The above screenshot shows the display of the virtual aid to navigation established in partnership between the U.S. Coast Guard and the U.S. Army Corps of Engineers on the Mississippi River. The virtual aid is significant in that it allows mariners to see a hazard when it is not possible to place a floating aid to mark it. U.S. Coast Guard image.

Marine Link has a very interesting post on the Coast Guard’s Navigation Center. It discusses its role in management of aids-to-navigation, issuance of Notice to Mariners, interface with NOAA and the Army Corps of Engineers, maintenance of GPS including ground based differential GPS equipment, Automatic Information System (AIS) monitoring and quality control, long range tracking of US flag merchant ships, and maintenance of a Maritime Domain Awareness within 1000 miles of the US.