It seems that it is possible – even easy – to send spoof travel information messages to satnav systems.
A pair of researchers from infrastructure developers Inverse Path detailed the hack at a Canadian security conference a couple of weeks ago. They used inexpensive off-the-shelf kit -- a $40 RDS encoder (price tag: $40), an FM transmitter and a hand-held antenna -- to insert data into the RDS-TMC (radio data system-traffic message channel) transmissions used by many satnav systems for real-time travel information.
The researchers showed how this could be used to fake a particular event or traffic report, which might appear as a pop-up (a bomb alert, for instance) or which might be used automatically for route calculation (notification of a road closure could cause the satnav to produce a new route).