Publications

Abstracts for all the papers authored by the Space Technology Centre are listed below:

  • S. Parkes, C. McClements, M. Dunstan
    ISWS International SpaceWire Seminar 2003
    November 2003

    The University of Dundee is working with EADS Astrium, Galileo Avionica, INETI and SciSys to develop an intelligent camera for vision-based navigation of a planetary lander. This research is funded by ESA within the current Navigation for Planetary Approach and Landing (NPAL) study led by EADS Astrium in France. The camera unit has to perform image processing to select image feature points and to track them from frame to frame. With knowledge of the tracks of several feature points and the linear and rotational acceleration of the spacecraft, provided by an inertial measurement unit, it is possible to reconstruct the path of the spacecraft and to determine its position and orientation relative to a planet’s surface. The University of Dundee is responsible for the development of the image processing chip that performs the feature detection and tracking.

  • S. Parkes, C. McClements, G. Kempf, S. Fischer, A. Leon
    ISWS International SpaceWire Seminar 2003
    November 2003

    A SpaceWire network comprises SpaceWire links, nodes and routers. The nodes are the functional units that wish to use the onboard communication services of the SpaceWire network and are fitted with one or more SpaceWire interfaces. These units are connected together directly using point-to-point SpaceWire links or indirectly via SpaceWire routers. SpaceWire interfaces, links and routers are the three elements of a SpaceWire network. This paper explains the operation of a SpaceWire router and describes the radiation tolerant SpaceWire router ASIC being developed for ESA.

  • C. McClements, S. Parkes, A. Leon
    ISWS International SpaceWire Seminar 2003
    November 2003

    A SpaceWire system comprises several units connected together with SpaceWire links, either directly, or indirectly via one or more SpaceWire routers.  The SpaceWire links are high-speed, bi-directional, point-to-point communication links operating at a baud rate of between 2 and 400 Mbits/s. SpaceWire runs over a cable containing four twisted pairs. At each end of a SpaceWire link is a coder/decoder (CODEC) which encodes packets of data to be transmitted into a serial bit-stream and decodes an incoming serial bit-stream into a data packets. The serialised data is encoded using a data-strobe technique where the strobe changes state at a bit interval whenever the data remains constant. This allows simple clock recovery in the receiver by XORing the data and strobe signals together and provides better skew tolerance than data-clock encoding. The data-strobe signals are transmitted using low-voltage differential signalling (LVDS). SpaceWire CODECs are used in both nodes and routers and consequently form an important element of any SpaceWire system.

  • S. Parkes, J. Rosello
    ISWS International SpaceWire Seminar 2003
    November 2003

    SpaceWire is a communications network for use onboard spacecraft. It is designed to connect high data-rate sensors, large solid-state memories, processing units and the downlink telemetry subsystem providing an integrated onboard, data-handling network. SpaceWire links are serial, high-speed (2 Mbits/sec to 400 Mbits/sec), bi-directional, full-duplex, point-to-point data links which connect together SpaceWire equipment. Application information is sent along a SpaceWire link in discrete packets. Control and time information can also be sent along SpaceWire links. SpaceWire is defined in the European Cooperation for Space Standardization ECSS-E50-12A standard.

  • S. Parkes
    ISWS International SpaceWire Seminar 2003
    November 2003

    SpaceWire time-codes provide a means of distributing time information across a SpaceWire system. Time can be distributed across a large network with relatively low jitter. This time information can be provided as ticks or as an incrementing value which may be synchronized to spacecraft time. Time-codes provide a mechanism for supporting distributed system synchronization. They may also be used to implement isochronous communication channels, complementary to the asynchronous channels provided naturally with SpaceWire.

  • Steve Parkes
    Hobsons Postgrad UK
    September 2003
  • S. Mills, S. Parkes
    DASIA (Data Systems in Aerospace) 2003
    June 2003

    The SpaceWire standard defines a network designed for handling payload data and control information onboard a spacecraft. Among the goals of SpaceWire are re-usability and reliability. The use of network protocols on top of SpaceWire is expected to greatly enhance the re-usability and reliability characteristics of SpaceWire.

  • S. Parkes, C. McClements, S. Mills, I. Martin
    DASIA (Data Systems in Aerospace) 2003
    June 2003

    SpaceWire  is  a  communications  network  for  use  onboard  spacecraft.  It  is  designed  to  connect  high  data-rate  sensors,  large  solid-state  memories,  processing  units  and  the  downlink telemetry subsystem providing an integrated data-handling network.  SpaceWire  links are serial, high-speed (2 Mbits/sec to 400 Mbits/sec), bi-directional, full-duplex, point-to-point data links which connect together SpaceWire equipment.  Application information is sent along a SpaceWire link in discrete packets.  Control and time information can also be sent along SpaceWire links. SpaceWire is defined in the ECSS-E50-12A standard.

  • S. Parkes, M. Dunstan, D. Matthews, I. Martin, V. Silva
    DASIA (Data Systems in Aerospace) 2003
    June 2003

    The European Space Agency (ESA) is preparing for unmanned and/or manned exploration of several planets including Mercury and Mars. To support this endeavour several key technologies have to be developed. Among these necessary technologies are navigation sensors that can support landing and sample-return capsule rendezvous operations. A vision-based navigation sensor is currently being developed by ESA which will enable surface relative navigation. The Planet and Asteroid Natural-scene Generation Utility (PANGU) is a system for generating simulated surfaces of planets and for producing images of those surfaces from specified camera positions and orientations. PANGU was implemented specifically to support the development of vision-based navigation sensors and is now being used to validate associated image feature tracking algorithms.

  • V. Silva, S. Parkes
    DASIA (Data Systems in Aerospace) 2003
    June 2003

    The definition of guidelines for the design of an optimal GNC sensor architecture for spacecraft is a recurrent problem. Since the beginning of Space Age several generations of GNC sensors have been developed, flight tested and successfully used in space missions. With the advent of new technologies and materials, GNC sensors performances significantly improved on last decades and new sensors emerged. Concepts are evolving from ground-based to autonomous GNC systems. Hazard avoidance systems for planetary landers are replacing hazard tolerance systems. Both Lidar-based and Vision-based GNC systems are currently being developed to support autonomous landings. The optimum mix of sensors and the best way to fuse sensor data is an important area of research for future planetary lander space missions.

  • S. Parkes
    European Space Agency Workshop on Spacecraft Data Systems (2003)
    May 2003

    SpaceWire is a communications network for use onboard spacecraft. It is designed to connect high data-rate sensors, large solid -state memories, processing units and the downlink telemetry subsystem providing an integrated data-handling network. SpaceWire is now an approved ECSS standard (ECSS E50-12A) and is being used on many ESA and NASA missions. This paper reports research and development being done by the University of Dunee on components, software and development support for the SpaceWire.

  • S. Parkes, S. Mills, S. Fowell, R. Ward
    Workshop on Spacecraft Data Systems
    May 2003
  • J. Hughes, S. Parkes
    Behaviour and Information Technology
    March 2003

    This article reviews the technique of verbal protocol analysis and gives a profile of its use within software engineering research over the last two decades. An overview is given of the procedures used in verbal protocol analysis, and commonly-found difficulties in the application of the technique by researchers are described. The article reports on published efforts to develop tools to automate the procedures. A review of the literature shows trends in the use of the verbal protocol analysis in software engineering research from the 1980s to the present.

  • S.Parkes, I. Martin, M. Dunstan, S. Mills
    DASIA (Data Systems in Aerospace) 2002
    May 2002

    The ESA Bepi Colombo mission to Mercury is due for launch in 2009 and is expected to include a lander. Computer vision based navigation is being considered for the lander to enable it to land softly, close to a pre-designated target landing spot, avoiding any small craters, boulders or other obstacles not visible in an orbital survey. The development and testing of a vision-based lander guidance system requires high-resolution images of the planet’s surface which are not available for Mercury.

  • S. Parkes, C. McClements
    DASIA (Data Systems in Aerospace) 2002
    May 2002

    This paper begins with an overview of SpaceWire networks, which are made up of nodes and routers. The method of addressing SpaceWire packets for transfer across a SpaceWire network is described and then two of the key features of SpaceWire networks – bandwidth sharing and fault tolerance – are highlighted and explained. Priority addressing as a means of providing quality of service control is introduced. Finally the time distribution mechanism of SpaceWire is explained.

  • S. Parkes, V. Silva
    DASIA (Data Systems in Aerospace) 2002
    May 2002

    Computer vision technology is being developed by ESA to support the navigation and autonomous landing of spacecraft on a planet’s surface. A computer vision system is used to navigate the lander relative to the planet’s surface and to detect any obstacles close to the target landing site. The computer vision system will be supported by other Guidance and Navigation Control (GNC) sensors. This paper provides a review of GNC sensors for possible use on a planetary lander in support of a primary vision-based sensor. It also describes how those sensors will be simulated.

  • S. Parkes
    International Conference on Advanced Engineering Design (2001)
    June 2001
  • S. Parkes I. Martin, S. Strandmoe
    DASIA (Data Systems In Aerospace) 2001
    May 2001

    The ESA Bepi Colombo mission to Mercury is due for launch in 2009.  There are three components planned for the mission: a planetary orbiter, a magnetospheric satellite and a surface element.  Computer vision based guidance is being considered for the surface element to enable it to land close to a pre-designated target landing spot, avoiding any small craters, boulders or other obstacles not visible in an orbital survey.  The development and testing of a vision-based lander guidance system requires high-resolution images of the planet’s surface which are not available. The Planetary and Asteroid Natural scene Generation Utility (PANGU) is a tool for generating realistic simulated planetary surfaces and for producing the images of those simulated surfaces. This paper describes PANGU.

  • S. Parkes
    DASIA (Data Systems In Aerospace) 2001
    May 2001

    Virtual satellite integration is the connection of geographically distributed spacecraft subsystems early on in the development lifecycle using the Internet to provide the means of communication. Early interconnection of the subsystems reduces development risk due to misunderstanding or misinterpretation of subsystem specifications. This paper introduces the concept of virtual satellite integration. It begins with a brief description of SpaceWire, a satellite on-board data-handling network designed for equipment compatibility and intended to encourage equipment reuse. SpaceWire also provides a means for simplifying the connection of electronic ground support equipment to the spacecraft data handling system. Work on communication protocols for spacecraft on-board interfaces being done by panel 1K of the Consultative Committee for Space Data Standards (CCSDS) is summarised and then virtual satellite integration is explained. Finally current work at the University of Dundee is outlined.

  • S. Parkes, J. Rosello
    DASIA (Data Systems In Aerospace) 2001
    May 2001

    SpaceWire is a network designed for handling payload data and control information on-board a spacecraft. SpaceWire provides a unified, high-speed, data-handling network for connecting together sensors (e.g. optical or radar instruments), processing elements (e.g. Digital Signal Processors), mass-memory units, downlink telemetry sub-systems and Electronic Ground Support Equipment. It is intended to meet the needs of future, high-capability space missions SpaceWire has been submitted to the European Cooperation for Space Standardization as draft standard ECSS-E-50-12. This paper provides an overview of SpaceWire and lists some space missions currently using or planning to use SpaceWire.