An energy-aware indoor positioning system for AAL environments

Ambient Assisted Living (AAL) is a field of research activities focusing on IT support for healthcare, comfort and control applications for private home environments and seniors that has gained importance over the last years. AAL facilities often require positioning services, and generally need to offer easy installation and low energy consumption. We present an approach based on an ultrasound and RF system for three-dimensional indoor positioning and tracking using wall-mounted anchor nodes and a mobile positioning target. The target is a multifunctional customized handheld display and input device connected to the AAL environment. Positioning is achieved using TDoA distance measurement and a multilateration algorithm. To fulfill the low energy requirement, wall nodes are woken up only for positioning cycles by an ultrasonic pulse decoded by a custom electronic circuit and RF traffic is modelled with a small protocol footprint.