The SNMS performs monitoring and analysis of structure-borne and cavitation noise generated in the submarine or surface vessel, from a series of sensor arrays fitted at selected positions throughout the vessel. The purpose is to assist ship staff to maintain a low-noise signature.
The SNMS’ main functions are as follows:
The LAN-XI data acquisition units provide a very high dynamic input range. From the quietest of whispers to the loudest of bangs, Brüel & Kjær’s 160 dB DYN-X input technology ensures that the input ranging of the units is always optimal – avoiding high-level overloads at the same time as utilising the extreme low noise floor.
The family of LAN-XI hardware comprises a number of module types, optimised for different applications. Modules are available that can measure up to 25.6, 51.2, 102.4 and 204.8 kHz (with a corresponding sampling frequency of 65.5, 132, 264 and 528 kHz, respectively).
Interfacing between the data acquisition hardware and acquisition workstation is via standard TCP/IP technology. This offers the flexibility of using standard copper/fibre transmission, providing high-speed, redundant networks.
Power over Ethernet (POE) means the power needed for each input module is carried by the LAN cables rather than by separate power cables. This minimises the number of cables required, resulting in lower cost, faster setup, easier maintenance, and greater installation flexibility.
IEEE standardised LAN network protocol is used to synchronize the different modules in the system with sub-microsecond accuracy. This can be used with any LAN-XI module, either as stand-alone, in a frame, or in a distributed system. All modules distributed throughout the vessel can be synchronized using the same LAN cabling as the signal and module power.
At the central control station operators have immediate access to all sensor channels in the system, and it is from this location the analysis and data management takes place. The workstation runs a full suite of PULSE application software, comprising many functions and displays, such as third-octave, narrowband FFT, waterfall, Demon and Lofar analysis, and many more.
The complete operation of the SNMS is controlled by a dedicated application. A customer user interface would typically provide:
The workstation is optimised to manage the large data throughput and real-time analysis requirements required by the application.
Typically, the LAN-XI modules are distributed around the vessel at suitable locations close to the sensors to ensure maximum flexibility and short runs of expensive analogue signal cabling.
The modules are robust, extremely compact units well suited for mounting in the often hot and confined spaces of a submarine. The LAN-XI modules provide all data acquisition, powering and conditioning functionality:
The modules are robust, extremely compact units well suited for mounting in the often hot and confined spaces of a submarine.
High vibration levels can be analysed 'on the spot' using detailed vibration analysis tools, and pass/fail tolerance level bands can be configured.
For applications such as acoustic sea trials, noise surveys and ranging, the requirements for the measuring/analysis system may be of more of a short-term nature, rather than a permanent installation. Here, between 300 and 400 channel systems (or more) are used as 'carry-on' systems to perform specific time-limited tasks. Data acquisition modules are often located in portable racks for ease of use, rather than being distributed around the vessel. The full range of PULSE analysis tools is available for any challenging measurement and analysis tasks.
The SNMS is based on Commercial-Off-The-Shelf (COTS) equipment with an architecture exploiting commercial processing development. This facilitates regular upkeep of both software and hardware, with minimal impact on submarine scheduling, whilst simplifying maintenance practices, system support and training.
The use of COTS equipment reduces the total cost of ownership versus earlier bespoke systems, fully addressing twenty-first-century demands for technological innovation, adaptability and obsolescence.
HBK has a wide range of OEM sensors for diverse naval applications. Ranging from high-sensitivity hydrophones to radiation-hardened, EMI-immune and water-proof accelerometers designed for extreme long-term operating conditions. Strategically mounted accelerometers and hydrophones provide input to the measuring/monitoring system. Hydrophones are used for cavitation sensing and waterborne noise monitoring, and accelerometers for hull vibration monitoring.
In the high electro-magnetic environments often found around the heavy machinery in ships, it can be a challenge to prevent noise-pickup from corrupting the low level vibro-acoustic signals measured. Constant Voltage Line Drive (CVLD) sensor technology can be used to advantage to reduce noise pick-up. The CVLD sensor produces the signal as a modulated current rather than a voltage, and is thus not sensitive to EMI induced voltage signals – even in long sensor cables.
The main system component of the SNMS is the LAN-XI data acquisition hardware, which is a versatile system of modular units that can be combined in frames, set up as distributed or used as a stand-alone data acquisition system.
Portable vibration meters are available for manual machinery vibration surveys and troubleshooting to examine and monitor parts, assemblies and sub-assemblies for increased vibration. HBK‘s Hand-held Analyzer Type 2250-H would be ideal for this task.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
