Because of the advancement in satellite navigation technologies and the increased coverage of the American GPS satellite network, many more administrators are choosing GPS as a source for a timing reference to synchronize their time servers too.
Traditionally many more people opted to receive a timing source from either across the Internet or via specialist national time and frequency transmissions. However, the Global Positioning System is now by far the most popular method to receive a UTC time source from.
UTC (Coordinated Universal Time) is the global timescale based on the time told by atomic clocks which are the most accurate of time keeping devices.
A GPS time server is a relatively simple piece of hardware. Normally it consists of a dedicated NTP server with software, a GPS receiver and a GPS antenna. The antenna is the only drawback in using a dedicated GPS time server as it has to be positioned on the roof to have a clear view of the sky, although some dedicated GPS time servers can still keep time synchronized if they only receive a signal for a few hours a day, although this is not the most accurate way of time synchronization.
Once connected, the GPS time server will receive the time signal from the GPS satellites and then distribute it to all devices that require synchronization.
Most time servers, whether they receive a GPS signal or not, will use Network Time Protocol (NTP) to distribute the time signal to all devices.
NTP is one of the Internet’s oldest protocols and is by far the most widespread time synchronization protocols used. NTP is under constant development and can accurately synchronise a network to within a few milliseconds of UTC time via a dedicated GPS time server.