An April 2024 Congressional Research Service Report stated that the U.S. Navy’s new USS Constellation-class frigates do not have a tracker illuminator system to guide semiactive radar-homing missiles to their targets. Naval News asked the U.S. Navy to comment on this issue and what is causing frigate program delays.
Peter Ong 30 Aug 2024
The April 4, 2024, Congressional Research Service’s (CRS) FFG 62 frigate report can be found here. Under “Performance Effectiveness,” on page 19, CRS stated, “Unclassified risks to operational effectiveness include that the FFG 62 design does not have a tracker illuminator system, which is typically installed on other Aegis platforms…”
In late April 2024, Naval News contacted the U.S. Navy’s Sea Systems Command (NAVSEA) for comment on the CRS report. During an additional follow-up call months later, the NAVSEA spokesperson said the media inquiry went to the U.S. Navy at the Pentagon for answers. In July 2024, NAVSEA responded with the following comment from the U.S. Navy regarding the FFG 62 frigate design’s lack of a tracker illuminator system.
“While the FFG 62 weapon system shares commonality with other AEGIS surface combatants, it is designed to meet a different set of missions and requirements. Installation of fire control illumination is not required to meet the Constellation Class frigate requirements.”
U.S. Navy spokesperson
To better explain the tracker illuminators, Defense Industry Daily provides this brief: “The 3rd component, the AN/SPG-62 X-band radar `illuminators,’ which designate targets for final intercept by air defense missiles; DDG-51 destroyers have 3, and CG-47 cruisers have 4. During saturation attacks, the AEGIS combat system must time-share the illuminators, engaging them only for final intercept and then switching to another target.
In an era of supersonic anti-ship missiles that use final-stage maneuvering to confuse defenses, and can be programmed to arrive simultaneously, this approach is not ideal.
The US Navy’s Dual-Band Radar [DBR] relies on products from 2 different manufacturers, but they’re integrated in a different way. They also use a different base technology. The use of active-array, digital beamforming radar technology will help DBR-equipped ships survive saturation attacks. Their most salient feature is the ability to allocate groups of emitters within their thousands of individual modules to perform specific tasks, in order to track and guide against tens of incoming missiles simultaneously. Active array radars also feature better reliability than mechanically-scanned radars, and recent experiments suggest that they could have uses as very high-power electronic jammers, and/or high-bandwidth secure communications relays.
Many modern European air defense ships, from the British Type 45 destroyers, to the Franco-Italian Horizon destroyers and FREMM frigates, to Dutch/German F124 frigates, use active array search and targeting radars.”
This AN/SPG-62 “illuminators” statement by Defense Industry Daily could explain why using decommissioned Ticonderoga-class cruisers as docked missile defense AEGIS warships, such as in Guam ports, is not ideal. Naval News covered this cruiser idea for island missile defense here.
NAVSEA’s Comment on FFG 62 Frigate Program Delays
Naval News also asked NAVSEA for any comment on how the FFG 62’s design deviated from the Italian and French Navies’ variant of the FREMM multi-mission frigate, leading to program delays. Modifications to the FFG 62 design have resulted in commonality between the USS Constellation-class and FREMM frigate design from 85% to 15%.
NAVSEA replied, “The FREMM parent design (versus clean sheet) provided an incremental step to use an existing hull integrated with US Navy systems. Key design changes between FREMM and FFG 62 were an outcome of FMM [Fincantieri Marinette Marine] modifying their indicative parent design to comply with the requirements of the ship specification. There have been limited changes to the contract since award that were negotiated and agreed to with the shipbuilder.”
Naval News Comments
Naval News contacted Dr. Bradley Martin, a retired U.S. Navy captain, and Senior Policy Researcher at the RAND Corporation, a nonprofit Research Institute, for comment and analysis on the U.S. Navy’s reply.
Dr. Martin wrote via email: “The SPY radar is capable of operating in a track mode – i.e., beams from its phased array can be shifted from a search to track mode. However, some missiles rely [on] terminal illumination, specifically those with semiactive homing seekers. These kinds of missiles – most SM2s up to block 3 – track reflected RF energy from a ship’s illuminating radar.
“Wikipedia gives a good explanation of terminal illumination: The SPG-62’s role in Aegis fire control is to illuminate targets in the terminal interception phase. First, the ship’s main search radars—either theAN/SPY-1or theAN/SPY-6—detect and track the target. The Mk 99 FCS then launches surface-to-air missile(s) to intercept. If the interceptor missile uses semi-active radar homing (SM-2 or ESSM [Evolved Sea Sparrow Missile] Block 1), it will need an external radar to illuminate its target for terminal guidance, which is where the SPG-62 comes into play. The Mk 99 FCS points an SPG-62 toward the target, and it shoots a narrow radar beam that reflects off the target. The interceptor missile’s passive receiver homes in on these reflected emissions.”
Dr. Martin continued, “The weapons envisioned for the Constellation class are active homing – i.e., they have their own illuminators – do not require terminal illumination from the ship. The SM-2 Block IIIC, for example, has an active-seeker head, eliminating the need for terminal guidance from the ship.
“Lack of capability to provide terminal guidance limits the missiles FFG-62 can fire, but the ship should be arriving at a time when terminal illumination for semiactive missiles is less prevalent.”
Naval News contacted NAVSEA again to inquire if their answer implies that FFG 62 frigates will use only active-homing radar-guided surface-to-air (Standard family of) missiles in their Mark 41 Vertical Launch System cells. NAVSEA replied that such information isn’t releasable to the public and referred me to the FFG 62 Fact Sheet.
Dr. Martin also said this about the overall FFG 62 frigate program.
“I believe the FFG 62 will ultimately be an effective capability for the Navy. The design-requirements mismatch remains a matter of concern, but as this mismatch is resolved, the ship will ultimately fill a useful role.”
Dr. Bradley Martin, Senior Policy Researcher, RAND Corporation
