How Atomic Clocks Control our Transport Systems
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.
