Ranking System of the Galactic Empire

The quoted ranks fit quite well with modern navies
i.e.

Grand Admiral,
Grand Moff,
Moff,
Marshall= Fleet Admiral

General= Admiral
Colonel= Vice Admiral
Major= Rear Admiral

Commander= Commodore
Fleet Captain= Captain
Captain= Commander

Lieutenant= Lieutenant-Commander
Senior Warrant Officer= Lieutenant
Master Warrant Officer= Ensign

Warrant Officer= Senior Chief Petty Officer
Sergeant= Master Chief Petty Officer
Staff Corporal= Chief Petty Officer

Corporal= Petty Officer
Trooper= Enlisted