AN/SPG-62

The AN/SPG-62 radar is a critical component of the Aegis Combat System, designed to provide terminal illumination for semi-active radar homing missiles such as the SM-2 and the Evolved Sea Sparrow Missile (ESSM). Operating in the X-band frequency range of 8 to 12 GHz, it uses a continuous-wave signal to ensure precise and reliable target illumination. Its mechanically steered parabolic reflector antenna, with a diameter of 7 feet 6 inches (2.29 meters), allows it to focus a narrow beam of energy on a designated target, ensuring that the missile’s seeker can lock onto the reflected signal during the final phase of engagement.

This radar system is not a standalone unit but functions as part of the Mk 99 Fire Control System, which integrates with the ship’s broader Aegis Combat System. The process begins when the ship’s primary search radar, such as the AN/SPY-1, detects and tracks an incoming threat, whether it is an aircraft, cruise missile, or other hostile object. Once the target is identified and tracked, the Mk 99 Fire Control System coordinates the launch of a surface-to-air missile, which is then guided toward the target using mid-course updates until terminal guidance is required.

At this stage, the AN/SPG-62 becomes essential, as it directs a concentrated beam of continuous-wave radio frequency energy at the target. The missile, equipped with a passive radar seeker, detects the reflected energy from the target and adjusts its trajectory to ensure a successful intercept. This method, known as semi-active radar homing, allows the missile to remain relatively lightweight and cost-effective, since the complex radar transmitter is located on the ship rather than inside the missile itself.

The use of continuous-wave illumination provides several advantages in terms of accuracy and resistance to countermeasures. Unlike pulsed radar systems, continuous-wave radars can provide a constant signal that is more difficult for enemy electronic warfare systems to disrupt. This ensures that the missile maintains a reliable lock on the target even in environments where adversaries attempt to jam or deceive radar systems. The high average power output of 10 kilowatts further enhances the radar’s ability to penetrate through clutter and interference, making it highly effective in contested battlespaces.

The AN/SPG-62’s mechanically steered antenna may seem less advanced compared to modern electronically scanned arrays, but it remains highly effective for its specific role. By physically moving the parabolic reflector, the radar can direct its narrow beam with precision, ensuring that the target is illuminated exactly where the missile requires it. This design also provides robustness and reliability, as mechanical steering systems have been proven in decades of naval operations under harsh maritime conditions.

In practice, the radar is typically used in pairs or groups aboard Aegis-equipped warships, ensuring that multiple targets can be illuminated simultaneously if necessary. This is particularly important in high-intensity combat scenarios where a ship may need to defend itself against saturation attacks involving multiple incoming missiles. By coordinating with the Mk 99 Fire Control System, the AN/SPG-62 ensures that each missile launched has the necessary terminal guidance support to maximize the probability of a successful intercept.

The integration of the AN/SPG-62 into the Aegis Combat System highlights the layered defense philosophy of modern naval warfare. While the AN/SPY-1 or newer SPY-6 radars provide long-range detection and tracking, the AN/SPG-62 ensures that the final step of the engagement—the missile’s terminal homing—is executed with precision. This layered approach allows warships to engage threats at multiple ranges, increasing survivability and effectiveness in complex threat environments.