 Raytheon has developed the Patriot guidance enhanced missile (GEM-T), an upgrade to the PAC-2 missile.The upgrade involves a new fuse and the insertion of a new low noise oscillator which increases the seeker's sensitivity to low radar cross-section targets.In April 2013, Raytheon received U.S. Army approval for a second recertification, extending the operational life of the worldwide inventory of Patriot missiles from 30 to 45 years.