The Cricket Indoor Location System

Опубликовано 6 сентября 2016, 5:23

Indoor location information enables applications such as resource discovery, navigation, interactive virtual games, and location-enhanced sensing. Current location technologies, such as the GPS system, designed for outdoor applications are not accurate enough for typical indoor applications. This talk presents the design, implementation, and evaluation of the Cricket indoor location system that provides accurate location information in the form of user space, position, and orientation. Cricket consists of location beacons attached to the ceiling of a building and receivers, called listeners, carried by users and objects that need location information. The beacons periodically transmit location information using an RF signal; beacons also transmit an ultrasonic signal which enables the listeners to measure distances to nearby beacons. Listeners use the distance measurements to beacons to compute listener location. This active-beacon, passive-listener architecture is scalable with respect to the number of users, while the non-tracking nature preserves user privacy. This talk describes the Cricket hardware that enables accurate distance measurement between beacons and listeners, software algorithms for avoiding and filtering collisions caused by uncoordinated beacon transmissions, and algorithms to infer space, position, and orientation. Once deployed, the Cricket beacons use distances collected by a roaming listener to compute a local coordinate assignment that closely resembles their embedding in 3D space. This talk describes a mobile-assisted localization algorithm that solves this problem.