1. Exchanging Databases with Dissimilar Systems Using CCSDS XTCE
CCSDS Spacecraft Monitoring & Control WG
And
OMG Space Domain Task Force
Presented by Mario Merri, ESA

2. Outline Where does XTCE come from? Its goals and benefits
How does it work?
Usage so far
Conclusions
GSAW 2006

3. XTCE History
Object Management Group (OMG) standard originally developed by
European Space Agency
US Air force/Mission Operations (Lockheed Martin)
Boeing Communications & Satellites
NASA & JPL
Being adopted by CCSDS via Agency Review under responsibility of SM&C WG
GSAW 2006

4. CCSDS SM&C and XTCE ESA BNSC CNES CSA DLR INPE JAXA NASA/GSFC NASA/JPL
M Merri (chairman), M Schmidt, A Ercolani, J Muller
I Dankiewicz, S Cooper
BNSC
R Thompson (deputy chairman), B Harnett
CNES
B Béhal, E Poupart, R Soumagne
CSA
P Melanson
DLR
H Hofmann
INPE
PG Milani, AM Ambrosio
JAXA
T Yamada
NASA/GSFC
DC Lokerson, F Johnson, JK Marquart, JS Gal-Edd, C Fatig, R Jones , K Rice
NASA/JPL
A Oyake, P Shames, J Moholt
ASI
C Labonia
OMG
G Simon (Lockheed Martin), B Kizzort (Harris Corp.)
XTCE Splinter Group
GSAW 2006

5. XTCE Goals
XML-based non-proprietary standard format for TM/TC databases
Reduces
human errors,
ambiguities, confusion, and
lost time in difficult, sometimes lossy (painful), conversions between systems
GSAW 2006

6. Application field Exchange between Reuse database Reduce costs
working teams
missions
systems
agencies
Reuse database
Reduce costs
Planning
Scheduling
XTCE
Format
Instrument
Manufacturers
Command
Management
Spacecraft
Manufacturers
Real time
Simulators
Trending
Analysis
GSAW 2006

7. XTCE Benefits
Better interoperation between space agencies and contractors (or any other actor)
Let different philosophies collaborate in one data model
Accept time division multiplexing, packet TM
Separate “pure” telemetry and telecommand data from dedicated/proprietary processing data
GSAW 2006

8. XTCE in a nutshell (1/8)
An XML schema file representing telemetry and telecommand data required for:
Channel (de)coding and frame processing
Data transmission and packaging
Parameters calibrations, alarms, properties
Telecommand definitions, transmissions (pre and post checks) …
GSAW 2006

9. XTCE in a nutshell (2/8)
XTCE separate information and describe a hierarchy of space systems
The granularity of space systems is let to the user
That hierarchy allows integration of multiple databases into one overall database
ex: multi-satellite missions, multi-instrument satellite
GSAW 2006

10. XTCE in a nutshell (2*/8) One satellite DB Space System
Spacecraft level
Space System
Space System
One satellite DB
Instrument level
Space System
Space System
Device level
GSAW 2006

11. XTCE in a nutshell (2**/8)
Space System
Constellation level
Space System
Space System
Multi-satellite DB
Satellite level
Space System
Space System
Instrument level
GSAW 2006

12. XTCE in a nutshell (3/8) A space system in XTCE is able to describe:
Telemetry parameters, packaging and dedicated processing
Telecommand parameters, commands, packaging and dedicated processing
Streams (up and down, with coding information)
Maintain minimal configuration information
TM and TC definitions are 80% similar
GSAW 2006

13. XTCE in a nutshell (4/8) Header for configuration data
Space System
Header for configuration data
Default for generic settings
Services for frames identification
Telemetry and Telecommand …
Header
Defaults
Telemetry
Telecommand
Services
GSAW 2006

14. XTCE in a nutshell (5/8)
Telemetry data is distributed in several elements:
Parameter types
Parameters (instances of parameter types)
Containers
Messages
Streams
Algorithms
GSAW 2006

15. XTCE in a nutshell (6/8) Logical definitions sequence:
Parameter types (alarms, calibrations)
Parameter instances
Containers
Streams, messages and algorithms
Example: CCSDS TM frames, packets and XTCE containers
GSAW 2006

16. XTCE in a nutshell (7/8)
Parameters are put in sequence to form packets (containers)
Packets are put together to form frames
Streams are defined on top of generic frames
Frame
primary header
Frame
secondary header
Frame
data field
Op.ctrl
Err.ctrl
Frame
Packet
Packet header
Packet data field
Ver #
Type
P.hdr f
APID
Gr. f
SSC
P.h.len
Packet header
GSAW 2006

17. XTCE in a nutshell (8/8)
Telecommand data is distributed in several elements:
Parameter types
Parameters
Containers
Messages
Streams
Algorithms
GSAW 2006

18. XTCE application so far
James Webb Space Telescope XML schema have been converted
SCOS-2000 ASCII files have been converted
(other examples?)
GSAW 2006

19. CCSDS Documentation
Draft CCSDS Green book release along with XTCE1.1 for internal CCSDS review
CCSDS Magenta book (detailed user guide) is being written
GSAW 2006

20. Conclusions
Working with XML is of easy access due to the amount of libraries and tools available to work with XML schemas
The concepts implemented by XTCE are powerful and have the capabilities to represent any legacy system TM & TC database
Non TM&TC data is not considered in XTCE; (dedicated software instructions, SW configuration variables)
GSAW 2006

21. Questions and Answers ?
GSAW 2006