GPS Accuracy

KelloggKid

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I just built the Cat Tracker using the GPS tiny shield.  This morning I put it on the dash of my car as I drove to work and then uploaded the file to Google Earth.  The track appears to be consistently off by about 1/2 block from the streets that I drove on.  I have the GPS shield on the top of my stack and it was forward on the dash with a clear view of the sky.  Is this shield that inaccurate or did I do something wrong?


KelloggKid

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I just downloaded the spec sheet for the Jupiter GPS chip that is used on the shield and it's claiming an accuracy of within +- 2.5 meters so something else must be going on.  Perhaps its the way Google Earth converts the nmea file.  I laid down a track this morning that was about 8-9 miles in length and the Google Earth shows the track as being 200-400 feet off the entire distance.


Pat ONeil

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My experience with the GPS shield is that it is very inaccurate.     If I leave it in one position continuously it continually updates the location data and it varies by 15 meters.   It settles down somewhat but never stabilizes on a single location. If I move to another location and come back to first location,  the location is way off.

The specs say 2.5 meters accuracy and my unit is no where near this level of accuracy.   The accuracy makes the unit worthless for my application.   I am wondering if I got a bad unit or the GPS chip specs are misleading.

Anyone else have any experience with this GPS Shield?


Ben Rose

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Pat, do you have the chip antenna or external antenna version of the board? Have you tried it on another day? Never stabilizing sounds unusual.


Pat ONeil

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I have the external GPS antenna sold by TinyCircuits.....  Hoped for more consistent results especially when the unit is absolutely stationary.....    It's probably good enough to track cars across country but not cat/dog around yard.


rdfowler

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I ordered the GPS with the external antenna, and I'm get fairly decent accuracy. I tried it out on a trip to the store, and when I loaded the NMEA file into Google Earth, it showed tracks that, for the most part, were in the proper lane of the road.


 

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