Deploying and evaluating a location-aware system

Location-aware systems are typically deployed on a small scale and evaluated technically, in terms of absolute errors. In this paper, the authors present their experience of deploying an indoor location system (the Bat system) over a larger area and running it for a period exceeding two years.A number of technical considerations are highlighted: a need to consider aesthetics throughout deployment, the disadvantages of specialising sensors for location only, the need for autonomous maintenance of the computational world model, the dangers in coinciding physical and symbolic boundaries, the need to design for space usage rather than space and the need to incorporate feed-back mechanisms and power management. An evaluation of long term user experiences is presented, derived from a survey, logged usage data, and empirical observations. Statistically, it is found that 35% wear their Bat daily, 35% characterise their Bat as useful, privacy concerns are rare for almost 90% of users, and users cite the introduction of more applications and the adoption of the system by other users as their chief incentives to be tracked.Thia paper aims to highlight the need to evaluate large-scale deployments of such systems both technically and through user studies.