It’s easy to get lost in big buildings. But no navigation device can help you find your way around, for example in a conference: GPS signals can usually not be received or do not provide sufficient accuracy in localization, and digital building plans are hardly accessible to the public.
In the topikos project, Prof. Dr. Gerd Stumme and Bastian Schäfermeier are researching methods to enable users to be located within buildings and the mobility of many people to be visualised. Their aim: the methodology should be able to do without additional infrastructure and be used anywhere.
For localization, they use WiFi signals that every router in the building constantly sends out. Their signal strengths leave a more or less unambiguous fingerprint at every sufficiently covered location of a building. With the help of a smartphone, the signal strengths can be measured and compared with a database to determine the location. Since environments are constantly changing, it is too costly to create such databases manually and keep them up to date. Therefore, the researchers are developing algorithms that generate databases as automatically as possible. Among other things, Stumme and Schäfermeier are investigating approaches to identifying important places and their semantics. These are characterised by the fact that many people with similar interests often spend long periods of time there.
The team is faced with many practical challenges: In addition to a functioning methodology that is also robust against various sensors and signal interference, the battery requirements of smartphones must not be too high. And: The privacy of the users must not be violated.