Aucun titre de diapositive

1
UNIONICS Advanced On-Board Distributed Processing
Architecture
Initial results from the Bench-Top Demonstrator
2
Unionics - Summary

• Unionics is a new architecture for on-board
  avionics systems - scalable, processor
  independent, fault tolerant
• Single system can handle both real-time and
  processor-intensive (payload) applications.
• Represents strong BNSC investment in maintaining
  and developing an advanced avionics capability in
  the UK.
• Utilises SpaceWire links to provide
  re-configurable system and elegant degradation in
  event of component failure with in-built Failure
  Detection, Isolation and Recovery (FDIR)
  capability
• Spacecraft simulator and test-set provides
  realistic closed-loop test environment
• Demonstrator shows application of architecture to
  multi-spacecraft formation flying application
• Hardware and software demonstrator in advanced
  stage, with first version operational. More
  sophisticated demonstration applications under
  development e.g. demonstration of real-time AOCS
• Team is Astrium Ltd (system), SEA Ltd (hardware)
  and SciSys (software)

3
Unionics Architecture
4
Unionics Hardware

• Demonstrator Architecture
• Processor cards based on 21020 processors with
  SpaceWire links implemented in FPGAs
• Multiple processors on up to 3 spacecraft
  simulated to demonstrate distributed processing
  capability

• Status
• Unionics Bench-top demonstrator under final
  integration and test
• Verification system to simulate environment and
  exercise AOCS functions

5
Card Assembly
DSP NODE
DSP SUPPORT FPGA
SW ROUTER
MMU
RS422 ROUTER
3D SDRAM
SYSTEM WATCHDOG
6
Unionics FDIR

• A layered scheme is used to implement the FDIR
  system.
• At the lowest level is the hardware watchdog
  which is used to detect major node failures
  (crashed processor, failed hardware, etc.).
• Each software layer is responsible for monitoring
  a specific level of services and resources, and
  must feed status words to the layer below at
  regular intervals.
• Failure to set the status word, or setting a
  FAILED status word will trigger the appropriate
  recovery scheme at the next level down.

7
Contingency Operations

• Contingency operation tests validate that the
  Unionics inherent Failure Detection, Isolation
  and Recovery (FDIR) capability can successfully
  integrate into an hierarchical spacecraft and
  formation FDIR strategy.
• Integrated Unionics into FDIR strategy with 4
  distinct layers

• Lowest level, hot swapping individual units
  maintaining nominal operations.
• Second level internal Unionics reconfigurations,
  maintaining nominal operations.
• Third level spacecraft level reconfigurations
  with transition to safe mode.
• Highest level is formation reconfigurations,
  maintaining nominal operations.

• Initial results on system only containing second
  level FDIR show Unionics can detect errors inside
  Unionics domain and internally reconfigure whilst
  maintaining nominal operations.

8
Watchdog FPGA

• Provides hardware level watchdog to monitor
  health of each processor
• Provides system-wide monitoring.
• Receives periodic messages from DSP nodes
• Generates reconfiguration messages (asynchronous,
  over LVDS).
• Tested at component level, awaiting final
  integration.

9
Unionics Hardware - SpaceWire DMA Interface
17Mbits/s 6xFaster than the non-DMA interface!!!
10
Unionics Software Overview
11
Unionics Software Process reconfiguration
12
Unionics Software Layers
13
Unionics software AOCS, TC/TM and
Formation Flying

• The Unionics demonstrator will host a
  comprehensive AOCS implementation to test and
  demonstrate support of real time functions using
  an asynchronous network (SpaceWire).
• AOCS Implementation includes
• Monitors sensors and formats TM.
• Ground control can select sensors to monitor.
• Permanent ASH mode.
• Control algorithms
• Fully functional spacecraft simulator included as
  part of verification system to prove real-time
  operations
• ESA PUS compliant TC/TM Packet Manager
• Formation Flying functions will be demonstrated
  eg formation deployment (see figure sequence).

14
Unionics Software Lessons Learned

• Autocoding the AOCS from Matlab/Simulink, linking
  to the main infrastructure and porting to
  DSP21020 has proved straight forward.
• Building the Payload processing using the Multi
  Mission Imager library was straight forward.

• Porting Data Handling elements from CryoSat has
  been easy
• Mixing Real Time AOCS data and Payload data has
  raised issues for SpaceWire
• Moving from the old AD tool set to VisualDSP has
  proved difficult but necessary
• RTEMS on a DSP is very difficult
• Needed DMA for SpaceWire
• Now ready to test, test, test
• Moves Unionics Software from Demonstration to
  Mission Ready

15
Unionics Demonstration Environment Capabilities

• Real Time Simulator
• Unionics I/O
• Spacecraft Dynamics
• On-board Units (including failure injection)
• Ground TM/TC Link (S-band)
• Payload Data Download Link (X-band)
• Payload Observations

Manual control of individual Unionics power
supplies Graphical User Interface Autonomous test
scripts and manual control Results archiving and
post processing
16
Nominal Operations

• Nominal operation tests validate Unionics
  suitability to all on-board processing tasks for
  both single spacecraft and formation missions, by
  simultaneously exercising the following
  operations

• AOCS closed loop inertial pointing and slews
• TC/TM Tx/Rx/Processing, including on-board
  timeline
• Observations, image processing and payload data
  download
• Formation communications and synchronised
  operations

Initial results with simplified AOCS show hard
real time AOCS performance achieved during above
simultaneous operations across asynchronous
network. Successfully validated use of CCSDS and
PUS standards in Unionics based data
handling. Successfully validated reuse of
existing payload processing applications on
Unionics environment.
17
Test Bed for New Ideas and Methods

• To ensure Unionics is ideally placed for imminent
  use on a low cost, rapid development mission
  (such as the UK Earthshine mission), Unionics
  demonstrator used as test bed for new S/C
  development methods and ideas

• Autocoding. Full closed loop simulator developed
  in Simulink, with extensive reuse from previous
  projects. Autocoding applied to produce two
  blocks of C code AOCS and Spacecraft (i.e.
  everything except AOCS). AOCS code hosted on
  Unionics, Spacecraft code hosted on test
  environment.
• Third Party Software. Existing developments or
  third party software directly hosted on Unionics
  directly hosted applications from existing
  payload processing library.
• COTS Products. Extensive use of COTS products in
  test environment development (Test equipment
  based on Dspace real time test environment, and
  Simulink).

18
Unionics Current Status and Conclusion

• Hardware architecture implemented in 5 FPGAs
  (SpaceWire links, RS422 interface and MMU)
• Full set of PCBs has been produced by SEA,
  integrated with SciSys software and with Astrium
  Test Set/Simulator
• On-board software architecture to include RTEMS
  real-time OS , TMTC module, MMU, RS422 and
  SpaceWire drivers.
• Test environment and spacecraft simulator
  development at Astrium based on D-Space system,
  integrated with full Unionics system

• First version demonstrated and final phase in
  progress to implement full functionality
• Demonstration has shown functioning of in-built
  FDIR and incorporation into spacecraft FDIR
• Hosting of auto-coded applications on Unionics
  from MatLab generated code achieved
• Some issues with mixing on-board real-time data
  with payload data in SpaceWire system