Benefits of the Standardization Efforts for OnBoard Data Interfaces and Services

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Benefits of the Standardization Effortsfor
On-Board Data Interfaces and Services

• SpaceOps, 2006 June 21st, Rome, Italy

Olivier NOTEBAERT Dependability and Data
Processing Advanced Studies
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Benefits of the Standardization Effortsfor
On-Board Data Interfaces and Services

• SUMMARY
• Introduction
• Ground-Space Communication Standardization
• On-Board Communication Standardization
• Perspectives

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INTRODUCTIONExpectation for space systems
standardization

• Inter-Operability, Coherency, Modularity,
  Feasibility
• Focused on space missions needs
• Enables new kind of missions
• Allows introduction of new technology
• Favour emergence of standard products
• Supports systems Integration and verification
  process
• Improves systems quality assurance
• Simplifies contractual aspects
• Reduces overall costs

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ContextCCSDS Space Communications Service System

• Space Systems need inter-operable communications
  services

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Ground-Space Communication StandardizationCCSDS
TC/TM standardization

• CCSDS Telecommand and Telemetry
• Developed with the perspective of increasing
  complexity and need for interoperability of space
  systems
• Progressive maturity acquired in operation
  through early implementation (e.g. Eureca)
• Ground and On-Board SW and HW implementation
• Benefit
• A worldwide used communication system
• A number of standard HW and SW building blocks
  implemented for ground and space segments

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Ground-Space Communication StandardizationPacket
Utilization Standard

• ECSS Packet Utilization Standard provides a
  generic spacecraft operational concept
• It defines a set of services that are optional
  and tailored to application needs
• It enforces the harmonization of spacecrafts
  on-board data handling architecture

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Ground-Space Communication StandardizationImpact
for current onboard DHS SW systems

• Generic PUS Service library re-used and tailored
  for different kind of space missions

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On-Board Communication StandardizationSpacecraft
data systems functions and architecture

• Reliable and time critical functions
• Data acquisition, processing and distribution for
  Attitude and Orbit Control
• Failure Detection, Isolation and Recovery
• Payload data acquisition and processing
• Simple architecture (compared with ground
  networks)
• Central platform on board data processing SW and
  storage
• Dedicated Payload computer and storage
• Dedicated TC/TM system
• Buses and direct data links for data
  communications
• Power system segregated from data

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On-Board Communication StandardizationSpacecraft
data systems constraints

• On board data systems specific constraint
• Onboard processors are very limited in
  performance compared to ground technology
• Not all technology available (e.g. hard disks)
• HW Components are expensive
• Except for man flight, only SW maintenance is
  possible
• Very long life time
• Strictly limited budget for energy mass
• Consequences
• Systems are optimised (no useless functions
  onboard)
• Technology upgrades are more easily allocated to
  functional and performance support rather than to
  standardisation

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On-Board Communication StandardizationConstraints
for standardisation of spacecraft data systems

• Delays for time critical function shall be
  controlled and limited
• Quality of services shall be guaranteed
• Focus on needs
• No useless functions onboard
• Tailoring to mission and shortcuts must be
  possible
• Simple architecture and design
• No unreliability or big overhead shall be added
  from complex standardisation functions
• Resource limitation
• Allocate part of the budgets in support to
  standardisation (CPU, power, mass, initial
  development cost)

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On-Board Communication StandardizationCurrent
Standardization efforts for onboard data systems

• European space systems harmonization applied to
  onboard data systems and software
• Families of systems
• Generic architecture and functional building
  blocks
• CCSDS Standardization forOn-board data
  Interfaces and Services
• Common functions and architecture to future
  On-Board Data Handling Systems communications.
• ECSS standardization on-board data-links
• Point-to-point data links
• Buses
• Networks

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On-Board Communication StandardizationEuropean
Harmonization of Onboard Data Systems

• Classification into generic families
• Safety oriented systems (manned-flights)
• Availability oriented systems (robotics,
  launchers)
• Reliability oriented systems (science,
  observation, telecoms)
• Ground Technology oriented systems (ISS Payloads)
• cost oriented systems (scientific instruments,
  small missions)
• Develop technology for generic families needs
• Use commercial market technology developments
• Adapted in order to to prevent and/or manage
  effects of the space missions environment on
  commercial components.
• Standardize on-board communications

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On-Board Communication StandardizationCCSDS-Stand
ardization of Onboard Interface and Services

• CCSDS SOIS Working group objective
• Developing a range of standards for
  spacecraftonboard interfaces
• Promoting reuse of hardware and software designs
  across a range of missions
• Enabling interoperability of onboard systems from
  diverse sources
• Resulting in the reduction of the cost of space
  missions

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On-Board Communication StandardizationCCSDS-Stand
ardization of Onboard Interface and Services

• SOIS layered architecture
• Time Critical Onboard Applications (TCOA)
• High level communication services to the
  application layer
• e.g. Command and Data acquisition, file
  transfermessage passing, time access
• Time Critical Onboard Network Services (TCONS)
• Onboard network and transport layer
• Onboard Bus and LAN (OBL)
• Data link layer (Services to be provided by a
  range of onboard data links)

Application
Services
Transport
Network
Data link
Physical
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On-Board Communication StandardizationECSS
Standardization of Onboard Data links

• Analogue and Digital discrete I/F
• Standard published as draft / currently under
  public review
• Covers European harmonization of physical and
  electrical characteristics based on the existing
  large return on experience
• An extension for sensor buses is foreseen
• SpaceWire and RMAP protocol
• SpaceWire ECSS-E-50-12A issued
• Standard ground SpaceWire components are
  commercially available for test and for
  prototyping purpose
• Standard flight components qualified or under
  production
• Remote Memory Access Protocol
• Simple data communication protocol mapped on
  SpaceWire for direct device access
• Quite Mature - Draft available

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On-Board Communication StandardizationECSS
Standardization of Onboard Data links

• 1553 bus
• Working group started end of 2005
• Harmonization rules on standard physical and data
  link
• Protocol extension for generic communication
  services
• Command Distribution
• Data acquisition
• Time distribution and synchronisation
• Packet transfer
• ECSS draft document expected end 2006
• Can bus
• Draft document based on CanOpen
• elaborated by ESA from return on experience
  (SMART-1) and collaboration of industry
• Mock-up for services verification
• ECSS working group planned for 2007

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Standardization of On-Board Data Interfaces and
ServicesPerspective
On-board Application
Command Data Acquisition
Time Access
Message Transfer
File Services
Plugand Play
Get/Set
Memory Access
Time Distribution
Device Discovery
Packet Transfer
Test
Spacecraft Communication Protocol (IRD)
Standard Protocols (Mapping on standard data
links)
Spacecraft standard
Data link Layer
SpacecraftGuidelines IRD
Harmonization Rules
e.g 1553B, SpaceWire, Can bus
Physical layer
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Standardization of On-Board Data Interfaces and
ServicesPerspective
Impact on generic spacecraft software
architecture
Applications
IO system
TCOA
System control
Mission Avionics architecture dependent (real
time performances)
Standardonboard communication services
Bus control
Application layer(mission dependent)
AOCS
Payload
PUS Services
IO drivers
DHS core product
RTOS
OBL
RTEMS product
BSP
BIOS
Low level HW/SW interfaces Hardware dependent
OBC HW
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Standardization of On-Board Data Interfaces and
ServicesConclusion

• Benefits expected
• Harmonization and simplification perspective for
  onboard data systems and application SW
• Way toward On-board networks for enabling future
  missions
• Simplified operations and extension possibilities
• Services adapted to spacecrafts needs and
  constraints
• Inter-operable on-board HW and SW components
• Stability of components -gt gain in maturity and
  quality
• Better portability of application software
• Integration of new on-board technology without
  complete system redesign
• Costs for implementation compensated by benefits