[wafflemaker]

You can use Open Street Maps to monitor the flight without the internet connection.

I often use it to watch how the plane speeds up for take off and slows down for landing.

Sometimes you have to keep the phone closer to the window. Luckily you get the list of currently connected GPS sats so you can debug whether hiccups are software/hardware related or poor GPS coverage.

It's lot of fun observing how early planes start going down in altitude before landing or trying to guess river and city names from up top.

[sva_]

> luckily you get the list of currently connected GPS sats

How do you get this list?

[etskinner]

The almanac, which is part of every GPS transmission https://en.wikipedia.org/wiki/GPS_Almanac?wprov=sfla1

[closewith]

GPS really is amazing. It's hard to believe it works at all.

[fragmede]

My favorite part about GPS is that it only works because we understand relativity, proving Einstein right.

[dharmab]

It would work without an understanding of relativity, but the accuracy would drop by about a meter. https://physics.stackexchange.com/a/128951

[mschuster91]

Personally, I use GPS Toolbox. No idea about iPhones though.

[1] https://play.google.com/store/apps/details?id=com.eclipsim.g...