LT Davis is enrolled in the Undersea Warfare Program at the Naval Postgraduate School, Monterey. This article was submitted as a research paper for a course. –Ed.
EXECUTIVE SUMMARY
Since the early days of submarine operations, the Navy has attempted to solve communication problems with submarines. Traditionally, submarines receive a commander’s guidance and develop a plan to execute. Unlike our surface combatants, a submarine typically operates forward deployed with very little two-way communication to a parent command. If a submarine completes its mission or needs to contact its parent command, a submarine may come off-station and communicate at a safe distance to avoid counter-detection. While communicating safely at distance has been very successful in the past, emerging technologies could alleviate coming off station and potentially be an asset multiplier for the submarine force.
With the introduction of unmanned vehicles to the fleet, the undersea communications structure can adapt and include this technology. First, it is essential to develop the appropriate communications technology to leverage unmanned underwater vehicles (UUVs). Currently, the ability to transfer data to and from UUVs is slow, unless an UUV comes to the surface to transmit the data via satellite (Iridium) or possibly some other line of sight method. An UUV surfacing to transmit data increases the probability of detection. Instead, if UUVs could transfer data underwater quickly, a network of UUVs and a submarine could work in tandem,
providing real time analysis to each other while minimizing counter-de- tection. Researchers in industry and at universities are developing tech- nology towards solving this underwater communication problem.
Besides developing and upgrading communications technology, subma- rine leaders should also consider how the force wants to pair UUVs and submarines. Does the Navy view the submarine as a potential command platform for UUVs, or does the Navy want to maintain the status quo and intend to have submarines operating independently? This paper ad- dresses the command and control question and finds that a submarine is a suitable command and control platform for UUVs, increasing the capabilities of both the submarine and UUV while maintaining stealth capabilities. With near peer competitors developing better undersea tech- nology, the Navy needs to develop and implement emerging technology to maintain undersea dominance.
INTRODUCTION
Throughout history, military leaders sought new technologies and tools to gain an advantage over the adversary. Whether that technology is a tool, such as a longbow, or a complex system, such as a submarine, new technologies disrupted conventional tactics and changed the way a war is fought on both an operational and strategic level. In modern warfare, a network of highly advanced and integrated manned and unmanned plat- forms is one new technology that has revolutionized warfare. Integrated communications, command, and control (C3) facilitated the develop- ment of precision guided munitions, such as the Tomahawk Land Attack Missile, and allowed the United States to remove some aviators away from the battlefield with unmanned aerial vehicles (UAV). The U.S. Navy (Navy) relies on the communications structure for disseminating orders, for fixing a position via Global Positioning System (GPS), and for weapons placement. Even though the Navy has dominated the seas with the current C3 structure, change is required to maintain an advan- tage. While networks and communications have brought a significant advantage to both the surface and air components of the Navy, the under- sea domain lags behind due to the complexity of underwater operations. This paper explores these barriers and looks at new technology that can be leveraged for future use. The next technological leap in undersea war-fare is the collaboration between submarines and UUVs, which should be leveraged quickly to maintain undersea dominance.
MOTIVATION
The changes required in the Navy’s communications structure are due to an increasingly dynamic world. Globalization is occurring at a rapid pace. Currently, 50,000 merchant ships are registered for interna- tional trade and more than 150 countries have at least one merchant ves- sel flagged to their own country. International shipping is responsible for 90% of world trade and accounts for over half a trillion dollars annually in revenue across the world. With many countries dependent on mar- itime trade for food and raw materials, international shipping remains vital for world prosperity.
Besides traditional shipping, the maritime domain also contains a large of amount of submerged cables that connect the world. Undersea cables transmit data, which allow global institutions and sectors of com- merce to operate. Currently, over 400 submarine cables transmit 99% of all data across the internet at rates of up to 160 terabits/sec. With many American companies laying the cables, the Navy should periodically monitor these cables to protect national interest and prosperity.
U.S. prosperity depends on these maritime functions and both inter- national shipping and undersea cables are at risk. Traditional adversaries, such as Russia or China, are rapidly improving their naval technology to disrupt operations. In September 2015, a Russian spy ship, Yantar, cruised along the east coast of the United States and sailed to Cuba with two deep water submersibles. Although intentions were not clear, the Yantar, with the deep-water submersibles, had the ability to cut undersea cables. Threats to the maritime domain can also come from non-state actors and terrorist organizations. In 2016, Iranian-backed Houthi rebels fired anti-ship cruise missiles at the USS Ponce and USS Mason oper- ating near the Bab el Mandeb Strait, a strategic chokepoint. Both these instances highlight threats to different parts of the maritime domain. In both cases, the proposition of losing undersea communications or clos- ing off a strategic chokepoint are unacceptable to the United States. The Navy is currently tasked with protecting these vital national interests. In order to adequately protect them, the Navy needs to incorporate and integrate all available platforms in the monitoring and defense of these interests, including manned and unmanned undersea vessels.
CHALLENGE
To integrate submarines and UUVs, one must overcome the com- munication challenge. During World War I and II, German submarines communicated with command posts via shortwave radio signals. These signals were intercepted, and many German U-boats were sunk after the British broke the Enigma Codes. The breaking of the Enigma Code was a major turning point in the war. The United States and Great Britain were able to change strategy from convoy protection to hunter-killer groups. After the war, and with the advent of the nuclear age, the Navy developed various methods to maintain secure communications. Subma- rines utilize various mast and antennas to receive/transmit orders and in- structions across the energy spectrum. These communications, however, require a mast out of the water, slowing the submarine and increasing the probability of detection. Other communication advancements allowed the submarine to tow a VLF wire or buoy to maintain VLF communi- cations. These communications facilitated secure communications with less probability of detection, but still required that the submarine transits at slow speed in order to receive communications. Since the signal can only penetrate a few feet under the water, a speed restriction is also re- quired to ensure the towed communication equipment remains near the surface. In the late 1950s, the Navy sought to address the speed chal- lenge by testing extremely low frequency (ELF) communications. Al- though the data rate was low, the project proved that large antennas could communicate with a submarine at depth/speed. Following the end of the Cold War, the Navy ended the program due to the high cost and low data transmission rates. Submarines’ ability to communicate and receive data at depth without speed restriction would be a tremendous advantage to the operational commanders on the battlefield.
DEVELOPMENTS
Innovations in undersea communications will allow multiple plat- forms to successfully operate underwater simultaneously. Researchers at SUNY-Buffalo are developing software to help increase data transfer rates through waterproof modems. Underwater data transfer from UUVs is slow. In many cases, the amount of data that needs to be transferred requires the UUV to come to the surface and transfer data via Iridium or possibly a line of sight communication system. The researchers from SUNY-Buffalo have demonstrated data transfer rates up to 200 kilo- bits/sec at a distance of 200 meters. As research continues, data rates may increase to 300 kilobits/sec, along with range to 500 meters. Even though these rates and ranges seem small, they represent an exponen- tial advancement of current technology and facilitate rapid data transfer, minimize counter-detection, and extend the life of the vehicle.
While researchers in Buffalo are attempting to solve slow data rate transfers, the Defense Advanced Research Projects Agency (DARPA) is attempting to develop a network through Tactical Undersea Network Architecture (TUNA). The TUNA program will establish a tactical net- work via buoys connected via fiber optic cables. Simulation, modeling, and preliminary sea tests have been completed in the past two years. While the intent of TUNA is to restore tactical network connectivity for a carrier strike group, it could be utilized for undersea applications. UUVs could transfer data to a receiver situated on a buoy and incorporate that data into the tactical network via TUNA. A possible situation could be placing passive acoustic sensors on a small UUV in the sound channel. The UUV could transmit its data to a receiver and incorporate the data into the tactical network around the carrier or near a submarine. In this scenario, an UUV is the first line of an anti-submarine warfare defense picket around a CVN in a designated operating area. Advancements such as TUNA and waterproof modems could make the immediate incorpora- ton of UUV’s data feasible, thus increasing their effectiveness and mis- sion sets.
Besides advancements in communications, advancements in navi- gation are also being developed for undersea sensors. GPS is currently the main method to verify ships’ position. While GPS has revolutionized operations, it is a vulnerability that must be mitigated for future forces. Near peer competitors, such as China, have demonstrated the ability to destroy satellites in low earth-orbit. The Chinese Dong Ning -2 missile is capable of striking high earth-orbit satellites, such as the GPS constel- lation in medium earth-orbit. One can assume that China would likely target GPS satellites in the event of a conflict. To mitigate the effects on submarines and other undersea vehicles, DARPA is developing “under- water” GPS known as Positioning System for Deep Ocean Navigation (POSYDON). POSYDON would provide positioning and timing infor- mation to undersea platforms via a series of small acoustic sources in an ocean basin. DARPA is currently collaborating with BAE systems to complete the modeling of signal propagation in the water column. Even though the technology is still evolving, POSYDON represents a new communication ability that would change operational patterns for undersea vehicles.
VISION
In a 2011 Proceedings article, Admiral John Richardson and Lt. Cmdr. Brent Johnston advocated for incorporation of UUVs into the fleet and laid out some practical C3 recommendations. Their recommendations include having submarines utilize unmanned systems for transmitting communications, controlling UUVs with short range communications, and integrating UUVs into current C3 structure. Combining TUNA and the research at SUNY-Buffalo could fulfill the communication recom- mendations proposed in the article. During future operations, a SSN/ SSGN on mission could utilize a series of forward deployed UUVs as a force multiplier. A mission commander onboard the submarine could task the UUVs for various mission sets. The submarine could then con- duct its own mission and then meet the UUV at a preprogrammed ren- dezvous point. The data the UUVs gathered could be transferred at a quick rate wirelessly and analyzed onboard. If communications need to be transmitted to a parent command, the mission commander could task one of the UUVs to transit to an area safely away from the submarine and then transmit the message.
Command and control of the UUVs will become a priority once UUVs become more prevalent in theater. For the theater commander, UUVs should be treated as if they were a manned submarine, in terms of prevention of mutual interference and waterspace management. In other words, a mission commander would assign an UUV to operate in an area and the UUV would constrain itself to that area. In the event that an ob- jective required multiple UUVs operating in the same area, depth restric-tions could be placed on the vehicles to mitigate the potential risk of col- lision. If a submarine was operating in the area with a LDUUV or UUV detachment as part of a mission, the submarine commander should be given authority to task and operate undersea mission capable UUVs. The submarine commanding officer should be given authority and autonomy to utilize the UUVs in accordance with guidance and intent statements.
In a future conflict, a submarine could effectively utilize UUVs for targeting, communications, and intelligence gathering. In a potential scenario, a LDUUV operating independently in theater could deploy an undersea network, similar to the DARPA TUNA program. A nearby sub- marine, or even the LDUUV, could also deploy multiple small UUVs with a passive sonar to extend the reach of the submarine. The UUVs could acquire and potentially track an adversary submarine or surface action group and pass the real-time information through the network to the submarine. With tracking information, the submarine could move to an ideal attack position and fire a salvo of torpedoes, destroying the ad- versary submarine or surface action group, all the while minimizing the probability of counter-detection prior to firing a torpedo. The submarine could then designate a communication UUV to transit to an area away from the submarine and communicate further intentions to the theater commander.
This future scenario would require significant training for the sub- marine crew. Fleets could incorporate UUV operations as a part of the pre-deployment work up and certification process. The certification pro- cess will verify that the submarine crew could handle operations with UUVs while forward deployed. As mentioned earlier, a dedicated mis- sion commander of the UUVs onboard enhances a submarine ability to conduct operations. A mission commander and their staff can assist the submarine commanding officer and wardroom in the planning and exe- cution of missions incorporating UUVs. Whether the submarine crew or additional personnel with expertise controls UUV operations, the ability for a submarine to act as the command and control node of UUVs would mark an advancement in undersea warfare capabilities.
CONCLUSION
In a relatively short number of years, the Navy will operate with mul- tiple UUVs in theater, conducting their own missions and tasks. UUVs represent a great force multiplier and allow the Navy to maintain an ad- vantage over near peer rivals. However, in order for UUVs to operate forward deployed, communications and navigation advancements are required for successful deployment. Advancements in underwater data transfer capabilities could potentially allow a submarine and a series of UUVs to pass real-time information to each other, increasing situational awareness. The ability of TUNA to network multiple platforms under- water could potentially expand the area from which all UUVs operate in tandem. In order to have multiple UUVs operating in the same area, the UUVs must know its own position with accuracy. Through POSYDON, multiple UUVs and a submarine could operate inside a relatively small area with safety requirements met.
For command and control of UUVs, the submarine force is well situ- ated to act as the command and control node. With the potential advance- ment of POSYDON, a submarine could task UUVs to a specific rendez- vous point with high certainty that the UUV will arrive at that location for data transfer. This command and control ability would expand the submarine capabilities and situational awareness, all while maintaining stealth for the submarine and UUV. The advancement of communication and navigation capabilities underwater represent the next great technolo- gy leap that can combine the unique capabilities of both a submarine and UUV, resulting in a more lethal and capable force.
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