AN/AVQ-21

AN/AVQ-21. The AN/AVQ-21 was an X band airborne radar system developed for the United States Navy during the Cold War. Primarily integrated into carrier-based attack aircraft, it provided critical capabilities for all-weather navigation and weapon delivery. Its development represented a significant step in the evolution of tactical aviation avionics during the 1960s.

Overview

The AN/AVQ-21 system was designed as a compact, high-performance radar for installation in the nose of fighter and attack planes. It served as a key sensor for missions conducted by the United States Navy and the United States Marine Corps, enabling operations in adverse conditions where visual cues were unavailable. The radar's primary functions included terrain following, ground mapping, and providing targeting data for air-to-ground munitions. Its introduction coincided with a broader Department of Defense push to enhance the all-weather capability of its tactical air wings.

Development and Design

Development of the AN/AVQ-21 was led by the General Electric Aerospace Division under contract from the United States Navy's Naval Air Systems Command. The program emerged from earlier radar technology used in aircraft like the F-4 Phantom II and aimed to provide a more advanced, reliable system for newer platforms. Engineers utilized planar array antenna technology and solid-state electronics where possible to improve reliability over previous vacuum tube-based systems. The design emphasized a high degree of integration with the aircraft's central computer and inertial navigation system to automate navigation and attack profiles.

Operational History

The AN/AVQ-21 entered service in the mid-1960s, becoming operational with fleet squadrons aboard aircraft carriers such as the USS Enterprise (CVN-65) and USS Kitty Hawk (CV-63). It saw extensive use during the Vietnam War, where its all-weather and night attack capabilities were heavily utilized in operations like Rolling Thunder and Linebacker II. The system was deployed on the A-6 Intruder, where it formed a core part of the aircraft's DIANE (Digital Integrated Attack and Navigation Equipment) suite. Its performance in Southeast Asia demonstrated the value of integrated radar systems for precision strike missions in contested environments.

Technical Specifications

Operating in the X band frequency range, the AN/AVQ-21 utilized a pulse-Doppler mode for improved clutter rejection and moving target detection. The system featured multiple operational modes including a high-resolution Doppler beam sharpening mode for detailed ground mapping. It interfaced directly with the aircraft's weapons release computer to enable computed bomb release points for unguided bombs and early guided bombs like the AGM-62 Walleye. Power was supplied by the aircraft's main electrical system, and cooling was provided by a dedicated liquid cooling unit.

Variants

Several variants and related systems were developed from the core AN/AVQ-21 technology. The most direct development was the improved AN/APQ-148 radar, which featured enhanced reliability and additional modes for the later A-6E Intruder model. Technology and components from the program also influenced the design of the AN/APQ-126 radar used on the F-111 Aardvark and the AN/APQ-146 for the OV-10 Bronco. Furthermore, experience gained informed the development of the more advanced AN/APG-65 radar for the F/A-18 Hornet.

Category:Avionics of the United States Category:Radar Category:Military electronics of the United States