  Global Navigation Satellite Systems (GNSS) provide precise location, while
Real Time Kinematics (RTK) allow mobile receivers (termed rovers), leveraging
fixed stations, to correct errors in their Position Navigation and Timing (PNT)
solution. This allows compensating for multi-path effects, ionospheric errors,
and observation biases, enabling consumer receivers to achieve centimeter-level
accuracy. While network distribution of correction streams can be protected
with common secure networking practices, the reference stations can still be
attacked by GNSS spoofing or jamming. This work investigates (i) the effect RTK
reference station spoofing has on the rover's PNT solution quality and (ii) the
potential countermeasures towards hardening the RTK infrastructure.
