As adversaries develop missile technology to attack the U.S. in ways that can challenge our missile defense - such as conventional and nuclear intercontinental ballistic missiles, sea-launched land-attack missiles, hypersonic weapons, and space-based missiles that orbit Earth - it's critical to have radar systems capable of providing early detection.

The U.S. Department of Defense (DoD) budget for Fiscal Year (FY) 2019 highlights the importance of missile defense programs and calls for investments that “focus on layered missile defenses and disruptive capabilities for both theater missile threats and North Korean ballistic missile threats.”

Missile defense technology now under development by the U.S. is designed to counter all types of ballistic missiles – including short, medium, intermediate, and long ranges. Because ballistic missiles used by various players have different ranges, speeds, size, and performance characteristics, the Ballistic Missile Defense System is by design “an integrated, layered architecture that provides multiple opportunities to destroy missiles and their warheads before they can reach their targets,” according to information from the Missile Defense Agency.

The U.S. Air Force maintains three Ballistic Missile Early Warning System (BMEWS) radars that can detect attacks as well as carry out general space surveillance and satellite tracking. These BMEWS radars are at located at Thule Air Force Base in Greenland, Clear Air Force Base in Alaska, and Fylingdales Royal Air Force Station in England. (Figure 1.)

Figure 1: Pictured: The U.S. Air Force Ballistic Missile Early Warning System. Photo: U.S. Air Force Space Command.

Phased-array antenna technology sets these systems apart from mechanical radars, which require being physically aimed at an object for tracking and observation. Phased-array antennas remain in a fixed position, and Space Command describes its aiming or “beam steering” as being done in millionths of a second by electronically controlling the timing or “phase” of incoming and outgoing signals.

By controlling the phase through the numerous segments of the antenna system, the beam can be rapidly projected in different directions to enable interweaving of tracking pulses with surveillance pulses – so multiple targets, indicative of a massive missile attack, can be tracked at once.

Northrop Grumman and the ‘SMORS’ project

In 2018, the U.S. Air Force awarded Northrop Grumman with a contract to sustain and modify a worldwide network of ground-based radars deemed critical for missile warning and defense, as well as for space tracking missions.

Northrop Grumman’s work on the Sustainment and Modification of Radar Sensors (SMORS) project “will uphold and enhance the Air Force’s ability to detect missile attacks early, while also providing forces with critical situational awareness of objects in space,” says Joseph J. Ensor, vice president and general manager, space and intelligence, surveillance, and reconnaissance systems division, Northrop Grumman.

The goal is to ensure the high availability of ground-based radar systems for Space Command, including not only the BMEWS, but also the Precision Acquisition Vehicle Entry Phased Array Warning System (PAVE PAWS), and Perimeter Acquisition Radar Attack Characterization System (PARCS) radars, along with associated support systems.

The Air Force operates two PAVE PAWS radars, at Beale Air Force Base in California and Cape Cod Air Force Station in Massachusetts, both of which can detect submarine-launched ballistic missile attacks and also do space surveillance and satellite tracking. These are ground-based, two-faced UHF-band phased array radars.

PARCS, based at Cavalier Air Force Station in North Dakota, is a single-faced UHF-band phased array radar.

Achieving an LRDR milestone

In other missile defense radar news, in 2018, Lockheed Martin’s long-range discrimination radar (LRDR) completed a closed-loop satellite track with tactical hardware and software; it is now being built at the Missile Defense Agency’s site in Clear, Alaska. It’s expected to be operational in 2020.

To make the project happen, Lockheed Martin invested in a solid-state radar integration site (SSRIS) in Moorestown, New Jersey, to conduct testing. The SSRIS is a scaled version of the final LRDR radar and the company plans to continue using it for solid-state radar development.

“We designed and produced a scaled LRDR system that’s running with the actual tactical processing equipment and tactical software successfully,” says Chandra Marshall, LRDR program director for Lockheed Martin.

The SSR concept centers on a scalable, modular, and extensible gallium nitride (GaN)-based radar building block. Once completed, the radar system will serve as a critical sensor within MDA’s layered defense strategy to protect the U.S. from ballistic missile attacks. LRDR will provide acquisition, tracking, and discrimination data to enable defense systems to lock on and engage ballistic missile threats, according to Lockheed Martin.

Importantly, LRDR adds the capability of discriminating threats at extended distances by using the inherent wideband capability of the hardware combined with advanced software algorithms. LRDR integrates proven SSR technologies with proven ballistic missile defense algorithms, which are all based upon an open architecture platform. Lockheed Martin views SSR as the cornerstone of its current and future radar development and in its development of LRDR.

Putting missile defense to the test

In yet another example of ballistic missile radar advances during 2018, an operational live-fire test of the Aegis Weapon System Engage On Remote capability in Kauai, Hawaii, demonstrated its ability to track and intercept an intermediate-range ballistic missile (IRBM) target with an Aegis Ashore-launched Standard Missile-3 (SM-3) Block IIA interceptor.

The flight test involved an IRBM target launched by a U.S. Air Force C-17 in the ocean thousands of miles southwest of the Aegis Ashore Test site that launched the SM-3 Block IIA interceptor. Engagement relied on a ground, air, and space-based sensor/command and control architecture linked by the Ballistic Missile Defense System’s Command and Control, Battle Management, and Communications suite.

The flight test demonstrated “the effectiveness of the European Phased Adaptive Approach Phase 3 architecture,” says Missile Defense Agency Director Lt. Gen. Sam Greaves. “It was also of great significance to the future of the multi-domain missile defense operations and supports a critical initial production acquisition milestone for the SM-3 Block IIA missile program. This system is designed to defend the U.S., its deployed forces, allies, and friends from a real and growing ballistic missile threat.”

Sidebar 1