This is a satellite operated by the United States Department of Defense (official name is NAVSTAR), and orbits the earth at an altitude of 20,000 km.
Initially, this was a military satellite, but at present, information is partially disclosed to the public and used in various equipment including car navigation systems and cellular phones.
The GPS satellite is mounted with a high-accuracy atomic clock with an accuracy deviation of 1 second per 100,000 years.
Mechanism by which this watch sets the time and date
This watch receives GPS signals from GPS satellites to set the time and date based on the following information.
Precise time and date based on the atomic clock
Information about a time zone where you are and its adoption of DST (Daylight Saving Time)
(The current location is basically positioned by more than 4 GPS satellites, and which zone of the total of 39 time zones around the world you are in, and details regarding its adoption of DST (Daylight Saving Time), is identified.)
To receive information about a time zone where you are, it is necessary to adjust the time zone.
How to adjust the time zone
Unlike navigation equipment, this GPS solar watch is not designed to constantly receive GPS signals from GPS satellites without any operation.
This watch receives GPS signals only in the time zone adjustment mode, automatic or manual time adjustment mode.