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I was looking for a comparitive statement of the accuracies achived by various GNSS systems such as QNSS, COMPASS, GLONASS, GPS..etc. however i find only discriptions of only GPS everywhere

userX
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Trolling through the wikipedia entries for each system should give you an idea. Here is a summary:

  1. Beidou (COMPASS) - 0.5 m (theoretical) http://en.wikipedia.org/wiki/Beidou_Navigation_Satellite_System#Position_calculation
  2. GPS - 5 m (civilian) 3 cm (Real Time Kinematic) http://en.wikipedia.org/wiki/Global_Positioning_System#Carrier_phase_tracking_.28surveying.29
  3. GLONASS - 5 m (if you can get enough satellites) http://en.wikipedia.org/wiki/GLONASS#Accuracy

What most people use is some kind of hybrid system in their phone. This doesn't necessarily increase precision, but does speed up the time to acquire a solution. So your phone will get ~5 m.

Surveyors these days use multiple systems, GPS, GLONASS and to some extent COMPASS and QNSS. Using them all together should get you better than 0.1 m, but requires expensive hardware.

Coming soon is the new GPS satellites, these have three frequencies, which means you can solve for ionosphere and get a better solution.

Alex Leith
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  • Just a small clarification.The Beidou 1 is basically an augmented system, hence it's theoretical Accuracy is so good. If you used Augmented GPS, then you do get equivalent accuracy as well. – Devdatta Tengshe Oct 22 '13 at 04:58
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The best reference on GNSS for normal users probably is Navipedia. It contains sites on the performance of each system (e.g. GALILEO Performances).

Jakub Kania
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I'm not a specialist but I use RTK GNSS systems quite a bit.

I would say that they are all the same (+- 5m) if you use them "out of the box" with a small standard receiver.

Now if you invest into professional receiver (RTK which is not pure GNSS anymore) you will reach 1cm precision in specific conditions.

Using GPS or GLONASS or any other or a mix of them will IMO not really change the precision you get.

The number of satellites your receiver can "see" and their position in the sky WILL change the precision you get. Usually, the more you see and the better they are positionned (all around you, not in line, not too low...), the more precise you get.

So depending on where you live, you will probably invest in different systems or a system that can receive different signals.

In Europe for example, when there was only GPS available, the precision was IMO better in the morning because of the satellite's positions. Now that I use a mix of GPS and GLONASS, I don't see any difference anymore.

Jake
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Legzav
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For the most part, the receiving equipment determines the accuracy.

Willy
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  • While this answer, in principle is right, it really isn't useful without supporting information. Please consider adding more details and information and expanding this answer. – Devdatta Tengshe Oct 22 '13 at 05:02