NB-IoT Rel17 has no protection against GNSS jamming. If the UE is not aware of its position, then the UE is not allowed to transmit. However, UEs that know their position before a GNSS jamming takes place, may transmit for as long as their GNSS position is valid. In release 18 there are new features introduced, which would allow UEs to potentially extend the validity of their uplink transmissions by having the eNB adjust the TA and frequency shifts of the UE during an exchange.