Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine a differential UE-specific timing advance (TA) based at least in part on a difference between a first UE-specific TA associated with a current global navigation satellite system (GNSS) position fix and a second UE-specific TA associated with a previous GNSS position fix. The UE may transmit, to a non-terrestrial network (NTN) node, an uplink message at a time that is based at least in part on the differential UE-specific TA. Numerous other aspects are described.