From submarine incursions to increasingly sophisticated drug smuggling, sonar's missions are many and varied. To address these issues, fleets need systems for coastal patrol ships and small vessels
In recent years, a number of technological and operational trends in sonar development have emerged, supported by the increased demand for these systems for small vessels.
According to Gabriel Jourdon, head of hydroacoustic stations (GAS) at Thales, anti-submarine defense (ASW) has been the main task of sonar stations for decades. At the same time, the number of submarines in the world is growing, more and more countries are adopting them for service, and this causes concern in the military community.
“Active economic activity at sea, in particular the use of ocean resources, forces states to take measures to control and protect their economic zones,” he said. - Territorial conflicts at sea arise here and there, and the invasion of a submarine into the exclusive economic zone is the main problem. This problem is compounded for some countries by the fact that large areas need to be protected.”
These interrelated trends are driving the demand for PLO systems, in which sonars are a key component. “Most fleets and countries are faced with the task of protecting their national sovereignty, their commercial and economic interests and countering the invasion of submarines into their national waters,” says Jourdon.
Money matters
However, the high cost of such PLO ships. such as frigates, contributed to the fact that GAS began to be installed on smaller platforms and even non-military ships, which were not originally intended for high-intensity ASW. This, for example, fully applies to coastal zone patrol ships (SKPS).
“The idea here is to either complement existing ASW assets, or alternatively give the fleets of developing countries basic ASW capabilities. Its implementation will require effective, sea-tested solutions with stable characteristics and real capabilities of the PLO."
The GAS should not negatively affect the navigation capabilities of the ship, added Jourdon, noting that his company's compact hull sonar BlueWatcher was designed from the outset to "have a minimal impact on the ship's maneuverability and speed."
Thales focuses on the development of sonars for SKPS and other small vessels. At Euronaval 2014, for example, she showed a line of new GASs. In addition to BlueWatcher, it also includes the CAPTAS-1 GAS with variable immersion depth.
The BueWatcher "provides superior detection and tracking capabilities in noisy shallow waters," Jourdon said, but he noted that this compact GAS can also operate at depths over 10 km. "It makes an invaluable contribution to the ship's security system while also helping to avoid obstacles in front of the ship."
The CAPTAS-1 “is the key PLO tool” in the company's compact radar range, providing detection at medium ranges up to about 30 km. “He is making a big contribution to the submarine containment process,” he added.
Both multifunctional systems are designed to work in a wide variety of conditions, and they have proven themselves well on ships with small displacement. In some fleets, they are usually used as an additional element of an ASW. Both Thales products are in good demand in promising foreign markets including Asia, Latin America and the Middle East.
Jourdon added: “Recently, demand has evolved towards efficient sonar systems that can become an indispensable element of fleet operations to ensure security in coastal and deep waters. They should be compact for installation on small ships, easy to operate, perform the required tasks at an affordable cost."
Changing requirements
Thomas Dale, representative of the Marine HAS Department at Kongsberg Maritime Subsea, also noted the increased demand in the VCR industry, where multitasking capabilities are sorely needed. "Multitasking platforms and SKPZ should be able to find not only large objects such as submarines, but also smaller objects such as ultra-small submarines, floating containers or mines."
The requirements for the range of the GAS for SKPS and frigates are often different. The SKPZ requires a GAS with a range of 10-15 km. This is also evident in the fast patrol boat market, where medium-range sonar is often sufficient. Several boats "can swarm" at the same time, thereby expanding the field of view of all vessels in the group. “You add the GAS range of three, four, five vessels, as a result, you significantly increase the coverage range by using several vessels,” he explained.
According to Dale, the complex of tasks of the SKPZ, however, forces us to seek a balance between range and capabilities. “SKPZ operate more or less independently. The trade-off in the SKPS market is that you need a GAS at a reasonable price that is easy to install and that can work in several tasks - this is more important than just the range of the GAS alone”.
Medium frequency HAS can be especially useful for detecting small surface vessels. Dale noted that “it is difficult to spot an object like a rigid hull inflatable boat at night, especially if you are in choppy waters. But if you have a GUS, then you can hear it in passive mode or detect a ship or its wake in active mode."
Kongsberg is focusing on coastal waters, Dale said. “This segment is more than just PLO. Our products search for objects throughout the water column and on the seabed. They track surface ships as well as submarines and unmanned underwater vehicles. Our technology is designed to solve problems with reverberation (sound reflection) and work in coastal waters."
He drew attention to the SS2030 sonar mounted in the ship's hull and its container version of the ST2400 Variable Depth Sonar. Although they are primarily intended for coastal PLO, they have wider applications, for example, obstacle avoidance, mine detection and tracking of boats, underwater vehicles and other objects.
To this end, Kongsberg GASs have been installed on a range of small and medium-sized ships, including Coast Guard vessels and fast patrol boats. For example, the Chilean navy research vessel "Cabo de Homos" was equipped with the SS2030 GAS last year to search for and locate wrecked submarines, which has been successfully demonstrated in search and rescue exercises.
“Often SKPZs are built without sonars, but we hope that this will change as fleets become more aware of the multitasking capabilities of a mid-range sonar,” Dale said.
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Detecting divers and swimmers
UK based company Sonardyne International has benefited from the growing demand for detection systems for divers and swimmers. For example, in July last year it announced a new contract to supply an unnamed Southeast Asian customer with Sentinel diving detection sonars to be installed at all of its SKPS. The contract builds on a previous agreement to supply portable systems to one of the European fleets to protect its SKPS.
“SKPS is becoming an increasingly sought after resource for fleets and coast guards around the world in the fight against piracy, drug trafficking, terrorism and mine action,” said Sonardyne in a statement marking the contract signing ceremony. - The SKPZ platform is developing in its versatility thanks to new developments in shipbuilding, allowing these ships to be configured for various tasks through the use of commercial off-the-shelf systems, such as, for example. Sentinel.
“Sonardyne began shipping its systems to the SKPS market about two years ago,” said Nick Swift, head of maritime safety at the company. - We receive a lot of requests. There is a certain growth in demand in this area."
The Sentinel system can detect, track and classify threats at a distance of 1200 meters, it can be integrated into the ship's information management system or local situational awareness systems, such as the NiDAR long-range surveillance system manufactured by MARSS Group. It operates in active and passive detection and classification modes, and can be portable or installed in the ship's hull. Sentinel XF (extra functionality) is offered for military and national security structures.
“The system can be portable or can be installed in a ship's hull using the proprietary Sonardyne system,” Swift says. - We supply both configurations. Our system is inherently flexible and can be integrated into your surveillance system or your combat control system."
The hull-mounted version "is an excellent solution for newer and larger RCCs," while the portable version "can be easily deployed from any vessel and is very popular in the RCC market."
Swift added: “Depending on how the fleets are using their ships, they may not need a GAS in some area of operation. For example, when based in your port, you may need sophisticated comprehensive protection. And for deployment in a given area, you can take a portable system."
The aforementioned contract with an Asian country highlighted the importance of using systems to protect ships and other objects from underwater threats. “Sentinel… provides a rapidly deployable perimeter security system to complement commercial harbor, marine, private yacht, critical infrastructure and shoreline security systems,” he said.
According to Swift, the need for systems such as the Sentinel signals a shift towards asymmetric combat. “Previously, if the ship had a GAS, then it was intended for PLO, but now they started thinking about smaller objects, such as divers and automatic underwater vehicles. The latter are of growing concern. They are available in the civilian market, are fairly cheap and easy to operate. And they can cause significant damage to the vessel."
“The main use of the GAS Sentinel is to protect ships from terrorist and other attacks,” Swift continued. “It can be terrorism, a rogue state, or even a traditional conflict zone. Another area of its application is observation. If you have an SKPS, someone can send a diver or an unmanned aerial vehicle just to take pictures or watch the vessel. GAS Sentinel sets up an underwater cordon around the vessel so that no one can approach it unnoticed."
Ken Walker, head of the Marine Division at Ultra Electronics, also noted the development of the SKPZ market. Placing sonars on these ships can be very useful, because we are talking not only about additional capabilities of anti-aircraft missiles, but also about the fight against drug trafficking and terrorism.
“For example, smugglers are very sophisticated,” he said. "In the past, they used speedboats more, but now they use semi-submersibles, effectively using commercial submarines to transport drugs."
Walker also drew attention to the use of sonars in the activities of fisheries supervision, in the fight against illegal migration and in a number of other areas. Also, the weight, size and power consumption characteristics are improved and this attracts the attention of operators of small vessels.
Walker said his company is also seeing a growing demand for sonars for small vessels. “There has been a radical change in structure throughout the Western world. Budgets do not allow for carriers and large destroyers, as was the case in the era of the Cold War, so many are switching to smaller multitasking means to protect their sovereignty, and therefore we are seeing something like a resurgence in the field of SKPS and small frigates."
Necessity or Luxury?
Many countries do not seek to equip their SKPZ with anti-submarine defense systems and therefore the GAS on their board is not at all obligatory. As an example, we can cite the new Canadian SKPZ of the Harry DeWolf project, the first of which, according to the head of the Canadian Fleet Development Department, Casper Donovan, should become part of the fleet at the end of 2018.
“There was no need to have sonar capabilities on these ships. The ships are designed to conduct armed surveillance of Canadian waters and support government agencies in upholding and strengthening Canada's sovereignty when and where it is needed, in other words to perform police-type tasks,”he said.
“In carrying out these tasks, to detect other vessels, they will use other means than the GAS, for example, radars and optoelectronic sensors, as well as such means as, for example, the deck helicopter CH-148 Cyclone equipped with a set of special sensors, which is being developed for Canada by Sikorsky.
According to Donovan, based on the tasks of the ships of this project, they will not need some of the high-level complex combat systems that surface warships may need. submarines, we will not use a patrol vessel to resolve this situation. We will use one of our Halifax class frigates.”
The Canadian Navy has launched the Underwater Warfare Surte Upgrade project to upgrade Halifax frigates with ASW systems. The terms of the competition were published in the fall of 2017 and are currently undergoing an evaluation phase.
In accordance with this project, the capabilities of the ships will be expanded through the installation of hull HUSs, towed HASs, hydroacoustic buoys, torpedo detection systems and the integration of all these systems into the ship's BIUS. "This is a fairly large project that will add much more modern submarine warfare systems to the general capabilities of the ships," Donovan added.
He named the key technological trends of recent years - the growing level of digitization of systems and the growth of their processing power. This is what all military sensory systems have in common. "More and more of these systems are moving to digital, which means that data can be processed much more efficiently and faster."
This is especially important for GASs, since they receive and process huge amounts of acoustic data. In the case of sonars based on digital architecture, the process is greatly simplified."Data processing will be orders of magnitude better, which will improve our ability to find submarines, mines and other underwater threats."
However, according to Donovan, large-scale developments are being carried out not only in the field of hydroacoustic technologies. Nowadays, advanced, high-tech diesel-electric submarines are in great demand. “These submarines have always been very difficult to find. But now more and more countries are adopting diesel-electric submarines, more and more modern platforms are being supplied, which are undoubtedly quieter than the submarines of previous generations. And if the old submarines were difficult to find, the modern submarines are much more difficult to find."
In this regard, the fleets had to carefully analyze the methods of searching and detecting submarines. In the 1980s and 1990s, many western fleets used towed passive HASs. But now they are increasingly switching to active options that "ping" in the water column at low frequencies in order to detect modern low-noise submarines, "As part of our Underwater Warfare Suite Upgrade project, we are looking to acquire towed active low-frequency sonars."
Dale pointed to the increased information processing capacity. “This means that we can process multiple layers horizontally in one sound pulse or several pulses at the same time. We can detect an object if it is at surface level, in the water column or at the bottom."
He also noted the use of composite transducers in high-frequency sonars, which increases spectral width and resolution and allows three-dimensional processing so that “with a conventional hull HAS we can represent the seabed in 3D, for example, for object detection or navigation tasks”.
New technologies
According to Jourdon, acoustic technology has made significant progress in several areas in recent years. He noted the use of acoustic transducers for active emitters, highly advanced signal and data processing algorithms, and progress in detection and tracking capabilities. In addition, increasingly user-friendly and intuitive human-machine interfaces are being integrated into the systems, including the use of 3D to simplify complex sonar operations.
The systems have also become more compact and easier to install, while training equipment is also moving forward, "making it easier for crew to train on board."
Walker turned his attention to software. He noted, for example, Ultra's Ping Wizard technology, which makes it easy to select the optimal active mode by letting you emit a large number of different types of sound pulses at the same time.
“The system actually looks into the water and says, 'This is your best signal type. You should use it,”he explained. "The system has a very high level of artificial intelligence, simplifies the operator's work and, as a result, increases the level of command of the tactical situation."
According to Walker, there has been an interesting change in technology trends. If in the past the civilian sector seriously lagged behind the military world, now their positions in some areas have reversed. In sonars, this can be seen in the example of using GPUs from video game consoles.
“Twenty years ago, it was mainly military technology that informed the commercial world. And now it's the other way around. Currently, video processors are being ordered to increase the processing power and improve the quality of the displayed image. This is because the gaming industry, along with the telephone industry, is developing in the civilian world much faster than in the military."
Ultra Electronics supplies sonar systems to warships around the world, including the British Type 45 destroyers, the Australian Project Hobart destroyer and the Dutch Project Karel Dorman frigates. Its new GAS S2150 will be installed during the modernization of type 23 frigates. This sonar is also going to be installed on promising type 26 frigates; in addition, the company offers the S2150 variant for the 31e type frigate.
“While this is not a primary requirement for the Type 31e at this time, Ultra intends to offer its Integrated Sonar Suite, which includes a towed active-passive sonar and torpedo detection and protection system in a single towed module,” Walker said.
Accelerated changes
On the prospect, Walker noted two “megatrends” that will have a big impact in the future. “The first is large amounts of data. This is especially important for GAS, where very large amounts of data are generated and real-time processing is required for target detection. The second is artificial intelligence and self-learning of machines. For example, sonars will know if they have seen a given type of submarine before."
Dale said that any further changes in acoustic technology would naturally be constrained by the laws of physics. "I foresee small increments in performance, such as frequency range, processing power, and the number of simultaneous sound pulses."
He expects more widespread use of automatic surface vehicles, especially in conjunction with ships, for example, coastal patrol ships, “when the surface unmanned vehicle is connected to the RMS and you have the ability to transmit images from the GAS over a broadband radio channel. You are operating a machine with a VMS. I believe this is a good combination and will stimulate the coastal patrol market in the future.”
Jourdon believes that more complex, tightly coupled ASW networks with a wide range of platforms and sensors, including uninhabited systems, will be formed. “Compactness is another challenge, and Thales is looking at promising new sensors in this area. Thales is also a key player in the booming drone market. We strive to provide effective ASW capabilities to new crewed and unmanned vessels."
According to Jourdon, while submarines remain the main threat, the requirements for sonars have changed. Along with the detection of torpedoes, new asymmetric threats have emerged, such as semi-submersible or fully submersible drug submarines used by smugglers. Speedboats are also high on the list, especially given their use for terrorist purposes.
"The threats to be addressed affect the capabilities and performance of sonar stations, which must be effective in active and passive modes and in almost all environmental conditions, including shallow water and deep water."
