CPC Subgroup
G01C 19/52 operating by fluid means (G01C19/54 takes precedence)
Full Title
Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects > Rotary gyroscopes > for indicating the vertical > Erection devices for restoring rotor axis to a desired position > operating by fluid means (G01C19/54 takes precedence)