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GPS Accuracy

2,305 bytes added, 21:19, 19 May 2017
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|style="background-color: #FB9C75;"|4.4
|style="background-color: #F2E783;"|6.8
|}
==Garmin Fenix 5X and GLONASS==
Continuing the theme of poor accuracy with GLONASS enabled, the [[Garmin Fenix 5X]] demonstrates even worse performance than its peers. The values shown below are rather dramatically worse with GLONASS enabled than without. My anecdotal observation is that sometimes the Fenix 5X does a little worse with GLONASS than normal, possibly in line with other Garmin devices, and sometimes it seems to just get lost and produce dramatically worse results.
{| class="wikitable sortable"
!Device
!Accuracy
!Trueness
!Precision
!Repeatability
|-
|Fenix 5X 4.30
|style="background-color: #FEC97E;"|5.6
|style="background-color: #EDE683;"|6.9
|style="background-color: #FCA377;"|4.5
|style="background-color: #F3E783;"|6.8
|-
|Fenix 5X 4.30 GLONASS
|style="background-color: #F97B6F;"|3.5
|style="background-color: #FFE082;"|6.2
|style="background-color: #F8696B;"|1.6
|style="background-color: #F97B6F;"|3.5
|}
Below you can see a visual representation of the problems. Many of the tracks are a little worse than normal, but you generally follow the path. A small subset of the tracks are dramatically worse, either showing and offset from the actual path, or sometimes it looks like the sampling frequency has dropped, suggesting that the watch is only periodically able to get a location fix. This latter phenomenon is rather surprising to me and goes against my hypothesis of why GLONASS has worse accuracy. I would expect there would be more satellites available with GLONASS enabled, which would result in the watch selecting the subset with the strongest signal that are more likely to have a narrow angle of separation, which would result in increased Dilution of the Precision. These tracks suggest that the Fenix 5X is unable to get any location fix for brief periods.
{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"
|- valign="top"
|[[File:BridgeFenix 5X 4.30 GLONASS.jpg|center|thumb|x300px| The GPS tracks from the Fenix 5X with GLONASS enabled. This diagram has tracks color coded with green indicating good accuracy through to red indicating poor accuracy, and the lap markers as blue dots.]]
|- valign="top"
|[[File:BridgeFenix 5X 4.30.jpg|none|thumb|x300px|Here's the tracks from testing with GLONASS disabled for comparison.]]
|}
=GPS Accuracy and Sampling Rate=

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