Why GPS?

Time synchronisation can be conducted in multiple ways on a computer network. There are many time protocols but NTP (Network Time Protocol) is by far the most used (probably close to 99% of networks use NTP).

Most time servers receive a UTC time signal UTC (Coordinated Universal Time) yet, there are multiple places that NTP can receive a signal from but each has it downsides. The most widely used source of UTC is the Internet but no serious network administrator would dare to use the Internet as a timing source.

Internet timing sources can’t be authenticated using NTP’s security measure and an Internet timing source will exist outside a networks firewall so a TCP/IP port would need to be left open both of these problems could leave a network open to malicious attacks, abuse or even fraud. Another reason why Internet sources should not be used is that a recent survey found less than a third were accurate enough to UTC to be useful and those that were depended on the distance from the client.

Time and frequency transmissions broadcast in longwave are far more secure and far more accurate than any Internet timing source. These transmissions are broadcast by several national physics laboratories and provide a safe, secure and highly accurate method of receiving UTV. Unfortunately not every country has a timing broadcast and even in a country that does the signals are vulnerable to local geography and interference.

GPS however, is available everywhere on the planet, the only downside at all in using a GPS time server is that it needs an antenna to be situated on the roof, which in most cases is not normally an issue.

GPS Time Server – Receiving Time from Space

GPS time servers are network time servers that receive a timing signal from the GPS network and distribute it amongst all devices on a network ensuring that the entire network is synchronised.

GPS is an ideal time source as a GPS signal is available anywhere on the globe. GPS stands for Global Positioning System, the GPS network is owned by the US military and controlled and run by the US air force (space wing). It is however, since the late 1980’s been opened up to the world’s civilian population as tool to aid navigation.

The GPS network is actually a constellation of 32 satellites that orbit the Earth, they do not actually provide positioning information (GPS receivers do that) but transmit from their onboard atomic clocks a timing signal.

This timing signal is what is used to work out a global position by triangulating 3-4 timing signals a receiver can work out how far and therefore the position you are from a satellite. In essence then, a global positioning satellite is just an orbiting clock and it is this information that is broadcast that can be picked up by a GPS time server and distributed amongst a network.

Whilst strictly speaking GPS time is not the same as the global timescale UTC (coordinated universal time), a GPS time server will automatically convert the time format into UTC.

A GPS time server can provide unbridled accuracy with networks able to maintain accuracy to within a few milliseconds of UTC.

GPS Time Server – The First Choice for time synchronisation

GPS time servers have revolutionised the world of synchronisation. There advantages over other forms of timing references is many fold but as there are over 30 GPS satellites one will always be in range of a GPS receiver.

A GPS time server (Global Positioning System) bought fifteen years ago would have cost somewhere in the reason of £8,000-£10,000 ($15,000-$17,000) but thanks to the growing use of the technology the price of GPS receivers has plummeted and they can be bought for as little as £350 ($600). His has made GPS the dominate form of timing references for time synchronisation.

A GPS time server will come in several forms, some are designed to be fitted into standard server racks, these rack-mountable GPS time server will take up one or two standard U spaces depending on server type.

Other GPS time servers are smaller and more discrete, ideal to be located outside a server room. While GPS time servers offer unrivalled accuracy and a signal is available literally everywhere on the planet it does have one down-side in that a GPS antenna has to have a clear view of the sky. This means that the antenna has to be situated on a roof of a building otherwise there is a possibility that the signal will be lost.

GPS Time Server – The Synchronisation Choice

GPS (Global Positioning System) is now the preferred method of receiving a UTC (Coordinated Universal Time) time source for the purposes of synchronising a computer network.

GPS is an American military controlled system that was opened up for the use of civilians following a terrible air disaster in the late 1980’s. GPS receivers used to be astronomically expensive and all but the most wealthy network administrators would use the GPS signal as a source of UTC time.

However, due to advances in technology in recent years GPS technology has dramatically dropped in price and the GPS time server is now the globally preferred method of receiving a UTC timing source.

Other methods have continually been available of course with national time and frequency transmissions such as MSF in the UK, DCF in Germany and the WWVB signal in the USA having been the most popular method over the last decade.

However, there are drawbacks to using the national time and frequency transmissions. They are all broadcast on similar long-wave frequencies and are vulnerable to topography and interference from weather and other electrical appliances. These time and signal transmissions are also only available in a select few countries and even in the country of origin the local geography can prevent the signal getting through.

One of the reasons GPS is now so popular is that no matter where you are in the world the GPS receiver will always be able to receive a signal just as long as the GPS antenna can obtain a clear view of the sky.