Why do I need a time server when I can get time from the internet?

Time information is available from the internet, but this means allowing data to travel through your firewall, increasing the potential risk of hackers or viruses obtaining access into your network. Also, there are few or no guarantees that the information being provided is accurate or reliable.

What is a time server?

Network time servers synchronise all the time data on a computer network.

  • Accurate & reliable time data from a trusted source.
  • Control over configuration.
  • Synchronicity between users – eradicates discrepancies.
  • System time stamping (e.g. for e-commerce transactions, e-mail sent & receive, etc) is accurate.
  • Automatic systems procedures, such as backups, occur at the correct time and in the correct order.
  • Automatic updating so no need for manual intervention at all.
What is the difference between GPS and GNSS ?

GNSS stands for Global Navigation Satellite System, and is the standard generic term for satellite navigation systems that provide autonomous geo-spatial positioning with global coverage. This term includes e.g. the GPS, GLONASS, Galileo, Beidou and other regional systems (see below).

The term GPS is specific to the United States' GNSS system, the NAVSTAR Global Positioning System. As of 2013, the United States NAVSTAR Global Positioning System (GPS) and the Russian GLONASS are the only fully operational GNSS, and accordingly account for the bulk of UNAVCO's available equipment and project support.

GLONASS is a Russian GNSS, and is included in many UNAVCO Development and Testing projects. GNSS systems currently in various stages of development and deployment include Galileo, the European Union's positioning system; IRNSS, India's next generation regional system;QZSS, the Japanese regional system, and China's Beidou Global navigation satelite system.

What do I do if I am having GPS synchronization problems?

If after following the checklist below you still have synchronisation problems, please do not hesitate to contact us.
1. Check antenna is plugged into the receiving equipment.
2. Check if antenna is installed as per instruction.
3. Check if antenna is getting power by checking the red amber light at the bottom edge of GPS4500 antenna.
4. Check that there are no high frequency electrical interference sources near to the antenna.
5. Check antenna integrity, i.e. no water ingress, lightning strikes or perished cable.
6. Allow sufficient time for synchronisation to occur – this could take minimum of 30 minutes for a cold-start or 5-10 minutes for a warm start.
7. Ensure maximum sky coverage available for antenna by mounting on a roof or similar.
8. Check the maximum length of cable has not been exceeded or that the minimum cable length has been adhered to.
9. Use the manual to understand what the indicators on the equipment mean. Usually these indicators are useful for locating faults.

How do I know when I have synchronized to GPS?

All GPS receivers require at least 3-4 GPS satellites to compute a position and obtain a time offset in the receiver clock. The synchronization can be checked on the front panel through LED indication as well as can be checked on the display.

Can I use my GPS antenna inside ?

No. To receive GPS information, the antenna must be located outside. It will not work inside buildings. The best location for your antenna is as high as possible (e.g. on a roof or mast) with the antenna in clear view of the sky and away from any sources of possible high frequency electrical interference.


How does GPS work?

All GPS satellites have atomic clocks, which provide time data that is broadcast on a high frequency. The user’s receiver picks up information from at least four satellites simultaneously, which then measures the time delay for the signal to reach the receiver. This data is then converted into very precise position and time information.

What is GPS ?

The GPS (Global Positioning System) was the first GNSS, developed and operated by the United States Department of Defense, and was originally called NAVSTAR. This system was put into operation, in a development mode, in the 1980s and became fully operational in 1993. In addition to precise position anywhere in the world, the GPS system provides a free, civilian timing signal with accuracy that is now better than 10 nanoseconds.
The GPS system consists of at least 24 satellites (the ‘space segment’) and a set of receivers on the earth (the ‘control segment’).

What is reference clock?

reference clock is some device or machinery that spits out the current time. The special thing about these things is accuracy: Reference clocks must be accurately following some time standard.Typical candidates for reference clocks are (very expensive) cesium clocks. Cheaper (and thus more popular) ones are receivers for some time signals broadcasted by national standard agencies. A typical example would be a GPS (Global Positioning System) receiver that gets the time from satellites. These satellites in turn have a cesium clock that is periodically corrected to provide maximum accuracy.Less expensive (and accurate) reference clocks use one of the terrestrial broadcasts known as DCF77MSF, and WWV.

In NTP these time references are also named stratum 0, the highest possible quality. (Each system that has its time synchronized to some reference clock can also be a time reference for other systems, but the stratum will increase for each synchronization.)

What is Time Synchronization?

Time synchronization a problem from computer science and engineering and in daily life which deals with the idea that internal clocks of several computers and display clocks may differ. Even when initially set accurately, real clocks will differ after some amount of time due to clock drift, caused by clocks counting time at slightly different rates.
Time synchronization is the idea to make the clocks on different computers, servers etc to agree with each other.