Investigating the Use of Smartphones for detecting GNSS-related threats

Abstract

Public safety is a field in constant evolution aiming at adapting constantly in order to find the appropriate answer to new threats. In fact, because of rapid technological progress, many new vectors of attacks became more accessible. To mitigate that, public safety actors have been focusing on situational awareness as a way to assess a critical situation and act efficiently. This assessment is made using a wide amount of data coming from different sources. However, these sources need to be fully trusted and reliable, which is why more recent technologies such as smartphones are not yet fully exploited. In addition, such portable devices are also continually improved to integrate public safety requirements. Recent advances in supporting satellite data directly accessible through the Android API created a peak of interest. Exploiting the right parameters and their evolution was proven to be an efficient way to detect abnormal behavior such as GPS spoofing and jamming. It became possible to study relevant values such as Automatic Gain Control (AGC), Carrier-to-Noise Density Ratio (C/N_0) and measurement time. While often used, there is a lack of information on how to interpret those values. The work conducted in the following aims at filling that gap by providing observations and clear explanations. It helps to create a relevant knowledge base for the future development of sophisticated tools for public safety.