Thursday, April 23, 15:30 - 18:00, Location: Show and Tell Area B
Fabio Belloni, Antti Kainulainen, Andreas Richter, Ilari Teikari, Ville Ranki, Kimmo Kalliola, Visa Koivunen, Hannu Kauppinen, Jani Ollikainen
There exists numerous situations in everyday life where it would be important to determine the direction and/or location of a person or an object using a handheld wireless device. Examples of such situations include localizing and tracking pets or children in crowded places, finding lost items such as keys in a room, and locating your car in a large parking lot. In outdoor environments, GPS based positioning systems provide such services. However, in the case of indoor scenarios this still remains an open problem. Many solutions for indoor localization, positioning and tracking problem have been proposed in the past. Tracking systems can be classified into device-to-device and infrastructure-based technologies. While the latter may provide larger coverage, the former is more flexible and cost efficient as well as easier to deploy.
We focus on providing tracking capabilities to small handheld devices such as mobile phones. We have implemented direction finding and multiple radio frequency emitter tracking capabilities in a mobile phone using smart antenna technologies. Designing such a system is particularly demanding because of the small constrained space in a handheld device. Consequently, antenna array of arbitrary geometry is needed. The emitters to be tracked may be active tags, mobile phones, or any other transmitting source, for example. Tracking and localization capabilities are key enablers for future context-aware wireless services that adapt to local radio and user environment, and consequently enhance the user experience. In this presentation we demonstrate the developed tracking system in a multi-emitter tracking task and give an overview of the general structure of the system.
We have designed, developed and implemented a fully functional hardware demonstrator based on 2.4 GHz proprietary Nokia technology. The demonstrator consists of a modified N95 handset with antenna array and a radio transceiver built using a generic RF chip and FPGA processor. The transceiver connects to the phone via USB interface and the direction finding and tracking systems run in the phone processor under a Symbian S60 application interface. A small active RF tag and another mobile phone are used as emitters in the demo.
In addition, we have developed, designed and implemented sensor array signal processing algorithms for arbitrary array geometry and employed them for emitter parameter estimation and tracking. The emitter of interest is tracked using direction finding and sequential estimation algorithms.