Software-Defined-Radio techniques against jammers for in car GNSS navigation

It is well know that jamming is an easy and low cost attack method against GNSS-based applications. In the last years these types of attacks have increased significantly due to the availability of GPS jammers that can be easily found, for example, on the internet and due to the constant growth of in-car GNSS-based applications. Usually a jamming device, also called in-car jammer, is a quite simple electronic device which emits a single frequency tone or some type of chirp signal. These types of signal can be considered as an instantaneous narrow band and can be mitigated with very simple processing, based on Short Time Fourier Transform. These considerations lead to the development of an equipment able to reduce the effect of these harmful signals over a generic GNSS receiver through a Software Defined Radio (SDR) equipment. In this paper a brief introduction to the problem is presented and a time-frequency mitigation technique is shown along with some results for a set of in-car jammers.