The Nova Corps is the intergalactic police / military force that keeps the peace on Xandar and other planets of the Nova Empire.
Members of the Nova Corps wear a greyish blue uniform with shield shaped rank insignias on their upper arms. While in combat or potentially hostile situations, they also wear greyish armours with 3 circles and helmets with golden accents.
The comics books version of the Nova corps had its members' ranks displayed on their helmet instead of the shoulders with the corpsman being blank. In addition, corpsmen had a boomerang shape on their shape while other ranks ranks had between 1-3 suns with Nova Prime wearing the exact same uniform as a centurion but with the addition of a cape