Terminal High Altitude Area Defense
In contrast to the older AN/MPQ-53 Passive Electronically Scanned Array (PESA) radar set of the MIM-104 Patriot PAC-2, the Green Pine is an active electronically scanned array (AESA) solid state radar. Unlike the advanced AN/TPY-2 X band radar of the Terminal High Altitude Area Defense system, Green Pine operates at L band - in the 500 MHz to 2,000 MHz range.