special issue of fam fuerzas militares magazine

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SS nº 133 aÑo XI 2013 6,00 €

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World NAVAL FORCESFA

MSAESUNDERWATER MULTI-INFLUENCE MEASUREMENTS

AVANTEopV,s for ThE MiddlE EAsT

SERTTerrestrial Reconnaissance

and Exploration System

SPECIAL

NEW WEB

The Spanish shipbuilder Navantia is showcasing its AVANTE family of offshore patrol vessels (OPV) at DIMDEX. These ships will be able to carry out a wide variety of missions such as coastal surveillance and protection, protection of maritime traffic, health assistance to other ships, external firefighting, the fight and control of marine pollution, transport of personnel and provisions, search and rescue operations, rapid intervention, frogmen support, surface defence and passive electronic warfare. FAM

NAvAL SoLUTIoNS FoR ThE MIDDLE EAST

AvANTE oPv

avantia has developed a new family of opV’s, the “aVante class”, that includes a variety of options. it is a new concept of ships where they will share same hull lines, same compartment division, same arrangement of common spaces and maximum commonality of propulsion and auxiliary systems. What makes them different is the mission they will accomplish: combatant, patrol, support, research.

the ship and systems of the aVante family are specially designed to operate in the environ-mental conditions of the arabian gulf, where air temperature reaches 50º c and the seawater temperature could reach 37ºc. n this sense, the capacity of the HVac system is designed to such environmental conditions.

furthermore, the hull materials, the building process and the ships’ design itself are defined in

such a way that the aVante family ships can oper-ate under heavy dust/sand storms.

the pieces of equipment design and material are able operate under high humidity up to nearly 100% in conjunction to somewhat lower ambient temperatures than 50ºc.

the materials used and protection are defined considering that the ships will be able to oper-ate in aggressive seawater with the presence of industrial pollutants and a higher than usual salt content.

navantia says the aVante family of vessels are adaptable to perform the typical missions of the arabian gulf as:• patrolling• maritime safety• securing economical waters and islands.

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AvANTE 1400the "guaicamacuto" class patrol vessels (avante 1400) is a class of offshore patrol vessels or BVl (spanish: Buque de Vigilancia de litoral) in Ven-ezuelan navy service for patrol duty in economic exclusive zone. the contract for the BVl and poVzee was signed together on the november 25, 2005. the last vessel "tamanaco", would be constructed locally at Venezuelan Dams astilleros nacionales (DYanca) in puerto cabello, Venezuela.

• Guaicamacuto GC-21• Yaviré GC-22• Naiguatá GC-23• Tamanaco GC-24

Avante 3000the Bam (maritime action ship - Buque de accion marítima) (aVante 3000) is a modular type of vessel, adapted to different purposes on a common basis, being manufactured by navantia for the spanish armada (meteoro class). four units has been built and five more has been commanded in three dif-ferent configurations.

• Meteoro (P-41)• Rayo (P-42)• Relámpago (P-43)• Tornado (P-44)

Avante 2200the guaiquerí class patrol vessels (avante 2200 com-batant) are a class of ocean patrol vessels or poVzee (spanish: patrullero oceánico de Vigilancia de la zona económica exclusiva) in Venezuelan navy service. the poVzee vessels feature stealth technology with reduced radar and infrared signatures as well as special design to minimize the propulsion system's noise emissions and vibrations.• Guaiquerí PC-21• Warao PC-22• Yekuana PC-23• Kariña PC-24

IN SERvICE

FAM Report

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• securing gas and oil rigs• securing coastal boundaries.• search and rescue• law enforcement

the ship and systems are specially designed to operate in environmental conditions of high air and seawater temperatures and humidity nearing 100%.

the combatant version has been designed for naval operations in crisis time (command, anti-air, anti-surface, electronic and mine warfare) for protection of the exclusive economic zone control

the patrol version has been designed for protec-tion and surveillance of national waters, allowing a fast intervention or escorting convoys and war-ships

the support version has been designed for emer-gency situation assistance (fire, pollution, sani-tary), divers support or transport of loads and personnel

the research version has been designed for hydrographic and oceanographic survey and remote operated Vehicle (roV) operations

furthermore, the mission combined with a determined size of the ship (specified in tones) provides a wider catalogue of products: avante 300, avante 700, avante 1400, avante 1800, avante 2200 and avante 3000.

navantia has recently built four of the ships for the spanish navy (aVante 3000) and four units of each class for the Venezuelan navy (aVante 2200 and aVante 1400).

the aVante 3000 has a length of 93.90m, a dis-placement of over 2,900t and a maximum speed of 21 knots. Her main missions are the protection and escort of other ships, the control of maritime traffic, terrorist actions, piracy, fishing legislation

Above, two Avante 2200 and one AvANTE 1400 fron

the venezuelan Navy. Left, Command brigde of the

"Guaicamacuto" GC-21. In the other side, inside cabins of

AvANTE 1400, and infographics of AvANTE 1800.

Page 4, GC 21 "Guaicamacuto" (AvANTE 1400).

AvANTE oPv

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and environmental legislation, operations against drug and persons trafficking, and crisis situation support and humanitarian assistance.

the aVante 2200 has a length of 98.90m, a dis-placement of 2,200t and a maximum speed of 25 knots. it is able to perform a variety of mis-sions such as surveillance and protection of the exclusive economic zone, protection of maritime traffic, defence of strategic interests, search and rescue operations, support for other units and humanitarian actions, control of marine pollution, the fight against smuggling, drug trafficking and illegal immigration, surveillance and gathering of operational and environmental intelligence, surface defence and passive elec-tronic warfare.

the aVante 1400 has a length overall of 79.90m and the capacity to displace 1,500t and reach a maximum speed of 22 knots. FAM

FAM Report

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AVANTE OPV FAMILYModel AVANTE 1400 AVANTE 1800 AVANTE 2200

Length/Beam/Depth 79.9 x 11.8 x 7.0 m 89.80 x 13.2 x 7.2 m 98.9 x 13.6 x 7.2 m

Full load displacement (aprox.) 1.500 t 1.900 t 2.500 m

Design draught 3.7 m 3.8 m 4.1 m

Acommodation 35 + 29 82 92

Maximum/Cruising speed + 22 kt / 16 kt 28 kt /15 kt

Range at cruising speed + 4.000 nm + 5.000 nm

Provision endurance 35 days 21 days

Propulsion plantCODAD 2 diesel x 5,920 kW2 shaft lines, 2 CP propellers

CODOE 4 diesels x 4,440 kW, 1 x Electric 450 kw, 2 shaft lines

CODAD, 4 Diesels x 5,920 kW, 2 shaft lines, 2 CP propellers

Helicopters & RHIBs operation

Flight deck for medium size helicop-ter (AB-212, AB-412, AS-565)1 x 5.7 m RHIB (stern ramp)2 x 5.5 m RHIB (crane)

·Helicopter medium size ·Flight deck 16.1 long, 12.7 m wide ·Hangar Retractable type ·Helicop-ter in-flight refueling capacity.·Landing and securing aids.

Flight deck & hangar for 10 t class heli-copter (AB-212, AB-412, AS-565, NH-90)2 x 5.5 m RHIB (with crane recovery & deployment)

Command & Control

- Integrated Combat System - 1xCMS - 3xMultifunction consoles - 1xTacti-cal LAN- 1xTactical data link

6 x MFC, 1 x LSD, 3 Tactical s, Vid-eo distribution system, Redundant tactical LAN and Tactical Data Link

Integrated Combat System: - CMS - 5 x Multifunction tactical consoles - 2 x LSD - 1 x Video distribution system - Tactical pro-cessors - Tactical LAN - Tactical link system

Sensors

1 x 2D Air/Surface surveillance radar. - 1 x IFF (Interrogation & transpond-er). - 1 x LPI Surface/Navigation radar. - 1 x Navigation radar - 1 x Radar-EO fire control system director. - 1 x EO fire control system director. - 1 x ESM system Radar band. - 1 x ESM system Communications band.

Air Surveillance Radar 1 x 3D Air/Surface Surveillance radar ·Surface/Navigation Radar 1 x S Band 1 x X Band ·IFF 1 x Interrogator & Trasponder ·OPTRONIC 1 x IRST ·Electronic Warfare 1 x Radar ESM/ECM 1 x Communication ESM/ECM ·Underwater sensors 1 x Hull Mounted Sonar 1 x CAPTAS (W&S reserve) 1 x Bathythermograph

1x Air surveillance 3D radar - 1x IFF (Interrogator and Transponder) - 1x Surface and Navigation LPI radar - 1x Navigation radar - 1x EO surveillance and tracking system - 1x EO fire control system director - 1x ESM system in radar band - 1x ESM system in commu-nications band - 1x TAS system

Weapons1 x 76/62 mm Gun - 1 x 35 mm CIWS - 2 x 12.7 mm machine guns (manual operation)

Guns:1 x 76 mm 1 x 25 - 35 mm 2 x 12.7 mm ·Fire Control System 1 x Radar-EO Pedestal 1 x EO Pedestal ·Vertical Launcher System . 8 x cells SAM system ·Surface to Surface Missile 8 x SSM (two quadruple launchers) ·Torpedoes 2 x Triple 324 mm torpedo launchers ·Decoys 2 x Multipurpose Decoy launchers

Guns: 1x76mm, 1x35 mm, 2x12.7 mm - Fire Control System: 1x Radar-EO, 1x EO - SAM system: 1x VLS 8 cells - SSM system: 2x quad launchers - ASW torpedoes: 2x triple launcher - RF & IR Decoys: 2x launchers (12 tubes each)

AvANTE oPv

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TERRESTRIAL RECoNNAISSANCE AND ExPLoRATIoN SYSTEM (SERT)

the characteristics of the battle-field of the future make it vital to have effective terrestrial surveil-lance systems which provide time-ly information about the terrain and the enemy, allowing spanish army units to execute their plans and offer an effective challenge.

this means that the armed forces (mainly the army) need access to resources which meet their exist-ing needs both at technical and operational levels. among oth-er measures, this demands that reconnaissance units be equipped with the resources allowing them to perform their surveillance and reconnaissance missions. the objectives of the sert project are:•Development and manufacture

of a technological demonstra-

tor for a navigation, detection, identification and target loca-tion system using electro-opti-cal and radar-based sensors and self-protection for intelligence, armoured, field artillery and marines vehicles.

•Development of algorithms for the integration of cutting-edge radar-based and electro-optical sensors with advanced target identification and location functions.

•full integration across the vehi-cle's technical systems (obser-vation sensors) and tactical sys-tems (command and control).

•Development of an integrated night vision and navigation sys-tem for vehicles.

•Development of a remote con-trol system for small-calibre weapons.

• Presentation of thedemonstrator's results on national and international forums. FAM

E

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General Dynamics Bath Iron Works Awarded $21 Million Contract for Coast Guard offshore Patrol Cutter Program

the u.s. coast guard has awarded general Dynamics Bath iron Works a $21.4 million contract for the offshore patrol cutter (opc) program. Bath iron Works is one of three shipyards chosen from a field of eight competitors to proceed to phase i design work on this next-generation cutter program.

the Bath iron Works team includes l-3 communications (new York, n.Y.) and navantia, s.a. (spain), a shipbuilder that Bath iron Works has collaborated with for more than 30 years.

Bath iron Works president fred Harris said the coast guard design contract was an important development as the shipyard seeks to expand its customer base and maintain its design and manufacturing workload.

"our experienced engineering and design team will now focus on developing a preliminary opc design that meets or exceeds our customer's requirements," said Harris. "We will also continue our yard-wide actions to ensure we can build these ships affordably, safely and on -- or ahead of -- schedule."

at the end of the 18-month phase i period, the coast guard will select one team to develop phase ii detail design and build the first nine to 11 ships of a planned 25-ship class.

the opc is a next-generation ship which will replace the coast guard's aging fleet of medium endurance cutters, complementing the current and future fleet and extending the service's operational capabilities. the opc will feature increased range and endurance, more powerful weapons, a larger flight deck and improved command, control, communications, computers, intelligence, surveillance and reconnaissance equipment. FAM

NEWS

FAM World Navies

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NEWS

FAM World NaviesLOADING OF THE ALHD “ADELAIDE” ON BOARD THE BLUE MARLIN FOR TRANSPORTING TO AUSTRALIA

the alHD “adelaide” has been transported to Bae systems austra-lia, where the ship will be finished

the alHD “adelaide” was loaded on board the “Blue marlin”, owned by the Dutch company Dockwise, on 10th December 2013 in northern spain.

the operation began with the approaching and positioning maneu-vers of the alHD “adelaide” on the supporting bed installed on the “Blue marlin”. the operation finished once the mentioned vessel was refloated being the “adelaide” on the deck of the “Blue marlin”.

as well as it was done with the alHD “canberra”, the alHD “adelai-de” has been transported to Bae systems shipyard at Williamstown in australia. once there, the works on the ship continue and finally it will be delivered to the commonwealth of australia.

the contract to build two units of the alHD based on the lHD “Juan carlos i” owned by the spanish navy, was signed in 2007 and it sup-posed the introduction of navantia in the military australian mar-ket. the delivery of this ship, in advanced from scheduled date, means the consolidation of navantia as technological partner in australia and its positioning for future contracts with the australian

navy. at present, navantia is building 12 fast landing craft and is participating, with the design and transference of technology, in the building of 3 destroyers.

navantia wishes to highlight the excellent relationships and com-munications between the parties involved in this programme: commonwealth of australia, Baes and navantia.

main characteristics:- length overall: 230,8 m- Beam moulded: 32,0 m - Depth to flight deck: 27,50 m- maximum speed: more than 20 kt- range at 15 kt: more than 6000 nm- crew: 243- total accommodation capacity: more than 1400

the alHD is a multipurpose vessel with different capacities depending on the mission:-air: platform for helicopters and Vstol (up to 20 planes)-amphibious: platform for marines, vehicles, landing crafts(4xlcm-1e) and support elements. -transport and expeditionary: capability for troops, tanks and helicopters. - Humanitarian and rescue: capable to transport goods and provide assis-tance and medical support (aid containers + full medical facilities). FAM

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NEWS

FAM World Navies

NAVANTIA AND THE U.S. NAVy SIGN SERVIcE cONTRAcT OF 4 DESTROyERS

navantia has signed with the us navy a service contract of four destroyers who will be deployed during 2014 and 2015 in the naval Base of rota, as part of the BmDl, ac-cording to the agreement reached between both govern-ments in 2011 and signed in 2012. the contract includes the maintenance of these units in the periods of immo-bilization in rota, and has a duration of 1 years more 6 optional years.

navantia's experience in the design, construction and maintenance of the ships, similar to the spanish navy in its systems, as well as its excellent infrastructure and workforce skill capacity, have been decisive for the adjudi-cation of this contract.

likewise, the attainment of this contract with the us navy, with the highest level of requirements, supposes for na-vantia a great international prestige, guaranteeing his lea-ding world position in the naval military construction. FAM

NAVANTIA AND LOcAL PARTNER SELEcTED By TURkEy FOR cONSTRUcTION OF ONE LHD BASED ON THE “JUAN cARLOS I”

27th. December 2013.- the ssm of the government of turkey has announced today that the partnership formed by navantia and seDef, the turkish shipyard, has been selected in first place for the design and construction of one lHD and four lcm landing crafts for the turkish navy.

navantia will provide the design, transfer of technology, equipments and technical assistance to seDef for local construction. Besides the design, based on the lHD “Juan carlos i” for the spanish navy, navantia will also provide several components and systems, as the engines, the turbine and the ipms (integrated platform management system).

navantia’s design has been selected due to the fact that it is a built and proven design in the case of lHD “Juan carlos i, and a very advanced construction in the case of lHD “canberra” and lHD “adelaide” for the royal australian navy.

last, this contract means the entrance of navantia in the turkish market, where is presenting also the f-100 frigates, as well as the con-solidation of navantia as a reference in the lHD market. FAM

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AOR cANTABRIA INTEGRATED IN ROyAL AUSTRALIAN NAVy (RAN)the ship is candidate to be the best option for the ranthe spanish navy aor “cantabria”, built by navantia and commis-sioned in 2010 was deployed in australia in 2013, as part of the agreement signed between the spanish navy and the royal aus-tralian navy. the target of this mission is offer the ran the possi-bility of evaluating the capabilities of the ship and giving the crew the necessary training on the operational aspects of the ship. since her arrival, the ship has participated in a great number of sea exercises, providing logistic support to several ships, totally integrated in the ran: as expressed by ran the deployment has been totally successful and the capabilities of the ship have been highly evaluated.

About the shipthe aor “cantabria” is capable of providing underway replenish-ment during long periods at sea, minimising the time it spends in port. on its way back to spain, the ship visited the post of goa where the indian navy had the opportunity to be on board and be briefed about the ship and capabilities.provision of efficient replenishment at sea to war ships all around the world can be the key to the success of the missions. navantia has desig-ned, built and delivered a unique ship capable of supplying fluids (fas) and solids (ras), that incorporates the most demanding requirements:- Double hull in loading tanks area (marpol + opa 90) - outstanding platform stability for ras/fas opera-tions during

day and night - nBc protection: classification of space as citadel and sub-citadel, detection systems, “wash-down” and decontaminations units- integrated platform management system.- integrated commanding Bridge and auxiliary Bridge- reduced crew- High availability and autonomy.Main characteristics- length overall: 173.9 m - length between perpendiculars: 162.0 m - Beam: 23.0 m - Design draught: 8.0 m - Depth: 11.8 m - Weight: 9,800 t - Displacement: 19,500 t - propulsion: 2 x 10.890 kW 1 cpp - electric plant: Dg 4 x 1,270 kw - maximum speed: 20 kn- crew: 122 people FAM

NEWS

FAM World Navies

NAVANTIA’S NEW GENERATION OF SHIP MANAGEMENT SySTEMSDuring the last decade, Western navies assumed a challenge to improve warships operative capacity by integrating and automa-ting their primary and domestic functions. at the same time, the need for large crews was remarkably reduced by implementing commercial-off-the shelf equipment and the most updated tech-nologies available within the industrial field.navantia systems has developed a new integrated systems for plat-form control and management (ipms), provided with an open archi-tecture for the integration of all types of additional subsystems and their specific software so that all of them can operate under the same operative system. the results are new functionalities, meaning great saving for installation, purchasing, and maintenance costs.navantia systems has a wide experience in the integration of ipms that can be installed in any type of platform, from patrol vessels to aircraft carriers. the ipms consist of the following components:• operator Console: it is intended to provide surveillance, alarms war-

ning and commands generation.• Local Substations (LSS): information gathering, execution of con-

trol algorithms and sending commands to the machinery actuators.• Data Transmission Network (DTN): for interconnection of data bet-

ween consoles and substations, ensuring the information integrity• the consoles, lss and Dtn can be configured with any cots available

in the market. they can be suited to the ship´s characteristics.With the purpose of guaranteeing the system survivability, the ipms configuration implies a redundant and distributed architectu-re (not centralised) with identical functionality for all operator con-soles. the ipms architecture allows assigning the platform control to any combination of operator consoles.the main target in the development of the ipms is to make the platform status information available from any turned on console.the control of one subsystem is assigned to only one console, and just those users with supervisor category are allowed to modify that assign-ment. the ipms provides a high automation level, allowing reduced crews safely sail the ship. compleX organizes and presents the information in the optimal way to help operators get the knowledge of the platform’s state (propulsion, power plant, auxiliaries and damage control) and make the best decisions.

The main functions are:• Monitoring and Warning functions: analog and digital informa-

tion display, communications and sensors diagnosis, alarm warnings and trend charts.

• Automatic functions: ipms can operate under different levels of automation: manual, semiautomatic and automatic.

• Security functions: these functions are used to provide machinery and equipment automatic emergency stop, without the operator´s assistance, under risk operating conditions.

• Damage Control functions: including management of incidences related whit fire, flooding, smoke, nBQ alarms, stress and stability cal-culations, on line personnel location, Kill cards, etc.

other IPMS services: • navigation data, e-mail, videoconference, video surveillance, on line

help, on Board training system (oBts).• predefined configurations: set of commands issued with a single ac-

tion. e.g. firemain valves, tightness conditions. individual and sum-mary status is shown.

• Data logging functions: ipms has Data store units (Dsu) which collects and store continuously events, alarms, analog values, operator actions, etc.

• playback: projects historical data on the mimics, 3D scenes and Data Viewers. FAM

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AS A MEAN To ChARACTERIZE ThE ovERALL vESSEL SIGNATURE AND

PRoTECT ThE MARINE ENvIRoNMENT

UNDERWATER MULTI-INFLUENCE MEASUREMENTS

All the vessels, independently of their shape and size, emit to the sea a set of radiations

that make up the so-called vessel signature. This signature characterizes and identifies

univocally the vessel in the same way that the fingerprint identifies the human being.

The importance of this signature is well-known since early the past century, mainly

in the defense field and specially centered on the so-called acoustic and magnetic

signatures. As an example, detection of vessels based on their acoustic signatures had

a great importance in the naval field during the Second World War.

Autor SAES

16

The underwater sound propaga-tion characterises by its high per-formance, being in fact the way of radiation today known that best propagates through this medium [1], being able to reach long distances in the case of low frequencies.

Vessels emit two types of generic signals: broadband and narrow-band. The former characterises by covering a wide spectrum of fre-quencies, meanwhile the latter is limited to a narrow spectrum.

There are different sound sources in vessels. The three main are: machinery noise, propeller noise, and hydrodynamic noise. In Figure 2 a scheme of sound underwa-ter propagation obtained from an underwater acoustic propagation model is shown.

Magnetic radiationThe ship magnetic influence is com-posed by two components: the stat-ic component (SM) and the alternat-ing one (AM). The static component is generated by the permanent and induced magnetic fields.

The permanent magnetic field of the ship is due to the magnetiza-tion of its construction magnetic materials by the Earth’s magnetic field. Besides, the Earth’s mag-

ence of threats in harbours/ports, critical infrastructures or cultural assets located on the sea floor, making it possible to implement specific actions to neutralize these threats.

This paper comprises four sections in addition to this introduction sec-tion: in the first section the main characteristics of the radiations that make up the multi-influence signature are described. In the next two sections, the importance of this signature in the defense and civilian fields is analyzed. In the next section, a system espe-cially adapted to measure multi-influence signatures is described. Finally, the paper is completed with the conclusion of the study.

2. CHARACTERISTICS OF THE MULTI-INFLUENCE SIGNATURE OF A VESSELAs previously stated, the multi-influ-ence signature of a vessel com-prises five types of radiation: acous-tic, magnetic, electric, pressure and seismic. Each of them incorporates specific characteristics. Next, a brief description of their main characteris-tics is presented.

Acoustic radiationThe sound generated by a vibrating source is propagated as a wave in an elastic medium such as the sea, originating pressure changes that are susceptible of being measured.

NTRODUCTIONIn parallel with technological improvements during the 20th cen-tury, and especially in the defense field, specific techniques have been developed to get smaller the level of the radiations emitted to the sea by vessels. At the beginning, reduction techniques were limited to the acoustic radiation. Next, the magnetic radiation was also tak-ing into consideration and more recently the electric-field, pressure and seismic radiations have also been considered of interest. The group of five radiations referred to above make up the so-called multi-influence signature of a vessel. In Figure 1 an example of the simu-lated electric signature radiated by a sweep gear is shown.

The monitoring of the multi-influ-ence signature has a great impor-tance in the defense field and in the case of vessels such as sub-marines becomes a matter of sur-vival. Also, it is becoming increas-ingly important in the civilian field related to the marine environment preservation, especially in the case of the marine fauna living in this environment, due to the influence of these radiations on their behav-iour. Finally, it is worth to outcome that the detection of this signature permits us to determine the pres-

I

Figure 1. Simulation of the electric

field radiated by a sweep gear Figure 2. Sound underwater

propagation paths obtained from an

acoustic propagation model

17

netic field, as an extern magnetic field, always contributes to the ship magnetic signature. This com-ponent depends on the ship course and localization of the area.

In addition to permanent and induced magnetic fields, CRM (Corrosion Related Magnetic) field also contributes to the static mag-netic component of the signature. This field is due to the existence of corrosion currents through the sea water, which have an associated magnetic field.

The alternating component of mag-netic signature is generated by:• The currents in the rotating

coils of ship turbines. These coils perform as magnetic dipoles, which generate AC magnetic signature.

• Sea water Foucault currents induced by the magnetic dipoles. These currents are time varying and are associated also with alternating electric fields.

• Electric currents flowing through ship hull due to elec-tric equipment failures or inad-equate design.

• Inherent magnetic field radi-ated by any rotating electric machinery in the ship.

Besides, power supply ripple gener-ates alternating currents through the water. In Figure 3 an example of simulation of the magnetic field generated by a vessel is shown.

Electric-field radiationThe ship electric signature is com-posed by two components: the static component UEP (Underwater Electric Potential) and the alternat-ing component ELFE (Extremely Low Frequency Electric).

The static component UEP repre-sents the near field influence and its temporal variation depends on speed and size of the ship. The static electric signature of a ship is due to the electric currents gener-ated by the galvanic corrosion pro-cess. In order to avoid this corro-sion, cathodic protection systems are used. There exist two types of cathodic protection systems: pas-sive and active or ICCP (Impressed Current Cathodic Protection). The passive systems use sacrifice anodes, whereas active systems use impressed current anodes and reference electrodes. Quite often, cathodic protection systems con-tribute drastically to electric sig-nature and constitute the main generator for this influence.

The alternating component ELFE cov-ers a bandwidth of approximately 3 kHz and represents the near and far field influence. ELFE component is due to the following factors:1. Modulation of the corrosion

current: galvanic current is modulated due to the spin of blades and propellers.

2. Ripple in machinery power sup-ply of the ship. It appears a tone of frequency corresponding to the power supply frequency.

3. Ripple in degaussing systems ICCP, corresponding to the mod-ulation suffered by the ICCP sys-tem current due to variations in the resistance between the shaft and hull of the ship.

In Figure 4 is shown an example of simulation of the electric signature radiated by a vessel.

Pressure radiationHydrostatic pressure due to water depth varies slowly with atmos-pheric pressure changes and tide rising and falling. Besides, it can vary fast with waves and train of waves, or with a ship.

Pressure variation due to a ship movement is usually very small. This small variation constitutes the ship pressure signature and it is produced by Bernoulli Effect of the water flow-ing from bow to stern. This flow originates a pressure increase at bow and stern of the ship and a dec-rement in the central zone (suction), which peak is directly proportional to ship speed and its underwater shape. Figure 3, shows this pattern in a simulation of the pressure sig-nature of a ship.

Therefore, induced pressure fluctua-tions by the ship superpose with the nominal static pressure of the bot-

Figure 3. Simulation of magnetic field

generated by a vessel

Figure 4. Example of simulation of the

electric signature radiated by a vessel

(longitudinal, transverse and vertical

components).

Figure 5. Ship Pressure Signature

Simulation

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UNDERWATER MULTI-INFLUENCE MEASUREMENTS

tom and natural disturbances caused by tide, waves and swells.

Seismic radiationSeismic influence is generated by the same sources as for the acous-tic influence. When an acous-tic wave reaches a surface, the majority of the energy is reflected but a percentage is absorbed by the new medium.

Thus, acoustic signals of very low frequency (below 10Hz) propa-gate up to the sea floor and trans-mit through it as a seismic pertur-bance. This type of perturbance travels much faster through sea floor than through sea water.

From this seismic point of view it is obvious that the acoustic energy penetrating into the sea floor may sometimes contribute considerably to medium-range and long-range acoustic transmission. One clear example that shows seismic influ-ences behavior is the existence of a critical frequency. For all frequen-cies below this limit absorption phe-nomena in incident waves appears, and this phenomena depends on characteristics of the materials and layers of the see floor.

3. THE MULTI-INFLUENCE SIG-NATURE IN THE DEFENSE FIELDThe intelligence databases have become an element of great impor-tance for the navies of the different countries. These databases contain as distinctive data the signatures of the vessels. At the beginning they contained acoustic data and some-times magnetic data. Currently, they seek to incorporate also data cor-responding to the rest of influences. These databases permit us to dis-criminate not only the type and class of the vessel but also the specific unit of the class, providing a consid-erable tactical advantage.

Currently, the trend of the last dec-ades relative to the reduction of the vessels signature is being accentu-ated. This trend is particularly intense in the case of submarines. They seek to increase their level of pro-tection becoming every time more stealth vessels as a mean to counter-act the development of increasingly intelligent weapons such as last gen-eration torpedoes.

In parallel with that stated above, every time more sophisticated sys-tems incorporating a wide range of sensors are being developed nowa-days. The use of these multi-influ-ence systems permits vessels to increase significantly their detection capacities from the combination of the data provided by their suite of sensors, making it possible a con-siderable reduction in the number of false alarms.

By other hand, in the defense facilities protection field the use of these multi-influence sensors is permitting to increase their secu-rity in a significant way. This fact is based on the early and more accu-

rate detection of the threats coming from the marine environment, such as: divers moving autonomously, manned and unmanned underwa-ter vehicles (SDV, ROV, UUV), mini-submarines, etc.

4. THE MULTI-INFLUENCE SIG-NATURE IN THE CIVILIAN FIELDDuring the last years, a growing awareness has emerged world-wide on the necessity of protecting the marine environment, especially from the human activities such as: fishing, sailing, harbour works or seismic oil and gas explorations that convey significant increases in the level of a range of pollutants such as acoustic noise and other sources or energy including the electric and magnetic ones.

This growing awareness has entailed the development of a range of national and international regulations focus to get an effec-tive preservation of the marine environment. Among these regula-tions is the Marine Strategy Frame-work Directive, promulgated by the European Union in the year 2008, which introduces a set of qualita-tive descriptors to determine the good environmental status. One of these descriptors states that: “The introduction of energy, includ-

Figure 6. Ship seismic signature physic

phenomena

Figure 7. Multi-influence Signature

measurement by MIRS

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FAM Special

ing underwater noise, is at levels that no adversely affect the marine environment”. The effective applica-tion of this Directive, and of other regulations related with the marine environment protection, implies both the measurement of the level of the energy radiations emitted to the sea [2] and the detection of the marine fauna presence in spe-cific areas on which high energy levels are detected, with the aim of protecting this fauna from the potential harmful effects of the radiated energy. This detection is mainly based on acoustic sensors, although other alternative detec-tion means are currently being ana-lyzed, such as the detection of the marine fauna based on the altera-tion of the underwater electric or magnetic fields originated by its presence. In Figure 8 two kinds of cetacean species: bottlenose dol-phin and sperm whale are shown. Both are endangered species.

Just like in the defense field, the use of multi-influence sensor sys-tems provides an effective pro-tection of harbours and critical infrastructures, such as oil refiner-ies and thermal power stations, against hostile intruders. This pro-

tection can also be extended to other fields of remarkable interests as is the case of marine reserves, ship wrecks or underwater archae-ological remains.

5.MULTI-INFLUENCE SIGNATURE MEASUREMENTS With regards to multi-influence measurements, the trend in the civilian field is to advance towards a standardisation process in the proce-dures and parameters of the meas-urements. These standards already exist since time ago in the defense field. The precursor of this process is again the acoustic influence for which a standard has recently (2009) been developed by the Acoustical Society or America (ASA): “Quanti-ties and Procedures for Description and Measurement of Underwater Sound from Ships”. Additionally, in the European Union scope there exist specific programs focused to the definition of a European stand-ard. Measurements are usually nor-malised to common references in order to be able to compare these coming from different systems, as is the case of the 1-meter from the source reference for acoustic measurements or a common refer-ence point for all the vessels in the case of electric and magnetic fields measurements.

The fact that multi-influence sen-sors provide different detection ranges permits us to establish dif-ferent detection layers as a func-tion of the sensor range, Detection ranges depend on both the specific characteristics of the marine envi-ronment and these ones of the vessel under test and the used sen-sors. In a first approach, it can be stated that both acoustic and seis-mic sensors provide detection dis-tances in the range of kilometers, being the seismic sensor especially dependent on the characteristics previously referred to, electric-field and magnetic sensors in the range of hundreds of meters and pres-

sure sensors in the range of tens of meters.

The wide range of operational envi-ronments in which multi-influence measurements are susceptible to be taken makes highly advisable to have at our disposal modular and portable systems with small dimensions and weights. These kinds of systems permit us their deployment and recovery in differ-ent marine areas within a reduced time interval and without requiring complex means. Other aspects to be stressed are: the capacity of data transmission to base cent-ers (located on shore or onboard vessels) with an adequate band-width to cover the characteristics of the signatures under test and the capacity of storing and pro-cessing the measured influences, focused to provide accurate and useful information to the system operator.

MIRS system developed by SAES, (outlined in the next section) is an example of a system that complies with the characteristics previously described.

6. INDUSTRY SOLUTIONSThe use of advanced multi-influ-ence processing techniques allow the development of last generation systems in the segments of activ-ity in which SAES operates.

MIRS - Multi-influence Range port-able System for surface ships and submarines

The SAES Multi Influence Range System (MIRS) for surface vessels and submarines provides real influ-ence measures (magnetic, electric, pressure, acoustic, and seismic) in a

Figure 8. Species of cetaceans:

bottlenose dolphin (left) and sperm

whale (right)

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real and controlled scenario, to suc-cessfully counter related threats. MIRS is among the best systems in the world in its class and compared to fixed stations, a decisive advan-tage of the MIRS system is that, due to its portability, low weight, power consumption and high per-formance can obtain all signatures of the ship in different geographical locations .

MIRS is also a tool for testing and calibration of:• Systems developed to reduce

those influences as degauss-ing systems, ASG, etc.

• Systems developed for MCM as the mine sweeping systems.

MIRS has been primarily designed using Commercial Off The Self (COTS) equipment for maximum reliability at minimum cost.

MIRS has two installations modes: can be located at a fixed station or, using the portable capability, can be located in the desired location, since it is easily deployable by two people from a rigid-hulled inflatable boat (RHIB).

The MIRS system has been tested in operational environments show-ing its versatility ease of use and accuracy taken as reference-cali-brated systems. In Figure 10 graph-ic outputs of the multi-influence signature of a merchant vessel are shown.

NAVAL MINESBased on the experience in Under-water sensors, SAES has devel-oped a complete set of Multi-influ-ence Naval Mines, at the forefront of the market, that use a variety of sensors to detect different physical influences.

MINEAThe family of MINEA products com-prises three kind of naval mines: cylindrical bottom mine, conical shape shallow water mine and moored mine. MINEA includes the following sensors:• Triaxial magnetic sensor.• Triaxial electric sensor, UEP

and ELFE.• Acoustic sensor.• Triaxial seismic sensor (except

moored mine). • Pressure sensor.

In addition, Exercise MINEA version is available to be used for MCM training and to gathering intelligence informa-tion by measurement and recording of ships influence signatures. The knowl-

edge of this intelligence is essential to programming the fire algorithm of the Combat units.

MILAMILA-6C is a smart computer con-trolled time-fuzzed underwater lim-pet mine. It can be fixed by frog-men onto the hull of the ships or be used as demolition charge as well. It has a conical shape and low weight in water. MILA is available in Exercise (reusable & inert) and Combat versions.

Figure 9. Underwater units of the

multi-influence measurement system

MIRS developed by SAES

Figure 10. Set of measurement of the

acoustic (upper left), seismic (upper

middle), magnetic (upper right),

electric (lower left) and pressure

(lower right) influences of a merchant

vessel taken by the MIRS system

developed by SAES

Figure 11. MINEA multi-influence

NAvAL mines.

Figure 12. MILA. Limpet Naval Mine.

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SIMOAC. Acoustic Monitoring System.Environmental protection configures nowadays as one of the areas of high-est interest worldwide. The acous-tic monitoring system SIMOAC has been designed on the basis of provid-ing a reliable measurement system based on calibrated acoustic sensors, that permit to measure and analyze the underwater acoustic environ-ment and to detect the presence of marine mammals in a specific area, besides their localization. SIMOAC configures as a versatile system, completely respectful with the envi-ronment and powered by renewable energy, based on marine nodes with capability of: including additional sen-sors, unwired communication with a base center on shore, automatic processing of the signals captured by the sensors and sending of selected data via internet to specific surveil-lance centers.

SIDISThe SIDIS system for marine envi-ronment surveillance and protec-tion characterizes by the wide range of tasks that is able to undertake: environmental monitoring, marine mammals detection, protection of ship wrecks or archaeological remains or protection of vessels and critical infrastructures in the marine environment.

SIDIS configures itself as a net of nodes that can operate in a stand-alone way or making part of an integrated surveillance system. These nodes characterize as multi-influence sensors (acoustics and non-acoustics), modular, versatile and high-performance systems.

The SIDIS design, based on a lay-er protection concept, increase its degree of effectiveness, its adapt-ability to be integrated with other sensors and surveillance systems to configure wider control systems. Furthermore, its highly efficient com-munication system and the inclusion of reaction capabilities become it in a complete security system.

7. CONCLUSIONAll vessels when sailing through the sea radiate a set of influences (acous-tic, magnetic, electric, pressure and seismic) that make up their multi-influence signature. Some of these influences (acoustic and magnetic) have being measured since decades ago to characterise the vessels in the defense field and to monitor the acoustic pollution in the civilian field. Recently the interest in the interna-tional community on having at our disposal the overall signature of the

vessels has emerged, with the aim of evaluating globally its impact on the marine environment.

In the defense field, from the point of view of the own fleet to have at our disposal multi-influence data from vessels permits us to perform specific tasks and studies focused to reduce the own signature in order to decrease the probability of being detected. By other hand, from the point of view of the threats this data permits us to characterise the vessels signature with the aim of increasing our capacity to detect them.

In the civilian field, the interest is centered on the marine environ-

ment preservation, especially of its marine fauna. In the dual defense-civilian field, protec-tion systems based on multi-influence sensors constitute a highly efficient mean to detect hos-tile intruders.

Due to the vari-ety of operational areas in the marine environment it is highly advisable to have at our disposal modular systems with contrasted capacities of data transmission, recording of the measurements and processing focused to provide relevant information to the sys-tem operator. The MIRS system developed by SAES configures as a verified and in-service system than complies with the require-ments established for the multi-influence measurement of all kind of platforms or naval devices in the whole spectrum of operational environments. FAM

Figure 13. SIMoAC Communication Buoy.

Figure 14. SIDIS configuration for harbor

protection.

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