The XTCE Standardization Approach of Telemetry

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The XTCE Standardization Approach of Telemetry
Command Databases The ESA example

• Jennifer Muller, Mario Merri
• ESA/ESOC

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Presentation Outline

• What is XTCE
• XTCE Application to ESOC Infrastructure
• Conclusions Perspectives

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1 - XTCE Contributors

• Object Management Group (OMG) standard originally
  developed by
• European Space Agency
• US Air Force/Mission Operations (Lockheed Martin)
• Boeing Communications Satellites
• NASA JPL
• CCSDS Books
• Red Book, developed by OMG, reviewed by CCSDS
• Green Book, high level tutorial for XTCE RB
• Magenta Book, detailed guidelines for XTCE RB

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1 - XTCE Covered Concepts

• Stream processing
• Channel coding, data extraction
• Parameter processing
• Randomization, commutation, packetization
• Calibration, conversion
• Command processing
• Transmission constraints, verification,
  authentication, formatting

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1 - XTCE Vision Exchange format
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1 - XTCE Goals

• Non-proprietary standard format to exchange TM
  TC data definitions that will reduce
• human errors
• ambiguities, confusion, and
• lost time and money in difficult, sometimes lousy
  (painful) conversions between dissimilar systems

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2 - Applying XTCE to ESA infrastructure

• 100 compatibility of XTCE with regard to ESA
  infrastructure is not ensured by ESA
  participation to XTCE..
• Validation of the XTCE concepts for ESA
  infrastructure, by a real application of XTCE to
  an ESA mission
• Initially, no alteration of current ESA legacy
  systems (i.e.. SCOS-2000 MIB)

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2 - ESOC Infrastructure Overview
Mission Control System (S2K)
Database Editor
Database Editor
Flight Dynamic System
Mission Planning System
S/C DB
OPS DB
S2K MIB

Spacecraft Simulator
Simulator Database Tool
SIM DB
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2 - Applying XTCE to ESOC Infrastructure

• SCOS-2000 MIB files are used by many systems
• Mission control system, Flight dynamic system,
  Mission planning system, etc..
• Find the best solution to convert S2K MIB files
  to an XML file compliant with an evolving XTCE
  standard
• Keep mapping knowledge external
• SCOS-2000 MIB files contain more than TM/TC data
  definition
• Separation of data (filtering)
• Work on TM/TC data for XTCE
• The remaining data go to another file

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2 - ESA S2K MIB and XTCE Scopes
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2 - Conversion Approach

• Create an adaptor layer (to bridge systems)
• Maintain the mapping knowledge outside of the
  adaptor code
• The legacy system format is stable, but XTCE is
  evolving
• XML allows us to separate the knowledge from the
  code (XSLT)
• As XTCE is XML, make use of XML technologies
  available
• Tool developed in Java 1.5 with XML, XSLT, XSD
  support

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2 - Conversion results

• Several mission databases converted
• Rosetta MIB in 2003 XTCE 0.x
• CryoSat MIB and MetOp-1 MIB XTCE 1.1
• Herschel-Planck MIB planned to be converted
• Non TM/TC data need to be stored in an additional
  XML file conforming to an internal XML schema
• Command sequences support is not good enough in
  XTCE, but will be supported by a dedicated XML
  Schema in preparation (OMG new meta model)

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2 - Conversion results

• Results for the Cryosat SCOS-2000 MIB
• 37 fields are lost mostly due to a complex S2K
  MIB design
• The information is available in XTCE, but cannot
  be extracted appropriately from the MIB.
• The information implied is related to CCSDS
  packets header and their displays that are
  interleaved with their definitions in S2K MIB.
• Almost all TM/TC data is covered by XTCE
  (although there might exist legacy system
  problems)

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3 - Conclusions

• XTCE is compatible with SCOS-2000 and is a
  powerful model to describe TM/TC data
• XTCE needs XML code samples to be interoperable
  with other standards
• ECSS standards (E70-31, E70-41 PUS)
• CCSDS packet telemetry and telecommand
• XTCE is not just another standard but
• A way to define how data is represented, not what
  should go inside, which is the job of other
  standards
• XTCE allows for evolutive approach through the
  use of legacy system adaptors to bridge systems

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3 - Perspectives

• NASA/JPL is using XTCE for the James Webb Space
  Telescope
• Once harmonized with other standards, XTCE should
  be used more and more widely
• inside ESA, through the initial use of the
  adaptor concept
• outside ESA (spacecraft manufacturers)

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Thank you for your attention