harmonise future investments
  in the area of infrastructure / tools
• Separation between simulation kernels and
  modelling tools
• Requires definition of common interfaces
• Standardisation
• Simulation Portability Standard (SMP2)
• System Modelling and Simulation (ECSS E10 part
  13)
• Engineering Database (ECSS E10 part 9)
• Mathematical and Analytical models (ECSS E10 part
  14)

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Evolution of simulation in the life-cycle
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The Future Virtual Spacecraft Design?

• Process definition improvements being defined, to
  create virtual spacecraft to support full project
  life-cycle
• Enlarge to mechanical domain (thermal /
  structural digital models)
• Allow virtual (E and M) AIT/AIV
• Enable full system design validation before
  hardware is being produced
• Have potential impact on model philosophy
• Start of these activities in phase B, but reuse /
  continuation in later phases
• TRP study
• Process definition
• Environment prototyping
• Demonstration with pilot project

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Conclusion

• The use and benefit of simulation is well
  recognised in the different areas of a space
  project
• Within a project, there are still many instances
  of simulators being developed for the different
  facilities with limited coordination and reuse
• Reuse is still hampered by lack of methodology
  and standards
• involvement of different parties (prime / sub,
  customer / supplier)
• differing requirements to the infrastructure
  (e.g. functional vs. R/T)
• Standardisation of architectures, interfaces and
  databases should allow to address this problems
• The concept of a virtual system design (already
  used in other domains such as aerospace) should
  allow to increase the quality and efficiency of
  the process