Often we find our personal computers don't show the right time even if we correct it. In order to fix this problem the GPS clock can be used in the computers or computer networks. The GPS system is used for computer timing applications for examples the NTP time servers and it is also used for accurate timing reference. The GPS or the global positioning system is first developed by the US military system with the objective to use for global navigation. This system is famous for providing accurate positioning information for navigation. The GPS system made from a constellation of 24 orbiting satellites. As each of the satellite has an on-board atomic clock, the GPS system provides highly accurate timing reference. The GPS clock provides right time with a certain way as follows.

The GPS system continuously broadcasts the GPS time where the time is referred to Universal Coordinated Time (UTC) which always remains same throughout the world and does not alters with the time zone. With some relatively low-cost equipment like the GPS receiver and antenna, the GPS timing can be received. The GPS signal is nothing but a very weak low power radio signal with two designated frequencies L1 and L2. The signal is transmitted at 1575.42 MHz and travels in a straight line and can pass through clouds, glass and plastics but is blocked by objects such as metal and brickwork. For this signals you have to place the antenna in the roof top in order to get good results.

Through the GPS system you can get the free-to-air time synchronization service and you don't have to pay set up or subscription charges. That's why many computer systems use the GPS clock for accurate time reference. With the GPS system you can get timing information to within a few nanoseconds of UTC. For the computer systems and networks this is a perfect timing application that they get from the GPS receiver.

The GPS receiver output helps to receive the output position and timing information via a RS232 serial interface. Some standard GPS interface protocol exists like the NMEA which consists of sentences, or character strings that are transmitted at 4800 bits per second. The GPS antenna is a signal amplifier which helps boost the GPS signal for transmission from the cable to receiver. In general they are small in size approximately 900 mm in diameter. The cable distance used for the GPS antenna and receiver and mostly depends on the amplification of the GPS antenna and the quality of the coax used in the installation.