Aviation Week has a couple of articles on the classified RQ-180 program:
http://www.aviationweek.com/Article.aspx?id=/article-xml/awx_12_06_2013_p0-643783.xml&p=1
http://www.aviationweek.com/Article.aspx?id=/article-xml/awx_12_06_2013_p0-643786.xml
The RQ-180 is an unmanned aerial system (UAS), designed for intelligence, surveillance and reconnaissance (ISR) missions, and is the likely successor to the RQ-170 Sentinel.
Cheers,
Bill