It turns out that even if the GPS of the smartphone is turned off, it is possible to specify the location from how to reduce the battery

While GPS functions on smartphones can be used conveniently, there are many people who are concerned that they will lead to privacy leaks. According to research by Stanford University and the Ministry of Defense of Israel, analyzing the consumption pattern of batteries, with a high probability of 90%, according to research by the Ministry of Defense of Israel and Stanford University, if GPS is turned off, It became clear that we can identify where smartphone is.

Levenstein_dist.eps - 1502.03182v1.pdf
(PDF file)http://arxiv.org/pdf/1502.03182v1.pdf


BBC News - Battery power alone can be used to track Android phones
http://www.bbc.com/news/technology-31587621

This is a fact that can pose a threat to privacy leakage, but this time the announcement only touched on Android terminals. In almost every case on Android applications can access battery usage without user's approval. There is no mention of the iOS terminal.

Although it is a method to specify the position, here the characteristic that the battery consumption becomes faster as the distance between the smartphone and the mobile phone base station becomes faster is adopted. In general, if the distance from the mobile base station becomes farther or there are obstacles such as buildings and mountains, the communication environment gets worse because the radio waves are disturbed. Terminals that recognize this will try to secure the communication performance by raising the transmission and reception power of radio waves, which leads to consumption of a lot of batteries. And there are some trends in the consumption pattern at this time for each region.


By matching this consumption pattern with the regional characteristics, if the behavior pattern of a user is known beforehand, the research team clarifies that the location can be identified with a high probability of 90% how much. Also, even if the behavior pattern is not known in advance, the specific rate is set at 60%, which is not an exaggeration to say that it is a very high number.


Of course, consumption of batteries changes with the use of cameras, music applications, games, etc. But the research team is building analysis algorithms to eliminate such external factors. In order to avoid this threat, at present it seems that there is no way to remove the battery any more, because it falls into a dilemma that a battery can not be used with a smartphone, a fundamental countermeasure such as OS level access restriction is necessary It may be.