For what it's worth, a smartphone WITH a barometer (and an altitude correction model on board, which I think is wired into Location Services on Android) is quite a robust altitude indicator. The GPS altitude can be compared with the barometer, integrated over a very long time - relative to altitude changes, but short relative to the weather. That can yield the sea-level pressure reading that will calibrate the barometer for short-term variability.
My phone doesn't generally do quite as well as my wrist altimeter (which often nails a known elevation within 5 m if the weather is stable), but many, many times better than an unassisted GPS. On Sat, Feb 17, 2018 at 6:53 PM, Poutnik <[email protected]> wrote: > Sure, but I was not speaking in context of aircraft, but e.g. of multi-day > mountain trekking. Neither I have heard about OSMAnd to be used for a > precise aircraft altitude control. > > Dne 18/02/2018 v 00:39 Robert Grant napsal(a): > > While my experience agrees with you regarding accuracy and stability, it's > still better to know the local pressure setting, especially if landing an > aircraft without a radio altimeter. Setting an altimeter based on GPS > sounds quite rare to me. > > On Feb 17, 2018 3:12 PM, "Poutnik" <[email protected]> wrote: > >> As being trained in past as the military meteorologist, in pre-GPS era, >> I am aware of that. But the offset value is bigger than GPS accuracy of the >> static value averaged. BTW, the most handy way how to calibrate the >> barometric altimeter at unknown altitude is the GPS device. While >> barometric altimeters have superior short-term accuracy and stability, GPS >> devices have superior long-term accuracy and stability. Fortunately, for >> most personal usage, absolute altitudes are not that important, rather the >> relative changes. >> >> Dne 17/02/2018 v 23:35 Robert Grant napsal(a): >> >> I'm pretty sure that none of the devices listed by the op use barometric >> altimeters; even the Garmin Glo is GPS altimetry. GPS is known for its >> lack of precision in determining altitude. In aviation, old school >> barometric altimeters are still the gold standard, but they require >> periodic barometric pressure adjustment. While GPS is great for navigating >> around the earth, it would be very foolish to use GPS altitude for landing >> an aircraft. Bottom line: don't expect any phone with only GPS altitude >> to agree precisely with a database supplied measurement. >> >> >> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon> >> Virus-free. >> www.avast.com >> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link> >> >> On Sat, Feb 17, 2018 at 1:41 PM, Harry van der Wolf <[email protected]> >> wrote: >> >>> >>> >>> 2018-02-17 19:41 GMT+01:00 Poutnik <[email protected]>: >>>> >>>> >>>> While Europe subtracts altitude by the correction, >>>> US adds altitude, so the higher value is the (over?)corrected one. >>>> >>>> >>> I didn't know that :) >>> >> >> > -- > Poutnik ( The Wanderer ) > > My Brouter profiles https://github.com/poutnikl/Brouter-profiles/wiki > > -- > You received this message because you are subscribed to the Google Groups > "Osmand" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Osmand" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
