Transcript D3.2 Plug and Play Services - The CCSDS Collaborative Work

INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
SOIF Space Applications Services
Joseph F. Smith
JPL
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Agenda
• Introduction
• Command and Data Acquisition Service
• Time Distribution Service
• Plug & Play Services
• Interactions and Conclusions
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Introduction
• For this discussion, we are limited in scope to the high level services
available to all SOIF users in the Space Applications Layer
• These are services available to all users (space applications), located
in the same layer as those services
• These services may use all lower layer SOIF services as needed
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Applications Layer: Message Transfer Service and File Transfer Service
Transport Layer: Connection Oriented and Connectionless Services
Data Link: Legacy Communications Service (Data Link)
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Introduction: Location of Services
Space Applications
Network Management
Socket
API
Communication
Services
Inter Processor
Communication
Services
Application
Layer
Transport
Layer
SOIF User Applications
Applications
API
API
API
SOIF C&DA
Service
SOIF Time
Dist Service
Plug & Play
Service
API
Message Transfer
(Basic & Extended)
API
API
File Transfer
Transport Layer TCP/UDP or SCPS-TP
Intra Processor
Communication
(Provided by OS)
SCPS-SP (as required)
Network
Layer
Network Layer: IP or SCPS-NP
Network Sub-Layer: “IP Subnetwork Drivers”
unique for each Data Link implementation
Data Link Sub-Layer: Data Transfer Capability (as required)
Data Link
Layer
Physical
Layer
Data Link Layer:
IEEE-1394, SpaceWire, MIL-STD-1553B, OBDH, etc.
Physical Layer:
IEEE-1394, SpaceWire, MIL-STD-1553B, OBDH, etc.
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Command and Data Acquisition Service
• Command and Data Acquisition Service (C&DA) is intended to allow
the Space Applications to have detailed control of simple
engineering sensors and actuators (effectors) without having
detailed knowledge of the devices
• C&DA is the most advanced of the three proposed SOIF Services
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Capability Set 1: Device Read and Write
Capability Set 2: Engineering Unit Conversion
Capability Set 3: Data Product Acquisition
Capability Set 4: Monitoring
Capability Set 5: Device Virtualization
Capability Set 6: Data Pooling (Data Base)
• Will not say anything more about this here since there are other
discussions planned on C&DA
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Time Distribution Service
• Proposed Time Distribution Service (TDS) is to distribute time from a
master clock to the distributed clocks, and to provide at time
interface to the users
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TDS is for clocks that are connected to the data bus
• TDS functions
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Master Spacecraft Clock
Distribution of time to distributed clocks
Interface of distributed clocks to Space Applications (Users)
• It is assumed that the techniques and procedures that are used to
keep the Master Spacecraft Clock synchronized to the ground are
beyond the scope of SOIF
• There may be clocks with various accuracies that are part the TDS
• We will need to have further discussions here in order to start to fill
in the details of the TDS
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
SOIF Plug & Play Service
• We can use another name for this service, any suggestions?
•
Plug & Play sounds like something for your PC, and we are talking about
something completely different
• The Plug & Play high level requirements are derived by a single
brainstorming session at JPL with members of the user community
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Science Instrument development community
Avionics subsystem developers
• Plug and Play requirements point to two separate functionalities in
the instrument/subsystem interface
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Services Discovery and Maintenance
Interfaces to Standard Services: commanding, telemetry, pointing, etc
• In general, the subsystems will be the providers of the services, and
the science instruments will be the consumers of these services
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This is not always the case, for example, the subsystems will also be
consumers of some services, such as commanding, telemetry, and
sequencing
Some science instrument services could be providers of services for
other science users; for example an context imager could provide
pointing information to a narrow angle limb sounder or imaging
instrument
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Plug & Play: Discovery
• A Plug & Play Service user would go through Discovery when it was
powered up, or was switched to a bus with different connectivity
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A different subnetwork, or a redundant subnetwork that may not have the
same user set connected (yet?)
Discovery would not necessarily be only to services located on the same
subnet, but to any service available to the subnet that may be located on
a different subnet
• When powered-up, a service provider would determine what users on
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the network would require its service
When powered-up, a service consumer would determine what
providers were on the network that could supply the needed service
With internetworking between spacecraft in a constellations, it
should be possible for a provider on one spacecraft to provide a
service to consumer on another spacecraft
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For example, an imager on one spacecraft could send the location to an
atmospheric sounder on another spacecraft of the location of a volcanic
plume
• Discovery has obvious interrelationships with FDIR, Networking
(addressing), and Network Management that are not yet developed or
understood
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Plug & Play: User Services
• Different types of User Services that may be supplied (Examples, not
a complete set)
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Engineering Services: Commanding, Telemetry, Sequencing, Mass/File
Storage, Pointing, Data Compression
Advanced Engineering Services: Mission/Science Planning & Scheduling
& Sequencing, Target Identification (from Science Data)
Science Support Services: Ancillary Data Base
Science Provided Services: Target Identification & Pointing, Ancillary
Data
• Definitions of user services implies standards for interfaces that
have not yet been identified or documented
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To what degree should Plug & Play provide standards for these
interfaces?
To what degree will different services require completely different types
of interfaces?
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Interaction and Conclusions
• Another study area for CCSDS is Monitor and Control
• There are obvious interactions between the three SOIF Space
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Applications and Monitor and Control
However, these have not yet been studied or understood, this will be
required in order to have an architecture in the Space Applications
area that makes sense
• CONCLUSIONS:
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We have a good start on Command and Data Acquisition, that needs to
be continued to the point that we have a workable prototype and
Red/Blue Book
We don’t really have an understanding of the Time Distribution Service or
the Plug & Play Service, and this presentation is intended to (only)
START that process
Future work in this area will be instrumental in the success of SOIF
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Perhaps second only to the Message Transfer Service
Because Plug & Play and MTS will be the interfaces seen by the Users
Interactions between these services and Monitor and Control are
important, and we must endeavor to get them correct the first time
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INTERPLANETARY NETWORK DIRECTORATE
Spacecraft Onboard Interface
Actions
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Plug & Play Model or Examples
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Technical note on instrument/device Plug & Play concepts. Work through
group between now and next meeting
Smith/Plummer
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Software Plug & Play technical note
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Includes description of PUS-S/W Bus diagram
GSFC S/W Bus
MDS
Team
Philippe David
Marquardt
Shames
Gather information and distribute on:
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SuperMOCA
Smith/Jones
Advanced Network Service Architecture (ANSA)
Fowell
FMS
Smith/Nietzel
ETSI Device Virtualization Standard
Plummer
European S/C Manufacturers device I/F standards P. David
USB
Plummer
FireWire
M. Ciccone
Appletalk
Smith
Charter after next meeting (after Fall 03)
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