This used to be true many years ago, but today, even cheap phone receivers use a very high number of satellites (so geometry is usually more favorable) and usually also contain a barometer, which can provide additional disambiguation via sensor fusion.
> especially when you are in the mountains where only get satellites readings from over your head
That might be true in a very steep ravine, but it's more of a concern for reaching communications satellites (of which there are much fewer or sometimes only one, depending on the system). Today, not getting a GNSS fix due to terrain is increasingly unlikely for the reasons mentioned above.
Also, in a hiking/mountaineering context, it's probably fair to assume that any GPS user will be located on the surface of the earth, so a precise lat/long fix is really all you need; you can determine the height using elevation models, which are pretty accurate these days.
> I commute daily with train, here in Germany
Some German trains were notorious for having bad cell signal due to metal-coated windows (applied for reflecting solar radiation). Try the same thing with an (open) car window and I bet you'll get excellent signal.
Some German trains were notorious for having bad cell signal due to metal-coated windows (applied for reflecting solar radiation).
It's the first thing I thought of, and it's why we had ceramic tinting put on our vehicle windows instead of conventional tinting (which in many cases, AIUI, has radio-blocking metal in it).
> especially when you are in the mountains where only get satellites readings from over your head
That might be true in a very steep ravine, but it's more of a concern for reaching communications satellites (of which there are much fewer or sometimes only one, depending on the system). Today, not getting a GNSS fix due to terrain is increasingly unlikely for the reasons mentioned above.
Also, in a hiking/mountaineering context, it's probably fair to assume that any GPS user will be located on the surface of the earth, so a precise lat/long fix is really all you need; you can determine the height using elevation models, which are pretty accurate these days.
> I commute daily with train, here in Germany
Some German trains were notorious for having bad cell signal due to metal-coated windows (applied for reflecting solar radiation). Try the same thing with an (open) car window and I bet you'll get excellent signal.