GPS week number rollover

GPS Week Number Rollover is like an age-old being resetting its birthday every 19 years! The GPS system uses a special kind of calendar, called the GPS Week Number calendar, to keep track of time. That calendar counts up from zero, just like a normal calendar counts up from one. But instead of counting up to 365 days or 366 days for leap year, the GPS calendar counts up to 1023 weeks (1023 is a very special number that means "all the way around"). The problem is, after 1023 weeks have gone by, the calendar resets back to zero. This means that the GPS system gets "confused" and has to reset itself. It happens every 19 years, just like the old being resetting its birthday every 19 years!