Standard Onboard interface Services – Overview and status

Standard Onboard interface Services – Overview and status

Chris Taylor

Stuart Fowell

October 09

SOIS - main drivers• The SOIS set of recommendations are intended to standardise the communication

services and protocols used within the flight data handling system. The main motivation for the work is cost reduction:

– Provision of requirements for subnetwork services/protocols • Standard protocols - less development and test, standardised test equipment • Common services regardless of media - less changes in middleware

– Standardisation of interfaces to subsystems, payloads and sensor/actuators• Reduced vendor costs, opportunity for reusable multi-vendor building blocks • Simpler payload integration and multi-Agency interoperability

– Standardisation of services to mission application software• Insulation from specific hardware and hardware changes• Reduced porting costs across missions• Opportunity to align with mission operations standards

Com

munication M

anagement

Time AccessService

FileServices

Message TransferService

DeviceEnumeration

Service

Packet Service

MemoryAccessService

Synchronisation

Service

DeviceDiscoveryService

Test Service

Datalink Extension Protocols

Datalink Specific Protocols

ApplicationLayer

ApplicationSupport Layer

TransferLayer

Subnetwork Layer

Network Protocol

Transport Protocol

SOIS – layered model

CMD & DataAcquisitionServices

Applications

Device Data Pooling Service

Device Access Service

Device Virtualisation

Service

Command & data Acquisition Services

SOIS C&DA service detail

SOIS - Protocols

• While SOIS CCSDS specifications initially concentrate on services there is also a need to specify protocols that implement the services

• The SOIS protocol specs are being developed in different ways– Subnetwork protocols are under preparation within the ECSS and SpaceWire

working groups– Application support protocols:

• CMD & Data Acquisition and Enumeration Services will be supported by SOIS and proprietary developed protocols

• Time Access service will directly interface with a local application• File Services will require a device specific access protocol• Message Transfer service will adopt the CCSDS Asynchronous Message

Service Protocol (last stages of publication)

Packet Service

MemoryAccessService

Synchronisation

Service


Test Service

Milbus ECSS available

Subnetwork Layer

SOIS – Subnetwork Protocol Standard

CANbus ECSS in progress

SpaceWire ECSS planned

SOIS input to SM&C discussion

Com

munication M

anagement


Time AccessService

File andPacket Store

Services


DeviceEnumeration

Service

Packet Service

MemoryAccessService

Synchronisation

Service


Test Service



ApplicationsPUS etc

ApplicationLayer


TransferLayer

Subnetwork Layer

Network Protocol

Transport Protocol

CFDP Users

CFDP

SM&C, PUS AMS, SOIS relationships - Discussion

• In order for us to proceed in a coordinated way it is necessary to determine how these three standards relate (PUS is not yet adopted by CCSDS so serves here only as an example)

• SM&C defines a set of mission operations services, it does not define how these should be implemented

• PUS defines services for command and control, some of which are directly compatible with those defined by SM&C. It also defines a messaging protocol (SM&C message abstraction layer?) and a transport protocol (intimately coupled with the SPP)

• AMS provides a messaging service and protocol but does not define the contents on the messages (part of the SM&C message abstraction layer?)

• SOIS defines communication related services across the onboard subnets and application support services that insulate applications from the specifics of the underlying hardware

SM&C, PUS and SOIS relationships – Onboard Architecture

• It us unclear (to me) where the Standard SM&C API resides:– Is it provided BY, or provided TO, the applications implementing the SM&C

services?

• The present architecture (fig 2.3. of the Green book) seems to indicate an API being provided TO the applications

• This is a crucial point for SOIS as we are not providing mission operations services, rather we provide communication related services in support of mission Applications

• Assuming that SM&C defines a standard API to be provided by onboard applications, then the mapping of between applications and SOIS is a local matter (although this should also be standardised)

• The collaboration needed with SOIS is therefore to ensure that the services provided by SOIS are sufficient to support the Applications providing the SM&C services

PU

S P

ac

ke

ts

Application Support Layer Services

Subnetwork Services

File and packet store

Command and Data Acquisition Services

File Transfer

Message Transfer Services

Time Access Services

File & Packet Store Services

SOIS

Flight Applications

SMC Service 2 SM&C Service N

SOIS, PUS, AMS and SM&C – (not 100%)

Synchronisation service

Test Service

Device Discovery Service

Memory accessservice

Packetservice

SOIS

Onboard

sub-systemsSensors &Actuators

Payloads

Time Source

TM/TCSpacelink

SM&C

PUS Services

Ground Applications

Cross Support I/F

AMS

AMSSM&C service 1

AM

S M

es

sa

ge

sSM&C Compliant API ?

CFDP

PUS

SOIS input to PUS Discussion

SOIS - main drivers• The SOIS set of recommendations are intended to standardise the communication

services and protocols used within the flight data handling system. The main motivation for the work is cost reduction:

– Provision of requirements for subnetwork services/protocols • Standard protocols - less development and test, standardised test equipment • Common services regardless of media - less changes in middleware

– Standardisation of interfaces to subsystems, payloads and sensor/actuators• Reduced vendor costs, opportunity for reusable multi-vendor building blocks • Simpler payload integration and multi-Agency interoperability

– Standardisation of services to mission application software• Insulation from specific hardware and hardware changes• Reduced porting costs across missions• Opportunity to align with mission operations standards

Com

munication M

anagement


Time AccessService

File and Packet Store

Services


DeviceEnumeration

Service

Packet Service

MemoryAccessService

Synchronisation

Service


Test Service



ApplicationsPUS etc

ApplicationLayer


TransferLayer

Subnetwork Layer

Network Protocol

Transport Protocol

CFDP Users

CFDP

SOIS Specification Status (October 09)

• Subnetwork services– Completed, imminent publication by CCSDS

• Application support services – Ready for issue as Magenta Books

• Device Access Service Issue 2• Time Access Service Issue 2

– Ready for 2nd Agency Review• File and Packet Store Services Issue 1.4 • Message Transfer Service Issue 0.3

– Under Development• Device Virtualisation Service Issue 0.1• Device Enumeration Service Issue 0.1• Device Data Pooling Service Issue 2

PU

S P

ac

ke

ts


Subnetwork Services



File Transfer




SOIS

Flight Applications




Test Service



Packetservice

SOIS

Onboard


Payloads

Time Source

TM/TCSpacelink

SM&C

PUS Services

Ground Applications

Cross Support I/F

AMS

AMSSM&C service 1

AM

S M

es

sa

ge


CFDP

PUS

Packet Protocol

SOIS subnetwork services

SOIS Application support services

PUS including File based services

Space data link protocols

ECSS protocols

Onboard datalink

Mass memory

Protocols

OnboardApplications

ApplicationSupportLayer

Command & Data Acquisition Services

Sub-NetworkLayer

PhysicalLayer

SubnetworkDriver

CPU

Packet Service

Memory Access Service

Device Access Service

Device Data Pooling Service


SoftwareBus Upper Layer of HAB

DeviceVirtualisation

Service

Devices(Transducers,

Payloads & Instruments)

DeviceEnumeration

Service

AttitudeControl

PowerMonitoring

ImageHandling

BioNet-SOIS-HAB

BioNet Middleware Services

BioNet Network/Device

BioNet MAC

BioNet PHY

BioNet APP

Ground Utilisation of Packets and File based On-board Services

Spacecraft M&C Services

On-board Data Management Services

File Delivery

File Management

Packet and Data Link Protocols

Packets

File Store

PFUS

SOIS

PUS

SM&C/PUS

CFDP SOIS

Space Link Standards

Onboard Communications H/W(e.g. MIL-STD-1553B, SpaceWire, CAN RS422)

System Services Application BB

MTL services

PUS library/TMTC

OBCPinterpreter Plan/

AutonomyFramework

Mission TL/ Mode mgmt

Central FDIR

AOCS

P/L Manager

Thermal

Power

Execution framework

OBC Hardware

CAN RS422

TM/TC

Devices

Sensors(Star Trackers, Sun sensors, Gyros, Earth

sensors, magnetometers)

Actuators(Reaction wheels, magneto torquers,

thrusters, etc)

OBT Mgmt

SSMM Mgmt

EquipmentMgmtContext

Mgmt

MIL-1553 SpW

CPU/NGmP

EEPROMBoot

PROM

OBTimer

SGM

HWwatchdog

BSPHDSW

Middleware services

Software bus

RTOS

SecurityUnit

Solid StateMass

Memory

File Mgt Compress

Encrypt

Payloads &Instruments

SSMM

RTU/Intelligent IO

Payload Control Computer

SOIS Layers

Legacy devices

SOIS

Application Suppport Layer

Subnetwork Layer

Standardized devices

Standardized devices

SOIS Layers

ADCs / DACs

SOIS Layers

Sensorand

actuators

RAM

DSP

Digital Sensorbus

Payload Data Processing

DSP

Libraries:Math, Security,

Payload,…

Reference Architecture and Building Blocks

Space Avionics Open Interface Architecture (SAVOIR)

SAVOIR Advisory Group : SAG : TEC-EC-ED-SW Nat. Agencies and Industry

Networks

StorageCompression

High Speed TelemetryEncryption

SOIS Layers

PUS- SOIS discussion

• In principle PUS and SOIS are complementary:– SOIS provides standard onboard communication related services to assist in

harmonising flight implementations and insulating mission applications from specific hardware details

– PUS standardises operational services and protocols and may take benefit from the SOIS flight services

• In practise, there are some overlaps and omissions which will need to be resolved:– The boundary of PUS within the flight system– The capability of the present SOIS to support all PUS services– The way in which file transfer is performed

• We will also have to take account of the emerging SM&C standards and how they influence both standards

Com

munication M

anagement


Time AccessService

FileServices


DeviceEnumeration

Service

Packet Service

MemoryAccessService

Synchronisation

Service


Test Service



ApplicationsPUS etc

ApplicationLayer


TransferLayer

Subnetwork Layer

Network Protocol

Transport Protocol

CFDP Users

CFDP

PU

S P

ac

ke

ts

PUS

File transfer protocol CFDP


Subnetwork Services



etc.Message Transfer

ServicesTime Access

ServicesFile & Packet

Store Services

SOIS

Flight Applications

PUS Service 1 PUS Service 2 PUS Service X PUS Service NPUS Service ------- -------

SOIS, PUS


Test Service



Packetservice

SOIS

Onboard


Payloads

Time Source

TM/TCSpacelink

PUS ServicesGround Applications

PU

S P

ac

ke

ts


Subnetwork Services



File Transfer




SOIS

Flight Applications




Test Service



Packetservice

SOIS

Onboard


Payloads

Time Source

TM/TCSpacelink

SM&C

PUS Services

Ground Applications

Cross Support I/F

AMS

AMSSM&C service 1

AM

S M

es

sa

ge


CFDP

PUS

Agenda for APPs WG

SOIS Meeting ObjectivesSOIS Meeting Objectives• Application Services WG (Mon-Friday CF204)

– Time Access service Submission for publication– File and Packet Store services RID Processing before submission for final Agency review– Message Transfer Service RID processing before submission for Agency review– Device Enumeration service Rid disposition and Update – Device Virtualisation Service Rid disposition and Update – Device data Pooling Rid disposition and Update – Device Access service Rid disposition and Update

• Subnetwork Services WG (No meeting)– All books finished Pending CESG check before publication and WG closure

• Wireless WG (Mon-Wed Room:Dj124/TB206)– Asset Tracking and Management Develop Magenta first draft– Intra-vehicle communications Initiate Magenta book – Green Book Pending CESG check before publication

• Area/Joint WG – Plug & Play (Wed/Thu) WG Discussion and proposal for how to proceed– AMS (Tue PM) WG Discussion on possible testing– PUS (Thu PM) SOIS contribution to BOF– SOA (Tue AM) SOIS contribution to BOF– CFDP & DTN (Wed/Thu) WG Discussion

26 October 2009

Application support WG

• Main goals for this week– Finalise text for those books ready for publication (MTS, Time, File services)– These will all need modifying to refer to ISO 7498 and not define ISO definitions

inline in the text. Remove MIB where applicable– Decide if file transfer is a service provided by SOIS, decide how it fits with CFDP– Decide how the other service definitions should proceed with or without plug and

play– For the plug and play session, we must determine:

• The scope of the activity deciding what we will and will not cover in SOIS• What is needed within this scope and if there are candidates for adoption• If there is enough common ground with at least two Agencies in order to

proceed• If we should raise a separate WG or continue the topic within the APS WG

– The more examples we have of how SOIS operates in practice the better.– We must update the Green book to better reflect the latest SOIS approach,

identify actions and victims

Standard Onboard interface Services – Overview and status

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