Meteksan Defence Takes Turkey’s Indigenous Know-how and Experience in Underwater Acoustics to the Field of Submarines

21 Mayıs 2019
16828517946_1c32371c1d_o - C - TSK

Mesut GÖRATEŞ / mgorates@meteksan.com

Business Development Director, Acoustic & Optic Systems, Meteksan Defence
 

Having been assigned by the Presidency of Defence Industries (SSB) as Turkey’s Centre of Excellence in Underwater Acoustics in 2009, Meteksan Defence is now carrying its expertise to the field of underwater sonar systems. Today, Meteksan Defence is meeting the sensor needs of Turkish submarines’ sonars through domestic production, without any external dependence. The company is also making significant contributions to the activities of the Turkish Naval Forces in modernising the submarines in its inventory and in its work on the next generation of submarines. A closer analysis of the projects conducted by Meteksan Defence makes it clear that the company has reached the point where it can provide indigenous solutions for all sonar system requirements (sensors and dry-end units) of a modern submarine.

When the projects conducted by Meteksan Defence are examined, it becomes apparent that the company arrived at a point where it can provide all sonar systems (sensors and dry-end units) of a modern submarine indigenously.

When the projects conducted by Meteksan Defence are examined, it becomes apparent that the company arrived at a point where it can provide all sonar systems (sensors and dry-end units) of a modern submarine indigenously.

 

There is no doubt that the most advanced project completed by Turkey in the field of sonars is the YAKAMOS, which is the sonar used aboard the ADA-class (MİLGEM) corvettes. The SSB assigned Meteksan Defence with the task of industrialising the YAKAMOS sonar developed by Turkish Naval Research Center Command (TNRCC), which operates under Turkish Naval Forces Command. This task has been fulfilled in two phases, with the industrialisation of the wet-end units being performed in the first phase, and the industrialisation of the dry-end units being performed in the second phase, both by Meteksan Defence. The industrialisation of the YAKAMOS sonar – which has taken up an exemplary position in the projects conducted to date by the Turkish defence sector – has served as a model for many other projects being conducted in this field. Following the completion of industrialisation efforts, and after taken over all responsibility related to the sonar, Meteksan Defence immediately launched the necessary works for indigenisation and for meeting the changing needs and technologies. The company has also made a series of improvements to YAKAMOS in line with a road map. These improvements have been applied to the third and fourth MİLGEM ships, which are equipped with Meteksan Defence sonars. How these improvements performed on the field was tested, and they were later applied as upgrades to the first and second ships of the MİLGEM project as well. As such, it has been ensured that all four ships of MİLGEM feature the same equipment and software, and provide the same performance.

Now that Turkey has obtained the required know-how and infrastructure from the YAKAMOS sonar and from other projects in the field of underwater acoustics, its next goal is the indigenisation of submarine sonars. Given the product range and ongoing sensor development works at Meteksan Defence, it can be said that the company is now ready to provide the necessary support to the SSB for the modernisation of sonar systems – which is the most critical system aboard submarines – through the use of indigenous products. Having proven its performance through sea trials, and as Turkey’s only platform-integrated sonar producer, Meteksan Defence is now a serious competitor to alternative foreign companies.

The Cylindrical Pressure Tank infrastructure, which is part of Meteksan Defence’s range of testing equipment, can simulate depths of up to 500 m, which exceeds the average safe depth limit for submarines.

The Cylindrical Pressure Tank infrastructure, which is part of Meteksan Defence’s range of testing equipment, can simulate depths of up to 500 m, which exceeds the average safe depth limit for submarines.

 

Keep Quiet to Hear Well

The most important feature of a submarine is its ability to disguise itself, which requires silent operation. This ability of submarines makes them a game-changing force multiplier that can maintain the element of surprise in the field of operation. An important factor that creates this force multiplier is the fact that submarines can move in three dimensions, which means that an attack mounted against the submarine is obliged to take the third dimension into account. To be able to perform their underwater operations successfully and to take the advantage of their third dimension, submarines must be able to maintain a clear picture of their operational environment, and know how to utilise this environment. This requires equipping submarines with highly sensitive “ears”, in other words with detection sensors and systems, which we know as sonar systems. The requirements of sonar systems aboard submarines are more challenging than those used on surface ships, and can be listed as:

  • Operation at Depth: The wet-end units of sonar systems on submarines engaged in deep sea operations should be resistant to the pressures generated by such depths (maintain impermeability), and also have a structure that allows them to perform under significant pressure and temperature changes.
  • Broad Frequency Band: Especially when the periscope cannot reach the surface, the submarine will not have visual contact with the operational environment, and will need to listen to ambient sounds to develop a correct tactical image of the field of operation. This requires the use of passive sonars that can carry out listening on a band as broad as possible. Given the challenges of the acoustic environment, these requirements mean a need for sonar systems equipped with technology, capable of performing precise listening of each segment of the frequency band; of making the detected noise signals ready for signal processing; of supressing the undesirable noise sources and frequency bands; and of carrying out target bearing detection, distance estimation, tracking, classification and analysis in the most accurate manner thanks to the technologies in their possession. These requirements also mean a need for experienced operators capable of operating these systems in the best way possible.
  • Precise Listening Even at Below Noise Levels: The underwater environment is a place of continuous noise from wildlife, sea states, waves, atmospheric conditions and sea traffic. This noise may involve different levels of reflection or penetration depending on the depth and nature of the sea bed, and is found in different frequency bands. To maintain a precise picture of what is happening around the submarine, it is necessary to have the capability of listening below this noise level as well.
  • Effective Algorithms: A submarine sonar needs to efficiently, continuously and rapidly process the signals it has detected over a very broad frequency band, and to produce a high-precision tactical image in the shortest possible time. This can be achieved through special algorithms, hardware and extensive knowledge in the field.

Having gained significant experience with the YAKAMOS sonar, Meteksan Defence has taken a number of steps to overcome the above-mentioned challenges:

  • The Cylindrical Pressure Tank infrastructure that is included in the testing infrastructure of Meteksan Defence, and which was developed partly with Meteksan Defence’s own resources and partly with the support of the SSB, can simulate depths of up to 500 m, going beyond the average safe diving depth limit for submarines. In the Cylindrical Pressure Tank, both pressure and temperature can be controlled to desired testing values, and the tank can thus be used for any performance tests that are conducted under different pressure and temperature conditions. This infrastructure is the first and only one of its kind in Turkey, and is also among the very few such testing infrastructures in the world. Meteksan Defence uses the Cylindrical Pressure Tank to test all of the components it has used, or will use, in the wet-end units of its submarine sonars, underwater weapon systems and early warning sensor network systems. The results obtained to date indicate that these components are able to carry out their tasks to the fullest extent.
  • Meteksan Defence designs its products and solutions through a holistic approach. The company’s works in the fields of radars, communication and underwater acoustics are often include common subcomponents, in terms of technology and capabilities. Meteksan Defence seeks to utilise many of its subcomponents in multiple solutions, fitting them together like Lego blocks, and has already achieved this to a significant extent. Accordingly, it can be said that, in its ongoing submarine sonar project, Meteksan Defence is capable of utilizing some of the electronic units that were developed during other product programmes, and that function across a broad frequency band. With the works it has undertaken to date in various projects, Meteksan Defence has proven its ability to carry out sensing and signal processing within the broad frequency band required by submarine sonars.
In its projects within this field, Meteksan Defence makes efficient use of the Bilkent Lake Open Water Test and Calibration Facility, established on the artificial lake located between the east and west campuses of Bilkent University. The company also allows all of its stakeholders to benefit from the means this facility and the Cylindrical Pressure Tank.

In its projects within this field, Meteksan Defence makes efficient use of the Bilkent Lake Open Water Test and Calibration Facility, established on the artificial lake located between the east and west campuses of Bilkent University. The company also allows all of its stakeholders to benefit from the means this facility and the Cylindrical Pressure Tank.

 

Experience Makes a Difference

In the field of underwater acoustics, one of the leading strengths of Meteksan Defence – or speaking more broadly, of Turkey, since the company is the country’s centre of excellence – is its design, analysis, modelling, simulation and testing infrastructures.

Design, analysis, modelling, simulation and testing infrastructures that address a certain field can be developed utilising the information available in literature. However, in most cases, solutions developed based only on data garnered from literature fail to provide the expected results in the field.

Trust in design, analysis, modelling, simulation and testing infrastructures can be built only if these infrastructures are updated and verified based on data collected in the field, and Meteksan Defence’s infrastructures have fully achieved this level of maturity.

Various ceramics developed by Meteksan Defence that are being used in its sonar systems.

Various ceramics developed by Meteksan Defence that are being used in its sonar systems.

 

The YAKAMOS sonar has been carrying out its tasks successfully in the world’s seas aboard TCG HEYBELİADA (F-511) and TCG BÜYÜKADA (F-512). The know-how and experience gained in this process were utilised in the verification of the design, analysis, modelling, simulation and testing activities related to the YAKAMOS sonar. Today, Meteksan Defence can know in advance with confidence, and with a very small margin of error, the performance on the field of the underwater acoustic systems it has developed using its design, analysis, modelling, simulation and testing infrastructures. This eliminates, to a great extent, the risks related to sonar systems, the developments of which are usually a very long process, and whose performance can be fully verified only after being integrated into its host platform. In the Turkish defence and aerospace sector, the only company with such mature infrastructures is Meteksan Defence, which has been further developing this infrastructures since it started working on submarine sonar systems by making use of computer-based engineering and testing tools, creating passive sensors aimed at operating in broader bands. While some of these tools have been purchased, others have been developed by Meteksan Defence, and the company has also made use of training and consultancy services. This is how it has been able to developed a highly critical infrastructure for submarine sonar systems through its own resources.

 

Raising a Team to Shape the Future

Another significant gain made by both the company and Turkey during the activities in the field of underwater acoustics is a wealth of qualified human resources.

Meteksan Defence has a team of 70 experts working on underwater acoustics projects who have an average of over 15 years of experience in the field. What is more important than all these figures, however, is the average 7-year tenure of these team members at Meteksan Defence, as they have experience of working together and accomplishing projects, which makes a huge difference in challenging and long-term projects.

The fact that Meteksan Defence operates under Bilkent Holding, and was established with a vision to support the educational and R&D activities of Bilkent University, also makes a difference in terms of university collaboration and R&D culture. Meteksan Defence is cooperating with Bilkent University and other universities in the field of underwater acoustics.  It is also utilising the infrastructure of the Bilkent Lake Open Water Test and Calibration Facility, that has been established on the artificial lake between the east and west campuses of Bilkent University, in its projects in this field. It also allows its stakeholders to benefit from what this facility has to offer, as well as those of the Cylindrical Pressure Tank.

Its close relations with the university ensures R&D remains a part of Meteksan Defence’s corporate culture. The project teams consider product innovation and satisfying user demand to be more important than keeping off-the-shelf products in hand. As has already been seen in the case of the Retinar Perimeter Surveillance Radar product family, Meteksan Defence is always ready to offer custom solutions in accordance with user requirements. The company’s underwater acoustics team carries out its activities based on the same approach, attributing particular importance to user demands.

As part of its activities in the field of underwater acoustics, Meteksan Defence is also contributing to the development of an ecosystem in Turkey. Providing a summary of their approach in this regard, Selçuk Alparslan, President of Meteksan Defence, said: “We turn to the ecosystem for any kind of work that is not covered under our main areas of operation. Meteksan Defence maintains what it calls the Approved Supplier programme, and we are implementing this system with great efficiency. Sustainability is at the core of our approach to our suppliers. Whenever any of our suppliers experiences a problem, we try to help them overcome it by providing the necessary support, which ensures our sector also wins in the long run. There are over 100 companies in our network of suppliers operating in the field of underwater acoustics.”

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All Components of the Submarine Sonar are Ready

Meteksan Defence has undertaken a series of underwater acoustics projects, with particular focus on submarines:

  • The acoustic detection sensors and low-noise front-end electronic units of the Intercept Passive Sonar and the Intercept Data Ranging Sonar that will be used aboard PREVEZE- and GÜR-class submarines are being designed and produced indigenously by Meteksan Defence.
  • Meteksan Defence’s MSH-01 hydrophones and their equivalents are retained as spare parts for the AY- and PREVEZE-class submarines’ Cylindrical Hydrophone Arrays, Passive Ranging Sonars and Own Noise Measuring Systems.
  • The contract entitled “Sonar Subsystem Procurement for Integration into the MÜREN Systems aboard PREVEZE-Class [Submarines]”, which aimed for the indigenous development, production and integration onto MÜREN (Indigenously Produced Integrated Underwater Combat Management System) of the preliminary electronics, signal processing hardware and software related to the sonar and acoustic systems, was signed between TÜBİTAK BİLGEM (Informatics and Information Security Research Center) and Meteksan Defence on July 31, 2018.
  • In addition, Meteksan Defence has also developed indigenously the sensor elements of flank array sonars of existing submarines, and these sensors have reached the Sea Acceptance Test (SAT) phase. Once the qualification phase has been completed, they will become available for use as spare parts.
An illustration of submarine sonars aboard a REİS-class submarine.

An illustration of submarine sonars aboard a REİS-class submarine.

 

Taking into account this project list and Meteksan Defence’s ongoing underwater acoustics works in the field of surface platforms and other fields, the company’s intention to gain experience in the development of all the components and interfaces required by submarine sonars becomes clearly apparent. These are listed below:

  • Meteksan Defence has developed indigenously the sensors required for the wet-end unit of sonars, and has proven that they meet the required performance levels. Some of these sensors are currently being used as spare parts for existing systems.
  • Electronic circuits have been developed indigenously that convert signals perceived as analogue in the frequency band of concern into digital signals, and have proven themselves in the field.
  • Meteksan Defence, in the framework of various projects, has been carrying out algorithm, software and hardware development activities related to the dry-ends of the submarine sonars.
  • As the sonar is the most important sensor aboard a submarine, it needs to be well-integrated with the combat management system, and Meteksan Defence’s projects also involve activities related to this integration. This allows the company’s products to operate in integration with the existing combat management systems in its users’ inventories, and to do this in an efficient manner.
Wet-end units of the YAKAMOS sonar.

Wet-end units of the YAKAMOS sonar.

Commenting on the point reached in the field of submarine sonars, Selçuk Alparslan, President of Meteksan Defence, said: “Our holistic approach to our projects shows that we have managed to develop all components of a submarine sonar indigenously. We can clearly say that if Meteksan Defence is assigned with a certain task today, it can successfully deliver a submarine sonar in a short project period through a low-risk development process. Another asset that we have gained from previous and ongoing projects is the ability to integrate the sonar into the submarine in a short period and with low risk, thanks to the compatibility of the sonar with existing interfaces.”

Another critical point for Turkey in the field of submarine sonars is the rate of local participation. Meteksan Defence has increased this rate to over 90 percent with YAKAMOS, and now, for the submarine sonars, it offers solutions with a high local participation rate that are not subject to any export restrictions. In various recent underwater acoustics projects, the company has successfully developed indigenous solutions for subcomponents and subsystems (LRU) that used to be procured from abroad, but whose procurement has become impossible over time for various reasons.

Meteksan Defence takes into account the importance of sustainability in the supply chain, beginning from the outset of the projects it undertakes, and this has significant impacts on the rate of local participation and export restrictions. Integrated Logistic Support (ILS) teams work together with the design teams from the outset, ensuring the continuity and sustainability of the supply chain for the selected subsystems. By creating such a structure, Meteksan Defence can now draw upon corporate processes that allow user requirements to be met in the shortest possible time.

 

Technology Takes Products to a Whole Different Class

The leading countries in this field have been working on submarine sonars for over a century. Although the late entry of Turkey and Meteksan Defence into this area can be seen as a disadvantage, it also comes with some significant advantages.

While companies with deep-rooted experience in the field of submarine sonars generally shape their solutions based on technologies of the past, Meteksan Defence’s solutions utilise state-of-the-art technologies in both the architecture and the components. This allows Meteksan Defence to come up with innovative solutions that ensure high performance in certain key parameters, and when this innovative approach is combined with the know-how of the Turkish Naval Forces and Meteksan Defence, the world’s best products emerge with competitive power.

Selçuk Alparslan, President of Meteksan Defence, emphasised the contributions of the Turkish Naval Forces and the SSB in this regard: “The Turkish Naval Forces, especially Turkish Naval Research Centre Command (TNRCC), and a number of sonar operators, all shared their experiences with us and provided us feedbacks based on their operation of our systems. This offered us precious know-how from the field, which consequently increased significantly the competitive power of our products worldwide. We are working in full compliance and coordination with the Turkish Naval Forces, and we are grateful to them for providing us with this opportunity. Furthermore, we are also working together with the SSB in the project phase of such works, and for defining the related road maps. Showing its trust in Meteksan Defence, the SSB has assigned significant responsibility to us, which is to become a centre of excellence, and with their support, we are doing our best to fulfil this task.”

 

Meteksan Defence’s MSH-01 hydrophones are retained as spare parts for the AY- and PREVEZE-class submarines’ Cylindrical Hydrophone Arrays, Passive Ranging Sonars and Own Noise Measuring Systems.

Meteksan Defence’s MSH-01 hydrophones are retained as spare parts for the AY- and PREVEZE-class submarines’ Cylindrical Hydrophone Arrays, Passive Ranging Sonars and Own Noise Measuring Systems.

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Technologies of the Future also on the Agenda

In addition to the above-mentioned efforts, Meteksan Defence is also working on technologies of the future and on capabilities that are yet to be acquired by Turkey:

  • Digital Sensors: In conventional submarine sonars, analog signals related to the targets are detected by wet-end sensors and they are transmitted to the dry-end through a cable.  Signal losses (attenuations) are likely to occur during this transmission. To resolve this problem, it is necessary to convert these analog signals into digital as close as to the sensors, if possible, inside the sensors. Meteksan Defence has already developed such sensors in the MİLDAR (Millimetre Wave Radar) and datalink projects, and is now carrying this know-how and experience to the field of underwater acoustics.
Trust in analysis, modelling, simulation and testing infrastructure can be built only if such infrastructures are updated and verified based on data collected from the field. Meteksan Defence’s infrastructure has fully achieved this level of maturity, which represents a remarkable accomplishment.

Trust in analysis, modelling, simulation and testing infrastructure can be built only if such infrastructures are updated and verified based on data collected from the field. Meteksan Defence’s infrastructure has fully achieved this level of maturity, which represents a remarkable accomplishment.

  • Fibre-Optic Acoustic Sensors: Fibre optic acoustic sensors, which appear on the SSB’s list of 10 technologies that will shape the future, stand out with the advantages they offer, such as high precision, small size, with a wide frequency range down to Hz level, low weight and resistance to electromagnetic effects. This acoustic sensor technology, which is gradually being used in field applications around the globe, especially in passive ranging sonars, flank array sonars and slim-line towed array sonars, has been developed in Turkey by Meteksan Defence as part of an R&D project conducted by the SSB. The company is continuing to work on adapting this technology to different types of sonars.
  • Single Crystal Ceramic Sensors: Single crystal piezoelectric sensors are preferred in new generation  designs, as single crystal piezoelectric charge/strain coefficients are three times higher and electromechanical coupling coefficients are much greater than those of the polycrystal ceramics. The most important performance advantage of single crystal ceramics is that they provide a wide frequency bandwidth and high Receiving Voltage Sensitivity (RVS)/Transmitting Voltage Response (TVR) at the same time. Meteksan Defence is the first company in Turkey to design a hydrophone using single crystal ceramics. The company has now completed the related acoustic measurements, revealing that the RVS and bandwidth obtained by single crystal ceramic is 6–11 dB higher and twice larger, respectively, than those obtained by polycrystal ceramics. These superior features mean a longer range of detection or reduced power consumption, since a lower level of power is required to ensure the same performance. These sensors are very critical particularly for systems with limited power source such as torpedoes. Meteksan Defence plans to use this technology first in hydrophones and hydrophone arrays, and later in single transducer arrays requiring fewer components.
Yan Dizin Sonari - C - Meteksan Savunma

Flank array sonar

The Operator Console, one of the dry-end units of the YAKAMOS sonar.

The Operator Console, one of the dry-end units of the YAKAMOS sonar.

  • Textured Polycrystal Ceramic Sensors: Today’s sensors make use of non-textured polycrystal ceramics with randomly oriented grains in their microstructures, resulting in averaging of the properties. The physical properties of the textured polycrystal ceramics are higher than non-textured polycrystal ceramics and closer to the single crystal ceramics. When transducer properties are considered based on non-textured, textured and single crystal ceramics, the bandwidth increases significantly from non-textured to single crystals. In terms of source levels at the resonance frequency, the difference between non-textured and textured ceramics is approximately 5 dB; the difference between non-textured and single crystal is 8 dB; and the difference between textured and single crystal is 3 dB. These results clearly indicate that inducing a texture in polycrystal ceramic microstructures through relatively inexpensive processes improves the acoustic properties significantly, thereby enhancing the properties closer to the single crystal ceramics. Meteksan Defence is continuing to work on new designs with superior performances by inducing crystallographic texture in lead-based and lead-free piezoceramics by means of templated grain growth method. It will be possible to use these textured ceramics in tonpilz-type (MİLGEM etc.) transducers and IPS-IDRS type hydrophones, in mine detection and classification activities, and for imaging purposes.
In Turkey, Meteksan Defence has developed fibre-optic acoustic sensor technologies as part of an R&D project conducted by the SSB.

In Turkey, Meteksan Defence has developed fibre-optic acoustic sensor technologies as part of an R&D project conducted by the SSB.

The hydrophone developed by Meteksan Defence.

The hydrophone developed by Meteksan Defence.

Another item on Meteksan Defence’s agenda for the future is export. Following the order placed by Pakistan Navy for four MİLGEM corvettes in 2018, YAKAMOS was selected as the sonar to be used aboard these vessels, and the company has also plans to export submarine sonar systems (other than YAKAMOS) and their subcomponents separately. Meteksan Defence has already made sales of its other product families to foreign countries before even Turkey, and this shows that the sector needs to be ready for new surprises.

 

 

 

 

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