A timepiece comprises a reception subunit, a timekeeping unit that holds
internal time data indicative of the current time, storage, and a CPU.
The CPU determines whether the internal time data acquired from the
timekeeping unit matches correction time data stored in storage, selects
a GPS satellite represented by satellite identification data stored in
the storage when the determination is affirmative, acquires GPS time data
included in navigation data which in turn is included in a GPS signal
obtained from the selected GPS satellite, corrects the internal time data
based on the GPS time data, and stores the correction time data in
correspondence to the satellite identification data representing that GPS
satellite.