The choice of the calibration site location is rather delicate
and a compromise must often be found. Indeed, it
must be easily accessible for the instrument maintenance
but not exposed to deliberate damage. In addition, it must
not be confined in a sheltered position where it would see
very different conditions compared to the altimeter mission,
but not exposed to harsh weather conditions. This
exercise consequently shows the limits of the in situ calibration
when using a tide gauge that was not initially installed
in that purpose.