The Northrop Grumman X-47B is a demonstration Unmanned Combat Aerial Vehicle. The X-47 began as part of DARPA's J-UCAS program, and is now part of the United States Navy's UCAS-D (Unmanned Combat Air System Demonstration) program to create a carrier-based unmanned aircraft. Unlike the Boeing X-45, initial X-47A Pegasus development was company-funded. The original vehicle carries the designation X-47A Pegasus, while the follow-on naval version is designated X-47B.
Canadian Aviation Blog