The US Marine Corps is overhauling its electronic warfare capabilities supporting land and littoral manoeuvre warfare against a backdrop of ongoing Sino-US tensions in the Asia-Pacific.
Regardless of whichever candidate wins the U.S. presidential election in November, Sino-US strategic rivalry is unlikely to dissipate. Relations between the two powers have been difficult since 1949 when the People’s Republic of China (PRC) was established on 1 October that year. Matters worsened during the 1950 to 1953 Korean War. That conflict saw the PRC aid the Korean People’s Army as it invaded what is now the Republic of Korea. A mutual defence treaty signed by the Republic of China (RPC) and the U.S. raised Beijing’s ire and prompted the first Taiwan Strait crisis of August 1954. Taiwan has remained a bugbear of Sino-US relations ever since as the PRC’s government claims Taiwan as part of the former’s territory. In 1955, Taiwan and the ROC signed a mutual defence treaty and passed the Taiwan Relations Act in 1979. The act allows the U.S. to arm Taiwan, as well as ensuring commercial and cultural ties between the two countries. The 1979 act includes a clause stating that the U.S. will “resist any resort to force or other forms of coercion that would jeopardise the security, or social or economic system, of the people on Taiwan.” This wording stops short of an explicit positive security assurance. Nonetheless, it seems to suggest that the U.S. government could resort to force to protect Taiwan from any future military action by the PRC to forcibly seize and occupy the country.
Relations between Washington and Beijing gradually improved from the early 1970s with President Richard Nixon visiting the PRC in 1972. Trade relations between the PRC and United States normalised in 2000, and China joined the World Trade Organisation (WTO) one year later. By 2010, the PRC had become the world’s second largest economy after the U.S. valued at almost $1.3 trillion. China’s economic growth has resulted in an increasingly muscular strategic posture. As the decade grew to a close the then U.S. Secretary of State Hillary Clinton announced a strategic ‘pivot’ towards the Asia-Pacific. This move was largely seen as a riposte to the PRC’s growing economic and political power. By 2012, the United States’ trade deficit with the PRC had grown to circa $296 billion. The deficit was set against regional tensions concerning the PRC’s maritime claims in the South and East China Seas.
This combination of bilateral and regional tensions between the United States and the PRC mar relations between the two countries. Issues regarding bilateral trade and the extent to which Chinese imports affect domestic U.S. manufacturing add further complications. U.S. defence exports to Taiwan anger the PRC. In March 2024 Beijing seemingly abandoned a pledge to seek unification with Taiwan through peaceful means. A presentation to the PRC’s National People’s Congress by premier Li Qiang was notable for not mentioning peaceful unification with Taiwan. While not imminent, one must be cognisant that tensions between the U.S. and China could erupt into conflict.
Supporting the force
U.S. forces deployed to the Asia-Pacific would almost certainly be called upon to respond to any PRC aggression in the region. These forces include the United States Marine Corps’ (USMCs’) 3rd Marine Division (3rd MD) headquartered in Okinawa, Japan. This unit includes one headquarters and one reconnaissance company. Three manoeuvre regiments; the 3rd and 12th Marine Littoral Regiments plus the 4th Marine Regiment form part of the 3rd MD’s order-of-battle. The division forms part of the 3rd Marine Expeditionary Force (3rd MEF), also headquartered in Okinawa. The 3rd MEF comprises the 1st Marine Aircraft Wing, the 3rd Marine Logistics Group along with the 3rd MD. The 3rd MEF can also form the 3rd Marine Expeditionary Brigade and 31st Marine Expeditionary Unit using its composite elements. Several independent formations further comprise the 3rd MEF. These include a single Electronic Warfare (EW) unit, the 3rd Radio Battalion (3rd RB). In its own words, the battalion’s role “is to conduct signals intelligence and electronic warfare, limited cyberspace operations and special intelligence communications in support of 3rd MEF and its subordinate elements.”
Should war with China erupt, the 3rd RB would have a key role to play in detecting and identifying People’s Liberation Army (PLA) tactical and operational level communications networks and radios. These networks are likely to include High Frequency (HF: three megahertz/MHz to 30MHz), Very/Ultra High Frequency (V/UHF: 30MHz to three gigahertz) and Satellite Communications (SATCOM) links. The battalion will likely exploit these networks for Communications Intelligence (COMINT). The unit will also use Communications Jamming (COMJAM) to electronically attack these networks and radios. As the 3rd RB has a limited cyberspace remit, it may use COMJAM techniques to insert malicious code into these networks. Cyberwarfare attacks could adversely affect PLA networks and/or infect PLA battle management systems to hamper command and control.
Further clues on the roles of the 3rd Radio Battalion can be gleaned from MCRP 3-32D.1 Electronic Warfare, the corps’ most recent public articulation of its EW doctrine. Formations like the 3rd MEF form the ground/littoral manoeuvre elements of the Marine Air-Ground Task Force (MAGTF). The MAGTF is an operational-level force. Marine Air-Ground Task Forces include command, ground combat, aviation and logistics elements. The command element’s Electronic Warfare Coordination Cell (EWCC) “synchronises, coordinates and deconflicts all EW operations for the MAGTF” according to the doctrine. These tasks include developing EW concepts of operations; planning and coordinating electronic warfare including electronic attack, electronic protection and electronic support, and supporting MAGTF manoeuvre elements. Assistance provided to MAGTF manoeuvre elements could include intelligence gathered by MAGTF EW units. Broadly speaking, electronic attack uses Radio Frequency (RF) energy to attack hostile communications and RF-dependent capabilities like radar and satellite navigation. Electronic protection works to safeguard friendly RF-dependent systems and networks from electronic attack. Electronic support comprises the activities required to provide friendly electronic attack and protection. EWCCs perform their missions either afloat or ashore.
Capabilities
According to the doctrine, Marine land warfare EW elements are “primarily directed against tactical communications systems.” A USMC spokesperson told AMR via a written statement that “Marine Corps EW capabilities and systems are typically employed at the tactical level (although) they may impact objectives at the operational level.” Generally speaking, land/littoral EW capabilities target V/UHF signals. V/UHF transmissions have a line-of-sight range and cannot follow the curvature of the Earth. Even with tall antennas, this can limit the V/UHF signal range to tens of kilometres. Marine land forces EW elements “are usually located in the forward area of the battlefield, either with or near forward units.” Some USMC electronic warfare systems can also target High Frequency radio traffic. Some HF signals can achieve a beyond line-of-sight range by refracting their transmissions via the ionosphere. The ionosphere is an atmospheric layer between 30 miles (48 kilometres/km) and 600 miles (965km) through which HF signals cannot penetrate. Bouncing HF transmissions off the ionosphere gives them a beyond line-of-sight range. HF is popular for long distance intra-theatre operational and strategic trunk communications. If warranted by the mission, an RB can be broken down into smaller Signals Intelligence Support Units (SSUs). These deployments can be as small as four marines and their accompanying EW kit.
The spokesperson continued that the USMC “employs a range of diverse systems to support ground manoeuvre elements.” Regarding materiel, land/littoral manoeuvre units deploy the Herrick Technology Labs Communications Emitter Sensing and Attack System-II (CESAS-II) vehicle-mounted system. According to reports CESAS-II can detect, locate, identify and attack hostile HF and V/UHF communications traffic. Additional jamming support is provided by L3Harris’ CVRJ (Counter Remote Controlled Improvised Explosive Device Electronic Warfare Vehicle Receiver/Jammer). The CVRJ is optimised to detect and jam RF-enabled RCIEDs and is likely to detect and jam V/UHF signals to this end.
Dismounted EW is provided via the Marine Corps’ Sierra Nevada’s Modi-II backpack and vehicle-mounted architectures, collectively known as the Multi-Function Electronic Warfare (MFEW) system. Modi-II targets RF-activated RCIEDs but can also perform COMJAM. The vehicle-mounted version of the Modi-II is known as the Modi Vehicle Power Adapter-II. The MFEW progressively replacing the CVRJ capability, the USMC spokesperson noted.
Future evolutions
The overhaul of the USMC’s land warfare EW posture is occurring via an order of battle reorganisation and the acquisition of new materiel. In 2017, the Marine Corps published its Information Environment Operations Concept of Employment (IEOCOE) for the Marine Air-Ground Task Force. An authoritative article by John Haystead in the Journal of Electromagnetic Dominance in 2022 said that the IEOCOE undertaking reevaluates how the corps sees EW and information operations, particularly in the land domain. This process is needed, Haystead argues, as “(Corps) ground-based (EW) capabilities … have always been extremely limited”. The IEOCOE has resulted in the creation of MEF Information Groups, or MIGs. MIGs are deployed with each Marine Expeditionary Force headquarters. The groups are responsible for all information operations which includes the tasks and missions of Marine Corps’ EW elements. An Information Command Cell is included in each MIG which comprises the Electromagnetic Spectrum Operations Cell. The cell is analogous to the erstwhile EWCC units. At the tactical level, plans are afoot to deploy EW teams in each Marine infantry company.
With the retirement of the Grumman/Northrop Grumman EA-6B Prowler from USMC service in 2019, the USMC is left with a single airborne EW capability in the form of the AN/ALQ-231 Intrepid Tiger-II series. Developed and fielded by the Marine Corps Spectrum Integration Laboratory, Intrepid Tiger-II is a podded system initially designed to jam hostile V/UHF communications systems and networks. The AN/ALQ-231 was ostensibly designed as a gap-filling system. The USMC needed an airborne EW capability when Prowler, and later US Navy Boeing E/A-18G Growler EW aircraft, were unavailable to support land manoeuvre elements. The initial AN/ALQ-231(V)1 equipped McDonnell Douglas/Boeing AV-8B Harrier-2 combat aircraft. Rotorcraft like the Bell UH-1Y Venom light utility helicopter carry the AN/ALQ-231(V)3 and plans call for the AN/ALQ-231(V)3 to also equip the Bell AH-1Z Viper attack helicopter.
A new Intrepid Tiger-II variant, in the guise of the AN/ALQ-231(V)4, is imminent. Reports suggest this new version can detect, locate and identify hostile V/UHF communications systems and networks. This electronic support function is in addition to the Intrepid Tiger-II’s COMJAM role. The AN/ALQ-231(V)4 is mooted for the AH-1Z, UH-1Y and the Marines’ Insitu/Boeing RC-21A Blackjack Uninhabited Aerial Vehicles (UAVs). A further evolution, the AN/ALQ-231(V)1 Block-X, could equip USMC McDonnell Douglas/Boeing F/A-18 series combat aircraft. This AN/ALQ-231 variant is also being touted for internal installation on the Corps’ Bell-Boeing MV-22B Osprey tiltrotors and Sikorsky CH-53E/K heavylift helicopters. One key additional feature for the AN/ALQ-231(V)1 Block-X is its reported capability to attack hostile radars. This may mean that the system’s bandwidth has been increased to 18 gigahertz/GHz or 40GHz to allow it to target radars. Finally, the USMC’s Lockheed Martin KC-130J tankers could receive the AN/ALQ-231(V)5. This would be installed in the aircraft and replace the AN/ALQ-231(V)1 configuration they currently use.
The MAGTF Electromagnetic Ground Family of Systems (MEGFOS) is enhancing Corps ground-based EW capabilities. Haystead’s article says that the MEGFOS architecture is not only intended for COMINT/COMJAM missions but supports counter-RCIED and counter-UAV missions. The architecture will be carried by the USMC’s Iveco/BAE Systems’ Amphibious Combat Vehicle wheeled platform. MEGFOS iterations will also equip the Marines’ forthcoming Advanced Reconnaissance Vehicle. Backpack and wearable variants of the MEGFOS architecture are in the offing. For example, the USMC spokesperson said that the MFEW architecture will be replaced by MEGFOS from 2027. Nevertheless, “(a)s MEGFOS is still in the early stage of development, the process of selecting a vendor is underway, but no vendor has been selected at this time.”
It is important to note that the MEGFOS architecture, and Corps’ EW capabilities in general, will not be stove-piped. Marine Corps electronic warfare systems will be networked into the Department of Defence’s Joint Electromagnetic Battle Management System (EBMS-J). The first iteration of the EBMS-J was released in late 2023. The EBMS-J federates data delivered from service EW command and control systems like the US Army’s Electronic Warfare Planning and Management Tool and the Corps’ Spectrum Services Framework. The goal of the EBMS-J is to improve electromagnetic situational awareness across the joint force. In turn, the EBMS-J forms a key part of the US Department of Defence’s Joint All-Domain Command and Control (JADC2) system. JADC2 is developing and deepening intra- and inter-force connectivity at all levels of war to facilitate Multi-Domain Operations (MDO). MDO stresses such levels of connectivity to facilitate rapid and better-quality decision-making vis-à-vis one’s adversary during synchronous operations. As the Marine Corps’ spokesperson noted “(USMC) systems are constantly being adapted and updated to meet changing threats in the current and emerging operational environment.” Strategic rivalries in the Asia-Pacific illustrate that these processes will be as relevant to the Marine Corps EW posture as they are to the force’s sea, land, air and space capabilities.
by Dr. Thomas Withington
