GPS IIRM-1 (USA-183)

GPS IIRM (Global Positioning System) or Navstar IIRM (Navigation System using Timing And Ranging) are the fourth evolution stage of the second generation of GPS satellites. The Block IIRM satellites include a new military signal and a more robust civil signal, known as L2C. There are eight satellites in the Block IIR-M series, which were built by Lockheed Martin. The GPS IIRM satellites were launched between September 2005 and August 2009.