GPS watches receive signals from up to 4 satellites to ensure the correct time is displayed.

How do GPS watches work?

How do GPS watches work? Much like radio-controlled watches, GPS watches have a transmitting receiver built into the mechanism of the watch that can pick up transmissions and adjust the time.
Reception can be either manual or automatic, depending on the watch. Usually, a watch will “call” for an update every 24 hours, normally between 02:00 and 06:00. Manual receives can be started following the manufacturer’s instructions.

How does the GPS tell the time?

Medium Earth Orbit (or MEO) satellites orbit anywhere between 5,000km and 13,00km above sea level, with orbital periods ranging anywhere from 2 to 24 hours. All MEO satellites hold huge amounts of data, including precise location, current UTC atomic time, and altitudinal/pressure information.
The data the satellites carry ensures that the time take for the signal to travel from the satellite to the receiving watch is accounted for, and the correct time is shown to the microsecond.
The layout of medium orbit satellites ensures that wherever the receiver is on the surface of the planet, there are always at least 3 satellites in full view, meaning a triangulated time update for precise accuracy.

What’s the benefit of a GPS-controlled watch?

What’s the benefit of a GPS-controlled watch? GPS-controlled watches are self-updating both for time and location. The GPS sensor in the watch can tell from the received signal if the location has changed enough to warrant updating the time zone and then adjusting the time accordingly. This is perfect for frequent travelers as this removes the need for the user to manually adjust the time-zone as they travel. At most, all you’d need to do is perform a manual receive.

How long do GPS-controlled watches last?

GPS controlled watches, like radio controlled watches, are powered by a Quartz mechanism. Whether battery-powered or solar-powered, a GPS watch will, with proper care, last as long as the MEO GPS network. Battery-powered GPS watches will need a replacement battery every 1-2 years and should be serviced every 5-7 years. Solar-powered GPS watches, such as the Seiko Astron range, G-Shock's MT-G GPS Hybrid, or Citizen Satellite Wave watches, should be serviced every 7-10 years.