The Galactic Empire: An Empire Reborn
Imperial Officers' Manual
Major Revision: 2.0 – 2008.10.31
An adaptation of the pre–Endor document and policies.
RIP 
... A Naval Cadet's Rank Insignia ...

Naval Cadet (NC) is the "cadet rank" of the Imperial Navy.

Naval Cadets are without full officer status within the GE, undergoing specialized training at the Imperial Academy... They will earn their full officer's commission – and the rank of Ensign – upon graduation.