Corrections are not applied for the effects of secondary precession, vertical velocities or real drift of the gyros which rules out movement in the yawing plane, secondary precession and pendulous oscillation, vertical velocities, earth precession, centrifugal forces and transport drift and gyroscopic inertia, earth rotation and real drift.  

Corrections are made for the effects of aircraft manoeuvres (the platform is always kept in the local horizontal), for apparent wander of the gyros (Earth rate and transport wander) and for the effects of coriolis on the accelerometers.