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Global Positioning System Time Signals: Accuracy and Adjustment

written by: Kristina Dems•edited by: Amy Carson•updated: 4/30/2011

GPS time adjustment is done by synchronizing the time between a GPS device and another electronic device. GPS time acts as a base for time adjustments in different devices because of its accuracy.

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    GPS Satellite GPS, or Global Positioning System, is used by all kinds of industries and individuals all around the work for different kinds of location based uses and navigation tasks. However, determining location is not the only use for GPS signals and devices. GPS uses time signals to determine accuracy and precision of location information, which means GPS receivers are capable of having a very accurate time base that can be used to provide accurate time for other applications like computers and other devices. This time adjustment can be done by synchronizing a GPS receiver with an electronic device like a computer or a digital clock.

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    How It Works

    GPS satellites carry several atomic clocks that are synchronized. By working together, this system of GPS satellites provide an accurate time signal that can be used to determine positional information for navigation and an accurate time base. Time transfer errors can be encountered but current studies are being done to improve the accuracy of GPS time by using different techniques like ion trapping and the cesium fountain.

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    One of the most common applications of adjustment via GPS time signals is achieving an accurate time for a computer. Personal computers used for recreation do not require accurate time, but sensitive systems like those used in different industries in the fields of science, engineering and other time-sensitive fields require a very accurate time base. Synchronizing time between a computer and a GPS receiver is one of the easiest ways of acquiring an accurate time base for a computer so it is gaining popularity among the different fields. All that needs to be done by users is connect a GPS receiver or a GPS device to a computer and have the right software to have the time sync between the two pieces of electronics.

    GPS time signals are also used to synchronize the time on mobile devices like cell phones and PDAs. For mobile devices that support GPS, they can receive GPS location signals and GPS time signals and that is what the devices use to synchronize their time. This kind of time synchronization is not very common among regular citizens but it can be very useful for professionals.

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    The accuracy of GPS time varies between GPS devices. At least four satellites need to be seen by a GPS device to achieve an accurate reading of time. Different GPS receivers can get signals from different numbers of satellites so the accuracy of the time signals they get vary too. This is why when you compare the time accuracy of different GPS devices, you can sometimes see variations that can be very minor or very large. Accuracy can also vary for a single GPS receiver because of variance of several factors like weather conditions that can interfere with GPS signals from some satellites.

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    GPS time adjustment will always depend on the accuracy of a GPS receiver so you can’t expect all GPS devices to provide the same accuracy when adjusting the time of your electronic device using GPS time.

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    GPS Primer,


    Photo Courtesy of Wikimedia Commons / Supplied by NOAA