This is drift for a "static" million dollar marine grade (i.e. highest grade we currently have) INS not in the ocean or moving. Drift is measured in non-moving conditions. These are the fiber optic and laser sytems you are referring to.
Even if we could make that cheap and small enough it would still need regular corrections far more frequently than a week to be as good as a GPS is now.
Even if we could make that cheap and small enough it would still need regular corrections far more frequently than a week to be as good as a GPS is now.