OVERVIEW: A Gun Director IR (Infrared) system is an electro-optical component of a fire-control system that enables passive target detection, tracking, and engagement using thermal imaging. It is primarily used for gun-based air and surface defense in low-visibility or night conditions.

GENERAL DESCRIPTION: First generation IR gun directors emerged in the late 1960s to 1970s as supplementary or backup systems for radar-guided gun fire control. Using single-element or rudimentary linear IR detectors, they provided limited-resolution thermal imaging for tracking hot targets such as jet exhausts or surface vessel signatures. Typically mounted in stabilized director platforms, these systems offered basic passive tracking capability, unaffected by radar jamming. However, their effectiveness was heavily constrained by resolution, weather, and clutter.

ROLE SUMMARY:
Category: Infrared Fire-Control System
Primary Use: Passive target tracking and gunfire direction under low-visibility conditions
Function: Infrared detection and angular tracking of heat-emitting targets
Platform: Naval ships, ground-based air defense systems
Integration: Supplemented radar fire-control systems; limited standalone capability

See Specific information under [Sensors/EW] and [Properties] sections.

SOURCE:
https://en.wikipedia.org/wiki/Gun_director
NATO Naval Fire-Control Doctrine Manuals