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GPS Accuracy Field Gone

I just updated my Garmin Edge 1030 to firmware version 10 and I can no longer find the GPS accuracy field. I used to use this field at the beginning of EVERY ride to determine whether my unit was going to record accurate position data. Why was this field removed? With the field removed, how do I determine whether my unit has locked on to a sufficient number of satellites to record accurate position data?

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0 mcinner1 over 4 years ago in reply to jonathonthornton

jonathonthornton

Your work looks really interesting and technically - but maybe you also make a simple datafield which contains only accuracy im meters and can be used in any layout?

0 jonathonthornton over 4 years ago in reply to mcinner1

mcinner1 I suspect the values from the Position.QUALITY_* table you listed above are mapped to bars in the existing "GPS Signal Strength" field. If this is the case, implementing a data field as you suggested would be reinventing the wheel.

0 jonathonthornton over 4 years ago in reply to mcinner1

mcinner1 For better of for worse, Garmin doesn't allow position data to be referenced by data fields, so I had to implement my solution as a widget or an application.

I had a lot of fun writing my widget. I used a really cool algorithm for computing the smallest enclosing circle around a set of points. See https://www.nayuki.io/page/smallest-enclosing-circle. I then used the Haversine formula to compute the great circle distance in metres between two points on opposite sides of the circle (overkill given the scale). See https://www.movable-type.co.uk/scripts/latlong.html. Then I converted my lat/long values to Mercator projection. See https://wiki.openstreetmap.org/wiki/Mercator. Lastly, I mapped the Mercator points to pixel positions. See https://stackoverflow.com/questions/929103/convert-a-number-range-to-another-range-maintaining-ratio

I'm still tweaking my implementation. Yesterday, I colour coded my graph (red: bad, yellow: ok, green: excellent). I'll release my widget in the Garmin IQ store soon.

0 mcinner1 over 4 years ago in reply to jonathonthornton

jonathonthornton said:
I suspect the values from the Position.QUALITY_* table you listed above are mapped to bars in the existing "GPS Signal Strength" field. If this is the case, implementing a data field as you suggested would be reinventing the wheel.

In principle you are right, but:
Toybox.Position delivers 5 values: 0, 1, 2, 3, 4 whereas 0 is: no signal available

The existing GPS signal strength datafield has 5 bars, and that does not match with position, because it is hard to believe that one bar lightning means: no signal...

But for me - personally - I‘m happy knowing the position values (HMs DIY). That way I never start an activity without having a good signal.

0 jonathonthornton over 4 years ago

My new GPS Accuracy widget is complete. You can download it from the Garmin IQ Store. https://apps.garmin.com/en-US/apps/0fad4f7b-422e-4539-96c4-ed82bf71bf4b

0 cheracogoff over 4 years ago in reply to jonathonthornton

Looks like a good widget but is it more accurate than the accuracy displayed on the view satellites screen? View satellite screen does take four steps to get to but is easily accomplished and it provides additional information.