Altimeters are only pilot calibrated to ensure planes travelling in various directions can trust their vertical separation is constant even amid rising or dropp

Altimeters are only pilot calibrated to ensure planes travelling in various directions can trust their vertical separation is constant even amid rising or dropping temperatures and pressures. In that context an altimeter that calibrates itself is quite undesirable There is the radio-altimeter which uses ground based radar but that is for spoken-aloud altitude readouts and terrain warnings and as far as I’m aware doesn’t factor in Boeing or airbus autopilot. At least in the U.K., the lingo has us refer to this always as height (ie, above the ground) and not altitude (within the air above a hypothetical sea level)