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NATO planning advanced submarine sensing and hunting technologies for Russian ultra quiet submarines

Russia is seeking to further bolster its sub-surface capabilities, with new generations of conventional and nuclear propulsion submarines, which promise to be significantly more difficult to detect and track for western naval forces. This includes the Yasen, Lada, Borei and Kalina classes of submarines. Russia’s United Shipbuilding Corporation (UAC) has announced the start of the development of a fifth-generation Husky-class stealth nuclear submarine to replace the existing Yasen-class boats.


Russian nuclear-powered submarines conducted an exercise near American military bases with the objective of avoiding detection as they came close to the US coast, a submarine squadron commander told a Russian military TV channel. “This mission has been accomplished, the submarines showed up in the set location in the ocean and returned to base,” the commander of the submarine squadron, Sergey Starshinov, told Zvezda. The date and location of the covert mission have not been disclosed, but the channel said the Russian nuclear-powered submarines “reached the very coastline of the US.”


Submarines are one of deadliest weapons which are hardest to detect, literally a pile of submerged nuclear weapons ready to unleash widespread destruction with single command. In case of a nuclear war the stealthy submarines have a greater chance of surviving the first strike. Once on high alert the boats can leave their bases stay undetected for months and can carry and fire missiles that could sink even the sturdiest ship and flatten entire cities.


NATO’s response to the underwater risk was initially hindered by reduced post-Cold War ASW focus, as emphasis shifted to expeditionary interventions and maritime security operations at distance. Rebalancing this emphasis and regaining ASW advantage is strategically vital for NATO, senior officials and analysts noted in a recent Royal United Services Institute (RUSI) report titled ‘Security in Northern Europe: Deterrence, Defence, and Dialogue’. In the report, Admiral James Foggo, commander of Allied Joint Force Command Naples, and Alarik Fritz, a senior research scientist at Center for Naval Analyses, argued that, with the North Atlantic critical to collective Western security, “the unavoidable operational reality is that, should conflict arise, whoever can exert control over this region can either protect or threaten all of NATO’s northern flank.”


Thus, deterring the most capable potential adversary – namely, Russia – is “the one constant that must guide NATO policies, operations, and forces”. Pointing to Russia’s increased underwater capability, they contested that “Russia’s submarines are more active than ever across the entire North Atlantic, not only testing our reactions but also familiarising themselves with the environment in which we operate.” Sustaining European stability will require, amongst other factors, NATO to “maintain [its] technological edge and positive balance of forces today and into the future”.


The latest ‘Trident Juncture’ exercise, off Iceland and Norway in October/November 2018, brought together NATO’s two main Standing Naval Forces (SNFs) – Standing NATO Maritime Groups (SNMGs) 1 and 2. Sixteen NATO and partner countries contributed more than 60 vessels (surface ships and submarines) and eight MPAs to serials covering ASW, amphibious, and other high-end tasks and constructed around carrier and expeditionary strike group operations. In a subsequent IISS speech in 2018, Adm Jones said task group operations are central to ASW, “doing what we call ‘all arms’ ASW – the ability to integrate mine counter-measures vessels, submarines, MPAs, … helicopters”.


To improve the output of ‘Trident Juncture’, Adm Foggo and Fritz argued that NATO should train for distributed maritime operations, enabled by advanced communications, multisensor networks, and coherent operating pictures, and should also look to actively exercise sea control to demonstrate and train abilities to deny freedom of manoeuvre to any adversary.



NATO builds technology and tactics to overcome Atlantic challenges

The RUSI paper also highlighted the role of new technologies and non-traditional modes of operation in regaining ASW advantage. “The alliance should use new technology and concepts to offset its disadvantage of space, time, and power in the northern region,” noted Rolf Tamnes, a professor at the Norwegian Institute for Defence Studies.


One participating organisation in ‘Dynamic Mongoose 2018’ was NATO’s La Spezia-based Centre for Maritime Research and Experimentation (CMRE). The CMRE studies all-things maritime, but was originally established as NATO’s ASW laboratory. The CMRE has been examining how NATO member states can add ASW through acquiring organic or shore-based unmanned systems, LePage explained. “The challenges of [employing] unmanned systems are many – especially for ASW, which is a high-end warfighting and sensing regime where you really bring your best arrays, your best sensors, your best dipping sonars, your [best] multistatic active sonobuoys,” with such high-end technologies deployed on highly capable manned platforms that bring good endurance and good speed of advance.


For exercises like ‘Dynamic Mongoose’, the CMRE deploys unmanned systems it is developing and/or decision support frameworks. In 2018, CMRE embarked its decision support team into SNMG1, on board the group’s flagship, the Royal Danish Navy Iver Huitfeldt-class frigate HDMS Niels Juel .


“Often, the tools available for planning, operations, and working on your [ASW] tactics are based on the concept of predicted sonar range, either passive or active,” said Dr Kevin LePage, the CMRE’s ASW programme manager. “If you’re trying to design your force laydown or dispositions for a mission, one of the first things you need is … predicted sonar range. You might place your assets one-and-a-half predicted sonar ranges apart, for instance, if you wanted to provide an [ASW] barrier. Predicted sonar range can be strongly dependent on your location in the operations box and also on the depth of your sensors and the target,” he said.


“We see a future where you need models that are able to accept as inputs all of the variable features of the environment, both for now and in the future – the ‘nowcast’ and the ‘forecast’ – to help you understand and drive the design of the force laydown to effectively conduct your mission. We see a future where there will be a more comprehensive evaluation in the area of operations of what your sonar coverage really is.” The reason for that, LePage explained, is that there are a lot of effects, either introduced by the bottom for littoral environments or by oceanographic fronts, that can cause dramatic changes on short spatial scales of predicted performance. Consequently, “your performance won’t be the same in every direction – even in [one] particular location, because in one direction there could be a front and in another it could be clear sailing”, he said.


“These are the kind of effects we think are going to be more and more important for decision makers to have at their fingertips, when they’re [determining] vulnerabilities and [how to] set their sensor depths and disposition of their platforms.” Thus, the CMRE embarked for ‘Dynamic Mongoose’ “to show … the importance of having this oceanographic ‘nowcast’ tied into good numerical models to provide the kind of detailed coverage predictions that will assist planners in the future”..


The different – and changing – dynamics of the North Atlantic’s underwater environment can shape force laydown, sensor effectiveness, and tactics. Alongside the challenge of harsh conditions including heavy seas, associated ambient noise, and cold water, the North Atlantic is characterised by bottom depths ranging from deep water to littoral environments (like Norway’s fjords), with constricted access in areas like the Greenland-Iceland-UK (GIUK)  gap. “In general, what we would expect is that, in littorals, you cannot really put energy onto a target or listen to a target without the energy interacting significantly with the bottom and the surface,” said LePage. “In deeper waters, however, you have the ability to have very low loss paths that are hardly ever interacting with the surface, or just periodically.”


The CMRE has been examining how NATO member states can add ASW through acquiring organic or shore-based unmanned systems, LePage explained. “The challenges of [employing] unmanned systems are many – especially for ASW, which is a high-end warfighting and sensing regime where you really bring your best arrays, your best sensors, your best dipping sonars, your [best] multistatic active sonobuoys,” with such high-end technologies deployed on highly capable manned platforms that bring good endurance and good speed of advance.


“The North Atlantic would be the big stadium, the real high-end game, with the highest stakes, against the most capable adversary, under the most difficult conditions. [It] is where you would keep your sea lines of communication open: that implies speed of advance for one of the ASW missions, conducting high-value unit [HVU] escort operations at high speed of advance. That places huge challenges on unmanned systems, unless they’re large,” said LePage. “You’re going to have to move quickly; you’re going to have to have endurance; you’re going to have to have seakeeping; you’re going to have to have robustness so that the operators are trusting what their unmanned systems are telling them.”


Conducting effective ASW operations using unmanned systems means tackling an already difficult problem with more, but perhaps less-capable sensors (being deployed on unmanned systems designed for improved affordability), connected through challenging environmental communications, and relying heavily on autonomy to execute intent and implement decisions and on software to reduce false-alarm rates while keeping actual submarine contacts. Consequently, LePage said, “there’s a lot of underlying S&T [(Science and Technology) work,] addressing critical enabling capabilities, that needs to be done to make maritime unmanned systems for ASW a solution for NATO countries in meeting their level of ASW ambition.”


LePage listed three primary North Atlantic ASW missions: a barrier mission, holding a target at risk as it transits a constrained geographical area; protected passage, where escorts move at speed to protect an HVU; and sanitising a ‘box’ at sea, for example to support expeditionary operations ashore. Each scenario requires different capabilities and, potentially, different unmanned systems and sensors. Generating persistent presence for ‘barrier’ missions, for example, may mandate less expensive but long-endurance surface or sub-surface systems. For HVU escort, however, high-speed – thus, larger – unmanned surface vehicles (USVs) may be needed, such as to provide a sprint-and-drift capability with an active dipping sonar; here, frigate-based unmanned helicopters could contribute, he noted.


However, with the potential offered by unmanned systems – especially adding presence to offset reduced manned platform numbers – LePage pointed to the benefits of seeking early wins in introducing unmanned capabilities. “One key advantage – an early win – might be that there are certain missions that high-end platforms are sometimes asked to take on that are placing that platform at uncomfortable levels of risk,” he said. “If it had some organic [unmanned] capability that could assist it to do some of those missions, maybe that would be an early and easy solution.” One example is using a submarine-based organic UUV for near-shore, shallow-water operations.


Multistatic technologies

NATO can also add ASW value by improving integration of existing sensors. Here, the CMRE’s ongoing work on multistatic concepts offers another early win. Such concepts seek to integrate an array of platforms and sensors in networked form to offer multiple target aspects and improved detection opportunities.


“Multistatics means that, if I had two frigates that were both [fitted with low-frequency active sonar or a hull-mounted sonar] and they were sailing along, say, seven miles [11 km] apart and pinging away, the second frigate could also process the pings of the first frigate,” said LePage. A benefit here is that this set-up – while not providing improved stealth against the target submarine or altering that boat’s own underwater picture – gives another target aspect or another detection opportunity.


Identifying underwater sonar reflections is like flying above a forest with the sun glinting off a lake below, LePage said. “There’s nothing else in the forest that’s going to glint like that,” he said. While noting that many underwater objects detected will be man-made, other systems like AIS [Automatic Identification System] or radar may help confirm that a subsurface hull detected belongs to a cargo ship. “Multistatics gives that opportunity for a high-strength target glint,” LePage said.


Unmanned systems that simply listen for contacts without moving or transmitting can add another layer of complication for the target submarine. “The submarine might have absolutely no idea where they are; so he’s optimising against some source banging away somewhere – it could be a buoy, it could be an unmanned system, it could be a frigate – but he doesn’t really know what his vulnerabilities are on his bistatic target strength and his Doppler. So he is losing the upper hand.” LePage noted that USVs fitted with towed array sonars or unmanned air vehicles deploying sonobuoys demonstrate how unmanned systems could add to the multistatic layers.


Although the CMRE has been developing multistatic approaches for some time, a current area of focus is standardisation agreements (STANAGs). “There’s work on standardising [multistatic] message sets so that countries can process each other’s pings,” LePage said. Such standards would support acoustic data sharing between different systems and different navies. “Right now, I think you would have a sort of ‘vendor lock’, or you might have a national multistatic capability between all the frigates of a certain class, but maybe no ability to work with a helicopter from [another] navy with an active dipping sonar.”


Collaboration to improve multistatic message content sharing would help overcome such barriers. LePage noted that the NATO Industrial Advisory Group is studying multistatic message content. He also highlighted bilateral collaborative experimentation, such as between France and the UK. Given than an SNMG consists of ships drawn from different navies, “you would need some sort of standards and upgrades to the processing software suites, exploiting messages for the various platforms to be able to exploit pings sent by other platforms. Right now, pings sent by other platforms are interference that might blind you to a certain area in the water.” Without integrated multistatics, LePage continued, “several sources going off at the same time in operations is interference. We want to turn that interference into collaboration and more detection opportunities.”


US Navy seeking advanced sub-hunting technology

The U.S. Navy wants to upgrade its ability to detect Russian submarines in response to assertive naval moves by President Vladimir Putin. The Navy is seeking to deploy a sophisticated surveillance device made by Lockheed Martin Corp. in the Atlantic Ocean. The device, towed by a ship, already is in use in the Pacific. As soon as mid-2016, the service also wants to send to the Atlantic a prototype networked “undersea sensor system” that “addresses emergent real-world threats,” according to a Defense Department budget document.


The prototype sensor network will be best used “in a choke point like Gibraltar” or a stretch of the North Atlantic from Greenland and Iceland to Britain, where Soviet submarines transited during the Cold War, Bryan Clark, a naval analyst for the nonpartisan Center for Strategic and Budgetary Assessments, said in an email.


The Navy proposals are evidence that “the U.S. military views Russian submarine activity in the Atlantic as both an immediate risk and an emerging long-term threat,” said Tom Spahn, a Navy reservist who writes on undersea warfare issues. The projects may be part of a strategy “to replace or upgrade our aging” undersea sensor system of hydrophones — underwater microphones — “made famous during the Cold War, which again points to Russia as the target,” Spahn said



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