A relay attack deterrence system includes a mobile platform including a plurality of mobile platform transmitter components and a mobile platform receiver component provided therein. The system further includes a fob device having a fob receiver component, a fob transmitter component, and a motion sensor component configured to produce motion information. The fob device is configured to receive, at the fob receiver component, one or more first signals from at least one of the plurality of mobile platform transmitter components and to selectably transmit, to the mobile platform receiver component, a second signal based on the motion information and position information derived from the one or more first signals.