The Delco Carousel 4A system did not use rate gyros and I am fairly certain that the pre-Type 82 Litton systems did not either. RLGs and FOLGs are rate gyros in concept (the outputs can only ever be proportional to angular rate) but what is basically required for an inertial system is angular DISPLACEMENT and not rate. The IRU/ADIRU software integrates the rate output to obtain the required angular displacement.
The accelerometer principle however I agree is identical.
Dude
