Talks and Poster Presentations (with Proceedings-Entry):
G. Retscher, E. Mok:
"Investigation and Testing of Location Systems Using WiFi in Indoor Environments";
Talk: IAIN/GNSS 2006 Conference,
Jeju Island, South Korea;
- 2006-10-20; in: "IAIN/GNSS 2006 Conference",
Many applications in the area of location-based services and personal navigation require nowadays the location determination of a user not only in outdoor environment but also indoor. To locate a person or object in a building systems have been developed that use either infrared, ultrasonic or radio signals, and visible light for optical tracking. The use of WiFi for location determination has the advantage that no transmitters or receivers have to be installed in the building like in the case of infrared and ultrasonic based location systems. WiFi can use standard IEEE802.11x hardware and for positioning the radio signals from access points which might have been installed already in the building are used. These access points can be found nowadays in our daily environment, e.g. in many office buildings, public spaces and in urban areas. The principle of operation of location determination using WiFi signals is based on the measurement of the signal strengths to the surrounding available access points at a mobile terminal (e.g. PDA, notebook PC). An estimate of the location of the terminal is then obtained on the basis of these measurements and a signal propagation model inside the building. The signal propagation model can be obtained using simulations or with prior calibration measurements at known locations in an offline phase. The most common location determination approach is based on signal propagation patterns, namely WiFi fingerprinting. In this paper the underlying technology is briefly reviewed followed by an investigation of two WiFi positioning systems. Testing of the system is performed in two localization test beds, one at the Vienna University of Technology and the second at the Hong Kong Polytechnic University. First test showed that the trajectory of a moving user could be obtained with a standard deviation of about +- 3 m.
Online library catalogue of the TU Vienna:
Created from the Publication Database of the Vienna University of Technology.