Use,GPS,for,Computer,Timing,Ap computer Use of GPS for Computer Timing Applications
----------------------------------------------------------Permission is granted for the below article to forward,reprint, distribute, use for ezine, newsletter, website,offer as free bonus or part of a product for sale as longas no changes a Gone are those times when the companies and the organisations didn't need a hi-tech system to handle them. Owing to the considerable increase in the business sector and thus, an enormous increase in the complexity of the organisational struc
The GlobalPositioning System (GPS) is now a familiar tool in helping motorists tonavigate but GPS has more uses than merely triangulating a position fordirection finding, it can be utilized to provide time and frequency informationworldwide.Developed by theUnited States military, GPS incorporates at least 24 communication satellitesin high orbit, all of which contain precise timing equipment to enable thesatellite to triangulate positions with accuracy.However, eachsatellites highly accurate atomic clock timing reference can also be used byNTP (Network Time Protocol) servers to synchronise computer networks using thehighly accurate GPS time signal as an external reference. GPS is an idealtime and frequency source because it can provide highly accurate time anywherein the world using relatively cheap components. EachGPS satellite transmits in two frequencies L2 for the military use and L1 foruse by civilians transmitted at 1575 MHz, Low-cost GPS antennas and receiversare now widely available, see herefor more information.The radio signaltransmitted by the satellite can pass through windows but can be blocked bybuildings so the ideal location for a GPS antenna is on a rooftop with a goodview of the sky. The more satellites it can receive from the better the signal.However, roof-mounted antennas can be prone to lighting strikes or othervoltage surges so a suppressor is recommend; installed inline on the GPS cable.The cable betweenthe GPS antenna and receiver is also critical. The maximum distance that acable can run is normally only 20-30 metres but a high quality coax cablecombined with a GPS amplifier placed in-line to boost the gain of the antennacan allow in excess of 100 metre cable runs.A GPS receiverthen decodes the signal sent from the antenna to a computer readable protocolwhich can be utilised by most time servers and operating systems including,Windows, LINUX and UNIX. The GPS receiveralso outputs a precise pulse every second that GPS NTP servers and computertime servers may utilise to provide ultra-precise timing. The pulse-per-secondtiming on most receivers is accurate to within 0.001 of a second of UTC (CoordinatedUniversal Time or Temps Universel Coordonné).GPS is ideal inproviding NTP time servers or stand-alone computers with a highly accurateexternal reference for synchronisation. Even with relatively low costequipment, accuracy of hundred nanoseconds (a nanosecond = a billionth of asecond) can be reasonably achieved using GPS as an external reference.
Use,GPS,for,Computer,Timing,Ap