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GPS and altitude accuracy – wrong info on VA3

The VA3's GPS accurately tracks the routes I cover while running or biking. The maps viewable in garmin connect perfectly trace my actual routes. Very pleased with the VA3's performance on that score.

But… when I use the Navigate function to save a location, the GPS coordinates displayed on the VA3 are approx. 30 miles SE of my actual physical location. The elevation is wrong by about 100 ft when compared to the physical location or to the displayed GPS coordinates.

However… when I use the VA3 to navigate to the saved location, the watch in fact takes me correct location (i.e. not to the displayed GPS coordinates, which are 30 miles away). In other words, the device reports GPS coordinates that are 30 miles distant (according to google maps and other gps mapping apps) but nevertheless returns me to the actual physical location that I saved using the Navigate function.

What gives? Anyone else having similar issues?

0 P_W_P over 7 years ago

Does anyone know which map datum the VA3 uses to display coordinates? If it's different that the datum used for comparison then people will perceive position errors (although typically hundreds of meters rather than tens of miles.)

-- Pete

0 cleansoap over 7 years ago

If it isn't WGS84 it's a bug. And before you say "well, that's it" the error against NAD83 is far smaller than the accuracy of the receiver.

0 Former Member over 5 years ago

Hi,

I just got a VA3 today and spent some time figuring this out, but I finally did, so thought I would share. I spoke with Garmin tech support person who told me that "Garmin uses the WGS84 format" and 'DEGREES,MINUTES,DECIMAL MINUTES'. A little Googling later and I discovered that most of the world uses DECIMAL DEGREES. I.E. 42.5= 42 and 5/10 of a degree. So it is just a matter of converting from Garmin's degrees minutes, decimal minutes to decimal degrees. As an example, 42.30.0000 from a Garmin watch would be 42.5 decimal degrees. If you don't convert your going to be 20-30 miles away. The degrees before the decimal point (i.e. 42) are the same. To convert the rest, take the numbers after the decimal point that Garmin gives you (in the above example, 30.0000) and divide that by 60 (=0.5). Then multiply that by 100 (=50)and tack that on after the decimal point to the degrees (42.50.0000). Once I did this, I saw everything lined up.

Cheers