Android GPS Jammer Localizer Application Based on C/N0 Measurements and Pedestrian Dead Reckoning

Several applications of today`s smartphones rely on the availability of GPS signals and the possibility to estimate the position of a person. One of the most important services among those is the E911 (E112 in Europe) mandate which states that the position of a person who is making an emergency call can be estimated and is forwarded to the appropriate public authorities. Everything that interferes with this service poses a threat to the safety and life of people being in a state of distress. In this paper the impact of a static jamming device on an Android smartphone is analyzed. Since Android enables the implementation of user applications and also the access to the smartphone’s hardware like inertial sensors or the GPS receiver by providing a Java-API (application programming interface). The effects of a jammer on the C/N0 measurements are used to detect the jammer in the vicinity of the mobile phone. Additionally the mobile device is equipped with a dead reckoning algorithm based on step detection and step length estimation to bridge the time when GPS is not available due to interfering signals. The dead reckoning algorithm is used furthermore to localize the jammer. A virtual coordinate system is defined based on two distances measured by step detection and heading estimation of a pedestrian holding the navigation device. The static position of the jammer in this coordinate system is estimated using C/N0 measurements of the GPS receiver.