AN/TPY-2 radars are high resolution, phased array, X-band radars designed and built specifically for the missile defense mission. The radar can be deployed in one of two modes: terminal or forward-based. The United States currently has 10 TPY-2 radars with plans to produce two more. 1 Seven of the TPY-2s will be in terminal mode and assigned to Terminal High Altitude Area Defens (THAAD) units. Five others are in forward based mode, two of which are deployed to Japan monitoring North Korean missile activity. 2 The remaining three are deployed in Turkey, Israel, and the Persian Gulf region and are oriented towards Iran. 3
In terminal mode, the TPY-2 radar is integrated with a THAAD system, and serves as its primary sensor. In this mode, the sensor is oriented upward to track the late stages of the missile track enabling the THAAD’s capability to intercept both outside the atmosphere and once a reentry vehicle enters the atmosphere. This mode carries a shorter range because of the orientation of the radar. 4
In forward-based mode, the radar provides crucial sensor tracks of missiles in boost/early midcourse phase to the GMD system. In this mode, the sensor is oriented outward to increase the range of the radar to detect missile launches over a larger territory. From these forward-based locations, the TPY-2 are able detect and track missiles in their boost and early midcourse phases, determining information such as its speed and trajectory. [5.”FY14 Ballistic Missile Defense System: Sensors”, Missile Defense Agency, 2014, http://www.dote.osd.mil/pub/reports/FY2014/pdf/bmds/2014sensors.pdf. ] The high resolution X-band imagery also allows the radar to identify the type of missile fired. TPY-2s do not, however, provide 360 degree coverage, and their range is limited by the curvature of the Earth.
Some have suggested “stacking” multiple TPY-2 radars. 5 Such an arrangement could include two TPY-2s with their arrays mounted and integrated to increase the range. These stacked radars would be housed at fixed sites, likely at the same locations as the UEWRs. The fixed site would permit the installation of a turntable to allow the radars to be reoriented more easily, similar to the one inside of the SBX. This would create a functional azimuth of around 270 degrees for a stacked TPY-2 configuration. 6