Location aggregation from multiple sources

Tracking the location of people, computers, vehicles, and other mobile objects and performing computation on such location data are quickly gaining interest. The idea of location-based services has captured the imagination of application developers, wireless service providers, and content providers alike. However, the location of people, the most interesting mobile object, is tricky to determine because we don´t track persons but rather the devices they carry or the transportation they use. That a person may be associated with numerous tracking devices simultaneously, but perhaps intermittently, makes location tracking challenging. We describe a methodology for aggregating location data from multiple sources associated with a single mobile object. We describe our existing location service infrastructure and illustrate scenarios where location aggregation is desirable and indeed required. Our experimentation in location-based services uses location data from wireless PDAs, vehicle tracking devices, and mobile and stationary computers.