Kratos Defense & Security Solutions, Inc. (Kratos) is engaged in providing mission critical engineering, information technology (IT) services and war fighter solutions. Its principle services are related to, but are not limited to, command, control, communications, computing, intelligence, surveillance and reconnaissance (C4ISR); military weapon range operations and technical services; missile, rocket and weapons system test and evaluation; public safety, security and surveillance systems; modeling and simulation; unmanned aerial vehicle (UAV) products and technology; advanced network engineering and IT services, and advanced IT services. The Company operates in two segments: Kratos Government Solutions (KGS) and Public Safety and Security (PSS). On December 24, 2008, it acquired Digital Fusion, Inc. In March 2009, Patriot Scientific Corp.'s Crossflo Systems, Inc. announced that it has acquired the Vigilys product line from Kratos Defense & Security Solutions, Inc.