SAVOIR SAFI Sensor Actuator Functional Interface Phase 1

SAVOIR SAFI Sensor & Actuator Functional Interface Phase 1 Summary CCSDS Spring Meetings 2012 17/04/2012 ESA UNCLASSIFIED – For Official Use

Contents • SAFI context, scope and organisation • Sensor & Actuators landscape and investigations • Interaction with SOIS • Conclusion SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 2 ESA UNCLASSIFIED – For Official Use

SAFI - Context Sensor and Actuators (S/A) play a major role in the avionics Software reference architecture Sensor/Actuator Functional Interface Electrical interface (Data & Power) • SAIF, Electrical interface (incl. power): identified one new requirement, the need to standardize the RS 422 protocol • SAFI, Functional interface: from the software control loop to the equipment at functional level – Work in progress SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 3 ESA UNCLASSIFIED – For Official Use

SAFI – Scope & Organization • The current focus is to investigate existing sensors and actuators from the functional interface point of view. In order to identify commonalities, and eventually propose a functional interface standard. • SAFI Phase 1 • Schedule: – – • Initiation of the Working Group and Kick-off meeting 12/05/; 31/05/; 23/06; 12/07; 01/09; 22/09; 07/10; 18/10 Webex meetings 25/10/2011 Presentation to ADCSS workshop 30/11/2011 Report on the interface standardisation concept SAFI Working Group: – – – • 17/03/2011 SAVOIR FAIRE members ESA Control representatives & Data Handling representatives (from SOIS WG) CNES Control representative Astrium Control representative Thales Control representative Phase 2: Deployment with Sensors/Actuators suppliers SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 4 ESA UNCLASSIFIED – For Official Use

Sensors & Actuators overview • Existing S/A landscape shows a large variety of practices in interface: • Digital: • • Some Sensors can provide a large amount of data. However, the largest part is usually used only for on-ground diagnostic. • Each supplier uses a different subset to implement different functionality for the same type of equipment. • There can be differences in the datation of the measure/command, in the use of reference frame, etc. Analog: • S/A may provide/require voltage (or currents) with different range/scale-factor and functional implication. • SAFI aims at a solution for most of the cases, but might exclude very specific cases. • The view of the Suppliers will be given in next phase. SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 5 ESA UNCLASSIFIED – For Official Use

SAFI - S/A investigations SAFI WG focused initially on 5 selected equipments which are considered to be the most commonly used by AOCS: • • • Sensors • Star tracker: investigated preliminary func. I/F standardization proposal • Gyro: under investigation • Sun sensor: under investigation Actuators • Reaction wheel: investigated preliminary func. I/F standardization proposal • Magneto torquer: under investigation Other equipments (ex. Thrusters, Magnetometers, GNSS receivers etc. ) will be investigated in a second phase. SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 6 ESA UNCLASSIFIED – For Official Use

SAFI – Approach for S/A standardised i/f • S/A functional I/F standardization is performed only for core data/command parameters which are directly used on board (by AOCS and FDIR). Parameters which are not used onboard but just exchanged with ground are not standardized. • Standardized functional I/F includes mandatory and optional parameters. • In particular: • Parameter Number Name: a common Id • Name: to be defined according to common agreed naming conventions • Mandatory or Optional • Description: what represents this data or command parameter • Format: data organisation, reference frame, coordinate, etc… • Unit: SI unit • Range: expected [min , max] values • Type: real, natural number, enumerated • Interaction with Electronic Data Sheet (EDS) from SOIS SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 7 ESA UNCLASSIFIED – For Official Use

S/A examples of standardised i/f – STR (1/3) Galileo AASTR Final Attitude Quaternion Sodern Hydra Time associated to STR measure for quaternion STR mode Quality Index of the Attitude Number of tracker windows STR Health status Number of SEU filtered Covariance_X Covariance_Y Covariance_Z Optic temperature TEC current Tracking loss counter … Final Angular Rate vector Number of expected stars Time associated to STR measure for angular rate Number of coherent stars Number of stars used for attitude determination Quality index X Counter since last Reset Quality index Y ON command for TEC number n Quality index Z Target temperature for TEC number n Peltier temperature flag Reset Command … STR Mode Uploaded Date Attitude initialisation (Optional) Angular rate vector initialisation Core data/commands package for any STR (This core should contain all data/commands used directly on-board by AOCS & FDIR) Number of trackable stars Number of identified stars Number of acquired objects Detector temperature Optics temperature Housing temperature SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 8 ESA UNCLASSIFIED – For Official Use TEC mode … Jenoptik Astro APS

S/A examples of standardised i/f – STR (2/3) • Core data for any STR 1. 2. Parameter Param. Number Name STR D 01 TBD 3. 4. Mandatory Description or Optional Mandatory 5. Format 6. Unit 7. Range 8. Type Final Attitude Quaternion provided by STR q =[scalar; vector(3)] - [-1; 1] Real 9. Interaction with Electronic Data Sheet - Reference frame: J 2000 frame --> STR frame STR D 02 TBD Mandatory Time associated to STR measure for quaternion (STR D 01) Time elapsed between the last synchronisation signal and attitude measurement ms TBD Real - STR D 03 TBD Optional Final Angular Rate vector provided by STR w = vector(3) Rad/s TBD Real - STR D 04 TBD Optional Time associated to STR measure for angular rate (STR D 03) Time elapsed between the last synchronisation signal and angular rate measurement ms TBD Real - STR D 05 TBD Mandatory STR mode (typically a number) Mandatory modes: Tracking / Acquisition / Non-operational mode - [0; TBD] Enumerated Modes number may be defined in the functional i/f Standard. If not, relation between number and mode will be contained in the electronic data sheet. - [0; 1] Real - Reference frame: STR frame vs Inertial Frame Other STR states shall be sub-modes (optional): Stand-by/ Software mode / Rate mode [TBC by Suppliers] STR D 06 TBD Mandatory Quality Index of the Attitude provided by STR (typically a number) Real value from 0 to 1: (1 being good quality. ) This value is not used directly in the attitude estimation. [To be discussed with Suppliers] STR D 07 TBD Optional Number of stars used for Attitude determination Number of stars [The case of fused measure shall be discussed with Suppliers. ] - [0; inf] Unsigned integer - STR D 08 TBD Counter since last Reset - sec [0 inf] TBD - STR D 09 TBD Mandatory STR Health status (typically a number) Mandatory states: OK / STR Severe warning (Restart is needed) / STR warning (Restart not necessary) - TBD Enumerated Health status number may be defined in the functional i/f Standard. If not, relation between number and health status will be contained in the electronic data sheet. TBD [0; inf] TBD - Optional sub-states can indicate the hardware involved (Electronic Unit, OH_n) SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 9 [To be discussed with Suppliers] STR D 10 ESA – For Official TBDUNCLASSIFIED TBD Current. Use date as used by STR CCSDS Unsegmented Code (CUC) time code format [TBC by Suppliers]

S/A examples of standardised i/f – STR (3/3) • 1. Parameter Number STR C 01 Core commands for any STR 2. Parameter Name TBD 3. Mandatory or Optional Mandatory 4. Description 5. Format 6. Unit 7. Range 8. Type 9. Interaction with EDS Reset Command (Typically a number in order to give the possibility to perform different type of reset) Reset command of the complete STR (mandatory). - - Enumerated TBD 1. Core commands for any STR Other reset command (optional). STR C 02 TBD Mandatory ON command for TEC number n n = TEC number - - Enumerated - STR C 03 TBD Target temperature for TEC number n Target temperature in °C: °C [-inf; inf] Real - STR C 04 TBD Upload Date to STR CCSDS Unsegmented Code (CUC) time code format [TBC by Suppliers] TBD [0; inf] TBD - STR C 05 TBD Mandatory STR Mode See STR D 05 - [0; TBD] Enumerated See STR D 05 STR C 06 TBD Optional Attitude initialisation (quaternion) See STR D 01 - [-1; 1] Real - STR C 07 TBD Optional Angular rate vector initialisation See STR D 03 Rad/s TBD Real - STR C 08 TBD Optional Validity time for the initialised attitude [TBC by Suppliers] - sec [-inf; inf] Unsigned integer - STR C 09 TBD Optional Enable aberration correction [TBC by Suppliers and Primes] No Aberration correction/ Enable Aberration correction based on velocity/ Enable aberration correction based on orbital parameters - - Enumerated TBD STR C 10 TBD Optional Velocity vector S/C velocity vector = vector (3) in J 2000 frame m/s [-inf; inf] Real - STR C 11 TBD Optional Orbital Parameters TBD TBD - STR C 12 TBD Optional Validity time for the velocity/Orbital Parameters TBD TBD - SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 10 ESA UNCLASSIFIED – For Official Use

S/A examples of standardised i/f – RW • • Rockwell Collins RSI + Bradford Engineering RWU Core data for any RW 1. Parameter Number 2. Parameter Name 3. Mandatory or Optional 4. Description 5. Format 6. Unit 7. Range 8. Type 9. Interaction with EDS Mandatory RW angular rate around rotation axis Rad/s [-inf; inf] Real Electronic data sheet shall provide information on how to merge Tachometer pulses and Speed direction information in order to obtain RW speed RW D 02 Motor Current Mandatory RW motor current Positive if positive rotation around Wheel axis. Negative if negative rotation around Wheel axis. - A [-inf; inf] Real Conversion between RW analogue or digital signal and effective motor current shall be defined in the electronic data sheet RW D 03 Bearing temperature Mandatory - - °C [-inf; inf] Real Conversion between RW analogue or digital signal and effective Bearing temperature shall be defined in the electronic data sheet RW D 04 On/Off Status Optional - 0 = OFF 1 = ON - [0; 1] Boolean RW D 01 • RW Speed Core commands for any RW 1. Parameter Number 2. Parameter Name 3. Mandatory or Optional RW C 02 ON/OFF TBD RW C 01 Torque Command Mandatory 4. Description 5. Format 6. Unit 7. Range 8. Type 9. Interaction with EDS Torque command around rotation axis Positive if positive rotation around Wheel axis. Negative if negative rotation around Wheel axis. 0 = OFF 1 = ON Nm [-inf; inf] Real Conversion between Torque around RW rotation axis and effective command to be sent to RW by OBC shall be defined in the electronic data sheet - [0; 1] Boolean Conversion between ON/OFF command actual command to be sent to RW by OBC shall be defined in EDS. ON/OFF Command [Necessity of this to be SAVOIR SAFI - Phase 1 Summary | Command 17/04/2012 | TEC | Slide 11 discussed with Suppliers and ESA UNCLASSIFIED – For Official Use Primes]

SAFI - S/A standardised i/f considerations • Preliminary investigation is concluded only for STR and RW. In both cases the existing equipments (coming from different European manufacturers) seem to share a similar core of parameters. However, other types of Sensor or Actuators may not have similar communalities. • An agreement within the WG was found on preliminary STR and RW functional standardised I/F for core data/command parameters. However, there are still some minor open points. These shall be submitted to suppliers in the next phase. • A functional standardised I/F together with an electrical I/F standard may reduce the impact of S/A equipment change. However, for some units mechanical and thermal compatibility may have a higher impact. SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 12 ESA UNCLASSIFIED – For Official Use

SAFI - S/A standardised i/f recommendations • Eventual S/A functional standardised interface should target only newly developed H/W. • Preliminary S/A functional standardised interface is based on existing units. SAFI WG shall ensure that this standardised i/f will not impose major limitations to evolution of future AOCS and units design, as foreseen by primes and suppliers. • AOCS shall be able to specify Sensor detection maximum delay and Actuators command maximum delay. In general, specification of all realtime performance is needed. • Functional standardization does not need to affect performance of S/A. SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 13 ESA UNCLASSIFIED – For Official Use

Interaction with SOIS • The CCSDS SOIS WG has defined a communications architecture which identifies services for accessing onboard devices, including AOCS related sensors and actuators • Specifically, the command Acquisition services provide two important subservices: • The Device Virtualisation Service (DVS) • The Device access service (DAS) • These services provide a framework that may be used to harmonise the suppliers specific interfaces in use today • The SAFI group has taken on the task of specifying a set of DVS and DAS based services for all common AOCS devices • These services will be used as input to the CCSDS WG for the definition of electronic data sheets SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 14 SAVOIR | Jean-Loup TERRAILLON | Malta | DASIA 2011 | 18/05/2011 | Pag. 14 ESA UNCLASSIFIED – For Official Use

Conclusion • The concept of standardizing the functional interface to S/A has been investigated and refined considering: • • • Needs of the software architecture. Constraints of the control functional chain. The opportunity offered by the SOIS standardisation. • The concept of a functional standard for data/command parameters (used on board) seems feasible for investigated S/A. • Examples of standardised interface have been investigated for selected S/A (STR and RW). The working group proposes to proceed with the next phase by involving representatives of S/A community to discuss further the standardised interface definition. SAVOIR SAFI - Phase 1 Summary | 17/04/2012 | TEC | Slide 15 ESA UNCLASSIFIED – For Official Use