Archive for April, 2010

European Rival to GPS takes a Further Step Forward

Wednesday, April 28th, 2010

The long awaited European rival to the USA Global Positioning System, Galileo, has taken a step forward to realisation with the delivery of the payload for first satellite.

The payload, which contains the “brains” of the Galileo satellite, includes the atomic clocks that are the basis for all global navigation satellite systems (GNSS) and provide both the positing information and the GPS time signal used by so many GPS NTP time servers for network synchronisation.

Galileo is set to not only rival the current American run GPS system, but for time synchronisation applications it is expected to operate in tandem ensuring even greater accuracy for those seeking a source of UTC time.

Galileo has undergone a lot of uncertainty since the multi-billion Euro project was first designed over a decade ago but the delivery of the first satellite’s payload to Rome, where the equipment is being finalised in preparation for launch early next year, is a real boon to the project which has often fallen into doubt.

Just like GPS, Galileo will be a fully operation navigational satellite system but will offer even greater accuracy that its aging predecessor and provide Europe with their own navigational system that isn’t owned and controlled by the US military.

As well as the positing information that will be used by motorists, pilots and other travellers, Galileo will also provide a secure and accurate source of time for the world’s computer networks and technologies to ensure synchronicity.

Currently, GPS is alone in providing this secure service, although radio transmissions in some countries provide an alternative to the GPS time server signals, although they are not as wide spread as GPS.

The first Galileo satellite is expected to reach orbit in early 2011, with the entire network planned to be operation in 2014 – although if past experiences with the project are anything to go on – you should expect at least a few delays.

Choosing a Source of Time for an NTP Synchronization

Monday, April 26th, 2010

Accurate time is essential in the modern world of internet banking, online auctions and global finance. Any computer network that is involved in global communication needs to have an accurate source of the global timescale UTC (Coordinated Universal Time) to be able to talk to other networks.

Receiving UTC is simple enough. It is available from multiple sources but some are more reliable than others:

Internet Time Sources

The internet is awash with time sources. These vary in reliability and accuracy but some trusted organisations like NIST (National Institute of Standards and Time) and Microsoft. However, there are disadvantages with internet time sources:

Reliability – The demand for internet sources of UTC often means it can be difficult to access them

Accuracy – most internet time servers are stratum 2 devices which means they rely on a source of time themselves. Often errors can occur and many sources of time can be very inaccurate.

Security – Perhaps the biggest issue with internet time sources is the risk they pose to security. To receive a time stamp from across the internet the firewall needs to have an opening to allow the signals to pass through; this can lead to malicious users taking advantage.

Radio Referenced Time Servers.

A secure method of receiving UTC time stamps is available by using a NTP time server that can receive radio signals from labs like NIST and NPL (National Physical Laboratory. Many countries have these broadcasted time signals which are highly accurate, reliable and secure.

GPS Time servers

Another source for dedicated time servers is GPS. The big advantage of a GPS NTP time server is that the time source is available everywhere on the planet with a clear view of the sky. GPS time servers are also highly accurate, reliable and just as secure as radio referenced time servers.

Common Internet Time Synchronisation Issues

Friday, April 23rd, 2010

Keeping the clock on a PC system synchronised is important for many systems, networks and users that need time accuracy for applications and transactions. Nearly everything on a modern computer system is time reliant so when synchronisation fails all sorts of issues can arise from data getting lost and debugging becoming near impossible.

There are several methods of synchronising a computer system’s clock but the majority of them rely on the time synchronisation protocol NTP (Network Time Protocol).

By far the most common method is to make use of the myriad of online NTP time servers that relay the UTC time (Coordinated Universal Time). However, there are many common issues in using internet based time servers – here are some of them:

Can’t access the Internet time server

A common occurrence with Internet time sources is the inability to access them. This can be caused by several reasons:

• Too much traffic trying to access the server
• Website is down
• Your connection is down

The time from the time server is innacuurate

Most online sources of time are what are known as stratum 2 time servers. This means they get their time from another time server (stratum 1) that it connected to an atomic clock (stratum 0). If there is an error with the stratum 1 device the stratum 2 device will be wrong (and every device that is trying to get the time from it).

The time server is leading to security problems with the firewall

Another common problem caused by the fact that all online time servers need access through your firewall. Unfortunately this gives the opportunity for malicious users to make use of this back door into your system.

Eliminating Time Server Issues

Internet time sources are neither guaranteed to be accurate, reliable or secure so for any serious time synchronisation requirements an external source of time should be used. NTP time servers that plug into a network and receive the time from GPS or radio sources are a much more secure and reliable alternative. These NTP servers are also highly secure as they do not operate across the Internet.

The Worlds Atomic Clock Timekeepers

Tuesday, April 20th, 2010

When you set your watch to perhaps the speaking clock or the time on the internet, have you ever wondered who it is that sets those clocks and checks that they are accurate?

There is no single master clock used for the world’s timing but there are a constellation of clocks that are used as a basis for a universal timing system known as UTC (Coordinated Universal Time).

UTC enables all the world’s computer networks and other technology to talk to each other in perfect synchronicity which is vital in the modern world of internet trading and global communication.

But as mentioned controlling UTC is not down to one master clock, instead, a serious of highly precise atomic clocks based in different countries all work together to produce a timing source that is based on the time told by them all.

These UTC timekeepers include such notable organisations as the USA’s National Institute of Standards and Time (NIST) and the UK’s National Physical Laboratory (NPL) amongst others.

These organisations don’t just help ensure UTC is as accurate as possible but they also provide a source of UTC time available to the world’s computer networks and technologies.

To receive the time from these organisations, a NTP time server (Network Time Server) is required. These devices receive the broadcasts from places like NIST and NPL via long wave radio transmissions. The NTP server then distributes the timing signal across a network, adjusting individual system clocks to ensure that they are as accurate to UTC as possible.

A single dedicated NTP server can synchronize a computer network of hundreds and even thousands of machines and the accuracy of a network relying in UTC time from the broadcasts by NIST and NPL will also be highly precise.

The NIST timing signal is known as WWVB and is broadcast from Boulder Colorado in the heart of the USA whilst the UK’s NPL signal is broadcast in Cumbria in the North of England and is known as MSF – other countries have similar systems including the DSF signal broadcast out of Frankfurt, Germany.

GPS as a Timing Reference for NTP servers

Friday, April 16th, 2010

The GPS system is familiar to most people. Many cars now have a GPS satellite navigation device in their cars but there is more to the Global Positioning System than just wayfinding.

The Global Positioning System is a constellation of over thirty satellites all spinning around the globe. The GPS satellite network has been designed so that at any point in time there is at least four satellites overhead – no matter where you are on the globe.

Onboard each GPS satellite there is a highly precise atomic clock and it is the information from this clock that is sent through the GPS transmissions which by triangulation (using the signal from multiple satellites) a satellite navigation receiver can work out your position.

But these ultra precise timing signals have another use, unbeknown to many users of GPS systems. Because the timing signals from the GPS atomic clocks are so precise, they make a good source of time for synchronising all sorts of technologies – from computer networks to traffic cameras.

To utilise the GPS timing signals, a GPS time server is often used. These devices use NTP (Network Time Protocol) to distribute the GPS timing source to all devices on the NTP network.

NTP regularly checks the time on all the systems on its network and adjusts it accordingly if it has drifted to what the original GPS timing source is.

As GPS is available anywhere on the planet it provides a really handy source of time for many technologies and applications ensuring that whatever is synchronised to the GPS timing source will remain as accurate as possible.

A single GPS NTP server can synchronize hundreds and thousands of devices including routers, PCs and other hardware ensuring the entire network is running perfectly coordinated time.

A Guide to Network Time Protocol

Sunday, April 11th, 2010

NTP (Network Time Protocol) is perhaps the oldest and most commonly used protocol employed by computers and yet it is probably the least understood.

NTP is used by nearly all computers, networks and other devices that are involved in communicating across the internet or internal networks. It was developed in the very earliest stages of the internet when it became evident that some method of ensuring accuracy over distance was required.

The protocol works by selecting a single time source, of which NTP has the ability to establish the accuracy and reliability of, which it then distributes around every device on the NTP network.

Each device is regularly checked against this reference clock and adjusted if any drift is noticed. A version of NTP is now deployed with virtually every operating system allowing any machine to be synchronized to a single time source.

Obviously if every network in the world selected a different time source as its reference, the reason for of all this synchronization would be lost.

Fortunately, a global timescale based on an international consortium of atomic clocks has been developed to provide a single time source for the purposes of global synchronisation.

UTC (Coordinated Universal Time) is used by computer networks worldwide as a time reference which means any device that is synchronised to UTC with NTP will in effect be synchronised with every network that uses UTC as its base time.

There are many different methods that NTP can access UTC time. The internet is a common location although this does provide security and firewall issues. A more secure (and accurate) method is to use a dedicated NTP time server that takes the time from external sources such as the GPS network (GPS works by broadcasting an atomic clock timestamp that is easily converted to UTC by a NTP server).

With NTP, a dedicated time server and access to UTC an entire network can be synchronised to within a few milliseconds of the universal time providing a secure and accurate network that can operate in complete synchronicity with other networks across the globe.

Synchronizing a PC to an Atomic Clock

Wednesday, April 7th, 2010

Atomic clocks are without doubt the most accurate time pieces on the face of the planet. In fact the accuracy of an atomic clock in incomparable to any other chronometer, watch or clock.

While an atomic clock will not lose even a second in time in thousands upon thousands of years, you’re average digital watch will perhaps lose a second in just a few days which after a few weeks or months will mean your watch is running slow or fast by several minutes.

The same can also be said for the system clock that controls your computer the only difference is that computers rely even more heavily on time than we ourselves do.

Nearly everything a computer does is reliant on timestamps, from saving work to performing applications, debugging and even emails are all reliant on timestamps which can be a problem if the clock on your computer is running too fast or slow as errors can quite often occur, especially if you are communicating with another computer or device.

Fortunately, most PCs are easily synchronized to an atomic clock meaning they can be accurate as these powerful time keeping devices so any tasks performed by your PC can be in perfect synchronicity with whatever device you are communicating with.

In most PC operating systems an inbuilt protocol (NTP) allows the PC to communicate with a time server that is connected to an atomic clock. In most versions of Windows this is accessed through the date and time control setting (double clicking the clock in the bottom right).

However, for business machines or networks that require secure and accurate time synchronization, online time servers are just not secure or accurate enough to ensure your network is not vulnerable to security flaws.

However, NTP time servers that receive the time direct from atomic clocks are available that can synchronize entire networks. These devices receive a broadcasted timestamp distributed by either national physics laboratories or via the GPS satellite network.

NTP servers enable entire networks to all have exactly synchronized time which is as accurate and secure as is humanly possible.