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Edge 520 GPS and Altimeter Accuracy

Former Member over 9 years ago

I have been using the 520 since September and have been patiently waiting for and installing the updates (including the latest one) in hopes that the bugs will get worked out and it will function the way it really should have out of the box.

First. GPS accuracy is horrible. Sometimes more than 100 feet off in any direction. This seems pretty insane considering that one of the big selling points on the 520 was the strava integration. 100 feet off on a segment start or finish is kind of a big deal. A good example of this would be the attached fit file and linked strava ride. While riding through Point Defiance Park I am shown to be nowhere near the road and consequently did not ride any of the 5 or so segments that I should have passed through. This ride was done on a gorgeous blue sky day during the winter where there is actually less of a tree canopy. Not that I think that should matter because I rode through this park more than a 100 times with a 510 and never had this issue. I would think that the 520 (being the newer model) would not be less accurate. Some other rides I have done through this park with the 520 actually show me in the water.

https://www.strava.com/activities/467738049

Second. The Altimeter is completely useless and often shows me riding below sea level. I know that you can correct the elevation with map data but that would require that the gps data was somewhat close to accurate. And why should I have to correct elevation data from a barometric altimeter anyway?

Is anyone else having similar issues that they have been able to correct on their own?

0 Former Member over 9 years ago

5630

I don't think anyone else is having issues with the GPS accuracy of the 520. You can't rule out that it may be a faulty receiver on your unit. Comparing the accuracy data field with another receiver in various reception conditions could show that. But if you believe the 520 tracking is worse than your 510 you might want to contact support about a replacement.

0 Former Member over 9 years ago

I don't think anyone else is having issues with the GPS accuracy of the 520. You can't rule out that it may be a faulty receiver on your unit. Comparing the accuracy data field with another receiver in various reception conditions could show that. But if you believe the 520 tracking is worse than your 510 you might want to contact support about a replacement.

Thanks.

I had searched and couldn't find much about GPS accuracy so I was thinking it may be an isolated case with mine. I actually do have a good way to verify the accuracy field since I never got around to selling the 510. I'll have to take them both out on a ride and see how they track.

I wish the GPS accuracy was logged so I could see it in the .fit file. Maybe it is and I just don't know where to look for it. If that were the case I could do a comparison between my 520 and my wife's 510 since we have done lots of rides together where our maps vary quite a bit (hers being the one that stays on the roads).

Edit: Here is a great example http://labs.strava.com/flyby/viewer/#397358675?c=c22v5sjp&z=F&t=1L-nnB&a=UzavFxgCpRc. Make sure Brock and Jill are checked and compare the paths. Hers is recorded with 510, mine with a 520 in the same conditions. The 510 is tracking perfectly with the road while my path has me doing some heavy duty bush whacking.

0 Former Member over 9 years ago

First. GPS accuracy is horrible. Sometimes more than 100 feet off in any direction.

Seems like your unit is not functioning correctly. Haven't seen any GPS problems with Edge.

Altimeter issues can be caused by poor GPS as well. By default, Edge 520 calibrates barometric pressure sensor using GPS altitude. In your case it is set way off.

You can easily fix altitude problem (by using 'Set Altitude' function prior to the ride), but it won't help GPS. I'd recommend calling Garmin and asking for clarification and/or replacement.

0 Former Member over 9 years ago

I wish the GPS accuracy was logged so I could see it in the .fit file. Maybe it is and I just don't know where to look for it. .

It is not logged. But the track comparisons clearly show that your 520 isn't tracking well. Also the elevation is set one time using GPS data and it shouldn't be so far off.

0 dpawlyk over 9 years ago

And why should I have to correct elevation data from a barometric altimeter anyway?

Because barometers are more accurate than GPS is for elevation. (Not having a barometer is cheaper and less complicated.)

Altimeter issues can be caused by poor GPS as well. By default, Edge 520 calibrates barometric pressure sensor using GPS altitude. In your case it is set way off.

The "calibration" is needed for absolute elevation. Cyclists are usually more interest in elevation gain (the measurement of which isn't affected by calibration).

0 Romanga over 9 years ago

Probably something wrong is with Unit

I have Edge 520 a quite a long time and in forest or in the city with buildings very close to bicycle patch never have any issue with GPS accuracy.

0 MATT_MCLENNAN over 9 years ago

I agree, I am finding that the altitude is much more accurate that my previous edge 500. The only time it is off is when it rains and the barometric altimeter port gets water in it.

0 Former Member over 9 years ago

Is anyone else finding that the accuracy of their phone is better than that of the Edge 520? This is very disappointing to me.

0 Former Member over 9 years ago

Is anyone else finding that the accuracy of their phone is better than that of the Edge 520? This is very disappointing to me.

Yes, the accuracy of my I phone 5 is much better than that of my Edge 520. Especially during my mountainbike rides in the woods, the accuracy is very disappointing. It misses about 20% of the Strava segments. And this unit is already the second one. First, I thought that I had a bad unit but as I am experiencing the same problems with the 2nd, I strongly believe that it is a type problem.

0 Former Member over 9 years ago

Is anyone else finding that the accuracy of their phone is better than that of the Edge 520? This is very disappointing to me.

Smart phones can get a position fix using cell towers and wi-fi hot spots. So in locations where GPS reception is poor (mountains, tree cover or tall building) there may be a noticeable difference. But the 520 tracking is pretty good and if you are getting poor tracking you can't rule out that you have a faulty uint. Check the Accuracy data field. With GLONASS enabled it should normally be around 10 ft.