example of eds usage in sois [recap from safi meeting 23/6/2012]
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ESA UNCLASSIFIED – For Official Use
Example of EDS usage in SOIS[recap from SAFI meeting 23/6/2012]
F. TorelliCCSDS SOIS WG, Darmstadt17/04/2012
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 2
ESA UNCLASSIFIED – For Official Use
Introduction
1. Objective:
– To give an example of how SOIS C&DA services and EDS can map to Star Tracker TM/TC ICD.
2. Inputs:
– STR_TM_TC_packets_V4.xls
– Report from CCSDS SOIS Spring Meeting 2011
– Notes from CCSDS SOIS Fall Meeting 2010
3. Entities involved:
– Dictionary of Terms (DoT)
– Electronic Data Sheet (EDS)
– Device Access Service (DAS)
– Device Virtualisation Service (DVS)
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 3
ESA UNCLASSIFIED – For Official Use
SOIS PnP Architecture
Device EnumerationService
Device EnumerationService
Device VirtualisationService
Device VirtualisationService
Device AccessService
Device AccessService
SubnetworkPacket or Memory
Access Service
SubnetworkPacket or Memory
Access Service
SubnetworkProtocol
Implementations
SubnetworkProtocol
Implementations
SubnetworkDevice Discovery
Service
SubnetworkDevice Discovery
Service
SubnetworkPlug-and-Play
Protocol
SubnetworkPlug-and-Play
Protocol
SubnetworkManagement and
Configuration
SubnetworkManagement and
ConfigurationPolicyPolicy
SOIS
SubnetworkImplementation
Hardware
Applications
DoTDoT
Standardised interface including semantics.Ref. sheet 1 in STR_TM_TC_packets_V4.
Device specific functional interface.Ref. sheet 2, 3, 4 in STR_TM_TC_packets_V4.
Contains syntactic and semantic types.
Contains the ICD of the devices w.r.t. the SOIS service interfaces.
EDSEDS
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 4
ESA UNCLASSIFIED – For Official Use
Dictionary of Terms & Electronic Data Sheet
– The DoT contains the attributes to be used to describe the device and in particular its interfaces (i.e. syntactic and semantic types).
– The DoT is the vocabulary used to build the EDS for a particular device.
– The elements of the DoT arranged (and instantiated) in the EDS for a specific device allow to associate a meaning to the raw data in the “TM and TC” of that device.
– The EDS describes the mapping between the layers in the SOIS Command & Data Acquisition (C&DA) in terms of service primitives and their parameters.
– The EDS describes the mechanisms to send/receive data to/from the devices and how to elaborate them along the C&DA stack.
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 5
ESA UNCLASSIFIED – For Official Use
Example of DoT (1/2)
Basic Syntactic Types:
Type Identified Max Range Comment
Real (single precision) Type [-inf, inf] Ranges of specific attributes can be smaller
Real (double precision) Type [-inf, inf] Ranges of specific attributes can be smaller
Integer (32bits) Type [-231, 231-1] Ranges of specific attributes can be smaller
Natural (32bits) Type [0, 232-1] Ranges of specific attributes can be smaller
Natural (16bits) Type [0, 216-1] Ranges of specific attributes can be smaller
Time (64bits) Type [(0, 0), (232-1, 1-2-24)] CUC format (s, sub-s)
Composite Syntactic Types:
Type Identifier Structure Range Comment
Quaternion Type Array of 4 Real(double) [-1, 1]
Real Vector Type Array of 3 Real(double) [-inf, inf] Ranges of specific attributes can be smaller
Integer Vector Type Array of 3 Integer(32bits) [-231, 231-1] Ranges of specific attributes can be smaller
The provided types are examples used along the presentation for practical reasons, but are not the finalised elements of the SOIS DoT.
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 6
ESA UNCLASSIFIED – For Official Use
Example of DoT (2/2)
Semantic Types:
Type Identifier Syntactic Type Unit Comment
Final Attitude Quaternion Type - Reference frame: J2000 frame --> sensor frame
Final Attitude Measurement Time
Time Type s, ms Time elapsed between the last synchronisation signal and measurement
Final Angular Rate Real Vector Type rad/s w = vector(3) Reference frame: sensor frame vs inertial frame
Final Angular Rate Measurement Time
Time Type s, ms Time elapsed between the last synchronisation signal and measurement
Mode Natural or Enum Type - Sensor mode
Direct Command Natural or Enum Type - Command Id (e.g. reset, Standby)
Linear Velocity Real Vector Type m/s S/C velocity vector = vector (3) in J2000 frame
Raw Attitude Quaternion Type - Reference frame: J2000 frame --> sensor frame
Raw Linear Velocity Int Vector Type m/s Velocity / Rc
SubNetwork Address Natural Type - Global address of the unit among the subnetwork
Service Type Natural or Enum Type - SOIS Service Id (e.g. PS, DAS)
The provided types are examples used along the presentation for practical reasons, but are not the finalised elements of the SOIS DoT.
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 7
ESA UNCLASSIFIED – For Official Use
Example of EDS for DAS
Subset of EDS for SODERN HYDRA (DAS Subnetwork)
EDS content for User (DAS) EDS content for Target (Subnetwork)
DoT Item Value DoT Item Value
–Device Id –STR-A – Subnet Addr
– Service Type
– Service Class
– STR address discovered by the subnetwork services
– Packet Service
– Best Effort
…
–Service Primitive
–Value Id
–Acquire_From_Device
–QRsFil
–Service Primitive
–Channel
–Pkt Type
–Pkt Field Position
–Pkt Field Size
–Packet_Receive
–SAInfo
–Attitude Tracking Mode Telemetry
–Byte pos. 16
–32bytes…
–Service Primitive
–Value Id
–Command_Device
–VabYc
–Service Primitive
–Channel
–Pkt Type
–Pkt Field Position
–Pkt Field Size
–Packet_Send
–IdUpdate
–Linear Velocity Update Command
–Byte pos. 8
–32bytes
Global subnetwork address is function of the subnetwork type (i.e. Mil1553), STR address within the subnetwork (i.e. RT 03), but also of the subnetwork management policy.
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 8
ESA UNCLASSIFIED – For Official Use
Example of DAS implementation using EDS information
To acquire the value Quat of QRsFil (filtered fused attitude quaternion), the Device Access Service user shall invoke the following service primitives:
Acquire_From_Device.request(DASAP, TransId, STR-A, QRsFil);
…
Acquire_From_Device.indication(DASAP, TransId, Quat, ErrorCode);
DAS service primitives can then be implemented by means of Packet Service primitives calls, for example as follows:
Acquire_From_Device.indication(DASAP, TransId, Val, ResultMeta)
{
Packet_Receive.indication(PSSAP, Mil-RT03, BE, SAInfo, PktData);
for (I = 0;I < Pkt Field Size; I++)
Val[I] = PktData[I + Byte Pos];}
In red, relevant output parametersIn blue, elements of the EDS
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 9
ESA UNCLASSIFIED – For Official Use
Example of EDS for DVS
Subset of EDS for SODERN HYDRA (DVS DAS)
EDS content for User (DVS) EDS content for Target (DAS)
DoT Item Value DoT Item Value
–Device Id –STR-Nom – Device Id – STR-A
…
–Service Primitive
–Attribute Id
–Conversion Law
–DVS_Acquire
–Final Attitude
–Identity
–Service Primitive
–Value Id
–Acquire_From_Device
–QRsFil
…
–Service Primitive
–Attribute Id
–Conversion Law
–DVS_Command
–Linear Velocity
–Double-To-Int
–Service Primitive
–Value Id
–Command_Device
–VabXc
–Service Primitive
–Value Id
–Command_Device
–VabYc
–Service Primitive
–Value Id
–Command_Device
–VabZc
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 10
ESA UNCLASSIFIED – For Official Use
Example of DVS implementation using EDS
To command the update of the linear velocity (VabXc, VabYc, VabZc) to value Vel, the Device Virtualisation Service user shall invoke the following service primitives:
Command_Device(STR-Nom, Linear Velocity, Vel, ErrorCode);
DVS service primitives can then be implemented by means of DAS primitives calls, for example as follows:
Command_Device(Device Id, Attribute Id, Value, ResultMeta){
if (Device Id == STR-Nom)Dev = STR-A;
elseDev = STR-B;
if (Attribute Id == Linear Velocity){
VelX = Double-To-Int(Value[0]);VelY = Double-To-Int (Value[1]);VelZ = Double-To-Int (Value[2]);Command_Device.request(DASAP, TransId0, Dev , VabXc, VelX);Command_Device.request(DASAP, TransId1, Dev , VabYc, VelY);Command_Device.request(DASAP, TransId2, Dev , VabZc, VelZ);
}}
In green, relevant input parametersIn blue, elements of the EDS
More elaborated conversion law can be applied here
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 11
ESA UNCLASSIFIED – For Official Use
SOIS PnP Architecture - Recap
Device EnumerationService
Device EnumerationService
Device VirtualisationService
Device VirtualisationService
Device AccessService
Device AccessService
SubnetworkPacket or Memory
Access Service
SubnetworkPacket or Memory
Access Service
SubnetworkProtocol
Implementations
SubnetworkProtocol
Implementations
SubnetworkDevice Discovery
Service
SubnetworkDevice Discovery
Service
SubnetworkPlug-and-Play
Protocol
SubnetworkPlug-and-Play
Protocol
SubnetworkManagement and
Configuration
SubnetworkManagement and
ConfigurationPolicyPolicy
SOIS
SubnetworkImplementation
Hardware
Applications
DoTDoT
Device specific functional interface, uses the existing equipment capabilities and fits in the SAVOIR-FAIRE SW architecture.
Types to be defined with the main contribution of SAVOIR-SAFI WG.
EDS contains different sections covering the different SOIS service/abstraction layers.Its content is mainly filled in by equipment manufacturer.
EDSEDS
Framework, specifications of formats and mechanisms need to be defined by SOIS WG to enable definition and usage of DoT, EDS and C&DA services.
Example of SOIS EDS | F. Torelli | ESTEC | 23/06/2011 | Slide 12
ESA UNCLASSIFIED – For Official Use
Summary
– Examples of DoT and EDS using elements of the provided Star Tracker TM/TC ICD have been presented as well as a possible service implementation.
– EDS, DVS and DAS allow flexibility in the usage and implementation, still preserving standard service interfaces.
– DAS interface (device specific functional interface) and the related sections of the EDS can be defined and used with the existing equipment without modifications.
– The mechanisms to access DoT and EDS and their formats are under definition by the SOIS WG.
– The implementation of DAS and DVS can easily follow a recurrent design pattern, which would in the future also enable auto-coding of part of the services and user applications.
– SAVOIR-SAFI in the short term would be very helpful in contributing to the definition of the Common Data Dictionary content (semantic and syntactic types) in order to represent the interfaces of the existing equipments.
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