The R.C.A.F. Meridian Convergency Computer is designed to help the navigator get the best performance out of a precision gyro which can be compensated for Earth rate, such as the N-I, the C-8, the LDG-I and the polar-path. These gyros are characterized by a low drift rate and provision is made for the effects of Earth rotation to be compensated for at the observer's latitude. Any heading set on the gyro will remain on the gyro provided the gyro remains at the same place. The only drift observed will be the random drift of the gyro itself.