netherlands mcm

7/22/2019 NETHERLANDS MCM

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FEATURE

Each NATO nation is responsi-ble for the defense of its own

coastal waters. For the Royal

Netherlands Navys (RNLN) Mine

Countermeasure (MCM ) Force, the

North Sea is its principal operating

area. There, unfavorable condi-

tions like sandy and muddy

seabeds, the variety of types of

modern mines and the differences

in the seabed require an efficient

mine warfare force consisting of

a mixture of minehunters and

minesweepers. Recently, technical,

operational and financial consider-

ations have led the RNLN to recon-

sider the need and type of its MCM

capability.

Due to recent cutbacks in the defense

budget a familiar problem for all

NATO members a proposed coastal

minesweeper project was canceled.

Happily though, a feasibility study

conducted during 1992 and 1993 sug-gested an inviting alternative for coastal

minesweeping: a remote controlled

unmanned, simulation sweeping craft

systems based on the existing Troika

drones used by the German Navy.

Therefore, in 1993 the navy

approved a new staff requirement for an

improved MCM capability, with a project

definition phase commenced in 1995.

THE NETHERLANDSNAVYSSOLUTION

All 15 Tripartite minehunters (Alkmaar

class) will be modernized and will have

provisions for acting as Guidance

Control Platforms (GCP) for the modi-

fied Troika system.

Upgrading of these minehunters,

especially the weapon, communication

and sensor systems will take place

beyond the year 2000 with a three-

nation Capability Upkeep Program

(CUP), involving staff from France,

Belgium and the Netherlands.

To overcome l imitations on the

sweeping depth of the relatively small

drones, all minehunters will be equipped

with an improved minehunting system

(IMHS). This will comprise a Hull

Mounted Sonar (HMS) and a Propelled

Variable Depth sonar (PVDeS) which is

a Remotely Operated Vehicle (ROV).

NETHERLANDS DEVELOP NEW

MINE COUNTERMEASURESFORTHE 21ST CENTURY

By Mark Romanow and Captain ( RNLN) A .L. Maas

27VANGUARD Issue 2, 1999

A lkma ar -c lass M ine Hun te r


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Taking into account the navys

roles, an improved minehunting system

and the procurement of three modern-

ized Troika systems should offer good,

flexible and sufficient MCM capabilities.

By 1998, the RNLN MCM service had

in service modernized MCM Vessels

tailored to perform their varied tasks.

This included 15 minehunters with an

IMHS and three minehunters configuredas GCP Troika with four drones each.

The specifications and design of the

command and control for the Troika-

mod system require close collaboration

with the German Navy. The work for the

Capability Upkeep Program (CUP) dur-

ing the project definition phase was

managed by a coordination Bureau

from the three neighbouring nations to

maintain the uniformity as much as pos-

sible of the Tripartite class mine-

hunters.

IMPROVEDMINEHUNTINGSYSTEMS (IMHS)

The operational limitations of the drone

influence sweeping system called for an

improved overall minehunting capabil-

ity, with all minehunters equipped with

an IMHS system.

The PVDS is a minehunting sonar

mounted on a ROV linked to the mine-

hunter with an umbilical cable. The

latest computer aided detection and

classification systems support the

sonar operators in the detection andclassification phase.

By guiding the PVDS close to the

bottom, it should be possible to detect

and classify camouflaged and partially

buried mines with a better probability

than the hull-mounted sonar. Indeed,

the vehicle can be positioned about 200

metres ahead of the parent ship, which

improves safety of the MCMV and crew.

MINE IDENTIFICATION ANDDISPOSAL SYSTEM (MIDS)

The need to be able to destroy ground

mines effectively, now and in the future,

led to the requirement for an expand-

able Mine Identification and Disposal

System (MIDS). Currently the PAP ROV

drone lays a disposal charge near the

identified mine and must be recovered

by the MCMV before the charge can be

acoustically detonated by the MCMV.

This extremely time consuming method

runs the risk of damage to the ROV,

whose cost can run up to US $1 million

each, by modern mines programmed to

destroy the ROV.

The One Shot Mine Disposal System

(OSMDS) is a cheap on the order of US

$20,000 expendable MIDS along the

lines of a guided underwater missile or

mini-torpedo and will replace the PAPsystem.

The model short-listed for the RNLN

CUP is the STN Atlas Elektronik Seafox.

The Seafox exists in both I (Inspection

recoverable) and C (Combat

expendable) versions. Each is 1.3 metres

in length, weighs approximately 40 kilo-

grams, has sensors including a 360 degree

sonar and a TV camera with lights, a speed

in excess of 6 knots with a 500 metre

range and equipped with a small shaped

charge warhead. A regular Tripartite

MCMV could carry approximately 10 Is

and 25 Cs, while the Troika version

could carry approximately 20 Cs.

The OSMDS is easily transportable

by two men and a standard load-out has

the safety advantage of requiring sub-

stantially less on board explosives than a

normal load-out of mine disposal charges.

TROIKA CAPABILITYUPDATEPROGRAM

Unmanned and remote controlled craft

are new for the RNLN. This results in

new demands on a command and controlsystem. Using unmanned craft required

a new design philosophy with safety

standards placed in a new light.

During sweeping operations, the

drone can be subject to high shock loads,

but with no one on board the vessel in

this situation, it is only the equipment

that is exposed to shock loads.

The result is that no naval person-

nel and a relative low investment is

placed in the high risk area.

But the Troika system only became

feasible when the requirement of targetsimulation (Target Setting Mode) was

dropped and was replaced by the

demand of producing a ship-like signa-

ture which will trigger known mines

(Mine Setting Mode).

A relatively short vessel like the 90-

tonne Troika (maximum speed of 10

knots) is unable to produce a magnetic

field with a length long enough to simu-

late the magnetic signature of a large

vessel. However, with the Troika the

steel construction of the hull itself

forms an integral part of the magnet.

Steel placed inside an electrical coil can

increase the field strength by as much

as 15 times. The design of the hull and

the coils can, therefore, not be seen

independently of one another.

The basic design of the existingGerman Troika is more or less followed.

The main body of the vessel is a

heavy unframed steel cylinder. This

steel cylinder has a good shock resis-

tance and most equipment items

are placed inside this cylinder. This

includes propulsion, engine, compres-

sors and most electrical cabinets.

Streamlined bow and stern pieces

are placed at the forward and aft

extremities of the cylinder to increasethe displaced volume. The part between

the forward and aft part of the cylinder

is covered with a permeable and non-

magnetic skin. This basic concept is

simple, relatively easy to produce and

has a good shock resistance. The final

result can be viewed in the picture.

THE ACOUSTICMINESWEEPINGSYSTEM

Modern naval mines are equipped with

passive and/or acoustic sensors. Theseenable the mine to measure the closest

point of approach and to determine the

optimal firing moment. The sensors

operate in the low, medium and high

frequency ranges.

In order to combat modern mines,

the acoustic mine sweeping system

should generate a broadband noise in

the LF and MF range. The HF transmitters



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should be able to mimic in the fre-

quency range of minehunting sonars in

order to use the drones in precursor

operations.

One of the options which is being

investigated at this moment is an LF air-

gun system in a compact towed body incombination with several MF and HF

transmitters integrated in the hull of the

drone.

The airgun system is a proven tech-

nique from the offshore industry. It is

very reliable, easy to maintain and has

very good shock resistance properties.

Depending on the number of airguns it

is possible to simulate any propeller

cavitation noise and spectral lines in

the LF-band.

COMMANDANDCONTROL

As laid down in the staff require-

ments, Troika operations must be con-

ducted safely, accurately and by a

minimum number of personnel.

This requires the drones to operate

as automatically as possible, guided as

in a pre-defined sweeping or transit

plan, to make monitoring and control of

the drones a one-man operation.

A second person is necessary for

planning and drone control in the worst

case situations. This requires the fol-

lowing: computer aided planning facili-ties; automatic execution of plans,

including automated scheduling; drone

positioning based upon its DGPS sys-

tem; automatic navigation safety

observation for the drones.

A transit plan (from harbor to the

operational area) consists of a number

of tracks for the drones and the control

vessel to follow.

A sweeping plan basically consists

of a number of parallel tracks, each

marked with the number of times to be

swept. For planning supporting com-

mand and control will be able to: advise

on track spacing by use of sweep

performance data; generate multipletracks; produce advice on the sweeping

effort for different tracks, assigning the

number of times a track has to be

swept.

Once a sweeping plan is estab-

lished, tracks are assigned to drones.

Real-rime scheduling is necessary to

cope with evasive manoeuvers, due to

other sea traffic; drone platform mal-

function such as machinery or sweeping

system malfunction; speed differences

and other navigation aspects.

Due to real-time scheduling the

tracks of a drone are not pre-pro-

grammed in detail. At the end of a track,

a new track will automatically be

assigned and a track turn generated.

During a sweeping operation, real-

time evaluation will be provided that

involves displaying the covered path,

estimates of overall effort and time for

the operation.

Command and control will transfer

the track to follow, including sweep sys-

tem setting, speed to sweep and other

data as far as defined in the plan to the

drones. The drone follows this trackusing its navigational sensors (DGPS,

compass etc.), its autopilot and machin-

ery. The actual position of the drones,

course, speed and several status data

will be transferred to the control plat-

form. These data are used for: monitor-

ing drone status and position;

scheduling, evaluation and planning;

and navigational safety calculations.

Because the drones will not be

equipped with a radar, they rely on the

control platforms navigation radar to

track all targets surrounding and includ-

ing the drones.

Command and control will integrate

and correlate data of tracked targets

with DGPS positional data and calculate

anti-collision warnings for the drones

HUMAN FACTORS

Command and control provides for

automatic sweep operations in accor-

dance with a pre-defined plan.

For operation monitoring, human

intervention, planning and evaluation,

two identical consoles are foreseen.

The drone operator has the follow-

ing tasks: monitor the navigational, tac-

tical and technical status of the drones;

manual navigation when necessary,

including evasive maneuvers; and act in

case of any damage to the drones.The navy concluded that monitoring

and control of four drones simultaneously

is manageable for one operator, provided

that not more than two drones need a

human action at the same time.

In the worst case situation, the sec-

ond console will be used for the drone

monitoring and control. In other cases,

this console will be used for operation

planning and evaluation.

HARDWARE ANDSOFTWARE

REQUIREMENTSOn the control platform itself, existing

equipment must be integrated.

So, as far as possible, the hardware

and software components, will be com-

mercial off the shelf. This also means

that, in defining system components,

hardware and software have the highest

possible commonality with the CUP pro-

gram and the IMHS developments. b

Mark Romanow is an independentDefence/ Geopol iti cal Analyst, based

in Edmonton.

Captai n ( RNLN) A.L. Maas isCommander Netherlands MineCountermeasures Force.


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