A range of mobile services rely on knowing the current positions of populations of so-called moving objects. In the ideal setting, the positions of all objects are known always and exactly. While this is not possible in practice, it is possible to know each object's position with a certain guaranteed accuracy.#R##N##R##N#This paper presents the TRAX tracking system that supports several techniques capable of tracking the current positions of moving objects with guaranteed accuracies at low update and communication costs in real-world settings. The techniques are readily relevant for practical applications, but they also have implications for continued research. The tracking techniques offer a realistic setting for existing query processing techniques that assume that it is possible to always know the exact positions of moving objects. The techniques enable studies of trade-offs between querying and update, and the accuracy guarantees they offer may be exploited by query processing techniques to offer perfect recall.
['Christian S. Jensen', 'Stardas Pakalnis']
TRAX: real-world tracking of moving objects