The navy of the United States of Sol Eridani and Centauri is called USSEC Fleet. It is structured like most any navy in existence, but is made up of forces from the member states of USSEC.
USSEC Fleet uses the time-tested basic structuring of navy using a meritocratic system of advancement and the ranks used by the US Navy and British Royal Navy.
USSEC FleetCom is the general designation for all structure purely designated for command within the fleet. It works very closely with the Colonial Ministry, coordinating the colonizing of new planets.