SOIS and Software Reference Architecture F. Torelli DASIA 2011

SOIS and Software Reference Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 ESA UNCLASSIFIED – For Official Use

Outline 1. SOIS architecture and services 2. SOIS architecture and Avionics System Reference Architecture 3. Impacts to the design of flight software 4. Status of SOIS publications and related developments 5. Conclusions SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 2 ESA UNCLASSIFIED – For Official Use

SOIS architecture and services SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 3 ESA UNCLASSIFIED – For Official Use

CCSDS SOIS Architecture SOIS provides an abstraction of the functionality of the spacecraft units in a layered fashion. Com m u nication M an agem ent Application Support Layer CMD & Data Acquisition Services Transfer Layer Standard Services Mission Specific Applications Application Layer Time Access Service File & Packet Store Services Message Transfer Service Device Enumeration Service Transport Protocol Standard Services Network Protocol Subnetwork Layer Memory Access Service Packet Service Synchronisation Service Device Discovery Service Test Service Datalink Convergence Protocols Milbus SpaceWire CAN Wireless ECSS Standard Protocols SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 4 ESA UNCLASSIFIED – For Official Use

Sub-Network Services Sub-network services: abstract from the physical location (within the spacecraft) of the unit to be accessed Communication Management – Mission Specific Applications Application Layer Application Support Layer CMD & Data Acquisition Services Transfer Layer Time Access Service File & Packet Store Services Network Protocol Subnetwork Layer Memory Access Service Packet Service Synchronisation Service Device Discovery Service Test Service Datalink Convergence Protocols Milbus SpaceWire abstract from the datalink protocol required by a specific communication media to access a unit – abstract from time constrains strictly related to the specific communication media used to access a unit – abstract from the addressing scheme required by a specific communication media to identify a unit. ESA UNCLASSIFIED – For Official Use Device Enumeration Service Transport Protocol – SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 5 Message Transfer Service CAN Wireless

Command & Data Acquisition Services Command & Data Acquisition services: – abstract from the protocol required to control the device (Device Access Service) Communication Management – Mission Specific Applications Application Layer Application Support Layer CMD & Data Acquisition Services Transfer Layer Time Access Service File & Packet Store Services Message Transfer Service Device Enumeration Service Transport Protocol Network Protocol Subnetwork Layer Memory Access Service Packet Service abstract from the type of communication service (i.e. memory access, packet-base) required to access the device (Device Access Service) Synchronisation Service Device Discovery Service Test Service Datalink Convergence Protocols Milbus SpaceWire CAN Wireless – abstract from time constrains strictly related to the device specific access protocol (Device Access Service) – decouple device physical access from device data consumption by the applications (Device Data Pooling Service) – add ontology to the raw command and data information related to devices (Device Virtualisation Service) – provide a uniform interface for each class of devices, independent from their actual implementation (Device Virtualisation Service). SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 6 ESA UNCLASSIFIED – For Official Use

Other Application Support Services Time Access Service: abstracts from the mechanisms required to access the on-board reference time and to handle time alarms. Communication Management – Mission Specific Applications Application Layer Application Support Layer CMD & Data Acquisition Services Transfer Layer Time Access Service File & Packet Store Services Message Transfer Service Device Enumeration Service Transport Protocol Network Protocol Subnetwork Layer Memory Access Service Packet Service Device Discovery Service Synchronisation Service Test Service Datalink Convergence Protocols Milbus SpaceWire CAN Wireless Message Transfer Service: – provides a high level and uniform mechanism to communicate between software applications within the spacecraft. File and Packet Store Service: – provides a standardised interface to mass memory file and packet stores – abstracts from the implementation details related to the mass memory file systems. SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 7 ESA UNCLASSIFIED – For Official Use

Plug and Play Services Plug and Play Services: provide mechanisms to discovery and configure devices connected to a sub-network Communication Management – Mission Specific Applications Application Layer Application Support Layer CMD & Data Acquisition Services Transfer Layer Time Access Service File & Packet Store Services Message Transfer Service Transport Protocol Network Protocol Subnetwork Layer Memory Access Service Packet Service Synchronisation Service Device Discovery Service – provide mechanisms to handle units redundancy – provide the means to interpret the content of Electronic Data Sheets and to configure the other services accordingly (C&DA). SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 8 ESA UNCLASSIFIED – For Official Use Device Enumeration Service Test Service Datalink Convergence Protocols Milbus SpaceWire CAN Wireless

Protocols supporting the Services The services are complemented by protocols Sub-Network Protocols: Communication Management implement the functionality specified by SOIS. Mission Specific Applications Application Layer Application Support Layer CMD & Data Acquisition Services Transfer Layer Time Access Service File & Packet Store Services TBD Message Transfer Service AMS Transport Protocol Network Protocol Subnetwork Layer Memory Access Service Packet Service Synchronisation Service – Mil-Std-1553, ECSS-E-ST-50-13C – CAN, ECSS-E-ST-50-15C draft – Spacewire, ECSS-E-ST-50-52 (RMAP), ECSS-E-ST-50-XX (SpW-D) SpaceWire Message Transfer Service Protocol: Asynchronous Message Service, CCSDS 735.1-B-0 File and Packet Store Service Protocols: – Network File Access, Network Packet Access and Remote Block Storage Protocols need to be standardised SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 9 ESA UNCLASSIFIED – For Official Use Device Discovery Service Test Service Datalink Convergence Protocols Milbus – Device Enumeration Service CAN Wireless

SOIS and Avionics System Reference Architecture SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 10 ESA UNCLASSIFIED – For Official Use

Avionics System Reference Architecture Application BB (mission dependent) AOCS Plan/ Autonomy Framework Satellite Conf and Eqpt Mgmt Central FDIR SSMM Mgmt Thermal System mode mgmt Power OBT Mgmt P/L Manager Software bus Execution platform PUS specific Abstract component services PUS and MTL services OBCP interpreter PUS monitoring Avionics Equipment virtual devices SOIS DVS TM/TC Security Unit SSMM Solid State Mass Memory File/ Compress / Encrypt SOIS Layers Libraries: mathematical , etc. RS422 Context Mgmt On-board time SOIS TAS Connector services Communication services addressing physical distribution across nodes SOIS MTS SOIS Subnetwork layer (1553, CAN, SpW) (including HDSW) OBC Hardware CAN Component services SpW RAM EEPROM Standardized devices Intelligent devices BSP OBTimer DSP Boot PROM SGM RTU/ Intelligent IO HW watchdo g SOIS Layers Onboard Communications H/W (e.g. MIL-STD-1553B, SpaceWire, CAN RS422) SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 11 ESA UNCLASSIFIED – For Official Use Legacy devices RTOS Sensor and actuators CPU/ NGmP MIL-1553 Container services Payloads & Instruments Space Linux ADCs / DACs Digital Sensorbus SOIS Layers Payload Compute r

SOIS in the Avionics System Reference Architecture 1/2 On-Board Computer (OBC): The full set of SOIS services is intended for implementation in the OBC flight software as part of the Execution Platform building block. Other Equipments: A reduced subset of SOIS service is foreseen for the external units such as RTUs, Solid State Mass Memory, Intelligent Sensors and Actuators, Payloads in accordance with their functionality and supported features. SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 12 ESA UNCLASSIFIED – For Official Use

SOIS in the Avionics System Reference Architecture 2/2 Application BB (mission dependent) AOCS Plan/ Autonomy Framework Central FDIR SSMM Mgmt Thermal System mode mgmt Power OBT Mgmt P/L Manager Communication Management Satellite Conf and Eqpt Mgmt Software bus Application Support Layer CMD & Data Acquisition Services Transfer Layer OBCP interpreter PUS monitoring Avionics Equipment virtual devices SOIS DVS TM/TC Security Unit SSMM Solid State Mass Memory File/ Compress/ Encrypt SOIS Layers Libraries: mathematical, etc. Component services Connector services Context Mgmt Communication services addressing physical distribution across nodes SOIS MTS On-board time SOIS TAS SOIS Subnetwork layer (1553, CAN, SpW) (including HDSW) OBC Hardware Message Transfer Service Device Enumeration Service Memory Access Service Packet Service Synchronisation Service Device Discovery Service Datalink Convergence Protocols SpaceWire CAN Wireless Standardized devices Legacy devices RTOS Intelligent devices BSP Sensor and actuators CPU/ NGmP Test Service Container services OBTimer CAN MIL-1553 RAM DSP SGM RS422 SpW EEPROM Boot PROM HW wdog RTU/ Intelligent IO SOIS Layers Onboard Communications H/W (e.g. MIL-STD-1553B, SpaceWire, CAN RS422) SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 13 ESA UNCLASSIFIED – For Official Use File & Packet Store Services Network Protocol Milbus Abstract component services PUS and MTL services Time Access Service Transport Protocol Subnetwork Layer Execution platform PUS specific Mission Specific Applications Application Layer Space Linux Payload Compute r ADCs / DACs Digital Sensorbus Payloads & Instruments SOIS Layers SOIS Layers

Impacts to the design of flight software SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 14 ESA UNCLASSIFIED – For Official Use

Traditional Flight Software In a traditional flight SW system, AOCS and equipment time requirements defining the bus schedule also drive the flight SW architecture and the SW tasks schedule. Bus and ASW Time Domain Mixed The system is designed as a “monolithic” entity tailored for the specific mission. Payload 2 Manager OBCP Interpreter MTL Manager TC Manager AOCS Processing Payload 1 Manager HK TM Processing HK TM Processing MilBus Manager MilBus Manager MilBus Manager AOCS Acquisitions Payload 1 Acquisitions Minor Frame 0 (125 msec) Minor Frame 1 (125 msec) MTL Manager EEPROM Manager Science TM Processing Mass Memory Monitoring Mode Manager MilBus Manager MilBus Manager MilBus Manager Payload 2 Commanding AOCS Commanding Large Data Transfer Payload 2 Acquisitions Minor Frame 2 (125 msec) Minor Frame 3 (125 msec) Minor Frame 6 (125 msec) Minor Frame 7 (125 msec) HK TM Processing Major Frame (1 sec) SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 15 ESA UNCLASSIFIED – For Official Use Scrubbing t

Motivations for an Improvement Such a synchronous schedule works to accomplish relatively simple mission requirements, however: 1. to improve the development process, 2. to accommodate more functions on board, 3. to enable new emerging technologies (e.g. multi-core processors, time and space partitioning, increased autonomy) It is advisable to move towards an avionics architecture based on composable building blocks where functional and timing requirements, if possible, are addressed at component level (separation of concerns). SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 16 ESA UNCLASSIFIED – For Official Use

Proposed Way Forward SOIS Services: The introduction of the previously mentioned SOIS standardised services supports this approach allowing to decouple the functional and timing requirements strictly related to the communication protocols from the ones related to the device access protocols and again from the ones related to the applications algorithms. These concepts will be briefly discussed for: - Sub-Network Services - Command & Data Acquisition Services - Message Transfer Service. SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 17 ESA UNCLASSIFIED – For Official Use

Sub-Network Services Characterisation Low level communication req. can be captured in the sub-network layer to define the bus profile and to expose to the upper layers of the flight software functional and non-functional attributes of the services primitives. AOCS Algorithm Duration AOCS Frequency Sensor Sensor Sensor Max Max Max Latency Latency Latency Command Command Command Accuracy Accuracy Accuracy Service Time and Functional Characterisation Sub-Network Service Primitives Bus Profile Bus Protocol Actuators Actuators Actuators Access Access Access Time Time Time Sensor Sensor Sensor Access Access Access Time Time Time Equipmen Equipmen Equip. t tPhysical Physical Physical Address Address Address Bus Bandwidth Allocation SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 18 ESA UNCLASSIFIED – For Official Use Traffic Scenario for the Nodes

Command & Data Acquisition Services Characterisation The requirements related to the mechanisms to access the on-board devices can also be isolated within the C&DA services group, mainly in DAS and DVS. Calib. Curves Engineering Data Format Electronic Data Sheet Common Data Dictionary Sub-Net Service Timing Device Required Interface Raw Data Format Device Access Req. Service Time and Functional Characterisation Device Enumeration Service Device Virtualisation Service Device Access Service Raw Command/Acquisition Sequence SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 19 ESA UNCLASSIFIED – For Official Use The services can be automatically configured and instantiated during the design phase based on the description of the EDS and provide a well characterised and standardised interface.

Message Transfer Service Characterisation In the Avionics System Reference Architecture, the Software Bus entity is in charge to support the communication between applications and SW components. Although the Software Bus can be implemented with different mechanisms, it is clear that the SOIS MTS provides the needed infrastructure. PUS Services APID Definition Tasks Deadlines Service Time and Functional Characterisation Message Transfer Service Primitives Asynchronous Message Transfer Service Protocol External Nodes Routing TM/TC Formats Sub-Net Service Timing Registration Table Message Traffic with Local and Remote SW Entities SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 20 ESA UNCLASSIFIED – For Official Use

Flight Software using SOIS Services ASW Time Domain ASW tasks schedule and I/O schedule are now related each others only due to the AOCS dependencies and the I/O operations are represented in terms of services (SOIS request & indication, time events). Components can be designed independently according to the functional and nonfunctional attributes of the interfaces. Payload 2 Manager TC Manager OBCP Interpreter SOIS C&DA AOCS MTL Manager SOIS C&DA SOIS FPSS HK TM Processing Bus Time Domain Payload 1 Manager Science TM Processing EEPROM Manager Scrubbing Monitoring Mode Manager SOIS SubNetwork SOIS SubNetwork SOIS SubNetwork SOIS SubNetwork SOIS SubNetwork SOIS SubNetwork AOCS Acquisitions Payload 1 Acquisitions Payload 2 Commanding AOCS Commanding Large Data Transfer Payload 2 Acquisitions Minor Frame 0 (125 msec) Minor Frame 1 (125 msec) Minor Frame 2 (125 msec) Minor Frame 3 (125 msec) Minor Frame 6 (125 msec) Minor Frame 7 (125 msec) Major Frame (1 sec) SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 21 ESA UNCLASSIFIED – For Official Use t

Improvements to Flight Software Some of the beneficial effects of the introduction of standard services: – the possibility to develop and analyse the software applications/components based on clear interfaces – the possibility to deploy some of the applications on a different processing core or partition without impacting the design of the avionics system – the possibility to exchange software/hardware components (e.g. sub-network services) with minimal impacts to the overall design. SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 22 ESA UNCLASSIFIED – For Official Use

Status of SOIS publications and related developments SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 23 ESA UNCLASSIFIED – For Official Use

Status of SOIS documentation SOIS Sub-Network Services: – published in 2009 and are currently used to drive new and upgraded ECSS protocols for CAN and Spacewire. SOIS Application Support Services: – Time Access Service published in 2011 – File and Packet Store Service and Message Transfer Service are currently under Agency review and will be published in 2011 – C&DA services are planned for 2011/2012 CCSDS SOIS work is now concentrated on: – the refinement of the communication architecture, particularly in terms of addressing and the provision of software APIs – The use of electronic data sheets to automate the process of interface definition and integration (C&DA and DES) SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 24 ESA UNCLASSIFIED – For Official Use

Present and Future Developments Ongoing activities supporting standardisation: – – – – – – A SOIS prototype is presently being prepared by SciSys (UK) in collaboration with ASTRIUM (F). This will result in an upgraded RASTA system at ESTEC and a published set of IPR free API’s. A prototype of the CCSDS file transfer protocol (CFDP) mapped to an implementation of the SOIS file and packet store services is being prepared by Spacebel (B). This will also result in an upgraded RASTA system. Packet Store Services have also implemented by Scisys (UK) in the frame of the MARC project. An ECSS standard for CAN Bus is under preparation. This is being driven by the Exomars program and will result in an IP core compatible with SOIS sub-network services. A SOIS/ECSS software component for Mil1553 Bus Controller has been developed by RUAG (S) and its counter part for Remote Terminal Units is being implemented. These software building blocks are produced in compliance with the flight software ECSS standards and validated on the RUAG’s flight hardware platforms (Tiger and Panther boards). An alternative SOIS/ECSS sub-network services implementation for Mil1553 Bus Controller have been developed by Terma (DK) and integrated in the Avionics System Test Bench at ESA. On 2011 the following additional activities are planned: – – – A TRP activity exploring the use of Electronic Data Sheets. A TRP activity demonstrating Plug and Play techniques. A TRP activity proving an end-to-end test-bed for the evaluation of file based communication and operations. SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 25 ESA UNCLASSIFIED – For Official Use

Conclusions SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 26 ESA UNCLASSIFIED – For Official Use

Conclusions 1/2 – The key characteristics of the SOIS services architecture have been presented. – It has been shown that some of the essential features of the Execution Platform in the Avionics System Reference Architecture can be specified and implemented using the SOIS services. Execution platform PUS specific PUS and MTL services Abstract component services OBCP interpreter PUS monitoring Component services Connector services Context Mgmt SOIS MTS On-board time SOIS TAS Container services Reg Table RTOS SOIS C&DA EDS Libraries: mathematical, etc. Bus Profile SOIS Sub-Network SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 27 ESA UNCLASSIFIED – For Official Use BSP

Conclusions 2/2 – Some services have been discussed in the context of the avionics and flight software design phase, here the flexibility given by these services demonstrates to be very beneficial as it allows to characterise the service interfaces without modifying the primitives. – A number of prototypes and flight software developments are ongoing under ESA contracts and in the near future will allow consolidate further the CCSDS standard specifications. SOIS and SW Ref. Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 TEC-SWS Slide 28 ESA UNCLASSIFIED – For Official Use

SOIS and Software Reference Architecture F. Torelli DASIA 2011 - Malta 17/05/2011 ESA UNCLASSIFIED – For Official Use