A Relative Positioning System for Spatial Awareness of Co-located Mobile Devices and Users

If a mobile computer knows how it is positioned and oriented in relation to other mobile devices nearby, then it can provide enhanced support for multi-device and multi-user interactions. Existing systems that provide position information to mobile computers are reliant on externally deployed infrastructure, such as beacons or sensors in the environment. We introduce a novel system, Relate, which provides fine-grained relative position information to co-located devices on the basis of peer-to-peer sensing, thus overcoming dependence on any external infrastructure. The system is realized as hardware/software plug-in, using ultrasonic devices for peer-to-peer sensing, USB to interface with standard mobile devices, and data abstraction and inference to map sensor data to a spatial model that maintains both quantitative and qualitative relationships. We present a set of services and applications to demonstrate the utility of the system and report experimental results on system performance.