PIRAZ

PIRAZ is a United States Navy acronym for Positive Identification Radar Advisory Zone. The zone is defined by the air search radar coverage of a ship patrolling a designated PIRAZ station. The concept was similar to radar picket stations established in World War II. The PIRAZ ship requires a Naval Tactical Data System radio-linked computer installation to effectively identify and track all aircraft anticipated to enter the airspace of the zone during combat.

The concept originated in the summer of 1966 as Yankee station was established for United States Task Force 77 aircraft carriers launching strikes against North Vietnam. A fixed patrol station within range of land-based aircraft made the stationed aircraft carriers vulnerable to attack. A PIRAZ station was established in the westernmost portion of the Gulf of Tonkin where air search radar coverage might extend over North Vietnam and the air-strike routes from Yankee station. This PIRAZ station radio call sign was "Red Crown." The first PIRAZ ships were USS Chicago, King, Mahan, and Long Beach.Belknap class frigates began rotating into PIRAZ station assignments in 1967; and USS Wainwright, assisted in the Son Tay Raid on 21 November 1970.

PIRAZ ships carried long-range RIM-2 Terrier or RIM-8 Talos surface-to-air missiles to defend their stations. Chicago fired RIM-8H Talos-ARM anti-radar homing missiles against North Vietnamese shore-based radar stations. Each PIRAZ ship was accompanied on station by a "shotgun" torpedo boat destroyer with quick-firing guns to defend the PIRAZ ships from torpedo boat attack. PIRAZ ships provided protective radar surveillance of the remotely piloted vehicles performing aerial photo reconnaissance of North Vietnam.

...
Wikipedia