Quantum Atomic Clocks The precision of the future

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The atomic clock is not a recent invention. Developed in the 1950’s, the traditional caesium based atomic clock has been providing us with accurate time for half a century.

The caesium atomic clock has become the foundation of our time – literally. The International System of Units (SI) define a second as a certain number of oscillations of the atom caesium and atomic clocks govern many of the technologies that we live with an use on a daily basis: The internet, satellite navigation, air traffic control and traffic lights to name but a few.

However, recent developments in optical quantum clocks that use single atoms of metals like aluminium or strontium are thousands of times more accurate than traditional atomic clocks. To put this in perspective, the best caesium atomic clock as used by institutes like NIST (National Institute for Standards and Time) or NPL (National Physical Laboratory) to govern the world’s global timescale UTC (Coordinated Universal Time), is accurate to within a second every 100 million years. However, these new quantum optical clocks are accurate to a second every 3.4 billion years – almost as long as the earth is old.

For most people, their only encounter with an atomic clock is receiving its time signal is a network time server or NTP device (Network Time Protocol) for the purposes of synchronising devices and networks and these atomic clock signals are generated using caesium clocks.

And until the world’s scientists can agreed on a single atom to replace caesium and a single clock design for keeping UTC, none of us will be able to take advantage of this incredible accuracy.

Network Time Protocol and Computer Time Synchronization

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Ask any network administrator or IT engineer and ask them how important network time synchronization is and you’ll normally get the same answer – very.

Time is used in almost all aspects of computing for logging when events have happened. In fact timestamps are the only reference a computer can use to keep tracks of tasks it has done and those that it has yet to do.

When networks are unsynchronized the result can be a real headache for anybody tasked with debugging them. Data can be often lost, applications fail to commence, error logging is next to impossible, not to mention the security vulnerabilities that can result if there is no synchronized network time.

NTP (Network Time Protocol) is the leading time synchronisation application having been around since the 1980’s. It has been constantly developed and is used by virtually every computer network that requires accurate time.

Most operating systems have a version of NTP already installed and using it to synchronise a single computer is relatively straight forward by using the options in the clock settings or task bar.

However, by using the inbuilt NTP application or daemon on a computer will result in the device using a source of internet time as a timing reference. This is all well and good for single desk top machines but on a network a more secure solution is required.

It is vital on any computer network that there are no vulnerabilities in the firewall which can lead to attacks from malicious users. Keeping a port open to communicate with an internet timing source is one method an attacker can use to enter a network.

Fortunately there are alternatives to using the internet as a timing source. Atomic clock time signals can be received using long wave radio or GPS transmissions.

Dedicated NTP time server devices are available that make the process of time synchronisation extremely easy as the NTP servers receives the time (externally to the firewall) and can then distribute to all machines on a network – this is done securely and accurately with most networks synchronised to an NTP server working to within a few milliseconds of each other.

Atomic Clocks Now Doubled in Precision

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As with the advance of computer technology that seems to exponentially increase in capability every year, atomic clocks too seem to increase dramatically in their accuracy year on year.

Now, those pioneers of atomic clock technology, the US National Institute of Standards Time (NIST), have announced they have managed to produce an atomic clock with accuracy twice that of any clocks that have gone before.

The clock is based in a single aluminium atom and NIST claim it can remain accurate without losing a second in over 3.7 billion years (about the same length of time that life has existed Earth).

The previous most accurate clock was devised by the German Physikalisch-Technische Bundesanstalt (PTB) and was an optical clock based on a strontium atom and was accurate to a second in over a billion years. This new atomic clock by NIST is also an optical clock but is based on aluminium atoms, which according to NIST’s research with this clock, is far more accurate.

Optical clocks use lasers to hold atoms still and differ to the traditional atomic clocks used by computer networks using NTP servers (Network Time Protocol) and other technologies which are based on fountain clocks. Not only do these traditional fountain clocks use Caesium as their time keeping atom but instead of lasers they use super-cooled liquids and vacuums to control the atoms.

Thanks to work by NIST, PTB and the UK’s NPL (National Physical Laboratory) atomic clocks continue to advance exponentially, however, these new optical atomic clocks based on atoms like aluminium, mercury and strontium are a long way from being used as a basis for UTC (Coordinated Universal Time).

UTC is governed by a constellation of caesium fountain clocks that while still accurate to a second in 100,000 years are by far less precise than these optical clocks and are based on technology over fifty years old. And unfortunately until the world’s science community can agree on an atom and clock design to be used internationally, these precise atomic clocks will remain a play thing of the scientific community only.

The Effect of Solar Flares on GPS

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Forthcoming space weather may affect GPS devices including satellite navigation and NTP GPS time servers.

Whilst many of us have had to cope with some extreme weather last winter, further storms are on their way – this time from space.

Solar flares are a regular occurrence on the surface of the sun. Whilst scientists are not completely sure what causes them we know two things about solar flares: – they are cyclical – and are related to sunspot activity.

For that last eleven years the sun’s sunspot activity – small dark depressions that appear on the surface of the sun – has been very minimal. But this eleven year cycle has come to an end and there has been a rise in sun spots at the end of last year meaning 2010 will be a bumper year for both sunspots and solar flares.

But there is no need to worry about becoming toasted by solar flares as these bursts of hot gases that flare from the sun never get far enough to reach the Earth, however, they can effect us in different ways.

Solar flares are bursts of energy and as such emit radiation and high energy particles. On earth, we are protected by these blasts of energy and radiation by the earth’s magnetic field and ionosphere, however, satellite communications are not and this can lead to trouble.

Whilst the effect of solar flare radiation is very weak, it can slow down and reflect radio waves as they travel through the ionosphere towards Earth. This interference can cause GPS satellites in particular extreme problems as they are reliant on accuracy to provide navigational information.

While the effects of solar flares are mild, it is possible GPS devices will encounter brief periods of no signal and also the problem of inaccurate signals meaning positing information may become unreliable.

This will not just affect navigation either as the GPS system is used by hundreds and thousands of computer networks as a source of reliable time.

Whilst most dedicated GPS time servers should be able to cope with periods of instability without losing precision, for worried network administrators not wanting to go into work to find their systems have crashed because of a lack of synchronisation may want to consider using a radio referenced Network time server that uses broadcast transmission such as MSF or WVBB.

Dual NTP time servers (Network Time Protocol) are also available that can receive both radio and GPS, ensuring a source of time is always constantly available.

A Guide to Synchronising a Network with NTP

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Network Time Protocol (NTP) is a TCP/IP protocol developed when the internet was in its infancy. It was developed by David Mills of the University of Delaware who was trying to synchronise computers across a network with a degree of precision.

NTP is a UNIX based protocol but it has been ported to operate just as effectively on PCs and a version has been included with operating systems since Windows 2000 (including Windows 7, Vista and XP).

NTP, and the daemon (application) that controls it, is not just a method of passing the time around. Any system running the NTP daemon can act as a client by querying the reference time from other servers or it can make its own time available for other devices to use which in effect turns it into a time server itself. It can also act as a peer by collaborating with other peers to find the most stable and accurate time source to use.

One of the most flexible aspects of NTP is its hierarchical nature. NTP divides devices into strata, each stratum level is defined by its proximity to the reference clock (atomic clock). The atomic clock itself is a stratum 0 device, the closest device to it (often a dedicated NTP time server) is a stratum 1 device whilst other devices that connect to that become stratum 2. NTP can maintain accuracy to within 16 stratum levels.

Any network that needs to be synchronised, has to first identify and locate a time source for NTP to distribute. Internet sources of time are available but thee are often taken from stratum 2 devices that operate through the firewall. The only way NTP can peer the time is if the TCP/IP port is left open to allow the traffic through. This could lead to security issues as malicious users can take advantage of this firewall hole.

Dedicated NTP time servers find a source of time via GPS or radio signals and so don’t leave a network vulnerable to attack. By attaching a NTP time server to a router and entire network of hundreds and even thousands of devices can be synchronised thanks to NTP’s hierarchical structure.

New Technologies and the Growing Importance of Time Synchronisation

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The NTP protocol (Network Time Protocol) has since the earliest days of the internet been responsible for synchronising the time across computer networks. Not only is NTP effective at this, but when connected to a source of UTC (Coordinated Universal Time) NTP is also extremely accurate.

Most computer networks connect to UTC via a dedicated NTP time server. These devices use an external connection to an atomic clock to receive the time and then distribute it across a network. By connecting externally, via GPS (Global Positioning System) or long wave radio , not only are NTP time servers incredibly accurate but they are also very secure as they don’t rely on an internet connection for the time.
NTP time servers are also increasingly being used for other new innovations. Not only have traditional technologies such as CCTV, traffic lights, air traffic control and the stock exchange, become reliant on time synchronisation with time servers but an increasing amount of modern technologies are too.

NTP time servers are now common in modern digital signage systems (the use of flat screen TVs for out of home advertising). These networked screens are often synchronised to allow scheduled and orchestrated campaigns.

A synchronized digital signage campaign is one method of making an out of home advertising campaign stand-out. This is increasingly important as more and more digital signage is being implemented making a conventional digital signage campaign difficult to engage and catch the eye.

By synchronising multiple screens together with a NTP time server and running a scheduled and timed campaign. This allows content to be scheduled or timed to maximise its impact.

Small time servers can eben be installed directly into the digital signage of LCD enclosure although as most of these tiem synchnisation devices require a GPS or long wave signal the antenna can be problamtic. A better solution is to network the digtal signage and use a single NTP server as a method fo synchonisation.

NTP may be the oldest protocol on the internet and NTP time servers have been around for nearly two decades but this comparatively antique technology and software has never been so much in demand.

The Atomic Clock Scientific Precision

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Precision is becoming increasingly important in modern technologies and none more so than accuracy in time keeping. From the internet to satellite navigation, precise and accurate synchronicity is vital in the modern age.

In fact many of the technologies that we take for granted in today’s world, would not be possible if it wasn’t for the most accurate machines invented – the atomic clock.

Atomic clocks are just timekeeping devices like other clocks or watches. But what stands them apart is the accuracy they can achieve. As a crude example your standard mechanical clock, such as a town centre clock tower, will drift by as much as a second a day. Electronic clocks such as digital watches or clock radios are more accurate. These types of clock drift a second in about a week.

However, when you compare the precision of an atomic clock in which a second will not be lost or gained in 100,000 years or more the accuracy of these devices is incomparable.

Atomic clocks can achieve this accuracy by the oscillators they use. Nearly all types of clock have an oscillator. In general, an oscillator is just a circuit that regularly ticks.

Mechanical clocks use pendulums and springs to provide a regular oscillation while electronic clocks have a crystal (usually quartz) that when an electric current is run through, provides an accurate rhythm.

Atomic clocks use the oscillation of atoms during different energy states. Often caesium 133 (and sometimes rubidium) is used as its hyperfine transitional oscillation is over 9 billion times a second (9,192,631,770) and this never changes. In fact, the International System of Units (SI) now officially regards a second in time as 9,192,631,770 cycles of radiation from the caesium atom.

Atomic clocks provide the basis for the world’s global timescale – UTC (Coordinated Universal Time). And computer networks all over the world stay in sync by using time signals broadcast by atomic clocks and picked up on NTP time servers (Network Time Server).

Network Time Protocol And Network Time Synchronization

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Synchronization of computer networks is something that many administrators take for granted. Dedicated network time servers can receive a time source and distribute it amongst a network, accurately, securely and precisely.

However, accurate time synchronization is only made possible thanks the time protocol NTP – Network Time Protocol.

NTP was developed when the internet was still in its infancy and Professor David Mills and his team from Delaware University were trying to synchronise the time on a network of a few machines. They developed the very earliest rendition of NTP which has continued to be developed to this very day, nearly thirty years after its first inception.

NTP was not then, and is not now, the only time synchronisation software, there are other applications and protocol that do a similar task but NTP is the most widely used (by far with over 98% of time synchronisation applications using it). It is also packaged with most modern operating systems with a version of NTP (usually SNTP – a simplified version) installed on the latest Windows 7 operating system.

NTP has played an important part in creating the internet we know and love today. Many online applications and tasks would not be possible without accurate time synchronization and NTP.

Online trading, internet auctions, banking and debugging of networks all rely on accurate time synchronisation. Even sending an email requires time synchronisation with email server – otherwise computers would not be able to handle emails coming from unsynchronised machines as they may arrive before they were sent.

NTP is a free software protocol and is available online from NTP.org However, most computer networks that require secure and accurate time mostly use dedicated NTP servers that operate external to the network and firewall obtaining the time from atomic clock signals ensuring millisecond accuracy with the world’s global timescale UTC (Coordinated Universal Time).

Choosing a Time Server for your Network

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Any network administrator will tell you how important time synchronization is for a modern computer network. Computers rely on the time for nearly everything, especially in today’s age of online trading and global communication where accuracy is essential.

Failing to ensure that computers are accurately synced together could lead to all manner of problems: data loss, security vulnerabilities, unable to conduct time sensitive transactions and difficulties debugging can all be caused by a lack of, or not adequate enough, time synchronization.

But ensuring every computer on a network has the exact same time is simple thanks to two technologies: the atomic clock and the NTP server (Network Time Protocol).

Atomic clocks are extremely accurate chronometers. They can keep time and not drift by as much of a second in thousands of years and it is this accuracy that has made possible technologies and applications such as satellite navigation, online trading and GPS.

Time synchronization for computer networks is controlled by the network time server, commonly referred to as the NTP server after the time synchronization protocol they use, Network Time Protocol.
When it comes to choosing a time server, there are really only two real type – the radio reference NTP time server and the GPS NTP time server.

Radio reference time servers receive the time from long wave transmission broadcast by physics laboratories like NIST in North America or NPL in the UK. These transmissions can often be picked up throughout the country of origin (and beyond) although local topography and interference from other electrical devices can interfere with the signal.

GPS time servers, on the other hand, use the satellite navigation signal transmitted from GPS satellites. The GPS transmissions are generated by atomic clocks onboard the satellites so they are a highly accurate source of time just like the atomic clock generated time broadcast by the physics laboratories.

Apart from the disadvantage of having to have a roof top antenna (GPS works by line of sight so a clear view of the sky is essential), GPS is obtainable literally everywhere on the planet.

As both types of time server can provide an accurate source of reliable time the decision of which type of time server should be based on the availability of long wave signals or whether it is possible to install a rooftop GPS antenna.