GPS NTP Server – Telling the Time in the Satellite Age

The Global Positioning System was developed by the United State s Military for their armed forces, however following the accidental shooting down of a Korean Airliner in 1983, the US government realised the benefits a civilian system would have in preventing such a disaster.

As a consequence the GPS network was opened up freely for civilian use and is currently the world’s only fully functioning global navigation satellite system (GNSS), although Europe and Russia are to have their own systems within the next decade.

Although the GPS system is primarily used for location finding the only information it relays is the time, which has proved beneficial in keeping computer networks synchronised using a GPS NTP server.

Each GPS satellite contains an atomic clock, these clocks beam to Earth an exact timing signal, precise to a second in several millions of years. The GPS receiver then works out the time each signal took to get to it (a minimum of three is therefore needed) and can work out its exact location by this triangulation.

GPS satellites have to provide exact timing information as light and radio waves can travel 300,000 km each second, a difference which would make navigation hopeless. However, this information can be used by a GPS NTP Server which converts the time signal from the satellites into UTC (Coordinated Universal Time) and then synchronises every clock on a network to that time.

Using the GPS network means a GPS NTP server can provide accuracy to a computer network to within a few milliseconds. GPS has therefore not only transformed the way in which the world navigates but also has also revolutionised computer networks with precise timing information making possible many of the Internet  processes such as online purchasing and email that we all take for granted.

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Galileo and the GPS NTP Server

Currently there is only one Global Navigation Satellite System (GNSS) the NAVSTAR GPS which has been open for civilian use since the late 1980’s.

Most commonly, the GPS system is thought to provide navigational information allowing drivers, sailors and pilots to pinpoint their position anywhere in the world.

In fact, the only information beamed from a GPS satellite is the time which is generated by the satellites internal atomic clock. This timing signal is so accurate that a GPS receiver can use the signal from three satellites and pinpoint the location to within a few metres by working out how long each precise signal took to arrive.

Currently a GPS NTP server can use this timing information to synchronise entire computer networks to providing accuracy to within a few milliseconds.

However, the European Union is currently working on Europe’s own Global Navigation Satellite System called Galileo, which will rival the GPS network by providing its own timing and positioning information.

However, Galileo is designed to be interoperable with GPS meaning that a current GPS NTP server will be able to receive both signals, although some software adjustments may have to be made.

This interoperability will provide increased accuracy and may make national time and frequency radio broadcasts obsolete as they will not be able to produce a comparable accuracy.

Furthermore, Russia, China and India are currently planning their own GNSS systems which may provide even more accuracy. GPS has already revolutionised the way the world works not only by allowing precise positioning but also enabling entire globe to synchronise to the same timescale using a GPS NTP server. It is expected that even more advances in technology will emerge once the next generation of GNSS begin their transmissions.

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