This document discusses a message-oriented architecture for ground control systems. It proposes integrating ground control applications using an asynchronous message bus to decouple components. The architecture is presented in 4 steps: 1) Components communicate via the message bus. 2) Business logic is separated from user interfaces. 3) On-board systems integrate with the message bus. 4) Manual operations integrate via web services. Benefits include asynchronous/synchronous communication, scalability, and integrating existing ground control systems.

1. European Ground System Architecture
Workshop (ESAW 2009)
Message Oriented
Architecture
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2. Agenda
1 Overview
2 Message Oriented Architecture
3 Message Bus
4 Ground Control System Message Oriented Architecture
5 Monitoring & Control System Message Oriented Architecture
6 Conclusions
7Q&A
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3. Overview
Event Logger
(Java RCP)
NETCOM GSTP
(Alignment of SCOS- Message Bus
2000 release 5.0 with
hifly)
Event Logger
Message Bus
TCP/IP
Integration of a
Commercial Message
CPD
Bus in hifly as Proof of
Concept in the scope of
NETCOM GSTP project TCP/IP
PDSserver
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4. Objetives
Take advance of the lessons learnt on the NETCOM project in
order to:
– Propose an Architecture for integration of the Ground Control System
applications
– Propose a Message Architecture for the Satellite Control System
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5. Message Oriented Architecture
Key Points
Ground Control Application Integration
Ground Control Applications interact
each other in the same way
Application
Integration
Asynchronous component communication
Components are no longer waiting
for response neither connected
Message
continuously each others Oriented
Architecture
Decouple components
Asynchronous Decouple
Components interface are Communications Components
messages, no more function calls
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6. Message Oriented Architecture
Ground Control Application Integration
File Transfer
Remote Procedure Invocation
Messages
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7. Message Oriented Architecture
Through Asynchronous Communication
CORBA 2 – Synchronous
SOAP 1.1 – Synchronous
CORBA 3 – Asynchronous
SOAP 1.2 – Asynchronous
Messages Bus – Asynchronous
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8. Message Oriented Architecture
Through Decouple Components
Function as interface – Very tight couple
Remote Process Call – Tight couple
CORBA – Loosely couple
SOAP & WSDL – Loosely couple
Messages Bus – Decouple
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9. Message Bus
Asynchronous/Synchronous Communications
Asynchronous communication
Point to Point – Implemented by a Queue interface
Publisher - Subscribers – Implemented by Topic interface
Message Acknowledgment – Implemented by ACK message
Heartbeat – heart beat message
Synchronous communication
Request and Reply (Point to Point) – Implemented by two Queues
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10. Message Bus
Messages definition
Data format
XML
Fixed length data fields
Proprietary format (Binary format)
Object Format
Persistence
Versioning
Sequencing
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11. Message Bus
Interoperability
Programming languages
C/C++
Java with support for Java Messaging Service
Fortran
Python
Operating Systems
Linux
Solaris
Windows
Message Version
Message field
Version Router
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12. Message Bus
Commercial Bus Messages
Open Source - ActiveMQ from Apache COTS – TIBCO
used in NETCOM prototype
Most popular Commercial Message Bus
Interoperability C++/Java JMS
Interoperability C++/Java JMS
http://activemq.apache.org http://www.tibco.com
Open Source – Message Queue from COTS – OpenFusion (CORBA 3 message service)
Sun
Interoperability Java/C++
Interoperability C++/Java JMS http:www.prismtechnologies.com/products/openfusion
https://mq.dev.java.net
Open Source – xmlBluster
Java JMS fully implemented in
Java
Interoperability C++/Java JMS
http://www.xmlblaster.org
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13. Ground Control System Message Oriented
Architecture
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14. Ground Control System Message Oriented
Architecture Step 1
Telecommand Variable
Event
History Packet
Logger
Display
Message Bus
Event Logger Telecomman Telemetry
Bussiness ds Bussiness Bussines PDSserver
Logic Logic Logic EV/TC/TM
Packets Archive
TCP/IP
Packetizer Releaser
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15. Ground Control System Message Oriented
Architecture Step 2
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16. Ground Control System Message Oriented
Architecture Step 3
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17. Ground Control System Message Oriented
Architecture Step 4
PIF On-Board TimeTag
MISC TCSpacon Multiplexer
Queue Model Releaser Monitoring
Message Bus
Event Logger Telecommand PDSserver
Telemetry Manual Stack
Bussiness Bussiness Packetizer Verifier WebServices EV/TC/TM
Bussines Logic
Logic Logic
HTTP/SOAP
Packets Archive
Web Manual Web Event
Stack with Logger with
AJAX AJAX
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18. Conclusions
Benefits from Message Oriented Architecture
Support for Asynchronous and Synchronous component
communication.
Support N-layer architecture
Hot plug/unplug components
Support to integrate with Ground Control System Components
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19. Conclusions
Proposed a Roadmap for a Message Architecture for the
Satellite Control System in four steps based on an Open Source
Commercial Message Bus (activeMQ).
Proposed the first step of an Architecture for integration of the
Ground Control System applications based on a Commercial
Message Bus.
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20. Thank you
Jesús Santana & T. Lopez-Ciudad
Ground Control Systems
Email: jsantana@gmv.com;
tlopez@gmv.com
www.gmv.com
© GMV, 2009 Property of GMV
All rights reserved