iFly GPS Forum

Sort of...it represents the level of horizontal accuracy.  Different platforms and different OS versions report this differently.  And different ADSB devices treat it differently.  But 4 bars typically means 3 meters or better, 3 bars=6 meters, 2 bars = 15 meters.  1=worse than 15 meters.  And if it's really bad, like over 30 meters or something, we put the grey "Weak GPS Signal" message.  

The log file has additional details...in John's case his device is reporting resolution is in the thousands of something (feet, I think)...which is typically cell tower resolution.  

I concur, also based on a foot excursion, that the .38 release seems to be accurate in both positioning & orientation now.

I didn't think to check altitude.

You might be right that it's lower than it should be (for me: about 50'), but that might not be the iFly's fault. I have 3 GPS apps: iFly, GPS Essentials, and GPS Status. GPS Status is consistently reporting an altitude that's close to what I understand my home's altitude to be. Whereas iFly and GPS Essentials are reporting an altitude about 50' lower -- but absolutely agreeing with each other (to the foot).

Something is definitely different between how GPS Status is getting/figuring its altitude vs. iFly & GPS Essentials, which appear to be using the same method. Well, as I like to say: a man with one watch "knows" what time it is, but a man with two watches is never sure.

Also: now that I think of it, on a recent trip to Southern California and back, when I was driving over the passes I was sometimes running GPS Essentials on my phone to look at altitudes. It was always indicating 100' below what the road signs said the altitude was and what my friend's iPhone was indicating. I just chalked it up to lag and/or the iPhone maybe having a better GPS setup (and/or barometer). I don't use iFly on my phone in the plane, so I haven't noticed any discrepancy to my barometer and other GPS sources, but I'll be looking next time I fly. My tablet, which I do use for iFly, is running an older version of Android and is (presumably) getting its GPS from the ADSB-In unit -- though I can turn that off and see what iFly starts reporting for altitude then.