The U.S. Air Force and Lockheed Martin Space Systems of Sunnyvale, Calif., successfully completed the critical design review for the GPS 3 space segment, clearing the way for production to begin, Lockheed Martin announced Aug. 23.

Lockheed Martin was put under contract in May 2008 to deliver the first two of as many as 12 satellites under the initial GPS 3 block, known as Block 3A, scheduled to begin launching in 2014. The four-day-long GPS 3 critical design review was completed two months ahead of schedule, following the completion of 65 distinct subsystem reviews that Lockheed Martin and its subcontractors completed, the press release said.

GPS 3 satellites are designed to produce more accurate signals than previous GPS satellites thanks to improved on-board atomic clocks. The spacecraft also will feature a more powerful M-code signal for military users and compatibility with the European Galileo navigation satellites, scheduled to begin launching as early as 2012.