The U.S. Air Force exercised a $50.7 million contract option with Rockwell Collins to complete the next phase of the Modernized User Equipment (MUE) program, which consists of receiver card development for ground and airborne applications, to include test and security certification for the next-generation GPS. The initial contract of $27.9 million was awarded in 2006 to Rockwell Collins to develop and demonstrate user segment receiver cards. That contract, which was executed through October 2007, supported preliminary design of the modernized receiver cards. The U.S. Air Force is in the process of modernizing all three components of the GPS system: the satellite; control; and user equipment segments. The MUE Receiver Card Development program represents the military user equipment portion of the next-generation GPS system that adds a new military signal and security architecture.