Reliable data to quantify sudden population movements. By tracking the movement of their mobile phones, Orange was able to measure the flight of residents of the Paris region, which started just before – or shortly after – the start of confinement.
On Europe 1 Wednesday morning, the operator’s CEO, Stéphane Richard, put forward the figure of 17% of the population of Paris and of the inner suburbs who packed their bags between March 13 and 20 to join their family or a secondary residence.
How did Orange get such a precise percentage? “This figure comes from INSEE which extrapolated raw data based on our subscribers – which represent 40% of the market -, but also of all the people who connected to our mobile network during this period”, specifies the operator .
Three antennas give position
In order to obtain exploitable data and observe the movement of the devices, the operator used the mesh of relay antennas in its network and the triangulation of the terminals.
“Our telephone constantly sends mini-signals to the three closest relay antennas or telephone terminals. The system can thus locate the terminal by aggregating the connection with these three fixed antennas which cover a specific area ”, explains Maurice Gagnaire, professor specializing in optical and radio networks at Telecom Paris.
“When the phone moves away from an antenna, the connection will be automatically resumed by another, further. The network understands that you leave the area of influence of the antenna even before the terminal is out of range, ”explains the expert. The tracking system will therefore see that the owner of a telephone, who “bounded” in the morning in Evry and the same evening on the Atlantic coast, packed up.
An internal tool to exploit the data
As each phone and its associated number have a unique IP address, their own signature, it is also easy to determine who has migrated from one area to another. This is how the operator was able to generate geolocation metadata for tens of thousands of users.
In order to deal with this automatic flow, Orange engineers reconfigured a commercial tool from one of its subsidiaries called Flux Vision. It is usually used to measure the movements of tourists to summer resorts, thus allowing tourist offices and local authorities to predict arrivals and to adapt infrastructures and commercial offers to arrivals more acutely.
Flux Vision software had to be recalibrated ten days ago to cover all of metropolitan France. Tens of thousands of geolocation points therefore appeared on the operator’s radars. A wealth of useful information for researchers, such as those from the French Institute for Medical Research (Inserm) who monitor population movements during the pandemic.
But a practice that questions the respect for the privacy of subscribers, studied closely, and who have not given their agreement. “France is not China! There is no tracking of individuals, “defended Stéphane Richard on Europe 1.
Almost anonymous data
Orange insists on completely anonymized data collection, which therefore complies with the European ePrivacy directive and the European Data Protection Regulation (GDPR).
“The question of the subscriber’s consent nevertheless arises, because even if they are anonymized, the number which is connected to the network corresponds internally to an e-mail or to an address which can possibly be exploited”, Ramzi alert Labri, founder of VA2CS, a company specializing in triangulation that geolocates fragile people.
This first collection could be followed by others. European Commissioner Thierry Breton met on Monday with the bosses of several large European operators, including Orange, who said they were ready to share their metadata with the JRC, the Commission’s scientific study center.