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How to Improve GPS Accuracy Levels

written by: Nanya•edited by: Rhonda Callow•updated: 3/26/2010

There are several techniques that can come in handy to improve the accuracy of GPS; let us take a look at the top 3 ways of improving GPS accuracy levels, and achieving unfathomable results, which are way beyond the normal limits.

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    With continuous progress in the field of technology, nobody is satisfied with mediocre performance and average accuracy in tracking levels. As such, researchers and tech geeks have come up with plenty of ways to improve GPS accuracy at optimal costs.

    The current accuracy levels are fairly high, as they allow you to track the precise location of an object within a distance of 4-20 meters. But, when it comes to aviation and other similar applications, very high accuracy levels are required.

    Now, let us move on, and take a close look at the add-on technologies that help in improving the accuracy of GPS readings.

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    1. Differential GPS

    Differential GPS, often referred to as DGPS in short, allows you to improve the accuracy of GPS readings up to an excellent level of about one meter to three meters, which is a lot better than the regular reading levels of 4-20 meters.

    How It Works

    It makes use of a network of stationary GPS receivers, and it is quite similar to civilian system run by the US Coast Guard on most of the waterways, and marine longwave radio transmission.

    In DGPS, the difference between the position of the reference object estimated by the satellite signals, and the actual pre-defined position is calculated, which is termed as error factor. Now, this error component is used as a carrier for transmitting FM signals, used by the local GPS received. Finally, necessary corrections are applied to achieve higher accuracy levels.

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    2. A Carrier-Phase Enhancement (CPGPS)

    CPGPS makes use of the 1.575 GHz L1 carrier wave, which plays the role of a clock signal for helps in resolving ambiguities. Usually ambiguities are caused due to frequent changes in C/A PRN, and location of the pulse transition, which is represented by the logic 0-1 and 1-0 transition.

    How Does CPGPS Help in Improving GPS Accuracy Levels?

    Basically, the root of the problem is that the C/A signal isn’t instantaneous; there is a considerable amount of tag lag between the instants when the signal reaches digital logic value ‘1’ from ‘0’, and vice versa. The end result is inconsistent satellite-receiver sequence matching.

    The 1.575 GHz L1 carrier wave helps in defining a precise transition point (due to very small period of 1/1000 that of C/A bit width). As a result, CPGPS can help in achieving up to 1% ambiguity levels, which amounts to about 3mm, while the regular ambiguity levels in GPS operation are in the range of 2 to 3 meters!

    To improve the GPS accuracy furthermore, DGPS can be clubbed with CPGPS to realize unbelievably high accuracy levels of about 20-30 centimeters.

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    3. Wide Area GPS Enhancement (WAGE)

    WAGE is another handy technique to improve GPS accuracy; this involves usage of a highly accurate orbital data, satellite clock, and high quality GPS receivers with additional equipments for enhanced detection.

    Basically, the setup is too complex to be discussed in detail, but in short, WAGE improves the horizontal accuracy of the GPS encrypted P(Y) Code.

    Additional range correction data is combined with the satellite broadcast navigation message to achieve greater accuracy levels, and WAGE accuracy has been found to be better than 4.82 m, 95% horizontal.

    Note: Off-late PPS accuracy has improved beyond WAGE specifications, and most of the latest generation atomic clocks on a chip, or receivers can easily outperform WAGE.

    As per the latest updates, WAGE specifications have been superseded by Talon NAMATH, and it is recommendable to upgrade to Talon NAMATH for obtaining higher accuracy levels, in case you’re using WAGE at the moment.

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    Advanced Techniques to Improve GPS Accuracy Levels

    Other techniques that can be used for improving the GPS accuracy levels include Local Area Augmentation System (LAAS), Wide Area Augmentation System (WAAS), Relative Kinematic Positioning (RKP), combination of speedometer pickup and gyroscope, EDGE (Exploitation of DGPS for Guidance Enhancement), and the list is virtually endless.

    You may also be interested in checking out how you can use your cell phone as GPS receiver.