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Location Systems


Andy Ward
Pete Steggles
Rupert Curwen
Paul Webster
Mike Addlesee
Joe Newman
Paul Osborn
Steve Hodges


For several years, we have been interested in context-aware computer systems, which automatically configure themselves based on what's happening in the environment around them. An example might be a videophone system with many cameras placed around a room, which would continuously select a camera view in which the user could be seen, thus allowing that user to wander freely around the room during the videophone conversation.

Such systems must gather information about their current context from sensors distributed throughout the environment (in the above example, the location and orientation of the user and cameras). In fact, location and proximity seem to be the types of information most useful to context-aware systems, so we have concentrated on developing sensors that can measure these qualities. Active Badges were used for our first experiments with context-aware systems, but we've since moved on to look at other location sensors, including:

The Bat system - Fine-grained ultrasonic location for indoor environments.
Our RFID tagging system - A low-cost, low-infrastructure proximity identification sensor.
Ultrawideband (UWB) radio - Novel radio technology for in-building positioning and WLANs.

Much of our work is used to support the Sentient Computing project here at AT&T Laboratories Cambridge.


  • Andy Ward, Alan Jones, Andy Hopper. A New Location Technique for the Active Office. IEEE Personal Communications, Vol. 4, No. 5, October 1997, pp. 42-47. (download)
  • Andy Ward. Sensor-driven Computing. PhD thesis, University of Cambridge, 1998. (download)
  • Andy Harter, Andy Hopper, Pete Steggles, Andy Ward, Paul Webster. The Anatomy of a Context-Aware Application. Proceedings of the Fifth Annual ACM/IEEE International Conference on Mobile Computing and Networking, MOBICOM'99, Seattle,Washington, USA, August 1999, pp. 59-68. (download)
  • Mike Addlesee, Rupert Curwen, Steve Hodges, Joe Newman, Pete Steggles, Andy Ward, Andy Hopper. Implementing a Sentient Computing System. IEEE Computer Magazine, Vol. 34, No. 8, August 2001, pp. 50-56. (download)
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