  The fact that almost every person owns a smartphone device that can be
precisely located is both empowering and worrying. If methods for accurate
tracking of devices (and their owners) via WiFi probing are developed in a
responsible way, they could be applied in many different fields, from data
security to urban planning. Numerous approaches to data collection and analysis
have been covered, some of which use active sensing equipment, while others
rely on passive probing, which takes advantage of nearly universal smartphone
usage and WiFi network coverage. In this study, we introduce a system that uses
WiFi probing technologies aimed at tracking user locations and understanding
individual behavior. We built our own devices to passively capture WiFi request
probe packets from smartphones, without the phones being connected to the
network. The devices were tested at the headquarters of the research sector of
the Elm Company. The results of the analyses carried out to estimate the crowd
density in offices and the flows of the crowd from one place to another are
promising and illustrate the importance of such solutions in indoor and closed
spaces.
