Quantum Atomic Clocks The precision of the future

  |   By

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.

Atomic Clocks Now Doubled in Precision

  |   By

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 Atomic Clock Scientific Precision

  |   By

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).

UTC What Time is it?

  |   By

From the early days of the industrial revolution, when railway lines and the telegraph spanned across time zones it became apparent that a global timescale was required that would allow the same time to be used no matter where you were in the world.

The first attempt at a global timescale was GMT – Greenwich Meantime. This was based on the Greenwich Meridian where the sun is directly above at 12 noon. GMT was chosen, primarily because of the influence of the British empire on the rest if the globe.

Other timescales had been developed such British Railway Time but GMT was the first time a truly global system of time was used throughout the world.

GMT remained as the global timescale through the first half of the twentieth century although people began referring to as UT (Universal Time).

However, when atomic clocks were developed in the middle of the twentieth century it soon became apparent that GMT was not accurate enough. A global timescale based on the time told by atomic clocks was desired to represent these new accurate chronometers.

International Atomic Time (TAI) was developed for this purpose but problems in using atomic clocks soon became apparent.

It was thought that the Earth’s revolution on its axis was an exact 24 hours. But thanks to atomic clocks it was discovered the Earth’s spin varies and since the 1970’s has been slowing. This slowing of the Earth’s rotation needed to be accounted for otherwise the discrepancies could build up and night would slowly drift in to day (albeit in many millennia).

Coordinated Universal Time was developed to counter this. Based on both TAI and GMT, UTC allows for the slowing of the Earth’s rotation by adding leap seconds every year or two (and sometimes twice a year).

UTC is now a truly global timescale and is adopted by nations and technologies across the globe. Computer networks are synchronised to UTC via network time servers and they use the protocol NTP to ensure accuracy.

Atomic Clocks the Key to Network Synchronisation

  |   By

Sourcing the correct time for network synchronisation is only possible thanks to atomic clocks. Compared to standard timing devices and atomic clock is millions of times more accurate with the latest designs providing accurate time to within a second in a 100,000 years.

Atomic clocks use the unchanging resonance of atoms during different energy states to measure time providing an atomic tick that occurs nearly 9 billion times a second in the case of the caesium atom. In fact the resonance of caesium is now the official definition of a second having been adopted by the International System of Unit (SI).

Atomic clocks are the base clocks used for the international time, UTC (Coordinated Universal Time). And they also provide the basis for NTP servers to synchronise computer networks and time sensitive technologies such as those used by air traffic control and other high level time sensitive applications.

Finding an atomic clock source of UTC is a simple procedure. Particularly with the presence of online time sources such as those provided by Microsoft and the National Institute for Standards and Time (windows.time.com and nist.time.gov).

However, these NTP servers are what are known as stratum 2 devices that mean they are connected to another device which in turn gets the time from an atomic clock (in other words a second-hand source of UTC).

While the accuracy of these stratum 2 servers is unquestionable, it can be affected by the distance the client is from the time servers, they are also outside the firewall meaning that any communication with an online time server requires an open UDP (User Datagram Protocol) port to allow the communication.

This can cause vulnerabilities in the network and are not used for this reason in any system that requires complete security. A more secure (and reliable) method of receiving UTC is to use a dedicated NTP time server. These time synchronisation devices receive the time direct from atomic clocks either broadcast on long wave by places like NIST or NPL (National Physical Laboratory – UK). Alternatively UTC can be derived from the GPS signal broadcast by the constellation of satellites in the GPS network (Global Positioning System).

Atomic Clock to be attached to International Space Station

  |   By

One of the world’s most accurate atomic clocks is to be launched into orbit and attached to the International Space Station (ISS) thanks to an agreement signed by the French space agency.

The PHARAO (Projet d’Horloge Atomique par Refroidissement d’Atomes en Orbite) atomic clock is to attached to the ISS in an effort to more accurately test Einstein’s theory of relatively as well as increasing the accuracy of Coordinated Universal Time (UTC) amongst other geodesy experiments.

PHARAO is a next generation caesium atomic clock with an accuracy that corresponds to less than a second’s drift every 300,000 years. PHARAO is to be launched by the European Space Agency (ESA) in 2013.

Atomic clocks are the most accurate timekeeping devices available to mankind yet they are susceptible to changes in gravitational pull, as predicted by Einstein’s theory, as time itself is slewed by the Earth’s pull. By placing this accurate atomic clock into orbit the effect of Earth’s gravity is lessened allowing PHARAO to be more accurate than Earth based clock.

While atomic clocks are not new to orbit, as many satellites; including the GPS network (Global Positioning System) contain atomic clocks, however, PHARAO will be among the most accurate clocks ever launched into space, allowing it to be used for far more detailed analysis.

Atomic clocks have been around since the 1960’s but their increasing development has paved the way for more and more advanced technologies. Atomic clocks form the basis of many modern technologies from satellite navigation to allowing computer networks to communicate effectively across the globe.

Computer networks receive time signals from atomic clocks via NTP time servers (Network Time Protocol) which can accurately synchronise a computer network to within a few milliseconds of UTC.

Auditable Time Synchronization with an NTP Server

  |   By

Time synchronization is crucial for many modern applications. Whilst computer networks all have to be running in perfect time to prevent errors and ensure security other systems require time synchronization for legal reasons.

Average speed cameras, traffic light cameras, CCTV, parking meters and alarm systems to name but a few, all require accurate time synchronization not just to ensure the correct operation of the systems but also to provide an auditable and legal trail for use in prosecutions.

Failure to do so can lead to the system being completely useless as any legal case based around the technology would need to be provable.

For instance, a CCTV network that is not synchronized would not be admissible in court, a defendant could easily claim that an image of them on a camera could not be them as they were not in the vicinity at the time and unless the camera system can be audited and proved to be accurate then reasonable doubt would see any case against the suspect dropped.

For this reason, systems like those mentioned above require complete auditable time synchronisation that can be proven beyond reasonable doubt in a court system.

An auditable system of time synchronization is only possible by using a dedicated NTP time server (Network Time Protocol). NTP servers not only provide an accurate method of synchronization being accurate to a few milliseconds they also provide a full audit trail that can’t be disputed.

NTP server systems use the GPS network or specialist radio transmissions to receive the atomic clock time which is so accurate the chance of it being even a second out from UTC time (Universal Coordinated Time) is over 3 billion to one which is even greater than the accuracy of other legal evidences such as DNA.

When Time is Money Accuracy Matters

  |   By

We live in a fast paced world where time matters. In some industries even a second can make all the difference. Millions of dollars are exchanged hands in the stock exchange each second and share prices can rise or plummet.

Getting the right price at the right time is essential for trading in such a fast paced money market and perfect network time synchronization is the essential to be able to make that happen.

Ensuring every machine that deals in stocks, shares and bonds has the correct time is vital if people are going to trade in the derivatives market but when traders are sat in different parts of the world how can this possibly be achieved.

Fortunately Coordinated Universal Time (UTC), a global timescale developed after the development of atomic clocks, allows the same time to govern every trader, regardless of where they are in the world.

As UTC is based on atomic clock time and is kept accurate by a constellation of these clocks, it is high reliable and accurate. And industries like the stock exchange use UTC to govern the time on their computer networks.

Computer network time synchronization is achieved in computer networks by using the NTP server (Network Time Protocol). NTP servers receive a source of UTC from an atomic clock reference. This is either from the GPS network or through specialist radio transmissions (it is available through the internet too but is not as reliable).

Once received, the NTP server distributes the highly accurate time throughout the network, continually checking each device and workstation to ensure the clock is as precise as possible.

These network time servers can keep entire networks of hundreds and thousands of machines in perfect synchronization – to within a few milliseconds of UTC!

Time Synchronization on Windows 7

  |   By

Windows 7, the latest operating system from Microsoft is also their first operating system that automatically synchronizes the PC clock to an internet source of UTC time (Coordinated Universal Time). From the moment a Windows 7 computer is switched on and is connected to the Internet it will request time signals from the Microsoft time service – time.windows.com.

While for many home users this will save them the hassle of setting and correcting their clock as it drifts, for business users it may be problematic as internet time sources are not secure and receiving a time source through the UDP port on the firewall could lead to security breaches and as Internet time sources can’t be authenticated by NTP (Network Time Protocol) the signals can be hijacked by malicious users.

This internet time source can be deactivated by opening the clock and date dialogue box, and opening the Internet Time tab, clicking the ’Change’ setting button and unchecking the ‘Synchronize with an Internet time server< option.’

Whilst this will unsure no unwanted traffic will be coming through your firewall it will also mean that the Windows 7 machine will not be synchronised to UTC and its timekeeping will be reliant on the motherboard clock, which will eventually drift.

To synchronize a network of Windows 7 machines to an accurate and secure source of UTC then the most practical and simplest solution is to plug in a dedicated NTP time server. These connect directly to a router or switch and enable the safe receiving of an atomic clock time source.

NTP time servers use the highly accurate and secure GPS signal (Global Positioning System) available everywhere on the planet or more localized long wave radio signals transmitted by several national physics laboratories such as NIST and NPL.

Why we Synchronize the Time

  |   By

We live and work in a totally different world to the one that many of us were born into. We are now as likely to buy something from across the internet as stroll down the coal high street. And big business and commerce has changed too with the marketplace becoming truly global and the internet being the most common tool for trade.

Trading globally does provide its problems though as different timescales govern the different countries across the globe. To ensure parity a global timescale was introduced in the 1970’s knows Coordinated Universal Time (UTC). However, as e-commerce advanced so did the need to ensure accurate synchronization to UTC.

The biggest problem is that most clocks and watches, including those inbuilt into computer motherboards, are susceptible to drift. And as different machines will drift at different rates, global communication and e-commerce could be impossible. Just think of the difference a second can make in marketplaces like the stock exchange, where fortunes are won or lost, or when you purchase seat reservations online, what would happen if somebody on a computer with slower clock booked the same seat after you, the computer’s timestamps will show the person booked before you.

Other unforeseen errors can result, even in internal networks, when computers are running different times. Data can get lost, errors can be difficult to log, track down and fix and malicious users can take advantage of the time confusion.

To ensure truly global synchronization, computer networks can synchronize to an atomic clock allowing all computers on a network o remain within a few milliseconds of UTC. Compute networks use NTP servers (Network Time Protocol) to ensure accurate synchronization, most NTP servers receive the atomic clock time from either GPS satellites of radio frequencies.