https://phys.org/news/2018-06-indoor-positioning-wireless-network.html

"Based on collected observations of human behaviour, intelligent systems can make decisions themselves. The crucial thing for collecting this kind of data is localisation and positioning of people and things indoors," says Professor Egidijus Kazanavicius, director of the Real Time Computer Systems Centre, KTU.

Outdoors, people and objects can be located using the Global Positioning System (GPS), but this function usually does not work indoors. Although the body of research related to indoor positioning using WLAN is substantial, the methods offered usually have significant shortcomings—the positioning accuracy is low, and the WLAN-based positioning software usually needs to be installed into specific devices, which increases the price of the final product.