Posts by: Richard N Williams

The Truth about Time

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As a manufacturer of NTP time servers, synchronizing computer networks and keeping them accurate to within a few milliseconds of international UTC time (Coordinated Universal Time), we often think we can keep pretty good track of time.

Time, however, is quit elusive and is not the fixed entity we often assume it is, indeed time, and the time told on Earth is not constant and is affected by all sorts of things.

Since Einstein’s famous equation, E=MC2 it has been acknowledged that time is not constant, and that the only constant in the universe is the maximum velocity of light. Time, as Einstein discovered, is affected by gravity, making the time on Earth run slightly slower than time in deep space, likewise, on planetary bodies with a larger mass than Earth, time runs even slower.

Time slows down when you approach very fast speeds too. The property of time, known as time dilation, was discovered by Einstein and means that at close to the speed of light, time almost stands still (and makes interstellar travel a possibility for science fiction writers).

Generally, living on Earth, these differences in time are not felt, and indeed the slowing of time caused by Earth’s gravity is so minute, highly precise atomic clocks are required to measure it.

However, the time we use to govern our lives is also affected by other factors. Since humans first evolved, we have been used to a day lasting just over 24 hours.  However, the length of a day on Earth is not fixed, and has been changing for the last few billion years.

Each day on Earth differs from the previous to the next one. Often these differences are minute, but year on year, the changes add up as the affect of the moon’s gravity and tidal forces act as a brake on the Earth’s spin.

To cope with this, the global timescale UTC (Coordinated Universal Time) has to be adjusted to prevent the day from drifting out of sync (and we end up with noon at night and midnight during the day—although at the current slowing of the Earth, this would take many thousands of years).

The adjustment in our time is known as leap seconds which are added either once or twice a year to UTC. Anybody using a NTP time server (Network Time Protocol) to synchronise their computer network too, needn’t worry, however, as NTP servers will automatically account for these changes.

Our Time and Travel Reliance on GPS

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Since the Global Positioning System (GPS) first became available for civilian use in the early 1990’s, it has become one of the most commonly used modern pieces of technology. Millions of motorists use satellite navigation, while shipping and airline industries are heavily dependent on it.

And its not just wayfinding that we use GPS for, many technologies from computer network to traffic lights, to CCTV cameras, use the GPS satellite transmissions as a method of controlling time—using the onboard atomic clocks to synchronise these technologies together.

While plenty of advantages to using GPS for both navigation and time synchronisation exist, it’s accurate in both time and positioning and is available, literally everywhere on the planet with a clear view to the sky. However, a recent report by the Royal Academy of Engineering this month has warned that the UK is becoming dangerously dependent on the USA run GPS system.

The report suggests that with so much of our technology now reliant on GPS such as road, rail and shipping equipment, there is a possibility that any loss in GPS signal could lead to loss of life.

And GPS is vulnerable to failure. Not only can GPS satellites be knocked out by solar flares and other cosmological phenomenon, but GPS signals can be blocked by accidental interference or even deliberate jamming.

If the GPS system does fail then navigation systems could become inaccurate leading to accidents, however, for technologies that use GPS as a timing signal, and these range from important systems at air traffic control, to the average business computer network, then fortunately, things should not be that disastrous.

This is because GPS time servers that receive the satellite’s signal use NTP (Network Time Protocol). NTP is the protocol that distributes the GPS time signal around a network, adjusting the system clocks on all the devices on the network to ensure they are synchronised. However, if the signal is lost, then NTP can still remain accurate, calculating the best average of the system clocks. Consequently if the GPS signal does go down, computers can still remain accurate to within a second for several days.

For critical systems, however, where extremely precise time is required constantly, dual NTP time servers are commonly used. Dual time servers not only receive a signal from GPS, but also can pick-up the time standard radio transmissions broadcast by organisations such as NPL or NIST.

A Galleon Systems NTP GPS Time Server

Importance of Atomic Clock Time Sources for Technology

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Timekeeping and accuracy is important in the running of our day-to-day lives. We need to know what time events are occurring to ensure we don’t miss them, we also need to have a source of accurate time to prevent us from being late; and computers and other technology are just as reliant on the tine as we are.

For many computers and technical systems, the time in the form of a timestamp is the only tangible thing a machine has to identify when events should occur, and in what order. Without a timestamp a computer is unable to perform any task—even saving data is impossible without the machine knowing what time it is.

Because of this reliance on time, all computer systems have in-built clocks on their circuit boards. Commonly these are quartz based oscillators, similar to the electronic clocks used in digital wrist watches.

The problem with these system clocks is that they are not very accurate. Sure, for telling the time for human purposes they are precise enough; however, machines quite often require a higher level of accuracy, especially when devices are synchronised.

For computer networks, synchronisation is crucial as different machines telling different times could lead to errors and failure of the network to perform even simple tasks. The difficult with network synchronisation is that the system clocks used by computers to keep time can drift. And when different clocks drift by differing amounts, a network can soon fall into disarray as different machines keep different times.

For this reason, these system clocks are not relied on to provide synchronisation. Instead, a far more accurate type of clock is used: the atomic clock.

Atomic clocks don’t drift (at least not by more than a second in a million years) and so are ideal to synchronise computer networks too. Most computers use the software protocol NTP (Network Time Protocol) which uses a single atomic clock time source, either from across the internet, or more securely, externally via GPS or radio signals, in which it synchronises every machine on a network to.

Because NTP ensures each device is kept accurate to this source time and ignores the unreliable system clocks, the entire network can be kept synchronised to with each machine within fractions of a second of each other.

How GPS Keeps Clocks Accurate

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While many of us are aware of GPS (Global Positioning System) as a navigational tool and many of us have ‘sat navs’ in our cars, but the GPS network has another use that is also important to our day-to-day lives but few people realise it.

GPS satellites contain atomic clocks which transmit to earth an accurate time signal; it is this broadcast that satellite navigation devices use to calculate global position. However, there are other uses for this time signal besides navigation.

Nearly all computer networks are kept accurate to an atomic clock. This is because miniscule accuracies across a network can lead to until problems, from security issues to data loss. Most networks use a form of NTP (Network Time Protocol) to synchronise their networks, but NTP requires a main time source to sync to.

GPS is ideal for this, not only is it an atomic clocks source, which NTP can calculate UTC (Coordinated Universal Time) from, which means that the network will be synchronised to every other UTC network on the globe.

GPS is an ideal source of time as it is available literally everywhere on the planet as long as the GPS antenna has a clear view of the sky. And it is not only computer networks that require atomic clock time, all sorts of technologies require accurate synchronisation: traffic lights, CCTV cameras, air traffic control, internet servers, indeed many modern applications and technology without us realising is being kept true by GPS time.

Top use GPS as a source of time, a GPS NTP server is required. These connect to routers, switches or other technology and receive a regular time signal from the GPS satellites. The NTP server then distributes this time across the network, with the protocol NTP continually checking each device to ensure it is not drifting.

GPS NTP servers are not only accurate they are also highly secure. Some network administrators use internet time servers as a source of time but this can lead to problems. Not only is the accuracy of many of these sources questionable, but the signals can be hijacked by malicious software which can breach the network firewall and cause mayhem.

Keeping a Windows 7 Network Secure, Reliable and Accurate

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Many modern computer networks are now running Microsoft’s latest operating system Window 7, which has many new and improved features including the ability to synchronise time.

When a Windows 7 machine is booted up, unlike previous incarnations of Windows, the operating system automatically attempts to synchronise to a time server across the internet to ensure the network is running accurate time. However, while this facility is often useful for residential users, for business networks it can cause many problems.

Firstly, to allow this synchronisation process to happen, the company firewall must have an open port (UDP 123) to allow the regular time transference. This can cause security issues as malicious users and bots can take advantage of the open port to penetrate into the company network.

Secondly, while the internet time servers are often quite accurate, this can often depend on your distance from the host, and any latency caused by network or internet connection can further cause inaccuracies meaning that you system can often be more than several seconds away from the preferred UTC time (Coordinated Universal Time).

Finally, as internet time sources are stratum 2 devices, that is they are servers that do not receive a first-hand time code, but instead receive a second hand source of time from a stratum 1 device (dedicated NTP time server – Network Time Protocol) which also can lead to inaccuracy – these stratum 2 connections can also be very busy preventing your network from accessing the time for prolonged periods risking drifting.

To ensure accurate, reliable and secure time for a Windows 7 network, there is really no substitute than to use your own stratum 1 NTP time server. These are readily available from many sources and are not very expensive but the peace of mind they provide is invaluable.

Stratum 1 NTP time servers receive a secure time signal direct from an atomic clock source. The time signal is external to the network so there is no danger of it being hijacked or any need to have open ports in the firewall.

Furthermore, as the time signals come from a direct atomic clock source they are very accurate and don’t suffer any latency problems. The signals used can be either through GPS (Global Positioning System satellites’ have onboard atomic clocks) or from radio transmissions broadcast by national physics laboratories such as NIST in the USA (broadcast from Colorado), NPL in the UK (transmitted form Cumbria) or their German equivalent (from Frankfurt).

How the Moon Affects Time on Earth

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We take it for granted that a day is twenty-four hours. Indeed, our body’s circadian rhythm is finally tuned to cope with a 24-hour-day. However, a day on Earth was not always 24 hours long.

In the early days of the Earth, a day was incredibly short – just five hours long, but by the time of the Jurassic period,  when dinosaurs roamed the Earth, a day had lengthened to about 22.5 hours.

Of course now, a day is 24-hours and has been since humans evolved, but what has caused this gradual lengthening. The answer lies with the Moon.

The moon used to be a lot closer to the Earth and the effect of its gravity was therefore, a lot stronger. As the moon drives tidal systems, these were a lot stronger in the early days of the Earth, and the consequence was that the Earth’s spin slowed, the tugging of the moon’s gravity and tidal forces on the Earth, acing like a brake on the rotation of the planet.

Now the moon is farther away, and is continuing to move away even farther, however the effect of the moon is still felt on Earth, with a consequence that Earth’s day is still slowing down, albeit minutely.

With modern atomic clocks, it is now possible to account for this slowing and the global timescale used by most technologies to ensure time synchronisation, UTC (Coordinated Universal Time), has to account for this gradual slowing, otherwise, because of the extreme accuracy of atomic clocks, eventually day would slip into night as the Earth slowed and we didn’t adjust our clocks.

Because of this, once or twice a year, an extra second is added to the global timescale. These leap-seconds, as they are known, have been added since the 1970’s when UTC was first developed.

For many modern technologies where millisecond accuracy is required, this can cause problems. Fortunately, with NTP time servers (Network Time Protocol) these leap seconds are accounted for automatically, so any technologies hooked up to an NTP server need not worry about this discrepancy.

NTP servers are used by time sensitive technology and computer networks worldwide to ensure precise and accurate time, all the time, regardless of what the heavenly bodies are doing.

Press Release: Galleon Systems Launch New Website

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Atomic clock and NTP server specialists, Galleon Systems, have relaunched their website providing an improved platform to showcase their wide range of time synchronisation and network time server products.

Galleon Systems, who have been providing atomic clock and time server products to industry and commerce for over a decade, have redesigned their website to ensure the company continues to be world leaders in providing accurate, secure and reliable time synchronisation products.

With detailed descriptions of their product range, new product pictures and a revamped menu system to provided better functionality and user experience, the new website includes all of Galleons extensive range of NTP server systems (Network Time Protocol) and atomic clock synchronisation products.

Time servers from Galleon Systems are accurate to within a fraction of a second and are a secure and reliable method of getting a source of atomic clock time for computer networks and technological applications.

Using either GPS or the UKs MSF radio signal (DSF in Europe WWVB in the USA), time servers from Galleon Systems can keep hundreds of devices on a network accurate to within a few milliseconds of the international timescale UTC (Coordinated Universal Time).

Galleon Systems product range includes a variety of NTP time servers that can receive either GPS or radio referenced signals, dual systems that can receive both, simple radio controlled atomic clock servers, and a range of large network digital and analogue wall clocks.

Manufactured in the UK, Galleon Systems have a wide range of NTP and time synchronisation devices used worldwide by thousands of organizations who need accurate, reliable and precise time. For more information please visit their new website: www.galsys.co.uk

How Atomic Clocks Control our Transport Systems

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Getting from A to B has been a primary concern for societies ever since the first roads were built. Whether it is horseback, carriage, train, car or plane – transportation is what enables societies to grow, prosper and trade.

In today’s world, our transportation systems are highly complex due to the sheer numbers of people who are all trying to get somewhere – often at similar times such as rush hour. Keeping the motorways, highways and railways running, requires some sophisticated technology.

Traffic lights, speed cameras, electronic warning signs, and railway signals and point systems have to be synchronised for safety and efficiency. Any differences in time between traffic signals, for instance, could lead to traffic queues behind certain lights, and other roads remaining empty. While on the railways, if points systems are being controlled by an inaccurate clock, when the trains arrive the system may be unprepared or not have switched the line – leading to catastrophe.

Because of the need for secure, accurate and reliable time synchronisation on our transport systems, the technology that controls them is often synchronised to UTC using atomic clock time servers.

Most time servers that control such systems have to be secure so they make use of Network Time Protocol (NTP) and receive a secure time transmission either utilising atomic clocks on the GPS satellites (Global Positioning System) or by receiving a radio transmission from a physics laboratory such as NPL (National Physical Laboratory) or NIST (National Institute of Standards and Time).

In doing so, all traffic and rail management systems that operate on the same network are accurate to each other to within a few milliseconds of this atomic clock generated time and the NTP time servers that keep them synchronised ensures they stay that way, making minute adjustments to each system clock to cope with the drift.

NTP servers are also used by computer networks to ensure that all machines are synced together. By using a NTP time server on a network, it reduces the probability of errors and ensures the system is kept secure.

Origin of Synchronisation (Part 2)

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Continued…

Most towns and cities would have a main clock, such as Big Ben in London, and for those living near-by, it was fairly easy to look out the window and adjust the office or factory clock to ensure synchronicity; however, for those not in view of these tower clocks, other systems were used.

Commonly, somebody with a pocket watch would set the time by the tower clock in the morning and then go around businesses and for a small fee, let people know exactly what the time was, thus enabling them to adjust the office or factory clock to suit.

When, however, the railways began, and timetables became important it was clear a more accurate method of time keeping was needed, and it was then that the first official time-scale was developed.

As clocks were still mechanical, and therefore inaccurate and prone to drift, society again turned to that more accurate chronometer, the sun.

It was decided that when the sun was directly above a certain location, that would signal noon on this new time-scale. The location: Greenwich, in London, and the time-scale, originally called railway time, eventually became Greenwich Meantime (GMT), a time-scale that was used until the 1970’s.

Now of course, with atomic clocks, time is based on an international time-scale UTC (Coordinated Universal Time) although its origins are still based on GMT and often UTC is still referred to as GMT.

Now with the advent of international trade and global computer networks, UTC is used as the basis of nearly all international time. Computer networks deploy NTP servers to ensure that the time on their networks are accurate, often to a thousandth of a second to UTC, which means all around the world computers are ticking with the same accurate time – whether it is in London, Paris, or New York, UTC is used to ensure that computers everywhere can accurately communicate with each other, preventing the errors that poor time synchronisation can cause.

Origin of Synchronisation (Part 1)

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Part One

With modern NTP servers (Network Time Protocol) synchronisation is made easy. By receiving a signals from GPS or radio signals such as MSF or WWVB, computer networks consisting of hundreds of machines can easily be synchronised together, ensuring trouble free networking and accurate time-stamping.

Modern NTP time servers are reliant on atomic clocks, accurate to billions of parts of a second, but atomic clocks have only been around for the last sixty years and synchronisation has not always been so easy.

In the early days of chronology, clocks mechanical in nature, were not very accurate at all. The first time-pieces could drift by up to an hour a day so the time could differ from town clock to town clock, and most people in the agricultural based society regarded them as a novelty, relying in stead on sunrise and sunset to plan their days.

However, following the industrial revolution, commerce became more important to society and civilisation, and with it, the need to know what the time was; people needed to know when to go to work, when to leave and with the advent of railways, accurate time became even more crucial.

In the early days if industry, workers were often woken for work by people paid to wake them up. Known as ‛knocker-uppers.’ Relying on the factory time-peice, they would go around town and tap on people’s windows, alerting them to the start of the day, and the factory hooters signalled the beginning and end of shifts.

However, as commerce developed time became even more crucial, but as it would take another century or so for more accurate timepieces to develop (until at least the invention of electronic clocks), other methods were developed.

To follow…