GPS week-number rollover

Legacy GPS LNAV week numbers are 10 bits. They roll every 1,024 weeks, about 19.7 years. Previous rolls: 21 August 1999 and 6 April 2019. The next legacy roll is 20 November 2038. CNAV 13-bit weeks last until 2137.

This is independent of Unix time_t. A receiver can fail the GPS week and still have a perfect 64-bit POSIX clock, or the reverse. GPS.gov is the primary public source for the civil-signal statement.