Search:

Home | Internet


Computer Time Synchronisation Using GPS

By: David Evans

GPS is a US military system designed for navigation and precise positioning. It consists of 24 earth-orbiting satellites, each with an on-board atomic clock. Accurate time combined with triangulation from a number of satellites can provide precise positioning anywhere on the globe. However, the precise timing information supplied by GPS can also be used for time and frequency applications such as computer network time synchronisation. This article discusses how the Global Positioning System can be utilised by GPS NTP server systems to provide precise network synchronisation. Additionally, it describes the equipment required in order to receive accurate time from the GPS system and to synchronise computer time.

Time is reverenced to UTC time, which does not vary with timezones, local time is calculated from UTC. The GPS satellites continuously transmit precise time information. GPS time is currently 14 seconds ahead of UTC and is not adjusted for leap seconds. GPS time can easily be adjusted to provide UTC time for computer network time synchronisation. The GPS satellites broadcast a very weak low-power radio signal. The signal has two frequencies, L1 and L2. L1 is intended as a civilian GPS band broadcast at 1575.42 MHz. L2 should provide stronger signal transmissions in the future. The signal travels in a straight line and can pass through clouds, glass and plastics but is blocked by objects such as metal and brickwork. Therefore, ideally, a GPS antenna requires a good view of the sky. The ideal location for a GPS antenna is on rooftop with a good view of the sky. Often, antenna installation on the side of a building or in a window can provide a good enough view of the sky to give adequate results.

The GPS system provides a subscription-free accurate timing resource. Many computer networks utilise the GPS clock as an accurate timing reference for computer synchronisation. Precise GPS NTP server systems utilise GPS reference clocks as an external synchronisation source. The GPS system can supply highly precise time and frequency information accurate to a couple of nanoseconds. This accuracy is generally more than enough for most computer network timing applications.

Most GPS receivers transmit time and positioning information in a serial format using the standard NMEA protocol. Information is transmitted as sentences of character strings. Also, a precise pulse output is generated which indicates the start of each second. This timing pulse can be converted to a RS232 signal level and fed into a RS232 control line interrupt to provide a precise timing reference. When the timing pulse is combined with the NMEA output sentences, a very accurate timing reference becomes available for use by NTP servers or computer timing equipment.

Article Source: http://www.newagelivingarticles.com

Dave Evans provides a technical authoring service to the time and frequency and network time synchronisation industries. Click here for more information on GPS NTP Servers.

Please Rate this Article

 

Not yet Rated

Click the XML Icon Above to Receive Internet Articles Via RSS!
Additional Articles From - Home | Internet

 Free Traffic


banner











Sign Up for a free account or learn more.
Article Directory Software
Click here to download the exact software that powers this directory for FREE. Start your own article directory today!
Google
Top Authors
Submit Articles
Member Login
Most Popular Articles
Submission Guidelines
Ezine Notifications
Article RSS Feeds
Little Book Of Becoming
Masters of the Secret
The Singularity Is Near
Distribute Your Articles to 1000's!
Wildwind Enterprises
Bookstore
About Us
Link to Us
Contact Us
Privacy Policy
Terms of Service
Links
All Links Directory All Links Directory is 100% SEO friendly Directory and Human Edited.

Accurate Online Psychic Readings Lilly provides a unique personal empowerment, spiritual approach to intuitive readings, as well as a vast array of other resources for the spiritual seeker. Access your Spiritual Guidance and turn negative karma into spiritual gold!

Psychic Sights An extensive portal of Psychic links, Metaphysical and New Age links and resources focused on quality.

Earth Spirits.org

Gaiam.com, Inc
Spiritual Cinema Circle
Visit the metaphysical directory for a complete list of metaphysics related websites.
Royalty Free Images
NewAgeLivingArticles.com » Copyright © 2007 WildWind Enterprises
Terms of Service | Submission Guidelines | Contact Us | Link to Us| Privacy Policy | About Us | Article Submissions With A Click 100's of Sites!

Powered by Article Dashboard