Feel free to put your own suggestions in your reply.
From lowest to highest with federal/imperial rank for comparison :
Recruit <-> Outsider <-> Conscript
Cadet <-> Serf <-> Pilot
Midshipman <-> Master <->Flying Officer
Petty Officer <-> Squire <-> Flight Lieutenant
Chief Petty Officer <-> Knight <-> Squadron Leader
Warrant Officer <-> Lord <-> Wing Commander (hope there is not copyrights problems there, plus a nice hat tip)
Ensign <-> Baron <-> Group Captain
Lieutenant <-> Viscount <-> Commodore
Lieutenant Commander <-> Count <-> Chief Marshal
Post Commander <-> Earl <-> Space Marshal
From lowest to highest with federal/imperial rank for comparison :
Recruit <-> Outsider <-> Conscript
Cadet <-> Serf <-> Pilot
Midshipman <-> Master <->Flying Officer
Petty Officer <-> Squire <-> Flight Lieutenant
Chief Petty Officer <-> Knight <-> Squadron Leader
Warrant Officer <-> Lord <-> Wing Commander (hope there is not copyrights problems there, plus a nice hat tip)
Ensign <-> Baron <-> Group Captain
Lieutenant <-> Viscount <-> Commodore
Lieutenant Commander <-> Count <-> Chief Marshal
Post Commander <-> Earl <-> Space Marshal