By Brian Kerg
Signatures, Success, and Failure: Two Vignettes
January, 20XX: With the likely election of an aggressively pro-independence candidate as the new president of Taiwan, the People’s Republic of China initiates a plan to reunify this ‘rebel’ province with its homeland. Chinese anti-access/area denial (A2/AD) assets are activated across the theater. Peoples’ Liberation Army Navy (PLAN) fleets steam to key chokepoints, deterring foreign intervention, while conducting live-fire missile exercises around the Taiwan Strait to intimidate Taiwan and potential interlopers. With the Chinese Weapons Engagement Zone (WEZ) ensconcing the area of operations, Beijing is confident that no foreign force can interfere with their plans without drastic escalation that no country will accept.
But across the area of operations, small U.S. Marine and Navy detachments operating out of Expeditionary Advanced Bases (EAB) within the first and second island chains rapidly deploy several long-range precision fires systems. Launching swarms of unmanned aerial, surface, and underwater reconnaissance systems, they acquire the locations of the most critical ships of the Chinese fleet, communicating this data to American maritime and joint operations centers.
With targets acquired, Washington informs Beijing that the PLAN fleet will be sunk unless the threat of military action against Taiwan is withdrawn. In the diplomatic dust-up that ensues, America and its partners close the trap with Distributed Maritime Operations (DMO), sending disaggregated fleets into the area of operations, further pressuring China with the threat of massed effects from maritime forces.
China sees the off-ramp and takes it. Ships return to port, Taiwan breathes a sigh of relief, and normal maritime commerce resumes. Deterrence by denial avoids a shooting war between great powers.1
The preceding vignette illustrates how Expeditionary Advanced Based Operations (EABO) and DMO, aided by emerging fires and intelligence, surveillance and reconnaissance (ISR) technologies, can prevent America’s adversaries from applying fait accompli strategies. But consider, instead, another way the story might have played out:
Unbeknownst to U.S. planners, China detected the American EABs long ago. The naval forces communicated using predictable techniques, on easily detectable spectrum, while exercising poor transmissions discipline and signature management. The PLAN had a reliable laydown of American EABs in their theater long before Beijing executed its reunification plan.
As China closed the noose around Taiwan, PLAN forces simultaneously isolated the EABs in the electromagnetic spectrum, cutting off their primary communications pathways. Targeting information was spoofed, rendering the long-range precision fires systems at the EABs useless. Isolated and blind, the EABs were caught unawares as Chinese amphibious forces landed in Taiwan, forcing the sorely outgunned U.S. forces to surrender.
With the U.S. unable to check Chinese aggression without escalation that would lead to large-scale combat, the rest of the international community looked the other way as China forced Taiwan back under its control.
EABO and DMO are the Navy’s and Marine Corps’ bid for success in disrupting the fait accompli strategies of great power competitors, providing the deterrence by denial called for in the 2017 National Security Strategy (NSS) and 2018 National Defense Strategy (NDS). In order to succeed in the A2/AD environment cultivated by America’s adversaries, EABO and DMO will necessarily be facilitated by emerging fires, ISR, and communications technologies. But the critical vulnerability to EABO, DMO, and consequently to deterrence by denial, is signature management.
The risk assumed in EABO and DMO puts signature management at a premium. Detection or denial of Command and Control (C2) systems will hamstring the promise of both operational concepts. Emerging C2 techniques and technologies provide viable solutions to signature management, validating EABO and DMO, and ensuring the sea services will maintain a critical edge in competition and in war.
DMO, EABO, and Deterrence by Denial
The 2017 National Security Strategy (NSS) and 2018 National Defense Strategy (NDS) describe strategic competition with revisionist powers, namely China and Russia, as the central challenge facing the United States now and in the future.2 In pursuing advantages, such competitors flout the rules-based international order to further their own interests at the expense of those of the United States and its allies. To prevent the United States and others from rolling back their gains, competitors secure their advantages through pursuit and application of fait accompli strategies that quickly seize objectives and create A2/AD zones, preventing opponents from having the time or political will to strike back, as prolonged escalation may be deemed too costly.3 An example of a successful fait accompli was the Russian annexation of the Crimean peninsula from Ukraine. Even though the annexation was internationally condemned, wresting control of Crimea back from Russia would almost certainly require large-scale combat operations that would be considered unacceptable.
Historically, the U.S. deterred adversaries through a strategy of punishment. However, the growing military and economic strength of potential adversaries, combined with fait accompli strategies, makes deterrence through punishment nonviable. Instead, deterrence by denial is emphasized by both the NSS and NDS as the preferred means of countering adversary fait accompli strategies. It is the responsibility of the joint force to develop viable deterrence by denial options. While all of the services are working on this problem, the Navy and Marine Corps are supporting deterrence through their respective sea denial and sea control concepts, specifically EABO and DMO. These concepts look to overcome the challenges of the current and future security environment by transforming the application of traditional military principles through disruptive technologies and concepts of operation.
The Navy and Marine Corps are refining the mutually supporting concepts of DMO and EABO to provide joint force commanders with feasible options for deterrence by denial. DMO is premised on the disaggregation of naval forces at sea, distributing their offensive capability geographically.4 Forces are distributed, increasing their survivability, while offensive effects are capable of massing through synchronization and aggregation of sensors and shooters across a theater. This distribution accounts for the ever-increasing threat range of adversary WEZ, reducing the risk to U.S. warships.
DMO is complemented by EABO, in which Marine Corps forces enable sea control and sea denial by establishing and operating from EABs at sea and ashore, using a variety of platforms deployed in littoral regions. Once established in their EABs, naval forces deploy and operate sensor, shooter, C2 systems, and other capabilities required to persist forward as stand-in forces.5
Operating inside the WEZ, EABO enables the stand-in naval forces that provide sea control and denial, and changes adversary decision-making to favor U.S. interests, deters aggression, and prevents conflict. During full-spectrum combat operations, EABO-enabled stand-in naval forces allow joint and naval commanders to exploit opportunities to leverage stand-off forces and win battles at sea and ashore.6
The EABO concept is highly promising and could resolve the wicked problem presented by adversary A2/AD capabilities combined with fait accompli strategies. But EABO is characterized by an extremely high level of risk for EAB-hosted inside forces. The most immediate problem is enabling C2 while reducing detection to ensure EAB survivability, and reducing jamming to ensure lethality and utility at the decisive moment.
Once deployed within an adversary’s WEZ, inside forces are at constant risk of detection; they must put a premium on concealment. The increasingly contested electromagnetic spectrum, and accelerating capabilities to detect and intercept signals of any kind, mean inside forces will be challenged to communicate with a higher headquarters. This is an imperative because it is required for the command to fire on targets that will incur operational and strategic effects.
As stand-in forces aim to be deployed to key maritime terrain allowing them to employ fires against adversary ashore and afloat targets, they will often be within detectable range of shore-based and afloat direction finding (DF) systems. Communications using higher-power settings needed to successfully connect to higher headquarters will be highly susceptible to detection. Space-based ISR will also be regularly conducting surveillance on this key maritime terrain. Any misstep in the use of current C2 systems will reveal the locations of EABs, allowing adversaries to take steps that will mitigate their utility to any plan for deterrence.
Emerging tactics and technologies can be employed to overcome these signature challenges, mitigating the greatest risks to the inside forces that will be conducting EABO.
For the purposes of communicating while avoiding detection and allowing inside forces to reduce signature and remain concealed in the electromagnetic spectrum, the High Frequency (HF) band is the premier option. In the EAB environment, communications systems using frequency bands higher than HF remain easily detectable; in concert with their low footprint, rapid set-up, and network flexibility, HF radios are the most viable candidate for successful signature management.7 But even HF in normal operating modes is likely to be detected if the location and direction of propagation are being scanned by current DF systems at the time of transmission.8
HF Low Probability of Intercept (LPI) is a tactic that rapidly varies the power output and frequency of HF channels used to transmit, greatly reducing the likelihood of detection.9 With appropriately trained personnel, certain maritime communications systems are currently capable of employing HF LPI.
The challenge is that no training standard currently exists by which to prepare naval communicators to use this technique. Whether HF-LPI is employed or not, and how well it might be executed, is completely at the discretion of individual ship and unit commanders. Though the principles behind HF-LPI are decades old, disruption must first occur in existing standard operating procedures and communications practices across the fleet to ensure HF-LPI is a technique in which personnel are reliably proficient. Such an initiative would be remarkably simple and affordable to implement today, providing an asymmetric advantage over enemy DF capabilities, if the will to employ HF-LPI is exercised.
Institutionalize over Time by Automating Spectrum Modulation
While training in HF-LPI techniques provides a short-term solution, automating this and similar means by which to conceal presence in the electromagnetic spectrum is the long-term answer by which to revolutionize signature management. Emerging spectrum modulation techniques, embedded in systems being researched and developed, will provide this capability.
While Frequency Hopping Spread Spectrum (FHSS) is a tried-and-true method to rapidly move across frequencies, new variations provide greater protection. Adaptive Frequency Hopping (AFH) currently avoids crowded frequencies to support Bluetooth, but can be similarly used to avoid frequencies that adversaries are scanning or monitoring. Direct Sequence Spread Spectrum (DSSS) randomizes bit transmission, and is currently in use supporting Wi-Fi networks. While most applications seek dispreads to increase the signal-to-noise ratio, anti-intercept methods would be complemented by reversing this process, hiding the signal in the noise. Fielding systems that automate these spectrum modulation techniques will minimize signal detection, interception, and exploitation.10
Guarantee Signal Integrity – Systems-Based Interceptor and Jammer Rejection
Eventually, inside forces will have to increase their signature when they employ their fires systems for the purposes of achieving deterrence, and when this time comes, signal integrity will trump the need for signature concealment. The Defense Advanced Research Projects Agency (DARPA) is currently developing communications technologies with the potential to achieve this end. The Hyper-wideband Enabled Radio-Frequency Messaging (HERMES) system works with extremely wide radio frequency bands, while deploying several interceptor and jammer rejection techniques, such as processing gain, integrated filters, and active cancellation.11 The broad spectral spreading further challenges detection systems and increases interference resistance.12 Similarly, the Protected Forward Communications (PFC) program allows military forces to persist and operate in a contested electromagnetic environment using a structured system engineering method.13 The PFC program would protect not only external communications from an EAB to higher headquarters – for example, the order to fire from an EAB at an enemy ship – but also internal communications and signals, such as the signal for a system to fire from an operator within the EAB, and signals from a sensor that would guide ordnance onto target.
Hide in Plain Sight – Nuke the Spectrum
It is not hard to hear a single voice, even in a large room. However, it is very difficult to hear that voice in a crowd. We need to build the haystack in which to hide the needle. At present, EABs and ships operating in the first and second island chains present isolated voices that are susceptible to detection and targeting at even a single breach of signature management discipline. Artificially raising the signature baseline will provide a robust electromagnetic canopy under which inside forces can conceal themselves. Rather than operating under an overarching philosophy of carefully maintained silence and signature control, saturating the spectrum with numerous false emissions can overwhelm an adversary’s ability to make sense of the environment and provide openings for one’s own forces to emit and communicate.
Currently, swarming technologies are being developed and fielded to provide combat power via small, cheap, attritable unmanned systems. The Office of Naval Research (ONR) and Naval Sea Systems Command (NAVSEA) are presently testing a ‘ghost fleet’ of small, interconnected attack boats.14 Similarly, DARPA is also experimenting with its Gremlins program, providing low cost swarms of interconnected, unmanned aerial systems launched from a larger aircraft.15 While these systems aim to provide sensor and shooter functions, the concepts can be easily modified to serve a signature deception function. Outfitting swarms of unmanned vehicles instead with transmissions systems that communicate on the same frequencies, power levels, and data rates as those C2 systems employed by inside naval forces, they would provide a swarming mask of signature in any operating environment.
A functional example is the Miniature Air-Launched Decoy (MALD), jointly developed by DARPA and Raytheon. The MALD is a low-cost, expendable air-launched system that simulates flight profiles and signatures of aircraft.16 Combining this system with similar decoys deployed across the maritime domain will further confound adversaries.17 By providing a litany of other targets to detect and target, naval planners will have ‘nuked the spectrum,’ creating an exasperating targeting dilemma for adversaries who will have to dedicate an untenable amount of resources to separate the signal from the noise. Naval inside forces, whether operating on EABs or aboard ships supporting DMO, will have the concealment they need to mass effects inside the WEZ and provide sea denial and sea control.
Managing Signature for Deterrence and Denial
The sea services aim to provide deterrence by denial through the related concepts of DMO and EABO. Stand-in forces operating from EABs inside an adversary’s WEZ can overcome enemy A2/AD, prevent competitors from employing fait accompli strategies, and secure U.S. interests across the globe.
However, the high risk assumed by inside forces makes signature management a paramount requirement for success. Conventional means and methods of communications and combat systems operation mean inside forces run a high risk for detection and jamming. By applying emerging tactics, such as HF LPI, along with emerging technologies, including HERMES, PFC, modulation techniques, and spectrum deception, stand-in forces can manage their signature and maintain signal integrity. In acquiring, fielding, and employing these tactics and technologies, EABO and DMO will be viable concepts by which deterrence by denial can be realized. Signature management secured in these ways will ensure the sea services maintain our nation’s advantage to prevent, and if necessary, win the next war.
Brian Kerg is a Marine Corps officer and writer currently serving as the Fleet Amphibious Communications Officer, U.S. Fleet Forces Command. He is a Non-Resident Fellow at Marine Corps University’s Brute Krulak Center for Innovation and Creativity. His professional writing has appeared in War on the Rocks, Proceedings, The Marine Corps Gazette, and The Strategy Bridge. His fiction has appeared in The Deadly Writer’s Patrol, Line of Advance, and The Report. Follow or contact him @BrianKerg.
1. Brian Kerg, et al., “How Marine Security Cooperation Can Translate Into Sea Control,” War on the Rocks (accessed 27 Jan 2020: https://warontherocks.com/2019/09/how-marine-security-cooperation-can-translate-into-sea-control/). Modified vignette used with author’s permission.
2. National Security Strategy of the United States of America, (accessed 28 Jan 2020: https://www.whitehouse.gov/wp-content/uploads/2017/12/NSS-Final-12-18-2017-0905.pdf).
3. Mike Gallagher, “State of (Deterrence by) Denial,” The Washington Quarterly 42 no. 2, (Accessed 27 Jan 2020: https://cpb-us-e1.wpmucdn.com/blogs.gwu.edu/dist/1/2181/files/2019/06/Gallagher.pdf)
4. Kevin Eyer and Steve McJessy, “Operationalizing Distributed Maritime Operations,” Center for International Maritime Security (accessed 28 Jan 2020: https://cimsec.org/operationalizing-distributed-maritime-operations/39831).
5. Headquarters, Marine Corps, “Expeditionary Advanced Base Operations,” U. S. Marine Corps Concepts and Programs, (accessed 28 Jan 2020: https://www.candp.marines.mil/Concepts/Subordinate-Operating-Concepts/Expeditionary-Advanced-Base-Operations/)
6. Jim Lacey, “The ‘Dumbest Concept Ever’ Might Just Win Wars,” War on the Rocks, (accessed 28 Jan 2020: https://warontherocks.com/2019/07/the-dumbest-concept-ever-just-might-win-wars/).
7. National Telecommunications and Information Administration, “Department of Defense Strategic Spectrum Plan,” NTIA, (accessed 01 Feb 2020: https://www.ntia.doc.gov/files/ntia/publications/dod_strategic_spectrum_plan_nov2007.pdf).
8. National Urban Security Technology Laboratory, Radio Frequency Detection, Spectrum Analysis, and Direction Finding Equipment, (New York: Department of Homeland Defense, 2019), 12.
9. G. Bark, “Power control in an LPI adaptive frequency-hopping system for HF communications,” HF Radio Systems and Techniques, Seventh International Conference, Conference Publication No. 441., August 1997.
10. Syed Shah, “Assured Communications,” Milcom 2015 Presentation, (October 2015).
11. Tom Rondeau, “Hyper-wideband Enabled RF Messaging,” DARPA, (accessed 28 Jan 2020: https://www.darpa.mil/program/hyper-wideband-enabled-rf-messaging).
12. DARPA Outreach Office, “The Incredible Loudness of Whispering,” DARPA, (accessed 28 Jan 2020: https://www.darpa.mil/news-events/2016-08-30).
13. Paul Zablocky, “Protected Forward Communications,” DARPA (accessed 28 Jan 2020: https://www.darpa.mil/program/protected-forward-communications).
14. Kris Osborn, “The US Navy is Building a Swarm ‘Ghost Fleet’”, The National Interest (accessed 23 February 2020: https://nationalinterest.org/blog/buzz/us-navy-building-swarm-ghost-fleet-42372).
15. Scott Wierzbanowski, “Gremlins,” DARPA (accessed 23 February 2020: https://www.darpa.mil/program/gremlins).
16. Raytheon, “MALD Decoy,” Raytheon Missiles & Defense (accessed 03 August 2020: https://www.raytheonmissilesanddefense.com/capabilities/products/mald-decoy).
17. Walker Mills, “A tool for Deception: The Urgent Need for EM Decoys,” War Room (accessed 03 August 2020: https://warroom.armywarcollege.edu/articles/tactical-decoys/).
Featured Image: U.S. Marine Corps Cpl. Dylan Griffen (Left), a field radio operator, and Lance Corporal Brent Millard (Right), an anti-tank missileman assigned to 1st Air Naval Gunfire Liaison Company, I Marine Expeditionary Force Information Group, conduct pre-flight maintenance at San Clemente Island, California, May 1, 2020. (U.S. Marine Corps photo by Sgt. Manuel A. Serrano)