Detecting GNSS Spoofing using a Network of Hardware Oscillators

In the face of growing concern about spoofing attacks on GNSS transmissions, we propose a scheme to cross validate GNSS based timing against intrinsic properties of local hardware oscillators. We demonstrate our approach as being able to detect certain types of spoofing attacks on the timing reference signal using an ensemble detector test-bed currently in development. Our primary contribution is a linear belief filter applied to a set of low-cost oscillators, organized in a maximum likelihood clock ensemble. Our approach is intended to improve the sensitivity of conventional threshold based detectors that compare time offset between the GNSS stabilized reference and a local free running detector clock to detect changes in offset or slew rate.