The Global Positioning System’s intended function is to provide a global system for location and navigation. It is primarily aimed at marine navigation, although it is also commonly used in consumer car sat-nav appliances. However, GPS Time Servers are a fundamental part of today’s internet infrastructure and also many corporate networks. They synchronize the processes and functions required to keep the internet and networks working smoothly and orderly. GPS time synchronization is essentially what keeps the internet ticking.
The GPS system is a satellite based system. It consists of a constellation of orbitting satellites. There are 24 satellites in total, positioned at critical locations above the Earth to provide complete coverage of the surface of the Earth. The systems primary function is location and navigation, but in order to aceive this, each satellite has an integrated gps atomic clock to provide very precise time. This precise time can be received by ntp servers using a GPS antenna and receiver to provide networks with an accurate time reference. A GPS receiver can synchronize it’s internal clock to with in a few nanoseconds of the correct time. However, with the introduction of electronic and operating system latencies, typically, the accuracy of network time clients is to within a few milliseconds of UTC.
TimeTools SR series NTP network time servers utilize the GPS system as an accurate time reference. It maintains an internal time that is closely synchronized to GPS. It can the provide an accurate time stamp to many thousands of client computers and other network devices using the Network Time Protocol. NTP is the primary means of disseminating accurate time around the internet and other networks. Almost all modern operating systems have either a NTP or SNTP (Simple Network Time Protocol) client. Additionally, networked devices such as routers, switches, CCTV cameras and DVR’s can also obtain accurate time. This is often important where a legally traceable time is required for evidence or data logging purposes.
UTC Time and Leap Seconds
Each GPS satellite in the constellation incorporates a highly-accurate atomic clock, which is synchronized to a reference clock at the US National Institute of Standards (NIST). The satellites are synchronized to what is known as GPS time. GPS time does not account for leap seconds and is therefore a number of seconds ahead of UTC time. As of May 2014, the difference between GPS time and UTC is 16 seconds. A UTC time server may utilize GPS to obtain accurate time, but it also needs to make a correction to account for leap seconds. The current difference between GPS and UTC is provided by the GPS system. Leap seconds are introduced to account for changes in speed of rotation of the earth. Periodically, a leap second is introduced at the end of a year to keep UTC time close to the solar mean.
A GPS Reference Clock For an Accurate Display of Time
TimeTools GPS Time Clock is a time display that shows very accurate time. It’s time is legally traceable back to a known accurate source – the GPS system. The time display synchronizes to an atomic clock server over an Ethernet network using the NTP protocol. Periodically the clocks request time from a server and update an internal real-time clock. The synchronized real-time clock is then used to display accurate time using either a large LED or analog clock face. A single GPS time server can act as a reference for a large number of clocks. In this manner the price of a typical system can be kept as low as possible.