We do have all the latest wiz bangs in our CX a/c including GPS updating RNP etc...
You cannot update the basic raw Inertial Reference Laser Ring Gyro position in flight. Once the IR is aligned on the ground it's done and dusted.
You can however adjust that position after its left the IR unit using GPS, but the IRS still thinks it is where it is
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Ahhhhhhhh it's all to complicated anyway, white mans magic !! ooh can I say that?