[zipper]

I never heard of a handheld GPS with a built-in barometric altimeter.

But they are available, and I’m sure it would come in handy for measuring cabin altitude.

http://www.yenra.com/handheld-gps/

[ColdWater]

I never heard of a handheld GPS with a built-in barometric altimeter.

No? Look here.

http://www.yenra.com/handheld-gps/