Thrifty tracking: online GPS tracking with low data uplink usage

A typical online GPS tracking system uses a cellular uplink to report the location of a device to a central server, and in a study based on 1.6 billion location updates we find at least 90% are sent with a fixed 1--300 second period. Through experiments with the cost of cellular data transmission we also find that every packet sent incurs significant overhead. With these observations in mind, we describe a thrifty tracking system that allows the specification of a target error or budget-bound, while it optimizes the other. In our experiments, thrifty tracking outperforms the status quo by up to 20X while providing improved guarantees and flexibility.