ASL
The pressure sensor, such as TGY-CAT01, can be configured
in the System ⭢ Extra ⭢ ASL menu:
It cannot compute altitude by itself, so the computation is done by the Tx.
The default values can be set by long pressing the OK button.
A short press of OK is used to change the between the pressure at the sea
level and temperature. The altitude is calculated as altitude above the
sea level.
If the desired value is altitude relative to start position, set the pressure and temperature a current pressure and temperature at the start position.
The altitude should be re-calculated on every value change.