Tech Chat | What’s the time now? – UTC and GPS Time

When asked for the time, you can read it from your PC, smartphone, watch or wall clock, which is what we use every day - your local time. Have you ever wondered how this time is defined? 

As we all know, there is a time difference between different countries and regions, which comes from the difference in the time zone. Our local time is based on UTC (Coordinated Universal Time) plus the time zone. For example, the local time in China is UTC+8, which is 8 hours added to the UTC base.

So what is UTC? And is there any other way to define time?

UTC 

UTC, Coordinated Universal Time, commonly known as GMT (Greenwich Mean Time).

Weather observations around the world, including surface, radar and other observations, are always taken with respect to standard time. Conventionally, the world meteorological community uses a 24-hour clock, similar to "military" time based on the 0° longitude meridian (also known as the Greenwich meridian).

Before 1972, this time was called Greenwich Mean Time (GMT), but is now referred to as Coordinated Universal Time or Universal Time Coordinated (UTC). It is a coordinated time scale, maintained by the Bureau International des Poids et Mesures (BIPM). It is also known as "Z time" or "Zulu Time".

More about UTC can get from BIPM.
https://www.bipm.org/en/home

In our daily life, the local time accurate to second is sufficient for most daily activities. However, for some large networks or systems, precise timing in milliseconds or even nanoseconds is required.

Then the precise GPS time is used to realize the synchronization of large networks or systems.

GPS Time

GPS Time (Global Positioning System time), is the atomic time scale implemented by the atomic clocks in the GPS ground control stations and the GPS satellites themselves. 

For GNSS receiver that can track GPS/GLONASS/BDS/GALILEO, the high accuracy time observations are key matter, on which all position calculations are based.

Due to the high accuracy of GPS time, it is mainly used in industrial fields, such as telecommunications, electric power grid, meteorology, factory automation.

In order to meet the high-precision timing needs of these industries, SingularXYZ has released ST100 GNSS timing receiver for nanosecond-level timing.

Capable of tracking multi-constellation including GPS, GLONASS, BeiDou and Galileo, ST100 can provide PPS (Pulse Per Second) with an accuracy of 15ns. 

More about ST100 GNSS Timing Receiver
https://www.singularxyz.com/ST100.html