T A New Location Technique for the Active Office

modern home and office are equipped with sophisticated computing and communications devices, many of which require significant effort or specialist knowledge to configure and use effectively. While the complexity of such devices will surely increase in the future, it may be possible to make them more user-friendly by transferring some of the configuration burden to the devices themselves. These computers would be context-aware, changing their behavior based on how and where they were being used. A context-aware computer or application must be able to determine the state of its surroundings. One method of discovering context is to monitor the locations of objects in the environment. In this article, we first present an overview of research into location-aware computing and evaluate currently available location sensor technologies. We then describe a new location sensor, tailored to provide information for context sensitive computers, which has been developed at the Olivetti and Oracle Research Laboratory (ORL). Finally, we examine potential applications of this system in an active office [1] where location-aware equipment will be commonplace. M uch of the existing research into context-aware computing has used location information provided by Active Badges 1 [2, 3], small computing devices worn by personnel. Each badge has a globally unique code that is periodically broadcast through an infrared interface. The infrared signals reflect off walls and furniture to flood the surrounding area, and are picked up by a network of sensors placed around the building. By determining which badges were seen by which sensors it is possible to deduce the location of a badge, giving a hint to the location of the badge's owner. Applications in which Active Badge information has been used include telephone call routing, security, and environmental control [4]. An extension to this system allows equipment to be tracked using a low-power version of the Badge called an equipment tag [1]. The developers describe a " nearest printer " service offered to users of portable computers. Tags placed on the computer and printers report their positions, and the computer is automatically configured to use the nearest available printer as it is moved around a building. The ParcTab [5] is a personal digital assistant (PDA) that uses an infrared-based cellular network for communication. The infrared transmissions from ParcTabs can be used to determine their locations in the same way Active Badges are located. Schilit et al. describe the use of the ParcTab system to implement …