Exchanging Databases with Dissimilar Systems Using

CCSDS XTCE CCSDS Spacecraft Monitoring & Control WG

And

OMG Space Domain Task Force

Presented by Mario Merri, ESA

GSAW 2006 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

– 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

XTCE Format

• Exchange between– working teams– missions– systems– agencies

►Reuse database►Reduce costs

Application field

PlanningScheduling

CommandManagement

Real time

Trending

Analysis

Simulators

SpacecraftManufacturers

InstrumentManufacturers

GSAW 2006 7

XTCE Benefits

• Better interoperation between space agencies and contractors (or any other actor)

• Lets different philosophies collaborate in one data model– Accepts time division multiplexing, packet TM

• Separates “pure” telemetry and telecommand data from dedicated/proprietary processing data

GSAW 2006 8

XTCE in a nutshell (1/8)

• An XML Schema language describing 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 describes a “SpaceSystem” - command & telemetry descriptions, in a hierarchical format

• The granularity of a space system’s description is left to the user, e.g. SpaceSystem may contain SpaceSystem(s)

• 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)

Space System

Space System Space System

Space System Space System

Spacecraft level

Instrument level

Device level

GSAW 2006 11

XTCE in a nutshell (2**/8)

Space System

Space System Space System

Space System Space System

Constellation level

Satellite level

Instrument level

GSAW 2006 12

XTCE in a nutshell (3/8)

• A space system in XTCE is able to describe:– Telemetry parameters, their packaging and dedicated

processing– Telecommand parameters, commands, its 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

• Default for generic settings• Services for frames

identification• Telemetry and

Telecommand …

Space System

Header

Defaults

Telemetry

Services

Telecommand

GSAW 2006 14

XTCE in a nutshell (5/8)

• Telemetry data is distributed in several elements:– Parameter types– Parameters (instances of parameter types)– Containers (aka packets)– Messages– Streams– Algorithms

GSAW 2006 15

XTCE in a nutshell (6/8)

• Logical sequence of definitions :– Parameter types (alarms, calibrations)– Parameter instances– Containers (Packets)– 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

Packet header Packet data field

Ver # Type P.hdr f APID Gr. f SSC P.h.len

Frame

Packet

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 Applications so far

• James Webb Space Telescope XML Schema have been converted

• SCOS-2000 ASCII files have been converted

• (other examples?)

• [ we may want to talk to Harris and Boeing about putting their work in here? –KR]

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

• XML is easy to work with due to the amount of libraries and tools available for it, and its broad industry acceptance

• XTCE powerful concepts are ideal for represent any legacy system TM & TC database [ that’s may little too strong… but something like that –kr]

• Non TM&TC data is not considered in XTCE; (dedicated software instructions, SW configuration variables) [ this actually may should be mentioned earlier in XTCE in a nutshell section…-kr]

GSAW 2006 21

Questions and Answers

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