Sensor network based localization for continuous tracking applications [invited paper]
Livio Denegri, Sandro Zappatore, Franco Davoli · 2010
The increasing interest in systems able to provide users im-mersive services (e.g. domotics, context-aware applications, immersive distance learning tools) has encouraged the devel-opment of cheap and effective platforms aimed at tracking objects and people within a certain space. In this context, wireless sensor networks (WSNs) can play a very impor-tant role, since specialized sensors can be fruitfully exploited in order to generate/receive signals by means of which the WSN can derive the position of nodes jointed to the objects to be tracked. The paper presents an original localization platform that ex-ploits a single-hop WSN, based on a Microchip MCU and a Cypress RF device, to tracking its moving nodes. Specif-ically, the nodes of the network are divided in three sets: the first set consists of anchor nodes that, accordingly to the commands from the sink (the central node of WSN), generate ultrasonic pulses. These ones are received by the second set of (moving) nodes, which estimate the pulse-trip-time and communicate it to the sink. Finally, the last set is constituted by general purpose nodes that collect any kind of data from the surrounding field. The sink gathers all the data, computes the position of moving nodes and transfers information to external users on the Internet. The algorithms adopted to manage the network and to lo-calize moving nodes are discussed. A working prototype based upon the hardware platform, software and protocol described in this paper has been deployed and tested, and some results are shown.