Communications in the ASSERT VM

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  • Communications in the ASSERT VM

    1. 1. STRASTSpacecraft communication facilitiesand the ASSERT Virtual MachineJuan Antonio de la PuenteGrupo de Sistemas de Tiempo Real y Arquitectura de Servicios TelemáticosUniversidad Politécnica de MadridditUPM
    2. 2. STRAST Spacecraft communications • Ground-spacecraft ‣ telecommand, telemetry ‣ oldest and best known • Ground-ground©2009 Juan Antonio de la Puente ‣ tracking stations, operation centres, etc. ‣ mostly IP • Spacecraft internals ‣ subsystems, instruments • Spacecraft-spacecraft ‣ rovers and landing vehicles ‣ spacecraft fleets 2009-09-04 Jornadas de Automática 2009 2
    3. 3. STRAST Sample configuration©2009 Juan Antonio de la Puente 2009-09-04 Jornadas de Automática 2009 3
    4. 4. STRAST Space link • Point-to-point wireless link between spacecraft and ground station • Inherently unreliable ‣ medium subject to interference, distortions©2009 Juan Antonio de la Puente ‣ spacecraft speed induces Doppler effects ‣ variable propagation path characteristics • Must tolerate very high bit error rates (BER) • At least one downlink and one uplink are required 2009-09-04 Jornadas de Automática 2009 4
    5. 5. STRAST Telemetry and telecommands • Telemetry (TM) ‣ information sent from spacecraft to ground segment ‣ engineering and payload data©2009 Juan Antonio de la Puente • Telecommands (TC) ‣ sent from ground segment to space fro control purposes • Radio links are used in both directions ‣ downlinks and uplinks • Relay stations may be used 2009-09-04 Jornadas de Automática 2009 5
    6. 6. STRAST Layered protocol architecture©2009 Juan Antonio de la Puente 2009-09-04 Jornadas de Automática 2009 6
    7. 7. STRAST Spacecraft subsystems Payload Payload subsystems©2009 Juan Antonio de la Puente Platform AOCS TMTC OBDH Power Thermal Propulsion 2009-09-04 Jornadas de Automática 2009 7
    8. 8. STRAST On-board computer hardware • ESA has qualified several OBC EAFTC computers in a space-ready flight chassis. Credit: based on ERC32/LEON NASA/Honeywell. processors • The current version is LEON3©2009 Juan Antonio de la Puente ‣ SPARC v8 compliant RISC architecture ‣ open-source VHDL model ‣ available under GPL ‣ speed ≈ 100 MHz ‣ power ≈ 1 W 2009-09-04 Jornadas de Automática 2009 8
    9. 9. STRAST On-board computer software • Many critical functions depend on software ‣ high-integrity requirements©2009 Juan Antonio de la Puente • Most software functions have real-time requirements ‣ have be carried out within specific time intervals • Verification & validation process is crucial ‣ safety management • Technology choice driven by high-integrity requirements ‣ e.g. Ada, RTOS, static analysis, temporal analysis 2009-09-04 Jornadas de Automática 2009 9
    10. 10. STRAST Sample hardware architecture Avionic Architecture Demonstrator Bus 2 PM1 (Master) Sensor N Sensor R Actuator N Actuator R Bus 1 Distributed Payload Data Handling Architecture EGSE Telemetry Formatter / Memory Module Context Saving FPGA Generic Encryption module Transmitter Memory Module Spw link TM/TC link©2009 Juan Antonio de la Puente PM2 (Hot Std-by) Transmission subsystem SpaceWire Spw links High Power Processing COTS Module Spw link Control Processor SpaceWire Module Payload Data Handling Unit Remotely integrated instrument I/O Module Internet High Power Processing COTS Module Spw tunnel SpaceWire Spw link 2009-09-04 Jornadas de Automática 2009 10
    11. 11. STRAST Sample software architecture System Management Application BBs Optional Mission Application BBs TM/TC S/C Mass BM OBCP PUS AOCS Mission Mngt Mngt Mem Pwr Services Mngt Mngt Mngt control ABB Container ABB Container ABB Container ABB Container ABB Container ABB Container ABB Container ABB Container Plug & Play Software Bus Execution Infrastructure (VM) File Eqmt •Plug & Play Software bus FDIR Time Mngt Mngt Mngt •FCR©2009 Juan Antonio de la Puente •Distribution transparency •Middleware services ABB Container ABB Container ABB Container ABB Container •RTK •CBBs OSI  model TM/TC Services TM Memory Serv. Cmd/Acq Services Mass-memory Application Transport RTK SGM management OBT related serv. SpaceWire Mgnt Network Middleware CCSDS SMU Internal Bus 1553 P.F SpW HRI Software Architecture HDSW BSP Deployed over HW Computer System Hardware Simulated Eqmt 2009-09-04 Jornadas de Automática 2009 11
    12. 12. STRAST Spacecraft on-board data links • Milbus (MIL-STD- 1553B — ECSS-E-ST-50-13) ‣ serial data bus, 1 Mb/s half duplex transfer rate ‣ TDMA master-slave: controller and remote terminals)©2009 Juan Antonio de la Puente • Spacewire (ECSS-E-ST-50-12C) ‣ serial link, 2..200 Mb/s full duplex data rate ‣ point-to-point: nodes and routers • Spacecraft discrete interfaces (ECSS-E-ST-50-14)  ‣ analogue, digital, serial point-to-point ‣ links between OBC and simple devices 2009-09-04 Jornadas de Automática 2009 12
    13. 13. However, it is incumbent on SOIS to detail the Management Information Bases (MIBs) for all of its recommendations. The plug-and-play services make use of the device discovery service in the subnetwork and the device enumeration application service. STRAST Spacecraft Onboard Interface Services Details of the services, the architecture, and associated protocols are given in subsequent (SOIS) subsections. User Applications Application Cmd & Data Time Message Device File Acquisition Access Transfer Enumeration Support Layer Services Service Services Service Service Network Management Services©2009 Juan Antonio de la Puente Transfer Transport Protocol Plug and Play Services Layer Network Protocol Memory Time Device Packet Test Access Distribution Discovery Service Service Sub- Service Service Service Network Layer Data Link Convergence Functions Data Link Denotes service access point 13 2009-09-04 Jornadas de Automática 2009
    14. 14. STRAST Spacewire network©2009 Juan Antonio de la Puente 2009-09-04 Jornadas de Automática 2009 14
    15. 15. STRAST Other communication-related functions • Ranging / Doppler • Advanced orbiting systems (AOS)©2009 Juan Antonio de la Puente • Proximity links • CCSDS file delivery protocol (CFDP) • Inter-planetary internet (IPN) 2009-09-04 Jornadas de Automática 2009 15
    16. 16. STRAST The ASSERT project • FP6-IST project led by ESA/ESTEC • Aimed at software for mission-critical on-board embedded systems©2009 Juan Antonio de la Puente • Key ideas ‣ Model-driven software engineering ‣ Separation between functional / concurrent & real-time aspects ‣ Enforcement of real-time properties at run-time by using a dedicated execution platform: the ASSERT Virtual Machine 2009-09-04 Jornadas de Automática 2009 16
    17. 17. STRAST The original ASSERT Virtual Machine • Property-preserving execution environment ‣ A Virtual Machine built upon certifiable components Automatically Generated Code • Middleware layer©2009 Juan Antonio de la Puente ‣ PolyORB-HI (ENST) ASSERT middleware • Communication layer SOIS MTS comms services ‣ SOIS MTS (SciSys) Comms ORK+ RT kernel drivers • RT kernel layer ‣ ORK+ (UPM) LEON 2 hardware including SpW ‣ Integrated in GNATforLEON ‣ Ravenscar profile compliant 2009-09-04 Jornadas de Automática 2009 17
    18. 18. STRAST Enhancing the Assert VM with communication facilities • VM-LAB project ‣ funded by ESA/ESTEV ‣ partners: UPD, Telecom ParisTech, UPM Application code • Aims©2009 Juan Antonio de la Puente ‣ develop native communication PolyORB-HI MW drivers for space networks SpW driver ORK+ kernel - generic driver architecture - SpaceWire driver LEON2 hardware including Spw ‣ enhance middleware support ‣ assess alternate kernel configurations - RTEMS 2009-09-04 Jornadas de Automática 2009 18
    19. 19. STRAST GR-RASTA system©2009 Juan Antonio de la Puente 2009-09-04 Jornadas de Automática 2009 19
    20. 20. STRAST Hardware architecture©2009 Juan Antonio de la Puente 2009-09-04 Jornadas de Automática 2009 20
    21. 21. STRAST Driver architecture SpaceWire Parameters HLInterface Registers©2009 Juan Antonio de la Puente Core Handler PCI AMBA Registers 2009-09-04 Jornadas de Automática 2009 21
    22. 22. STRAST Driver operation • init processor board Initialize PCI • scan PCI Configure • configure memory controller PCI-AMBA bridge • configure interrupt controller©2009 Juan Antonio de la Puente • locate IP cores/devices Scan -vendor AMBA -ID, IRQ, base address • reset • test computer link Configure • configure DMA channel device • init T/R buffers • enable reception • send message -set address -enable interrupt -handle interrupt Operate • receive message device -handle interrupt -check flags -get the message 2009-09-04 Jornadas de Automática 2009 22
    23. 23. STRAST Project output ‣ New version of ORK+ integrated with GNAT-GPL 2008 ‣ Spacewire and serial line drivers ‣ New version of PolyORB-HI integrated with drivers ‣ Documentation©2009 Juan Antonio de la Puente - VM architecture and development guide - Driver development guide - RTEMS assessment ‣ The new version of the ASSERT VM is fully integrated with the ASSERT development tools - MDE and automatic code generation - HRT-UML / AADL modelling languages - functional code from Simulink / SCADE - temporal analysis with MAST+ 2009-09-04 Jornadas de Automática 2009 23
    24. 24. STRAST Further work • Integrate Rapi-Time for accurate execution-time measurement©2009 Juan Antonio de la Puente • Develop MIL-1553-B driver • Complete ASSERT laboratory configuration 2009-09-04 Jornadas de Automática 2009 24

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