kongsbergk-posdp(os) dynamicpositioningsystem ......documenthistory documentnumber:385603 rev.a...

Kongsberg K-Pos DP (OS)Dynamic Positioning System

with Offshore LoadingApplication

Operator ManualRelease 8.2

385603/CJune 2014 © Kongsberg Maritime AS

Document history

Document number: 385603

Rev. A March 2014 This version describes the operation of the K-Pos DP at basissoftware release 8.2.0.

Rev. B April 2014 This version describes the operation of the K-Pos DP at basissoftware release 8.2.0. Updated for Class ER.

Rev. C June 2014 This version describes the operation of the K-Pos DP at basissoftware release 8.2.1.

The readerThis operator manual is intended as a reference manual for the system operator. This manual is based onthe assumption that the system operator is an experienced DP operator with good understanding of basicDP principles and general DP operation. If this is not the case, then the operator should first attend theappropriate Kongsberg Maritime training courses.

NoteThe information contained in this document remains the sole property of Kongsberg Maritime AS. Nopart of this document may be copied or reproduced in any form or by any means, and the informationcontained within it is not to be communicated to a third party, without the prior written consent ofKongsberg Maritime AS.Kongsberg Maritime AS endeavours to ensure that all information in this document is correct and fairlystated, but does not accept liability for any errors or omissions.

WarningThe equipment to which this manual applies must only be used for the purpose for which it wasdesigned. Improper use or maintenance may cause damage to the equipment and/or injury to personnel.The user must be familiar with the contents of the appropriate manuals before attempting to operateor work on the equipment.Kongsberg Maritime disclaims any responsibility for damage or injury caused by improper installation,use or maintenance of the equipment.

CommentsTo assist us in making improvements to the product and to this manual, we welcome comments andconstructive criticism.e-mail: [email protected]

Kongsberg Maritime ASwww.kongsberg.com

Operator Manual

Table of contents

Glossary..................................................................................................................13K-POS DP SYSTEM THEORY............................................. 19Dynamic Positioning System .................................................................................19The K-Pos DP system.............................................................................................19Basic forces and motions........................................................................................20K-Pos DP system principles ...................................................................................21

The Extended Kalman Filter ........................................................................ 22The Controller ............................................................................................ 23Thruster allocation ...................................................................................... 24

INTRODUCTION TO DYNAMIC POSITIONING.................. 25Main DP components .............................................................................................25

IMO definitions of the main DP components ............................................... 25Equipment classes ..................................................................................... 27Consequence Analysis ............................................................................... 28DP operator - a DP system component ........................................................ 29Training of DP operators ........................................................................... 29

Operational modes..................................................................................................32Special applications ................................................................................................33

Offshore Loading....................................................................................... 33The K-Pos family of DP systems ...........................................................................34K-Pos DP-11 and DP-12 ........................................................................................35K-Pos DP-21 and DP-22 ........................................................................................37K-Pos DP-31 and DP-32 ........................................................................................38Integrated Control System (ICS)............................................................................39

K-Chief - Marine Automation...................................................................... 39K-Thrust - Thruster Control......................................................................... 39

Heading reference systems.....................................................................................39Vertical reference sensors (VRS) ...........................................................................40Position-reference systems .....................................................................................40

Hydro Acoustic Position-Reference systems (HPR) ..................................... 40RADius...................................................................................................... 46Artemis .................................................................................................... 47Global Positioning Systems (GPS and DGPS) ............................................. 49Other satellite navigation systems ............................................................... 53Fanbeam ................................................................................................... 54The DP system's utilisation of the position measurements............................. 54

Operational planning ..............................................................................................55Resetting the DP system prior to operation............................................................55

385603/C 3

Kongsberg K-Pos DP (OS)

Resetting DP controller process stations ..................................................... 55Resetting DP Operator Stations .................................................................. 56

Thruster control command signals .........................................................................56General procedure for checking stand-alone dual-redundant DPsystems ...................................................................................................... 57

OFFSHORE LOADING....................................................... 58K-Pos DP Offshore Loading application................................................................58Weather vaning.......................................................................................................59Tandem loading (FSU/FPSO).................................................................................60Single anchor loading (SAL)..................................................................................60Single point mooring (SPM) ..................................................................................61Submerged turret loading (STL) ............................................................................62Operational modes..................................................................................................62

Approach mode ......................................................................................... 62Weather Vane mode.................................................................................... 63Connect mode............................................................................................ 63Loading mode............................................................................................ 63

Additional functions ...............................................................................................64Selecting a buoy ........................................................................................ 64Changing the setpoint radius....................................................................... 64Compensating for hawser tension................................................................ 64Setting weather vane limits ......................................................................... 64DP position limits ...................................................................................... 64Axis control............................................................................................... 64GPS relative settings .................................................................................. 65SAL buoy settings...................................................................................... 65FSU Position function ................................................................................ 65FSU Heading function................................................................................ 65

USER INTERFACE ............................................................ 66Operator station ......................................................................................................66Operator panel ........................................................................................................67

Push buttons ............................................................................................... 67Input keypad............................................................................................... 69Trackball .................................................................................................... 70Joystick...................................................................................................... 70Heading wheel............................................................................................ 70

Display layout.........................................................................................................72Top bar....................................................................................................... 75Dashboard layout........................................................................................ 78Side bar...................................................................................................... 84Working areas............................................................................................. 84Dialog boxes .............................................................................................. 84

4 385603/C

Operator Manual

Display views .........................................................................................................89Orientation of the OS and effect on display views ......................................... 89Tooltip/hotspot cursor and change of cursor image ........................................ 89Selecting display views and panes................................................................ 90View control dialog boxes ........................................................................... 91Zooming .................................................................................................... 92Preselect dialog box .................................................................................... 92

SYSTEM SETTINGS.......................................................... 95Changing user.........................................................................................................95Printing the display picture.....................................................................................96Printing system report ............................................................................................97Adjusting the panel light ........................................................................................97

Dimming level............................................................................................ 97Lamp test ................................................................................................... 98

Presentation Units dialog box.................................................................................99Editing Presentation Units ......................................................................... 100Vessel and sea current speed ...................................................................... 101Wind, waves and sea current direction........................................................ 101Resetting the presentation.......................................................................... 102

Set System Date/Time dialog box ........................................................................102Changing display colours .....................................................................................102

Changing the display palette on Operator Stations that are not set to havean independent palette selection................................................................. 103Changing the display palette on a single Operator Station............................ 103

Alarm Limits dialog box ......................................................................................103Position page ............................................................................................ 103Weather Vane page.................................................................................... 104Hawser page............................................................................................. 106Pipe page ................................................................................................. 106

Gain dialog box ....................................................................................................107Gain Level for High Precision controller mode ........................................... 108

Rotation Center dialog box...................................................................................109JOYSTICK ..................................................................... 112Joystick Settings dialog box .................................................................................112Rotation centre for joystick manoeuvring ............................................................113Joystick Calibrate dialog box ..............................................................................114

Calibrating the joystick ............................................................................. 115

MESSAGE SYSTEM......................................................... 117System diagnostics ...............................................................................................117Operational checks ...............................................................................................117

Audible and visual indications ................................................................... 118

385603/C 5


Message priority ...................................................................................................118Presentation of messages......................................................................................119

Defining the time span for the Historic Event Page...................................... 122Alarm states ..........................................................................................................123Acknowledging messages ....................................................................................124

Silence button........................................................................................... 125Alarm lamps .........................................................................................................125

Indications of errors related to the ALARMS button group ........................... 125Drive-off detection for Offshore Loading ............................................................126Messages on the printer ........................................................................................127

Event Printer dialog box............................................................................ 127Message explanations — online help ...................................................................128Operator advice messages ....................................................................................129Offshore loading related messages.......................................................................130

Warning and alarm messages for OLS, SAL and SPM buoys ...................... 131Warning and alarm messages for FSU buoys.............................................. 133Warning and alarm messages for STL buoys.............................................. 137Buoy depth monitoring............................................................................. 138

STARTING OPERATIONS ............................................... 139System start-up/shut-down and OS stop/restart ...................................................139

Stop/Restart dialog box ............................................................................. 139Restarting the system ................................................................................ 140

Logon Configuration dialog box ..........................................................................140Command transfer ................................................................................................142

Taking command ...................................................................................... 142Giving command ...................................................................................... 142Requesting command................................................................................ 143

Command Control dialog box ..............................................................................143DP-OS page ............................................................................................. 144Overview page ......................................................................................... 145Give page................................................................................................. 146Command Groups..................................................................................... 146Controls and indicators.............................................................................. 147

Connect dialog box...............................................................................................148CONTROLLER PROCESS STATIONS................................ 150Resetting controller process stations ....................................................................150

Resetting the controller PS in a single-computer system .............................. 150Resetting one controller PS in a dual or triple redundant system................... 150Resetting all controller PSs in a dual or triple redundant system................... 151

Redundant systems ...............................................................................................151Error objects............................................................................................. 152

6 385603/C

Operator Manual

Dual redundant system .............................................................................. 152Triple redundant system ............................................................................ 153Redundant Stations dialog box................................................................... 154

SENSORS ...................................................................... 158Gyrocompasses.....................................................................................................158

Sensors dialog box — Gyro page ............................................................... 158Gyro status lamp....................................................................................... 160Displayed heading information .................................................................. 160Rejection of heading measurements ........................................................... 160Faulty gyrocompasses ............................................................................... 161Heading dropout ....................................................................................... 161Gyro Deviation dialog box ........................................................................ 162

Wind sensors.........................................................................................................163Sensors dialog box —Wind page............................................................... 163Wind status lamp ...................................................................................... 165Faulty wind sensors .................................................................................. 165Rejection of faulty wind data ..................................................................... 166Operating without wind sensor input .......................................................... 166

Vertical reference sensors (VRS) .........................................................................166Sensors dialog box — VRS page ............................................................... 167VRS status lamp ....................................................................................... 168Displayed VRS information....................................................................... 168Faulty VRS .............................................................................................. 168

Sensors dialog box — Speed page .......................................................................169Sensors dialog box — Draught page....................................................................171Sensors dialog box — FSU Heading page ...........................................................173Sensors dialog box — Hawser page....................................................................173Sensors dialog box — STL page..........................................................................174Sensors dialog box — Rate Of Turn page............................................................175POSITION INFORMATION............................................. 177Handling position information .............................................................................177Position Presentation dialog box ..........................................................................178Datum Details dialog box.....................................................................................181Local N/E Properties dialog box ..........................................................................182UTM Properties dialog box..................................................................................183

Additional information ............................................................................. 184Methods for enabling position-reference systems................................................185Panel buttons ........................................................................................................186Reference System Settings dialog box .................................................................186Reference System dialog box ...............................................................................189

Enable page.............................................................................................. 189

385603/C 7


Weight page ............................................................................................. 190Validation page......................................................................................... 191

GPS Relative Settings dialog box ........................................................................192Reference System Properties dialog box..............................................................193

Quality Filter Actions................................................................................ 195Coordinate systems...............................................................................................196

Global and local position-reference systems ............................................... 196System datum........................................................................................... 196The reference origin.................................................................................. 197

Tests on position measurements ...........................................................................197Standard deviation of position measurements.............................................. 198Freeze test ................................................................................................ 198Variance test ............................................................................................. 198Prediction test........................................................................................... 199Divergence test ......................................................................................... 200Median test............................................................................................... 200

Procedures for enabling position-reference systems ............................................203Enabling the first position-reference system................................................ 203Enabling other position-reference systems .................................................. 203

Changing the reference origin ..............................................................................204Position dropout ...................................................................................................205MAIN MODES AND OPERATING PROCEDURES ............... 206Standby mode .......................................................................................................206

Returning to Standby mode/manual levers .................................................. 207Joystick mode .......................................................................................................207

From Standby mode to Joystick mode ........................................................ 208Joystick control of position and heading ..................................................... 208Position and heading information............................................................... 209Joystick electrical failure ........................................................................... 209Mixed joystick/auto modes........................................................................ 209Joystick mode with automatic heading control ............................................ 209Joystick mode with automatic position control in both surge and sway........... 210Joystick mode with automatic stabilisation ................................................. 211

Auto Position mode ..............................................................................................212From Joystick mode to Auto Position mode................................................ 213

Offshore loading modes .......................................................................................214Approach mode ....................................................................................................214

Changing the reference origin .................................................................... 214Weather Vane mode mode ....................................................................................215Connect mode.......................................................................................................215Loading mode.......................................................................................................216

Using the trackball to change the position setpoint in Loading mode ........... 217

8 385603/C

Operator Manual

Leaving the buoy ..................................................................................... 217

CHANGING THE POSITION SETPOINT ........................... 219Stopping the movement during change of position..............................................219Marking a new position setpoint on the Posplot view..........................................220Position R/B dialog box (range/bearing)..............................................................221Position Inc dialog box (incremental) ..................................................................221Position dialog box...............................................................................................222

Inc page ................................................................................................... 222Speed page ............................................................................................... 223

Circle Around Buoy dialog box ...........................................................................224Acceleration/Deceleration Settings dialog box ....................................................225CHANGING THE HEADING SETPOINT ............................ 227Stopping the rotation during change of heading ..................................................227Marking a new heading setpoint on the Posplot view..........................................228Heading dialog box ..............................................................................................229

Heading page............................................................................................ 229Rate Of Turn page..................................................................................... 231

Acceleration/deceleration factors in the yaw axis ................................................231OFFSHORE LOADING USER INTERFACE......................... 233Buoy Select dialog box.........................................................................................233DP Practice ...........................................................................................................234

DP Practice for Tandem and SPM .............................................................. 235DP Practice for OLS and SAL ................................................................... 235Practice Mode R/B dialog box ................................................................... 235

SAL Buoy Settings dialog box.............................................................................236Setpoint radius ......................................................................................................237

Tandem functions..................................................................................... 237FSU Position function ..........................................................................................238

Enabling the FSU Position function........................................................... 241FSU Position function implications .......................................................... 241Mode changes and operator interaction...................................................... 242

FSU Heading function..........................................................................................243Enabling the FSU Heading function .......................................................... 243Mode changes and operator interaction...................................................... 244

STL mean offset ...................................................................................................244STL goto base/buoy..............................................................................................245Axis Control dialog box .......................................................................................247Position Automatic Shutdown function ...............................................................248THRUSTERS .................................................................. 250Enabling thrusters.................................................................................................250

385603/C 9


Thruster Enable dialog box........................................................................ 251Automatic Thruster Start dialog box ....................................................................252Thruster Allocation dialog box.............................................................................253Allocation Settings dialog box .............................................................................256Power optimal allocation......................................................................................257Power Optimal Allocation dialog box..................................................................258Thruster Combinator Control Settings dialog box ...............................................259Clutch Settings dialog box ...................................................................................260POWER SYSTEM ............................................................ 262Power monitoring .................................................................................................262Power load monitoring and blackout prevention .................................................262SYSTEM STATUS INFORMATION ................................... 265Remote Diagnostics dialog box............................................................................265pcAnywhere Waiting... dialog box.......................................................................267Print Status dialog box .........................................................................................267Export Log Files dialog box.................................................................................270About dialog box ..................................................................................................270SYSTEM STATUS MONITORING ..................................... 273Introduction ..........................................................................................................273System architecture ..............................................................................................273

Operator stations....................................................................................... 274Process stations ........................................................................................ 274IO system................................................................................................. 275Monitoring functions................................................................................. 276

Equipment dialog box ..........................................................................................277PS page.................................................................................................... 278PS Redundancy page................................................................................. 279OS/HS page.............................................................................................. 280Event Printer page .................................................................................... 281Net Status................................................................................................. 282Print Image............................................................................................... 283

Station Explorer dialog box..................................................................................284IO Manager dialog box.........................................................................................286RBUS IO Image ...................................................................................................289

Overview level ......................................................................................... 289Detailed level ........................................................................................... 291

IO Terminal Block dialog box..............................................................................293Shortcut menu .......................................................................................... 296Signal Conditioning elements .................................................................... 296

IO Point Browser dialog box................................................................................298Properties — DpPs Serial port .............................................................................301

10 385603/C

Operator Manual

SerPort page ............................................................................................. 302Disable status page ................................................................................... 303

Resetting a disabled serial line .............................................................................304BUILT-IN TRAINER ....................................................... 307Trainer functions ..................................................................................................307Using the trainer ...................................................................................................307Setting the start position for the next session .......................................................309Leaving the trainer................................................................................................309DP ONLINE CONSEQUENCE ANALYSIS .......................... 310DP online consequence analysis...........................................................................310Selecting the DP class ..........................................................................................311Consequence analysis status messages.................................................................311Consequence analysis alarm messages.................................................................312OFFSHORE LOADING PANES ......................................... 313Circle around buoy pane.......................................................................................313Loading pane ........................................................................................................314

SAL loading ............................................................................................. 314SPM loading............................................................................................. 314STL loading ............................................................................................. 315FSU/FPSO loading ................................................................................... 316

Tandem functions pane.........................................................................................316DISPLAY VIEWS............................................................ 318Diesel view ...........................................................................................................318Joystick view ........................................................................................................320LTW view.............................................................................................................324

Light Taut Wire Plot view control .............................................................. 328Numeric view .......................................................................................................329Numeric offload view...........................................................................................332Posplot view .........................................................................................................333

Posplot view — riser disconnect limit ........................................................ 338Power view ...........................................................................................................340

Power Plot view control ............................................................................ 344Power consumption view .....................................................................................345Reference system main view................................................................................346

Refsys view control .................................................................................. 352Reference system view.........................................................................................355Sensor view ..........................................................................................................357STL Monitor view ................................................................................................360Thruster forces view.............................................................................................363Thruster main view...............................................................................................366

385603/C 11


Thruster view — tunnel thruster ..........................................................................370Thruster Sub Plot view controls ................................................................. 371

Thruster view — azimuth thruster .......................................................................373Thruster Sub Plot view controls ................................................................. 374

Thruster view — propeller/rudder.......................................................................376Thruster Sub Plot view controls ................................................................. 378

Thruster setpoint feedback view...........................................................................379Trends view ..........................................................................................................380

Trend Plot view control ............................................................................. 383

12 385603/C

Operator Manual

Glossary

Abbreviations

ARP Alternative Rotation PointBIST Built-In Self TestBITE Built-In Test EquipmentcPos Kongsberg Compact Dynamic PositioningCCW Counter ClockwiseCG Centre of GravityCOG Course Over GroundCW ClockwiseDGPS Differential GPSDP Dynamic PositioningDPC DP ControllerDQI Differential Quality IndicatorEBL Electronic Bearing LineFLP Floating Loading PlatformFLT Floating Loading TowerFPSO Floating Production, Storage and Offloading vesselFSU Floating Storage UnitGPS Global Positioning SystemHDOP Horizontal Dilution Of PrecisionHiPAP High Precision Acoustic PositioningHPR Hydroacoustic Position ReferenceICS Integrated Control SystemI/O Input/OutputIMO International Maritime OrganisationKM Kongsberg MaritimeK-Pos Kongsberg Dynamic Positioning systemLTW Light-weight Taut WireMOB MOBile transponderOS Operator StationOT Operator TerminalPMS Power Management SystemPS Process Station

385603/C 13


RIO Remote Input - Output

rms root mean square

ROT Rate Of Turn

ROV Remotely Operated Vehicle

RPM Revolutions Per Minute

SAL Single Anchor Loading

SPM Single Point Mooring

UPS Uninterruptible Power Supply

UTC Universal Time Coordinated

UTM Universal Transverse Mercator

VRS Vertical Reference Sensor

WGS World Geodetic System

WT Wing Terminal

14 385603/C

Operator Manual

General terms

Apparent wind See Relative wind.

Bearing The horizontal direction of one terrestrial point from another,expressed as the angular distance from a reference direction,clockwise through 360º.

Blackoutprevention

A method of preventing a power failure due to overloading of thesupply generators.

Cartesiancoordinatesystem

A coordinate system where the axes are mutually-perpendicularstraight lines.

Commandgroup

A group of functions that reflect the way the system will operatefor a specific process area, for example, Propulsion and PropulsionSimulation.

Controllergroup

A group of one or more controller process stations.

Course The horizontal direction in which a vessel is steered or is intendedto be steered, expressed as angular distance from north, usuallyfrom 000º at north, clockwise through 360º. Differs fromHeading.

Crab angle The angle between the vessel heading and the track.

Cross-trackerror

The distance from the vessel's present position to the closest pointon the track.

Datum Mathematical description of the shape of the earth (represented byflattening and semi-major axis as well as the origin and orientationof the coordinate systems used to map the earth).

Dead reckoning The process of determining the position of a vessel at any instantby applying to the last well-determined position the run that hassince been made, based on the recent history of speed and headingmeasurements.

Destination The immediate geographic point of interest to which a vesselis navigating. It may be the next waypoint along a route ofwaypoints or the final destination of a voyage.

Feedback Signals returned from the process (vessel) and used as inputsignals to the Vessel Model.

Gyrocompass A compass having one or more gyroscopes as the directiveelement, and which is north-seeking. Its operation dependson four natural phenomena: gyroscopic inertia, gyroscopicprecession, the earth's rotation and gravity.

385603/C 15


Heading The horizontal direction in which a vessel actually points orheads at any instant, expressed in angular units from a referencedirection, normally true north, usually from 000º at the referencedirection clockwise through 360º. Differs from Course.

IntegratedControl System

Integrated Control System from Kongsberg. In an IntegratedControl System the K-Pos DP system communicates with otherKongsberg systems such as K-Chief (vessel control) and K-Thrust(thruster control) via a dual ethernet LAN.

InternationalHydrographicsOrganisation

Coordinates the activities of national hydrographic offices;promotes standards and provides advice to developing countriesin the fields of hydrographic surveying and production of nauticalcharts and publications.

InternationalMaritimeOrganisation

Formally called IMCO, the IMO is the specialised agency of theUnited Nations responsible for maritime safety and efficiencyof navigation.

Kalman filter The Kalman filter is a set of mathematical equations that providesan efficient computational (recursive) solution of the least-squaresmethod. The filter is very powerful in several aspects; it supportsestimations of past, present and even future states, and it can alsodo so, even when the precise nature of the modelled system isunknown.

Leg The straight line between two waypoints.Median value A number dividing the higher half of a sample or population from

the lower half, i.e. the middle number.

Navigation leg The leg of a voyage on which the vessel is currently travelling.Process Station One Central Processing Unit (CPU) plus I/O interfaces, possibly

shared with other CPUs in redundant configurations. A physicalPS may be single, part of a dual-redundant-physical PS or partof a triple-redundant-physical PS. The PS utilises RCU or PChardware.

Reference origin The reference point of the first position-reference system that isselected and accepted for use with the system. The origin in theinternal coordinate system.

Relative bearing The bearing of an object relative to the vessel's heading.Relative wind The speed and relative direction from which the wind appears to

blow with reference to the moving vessel.

Route A planned course of travel, usually composed of more than onenavigation leg.

SENC A database resulting from transformation of the ENC by ECDISfor appropriate use, updates to the ENC by appropriate means andother data added by the mariner. It is this database that is actually

16 385603/C

Operator Manual

accessed by ECDIS for display generation and other navigationalfunctions and is equivalent to an up-to-date paper chart. TheSENC may also contain information from other sources.

Setpoint circle The circle around the terminal buoy where the vessel is positionedduring offshore loading operations.

Safety Of LifeAt Sea

International convention for the Safety Of Life At Sea (SOLAS)developed by IMO.

StandardDeviation

The square root of the Variance.

Surge Vessel movement in the fore-and-aft direction.

Sway Vessel movement in the transverse direction.

Thruster In this document, this is used as a general term for any element ofthe vessel's propulsion system, such as an azimuth thruster, tunnelthruster, main propulsion or rudder.

Transponder In this document, this is the physical reference of aposition-reference system. For example: for an HPR system thismeans any deployed transponder; for an Artemis system, theFixed Antenna unit/beacon; for a Taut Wire system, the depressorweight.

True bearing Bearing relative to true north.

Unavailable Describes a status indication or entry field that is shown butappears dimmed. An unavailable entry field cannot be changed.

Variance A measure of the expected deviation from the mean. The squareroot of the variance is the standard deviation.

Vessel ReferenceModel

A mathematical model of the vessel which makes it possible tosimulate vessel movements and behaviour in the horizontal plane(surge, sway and yaw).

Yaw Vessel rotation about the vertical axis (change of heading).

385603/C 17


18 385603/C

K-Pos DP system theory


This section contains the following topics:Dynamic Positioning System...........................................................................................19The K-Pos DP system ......................................................................................................19Basic forces and motions .................................................................................................20K-Pos DP system principles ............................................................................................21

Dynamic Positioning SystemThe International Maritime Organization (IMO) has defined DP vessel and DP systemas described below:

Dynamically positioned vessel (DP vessel) means a unit or a vessel which automaticallymaintains its position (fixed location or predetermined track) exclusively by means ofthruster force.

Dynamic positioning system (DP system) means the complete installation necessary fordynamically positioning a vessel comprising the following subsystems: Power system,Thruster system and DP control system.

The K-Pos DP systemKongsberg K-Pos DP system is a computerised system for automatic position andheading control of a vessel and .

To control the vessel's heading, the K-Pos DP system uses data from one or moregyrocompasses, while at least one position-reference system (for example, DGPS orhydroacoustics) enables the K-Pos DP system to position the vessel.

Setpoints for heading and position are specified by the operator and are then processedby the K-Pos DP system to provide thrust control signals to the vessel's thruster and mainpropeller systems. The K-Pos DP system always allocates optimum thrust to whicheverpropulsion units are in use.

Deviations from the desired heading or position are automatically detected andappropriate adjustments are made by the system.

385603/C 19


The K-Pos DP system also provides a manual joystick control which may be used formanual control alone or for combined manual/auto control.

Without a position-reference system, the K-Pos DP system can provide automaticstabilization and control of the vessel heading using the gyrocompass as the headingreference.

The DP system includes control strategies that will reduce fuel consumption andgreenhouse gases.

Basic forces and motionsA seagoing vessel is subjected to forces from wind, waves and current, as well as fromforces and moments generated by the vessel's propulsion system.

The term “forces” in the following sections includes both forces and yawing moments,unless otherwise stated. The vessel's responses to these forces, i.e. its changes inposition, heading and speed, are measured by position-reference systems, gyrocompassesand vertical reference sensors. Reference system readings are corrected for roll andpitch using readings from the vertical reference sensors. Wind speed and direction aremeasured by the wind sensors.

The system calculates the forces that the thrusters must produce in order to control thevessel's motion in three degrees of freedom - surge, sway and yaw - in the horizontalplane.

Figure 1 Forces and motions

The vessel also moves in three vertical degrees of freedom: pitch, roll and heave.

20 385603/C


Figure 2 Pitch, roll and heave

Pitch(+ = bow up)

Roll(+ = starboard down)

Heave(+ = down)(CD3292)

The pitch and roll motions are not controlled by the K-Pos DP system. However, in orderto allow the position-reference system to correct for these motions, the system must haveinformation about them. This information is received from vertical reference sensors.

The K-Pos DP system does not control or require information about the heave motion,but the motion can be measured and displayed.

K-Pos DP system principlesA simplified block diagram of the K-Pos DP system is shown in system principles Figure3, and described in the sections that follow.

Figure 3 K-Pos DP system block diagram

385603/C 21


The K-Pos DP system relies on a mathematical vessel model which includeshydrodynamic characteristics such as current drag coefficients and virtual mass data.This model, called the Mathematical Vessel Model, describes how the vessel responds toan applied force, e.g. from wind or thrusters.

The Extended Kalman FilterThe Extended Kalman Filter estimates the vessel's heading, position and velocity in eachof the three degrees of freedom - surge, sway and yaw. It also incorporates algorithmsfor estimating the effect of sea current and waves.

The Extended Kalman Filter uses a mathematical model of the vessel. A mathematicalmodel itself is never a 100% accurate representation of the real vessel. However, byusing the Extended Kalman filtering technique, the model is continuously corrected.

The vessel's heading and position are measured using the gyrocompasses andposition-reference systems, and are used as input data to the K-Pos DP system. Thesemeasurements are compared with the predicted or estimated data produced by themathematical model, and the differences are then used to update the model.

Figure 4 Simplified block diagram showing the extended Kalman Filter

The Extended Kalman Filter provides the following advantages:• Optimum self-adaptive noise filtering of heading and position measurements

according to noise level and measurement-update rate.

22 385603/C


• Optimum combination of data from the different position-reference systems. Thesystem calculates a variance for each position-reference system in use, and placesdifferent weighting on their measurements according to each system's individualquality.

• In the absence of position measurements, the model provides a “dead-reckoning”mode. This means that the system is able to perform positioning for some timewithout position measurement updates from any position-reference systems.

In the Extended Kalman Filter, the Mathematical Vessel Model's reliability and thenoise level of the position measurement are the basis for deciding how much to trusteach measurement. As time elapses the model uncertainty will decrease by learningfrom measured vessel response.The process is adaptive. If, for example, only one position-reference system is activeand it has a low update rate, the model uncertainty will increase in the periods betweenmeasurements, and the vessel model will therefore be heavily updated with eachmeasurement.Offshore trials have verified that the K-Pos DP system principles give:• Improved suppression of noise in position measurement with a better station-keeping

performance.• Reduced power consumption and wear and tear on the thrusters due to the improved

suppression.• A robust handling of combined high and low update rate position sensors, such as

DGPS and traditional Long Base-Line hydroacoustic positioning.The Extended Kalman Filter is also used for the heading information based onmeasurement from the actual gyrocompass in use.Additional advantages can be obtained by use of:• Speed measurements

Speed measurements can be used as an addition to position measurements to improvethe vessel speed control, and to make calibration of position measurements fasterwhen sailing at high speed.A combination of speed measurement and a position-reference system will be betterable to handle drop out of position measurements during sailing.The speed measurement interface can be DGPS or Doppler Log.

• ROT measurementsROT (Rate Of Turn) measurements from ROT sensors can be used to improve theheading control of the vessel. This is useful when very accurate heading control isrequired during high-speed sailing, or when the vessel has a hull shape that makes itdifficult to control the heading.

The ControllerThe controller calculates the resulting force to be exerted by the thrusters/propellers inorder for the vessel to remain on station.

385603/C 23


The K-Pos DP Controller in K-Pos DP Offshore Loading systems work in the so-calledHigh Precision control controller mode.

High Precision control provides high accuracy station-keeping in any weather conditionat the expense of power consumption and exposure to wear and tear of machinery andthrusters.

High Precision

• Excursion FeedbackThe deviation between the operator-specified position/heading setpoints and theactual position/heading data, and similar deviations with respect to the vessel'svelocity/heading rate, drive the excursion feedback. The differences are multiplied bygain factors giving a force demand (restoring demand and damping demand) requiredto bring the vessel back to its setpoint values while also slowing down its movements.

• Wind Feed-ForwardIn order to counteract the wind forces as quickly as possible, the feed-forward conceptis used. This means that the K-Pos DP system will not allow the vessel to drift awayfrom the required position, but counteracts the wind-induced forces as soon as theyare detected.

• Current FeedbackThe excursion feedback and wind feed-forward are not sufficient to bring the vesselback to the desired setpoints due to unmeasured external forces (such as wavesand current). The system estimates these forces over time, and calculates the forcedemand required to counteract them.

Thruster allocationThe controller of the K-Pos DP system continuously calculates the actual forcerequirements in the alongships and athwartships directions (the force demand), and therequired rotational moment (the turning moment demand).

The Thruster Allocation distributes these demands as pitch/rpm/force/load and azimuthcontrol signals to each thruster/propeller, thus obtaining the force and moment requiredfor the position and heading control.

If it is not possible to maintain both the turning moment and the force demand dueto insufficient available thrust, priority is normally set to obtain the turning momentdemand (heading).

If a thruster/propeller is out of service or deselected, the “lost” thrust is automaticallyredistributed to the remaining thrusters/propellers.

The magnitude of thrust allocated is reduced if the available power is too low to meetthe thrust demand. The allocated thrust will however still be correct with respect to thedirection of thrust. Heading (or position) priority is also kept in such a situation.

Power optimal allocation is the primary barrier for preventing blackouts and requires thesame information as that required for Power Load Monitoring and Blackout Prevention.

24 385603/C

Introduction to dynamic positioning

Introduction to dynamicpositioning

This section contains the following topics:Main DP components.......................................................................................................25Operational modes ...........................................................................................................32Special applications .........................................................................................................33The K-Pos family of DP systems.....................................................................................34K-Pos DP-11 and DP-12 ..................................................................................................35K-Pos DP-21 and DP-22..................................................................................................37K-Pos DP-31 and DP-32..................................................................................................38Integrated Control System (ICS) .....................................................................................39Heading reference systems ..............................................................................................39Vertical reference sensors (VRS) .....................................................................................40Position-reference systems...............................................................................................40Operational planning........................................................................................................55Resetting the DP system prior to operation .....................................................................55Thruster control command signals...................................................................................56

Main DP componentsThe K-Pos DP control system with its computers, screens and panels is just a small partof the vessel's total dynamic positioning system.

Dynamic positioning is dependent on several main systems and functions on boardthe vessel.

IMO definitions of the main DP componentsDifferent authorities and classification societies define the main components differently,but they all include the same components. We will here relate this to the IMO definitions.

385603/C 25


DP vessel

Dynamically positioned vessel (DP vessel) means a unit or a vessel which automaticallymaintains its position (fixed location or predetermined track) exclusively by means ofthruster force.

Dynamic positioning system

Dynamic positioning system (DP system) means the complete installation necessary fordynamically positioning a vessel comprising the following subsystems: Power system,Thruster system and DP control system.

Position-keeping

Position-keeping means maintaining a desired position within the normal excursions ofthe control system and the environmental conditions.

Power system

Power system means all components and systems necessary to supply the DP systemwith power. The power system includes prime movers with necessary auxiliary systems,including piping, generators, switchboards and distributing system (cabling and cablerouting). There are also requirements for uninterruptible power supply (UPS) and powermanagement system (PMS) for DP Equipment Class 2 and DP Equipment Class 3systems.

Thruster system

Thruster system means all components and systems necessary to supply the DP systemwith thrust force and direction. The thruster system includes thrusters with drive unitsand necessary auxiliary systems including piping, main propellers and rudders (if theseare under the control of the DP system), thruster control electronics, manual thrustercontrols and associated cabling and cable routing.

DP control system

DP control system means all control components and systems, hardware and softwarenecessary to dynamically position the vessel. The DP control system consists ofcomputer and joystick systems, sensor system, display system (operator panels),position-reference systems and associated cabling and cable routing.

Computer system

Computer system means a system consisting of one or several computers includingsoftware and interfaces.

Redundancy

Redundancy means ability of a component or system to maintain or restore its functionwhen a single failure has occurred. Redundancy can be achieved, for example, byinstallation of multiple components, systems or alternative means of performing afunction.

26 385603/C


Equipment classesThe following is an extract of the IMO MSC/Circ. 645 Guidelines For Vessels WithDynamic Positioning Systems, regarding Equipment Classes:“A DP system consists of components and systems acting together to achieve sufficientlyreliable position-keeping capability. The necessary reliability is determined by theconsequence of a loss of position-keeping capability. The larger the consequence, themore reliable the DP system should be.”To achieve this philosophy the requirements have been grouped into three Equipmentclasses. For each Equipment Class the associated worst-case failure should be defined.The Equipment Classes are defined by their worst-case failure modes as follows:

Equipment Class 1

Loss of position may occur in the event of a single fault.

Equipment Class 2

Loss of position must not occur in any active component or system in the event ofa single fault.Normally, static components will not be considered to have failed where adequateprotection from damage is demonstrated.Single-failure criteria include:• Any active component or system (generators, thrusters, switchboards,

remote-controlled valves, etc.).• Any normally static component (cables, pipes, manual valves, etc.) which is not

properly documented with respect to protection and reliability.

Equipment Class 3

Loss of position must not occur in any active component or system in the event ofa single fault.Single-failure criteria include:• Items listed above for Class 2, and any normally static component which is assumed

to fail.• All components in any one watertight compartment, from fire or flooding.• All components in any one fire sub-division, from fire or floodingFor Equipment Classes 2 and 3, a single inadvertent act should be considered as a singlefault if such an act is reasonably probable.

Equipment classes from various classification societies

The general requirements listed in the previous section form the basis of the detailedrequirements for the technical arrangements.Different authorities and societies have different names for the various classes.

385603/C 27


Table 1 Classification societies and their Equipment Classes

Classification society Name of Equipment Classes (lowest class first)IMO Class 1, Class 2 and Class 3

Det Norske Veritas DYNPOS-AUT, DYNPOS-AUTR and DYNPOS-AUTRO

Lloyds Register of Shipping DP(AM), DP(AA) and DP(AAA)

American Bureau of Shipping DPS-1, DPS-2 and DPS-3

Bureau Veritas DYNAPOSAM, DYNAPOSAM R and DYNAPOSAM RS

RINA DYNAPOSAM, DYNAPOSAM R and DYNAPOSAM RS

IMO state that the Equipment Class for a particular operation should be agreed betweenthe owner of the vessel and the customer based on a risk analysis of the consequenceof a loss of position, or that the class may be set by IMO or the coastal state. Interestorganisations such as the International Marine Contractors Association (IMCA) in theUK have been working to set standards for the industry based on common practiceand experiences.

The Norwegian Petroleum Directorate (NPD) and NORSOK (competitive standings forthe Norwegian shelf) have indicated in their guidelines which classes shall be usedfor different operations.

The following general principles apply:• Class 3 for all operations in contact with hydrocarbons• Class 3 for diving where the diver is inside a structure• Class 2 for diving in open water where the diver has a free route back to the bell• Class 2 generally for all construction operations inside 500 metres of a platform• Class 1 for operations outside the 500 meter zone

For more information about redundancy requirements, refer to the document NORSOKStandard, Marine Operations J-003, Rev. 2 (August 1997).

Consequence AnalysisFor Equipment Classes 2 and 3, the DP control system shall include a software function,normally known as Consequence Analysis, which continuously verifies that the vesselwill remain in position if the worst-case failure occurs. Based on the single failuredefinition for the class, the worst-case failure shall be determined for the vessel and usedas the criterion for the Consequence Analysis. The analysis shall verify that the thrustersremaining in operation after the worst-case failure, can generate the same resultantthruster force and moment as required before the failure. The Consequence Analysisshould provide an alarm if the occurrence of a worst-case failure would lead to loss ofposition due to insufficient thrust in the prevailing environmental conditions.

28 385603/C


DP operator - a DP system componentA DP system consists of several systems and components acting together to achievethe dynamic positioning. If any of these systems or components fail, it may lead to asituation where the vessel drifts out of position.

Some failures will need immediate operator action to avoid incidents developing intoaccidents. One such failure is a thruster error. It happens from time to time that a thrusterfails, and maybe starts to run unintentionally with 100% force in a fixed direction.

The only action that can prevent the vessel from being driven out of position is that thethruster is stopped by the operator. This is normally done by using an emergency stopbutton for the specific thruster. If the DP system is unattended, a failure like this caneasily develop into an accident.

Watch-keeping practice varies between vessels. For most operations the DP system mustbe monitored by an operator at all times.

It is normal practice to have two watch-keepers on the bridge for Class 2 and 3operations, where one of them attend the DP system while the other perform all otherbridge functions. They will normally swap jobs several times during the watch tomaintain the required level of concentration on the DP.

Training of DP operatorsTo ensure optimal safety in an operation it is important that all involved personnelare well trained on the equipment in use, familiar with the vessel and have a fullunderstanding of the operation.

Training is generally considered to be one of the most powerful tools in ensuring thecompetency of DP Operators to deal with routine and extraordinary situations and isdirectly linked with the human factor element.

Guide-lines in this matter, the document Training and Experience of Key DP Personnel,issued by the International Marine Contractors Association (IMCA) are referred byIMO as an industry standard. The Nautical Institute “training scheme” or flow chart forDP operators, is built into these guide-lines. This training scheme is leading up to theDynamic Positioning Operator's Certificate, issued by the Nautical Institute in UK.

Generally we can say that the training scheme consists of 5 phases:1 A DP Basic/ Introduction course2 A minimum of 30 days' seagoing DP familiarisation3 A DP Advanced/Simulator course4 A minimum of 6 months' watch-keeping experience5 A statement of suitability by the MasterAll of the five phases are recorded in a DP Logbook, held by the trainee. All entriesare to be validated by the Master, and it is his responsibility that the candidate herecommends for the Dynamic Positioning Operator's Certificate has the required skillsand practical DP experience.

385603/C 29


The Nautical Institute issue two grades of certification: The “Full” certificate is issuedfor operators with qualifying experience from Equipment Class 2 or 3 systems, while a“Limited” certificate is issued for those with experience only from Class 1 vessels. A“Limited” certificate can be upgraded be additional sea time on Class 2 and 3. Forspecific details see the flow chart at the end of this section.

The certificate is solely a confirmation that the holder has undergone basic training andhas some DP watch-keeping experience. This is most probably experience from onevessel in one type of operation using one type of DP system in one specific way. Thecertificate must therefore not be regarded as proof of a fully-qualified DP operator whocan be set to operate any DP system on any vessel in any operation.

When changing vessel, or when changing equipment or when a new operation is beingperformed, the DP operator needs familiarisation.

Most vessels spend a lot of time off DP. To make it possible to do training on board, inaddition to “real” experience, all K-Pos DP systems are fitted with a built-in Trainerfunction. The built-in Trainer provides simple simulations for operator training purposes.All normal functions and operational modes can be simulated. The operator can alsodefine environmental conditions. For familiarisation with new equipment the built-inTrainer can be very useful.

The flow chart in Figure 5 is an overview of courses and watch keeping practice requiredto become a DP Operator.

30 385603/C


Figure 5 Dp Operator Certification

385603/C 31


Operational modesThe K-Pos DP system can be used in one or more of the following modes:• Standby mode on page 206

This is a waiting and reset mode in which the system is in a state of readiness, but inwhich no control of the vessel can be made using the system.

• Joystick mode on page 207In this mode, the vessel movement can be controlled in all three axes using thejoystick.The Joystick mode also allows automatic control of either one or two of the surge,sway and yaw axes.

• Auto Position mode on page 212In the Auto Position mode, the vessel is under full automatic control in all three axes.The operator can use standard functions to control the vessel's position, heading,speed and rate of turn.The operator can set warning and alarm limits for position and/or heading deviation.The vessel's position and heading is monitored continuously by the system, and amessage is given if the deviation limits are exceeded.Controller Gain Selection allows the operator to select one of three predefinedcontroller gain levels (High, Medium or Low) to adjust the vessel response.

• Auto Track (move-up, low and high speed) mode (refer to separat manual)This mode enables the vessel to automatically follow a predefined track. The systemcontrols the position, the heading and the speed using all available propulsion forces.Auto Track mode is normally not available on shuttle tankers.

• Autopilot mode (refer to separat manual)When available, this mode enables the vessel to steer along a selected course.

• Follow Target mode (refer to separat manual)When available, this mode enables the vessel to automatically follow a movingsubmerged target and keeps the vessel at a constant position relative to the target.

The system is supplied with either a Trainer function or a Simulator function:• The built-in Trainer function (see Built-in trainer on page 307) provides simple

simulations for operator training purposes, and for analysing the vessel behaviourduring changes in operational conditions.

• The Simulator function (refer to separate Simulator operator manual) provides thesame features as the Trainer function but with more functionality and flexibility indefining the operational conditions. The simulator can be provided as either a built-inor a stand-alone function.

In addition to these modes, various tailored modes have also been developed to optimisevessel operation for a wide range of applications and types of vessels.

32 385603/C


Special applicationsIn addition to the standard operational modes and functions, the following tailoredfunctions are available to optimie vessel operation for a wide range of applicationsand vessels:• Offshore loading• Cable laying• Pipe laying• Trenching• Dredging• Drilling

Kongsberg Maritime also supplies tailored functions for many other special applicationareas.

Offshore LoadingWhen loading oil offshore, it is possible to reduce the thruster/propeller force required toretain the vessel's position relative to the offshore loading buoy, by using the stabilisingeffect of the environmental forces acting on the vessel's hull. In order to achieve thisreduction, the vessel's bow must always face the environmental forces. The systemtherefore includes special weather vaning operation modes which cause the vessel toalways point towards the environmental forces.

Weather vaning causes the vessel to act like a weather vane. The vessel is allowed torotate with the wind, current and waves around a fixed point called the terminal point.Neither the heading nor the position of the vessel is fixed. The heading of the vessel iscontrolled to point towards the terminal point, while the position is controlled to follow acircle, called the setpoint circle, around the terminal point. This kind of weather vaningrequires a minimum sideways holding force, and the available thruster capacity on thevessel is used for maintaining the correct distance and heading towards the terminal point.

The vessel's position is not controlled in the athwartships direction. The vessel's motionsare only damped. The terminal point, the setpoint circle and the maximum and minimumdistances that the vessel may move from the terminal point are defined by the operator.The distance from the terminal point is monitored and an alarm is given if one of theselimits is exceeded.

For further information about the principles of offshore loading, see Offshore loading onpage 58.

385603/C 33


The K-Pos family of DP systemsThe range of K-Pos DP systems provides functions which fulfil the requirement forInternational Maritime Organisation (IMO) and all major classification societies, incombination with an independent joystick control system. The K-Pos DP system istype-approved by Det Norske Veritas (DNV) and American Bureau of Shipping (ABS).

The Heading Control System (HCS) (Autopilot) has a mark of conformity (wheelmark)in accordance with the Marine Equipment Directive (MED) (EU Council Directive96/98/EC on marine equipment) of the European Union.

The K-Pos concept consists of a number of different types of DP control systemsdesigned for various applications and types of vessels. All the systems are based onthe same hardware and software platform.• The stand-alone systems interface with other systems, such as power plant and

thrusters, via conventional signal cables and serial lines.• The integrated systems communicate with other KONGSBERG systems such as

K-Chief (Marine Automation) and K-Thrust (Thruster Control) via a dual ethernetLAN.

The design gives the K-Pos concept a high degree of flexibility and extensive possibilitiesfor upgrading. In addition, the K-Pos concept has a number of options in order to adaptto various demands and safety requirements.

The K-Pos systems are based on a small number of flexible hardware units which formthe building modules of the different system types. The same modules are also used asthe building blocks for integrated systems.

Basic K-Pos DP systems on page 34 shows the basic systems within the K-Pos DP family.

Table 2 Basic K-Pos DP systems

SystemsDP-11 Stand-alone single DP control system

DP-12 Integrated single DP control system

DP-21 Stand-alone dual-redundant DP control system

DP-22 Integrated dual-redundant DP control system

DP-31 Stand-alone triple-redundant DP control system

DP-32 Integrated triple-redundant DP control system

The flexibility of the K-Pos concept means that systems designed for a particular classnotation can be easily upgraded to fulfil the requirements of a higher class, as shown inBasic K-Pos DP systems and corresponding IMO Equipment Classes on page 35. Thetable shows the basic system types and the corresponding IMO Equipment Class. Theremarks indicate the first stage of the upgrading possibilities. The flexibility of theK-Pos concept allows a simple upgrade path.

34 385603/C


Table 3 Basic K-Pos DP systems and corresponding IMO Equipment Classes

System IMO Equipment Class RemarksDP-11/12 Class 1 Can be upgraded to Equipment Class 2

DP-21/22 Class 2 Can be upgraded to Equipment Class 3

DP-31/32 Class 2 Can be upgraded to Equipment Class 3

DP-21/22 with DP-11/12 Class 3 DP-11/12 as backup

DP-31/32 with DP-11/12 Class 3 DP-11/12 as backup

The IMO Equipment Classes are defined in the IMO MSC/Circ.645 Guidelines ForVessels With Dynamic Positioning Systems.

K-Pos DP-11 and DP-12The DP-11 and DP-12 are single DP control systems comprising a DP controller unit(DPC-1) and a dedicated operator station (K-Pos OS). The controller unit and theoperator station communicate via a dual high-speed data network for DP-12 and singlenetwork for DP-11. Both systems satisfy IMO Equipment Class 1 and correspondingclass notations. The DP-11 system (see Figure 6) provides a direct interface to thethrusters and includes the necessary interfaces to power plant, position-reference systemsand sensors. The DP-12 system is designed for integration with the KONGSBERGK-Thrust and K-Chief systems. In this configuration, the interfaces to the thruster andpower systems are via a dual data network to other parts of the integrated system.

385603/C 35


Figure 6 DP-11

36 385603/C


K-Pos DP-21 and DP-22The DP-21 and DP-22 are dual-redundant DP control systems comprising a dualredundant DP controller unit (DPC-2) and two identical operator stations (K-PosOS). The controller unit and the operator stations communicate via a dual high-speeddata network. Both systems satisfy the requirements of IMO Equipment Class 2 andcorresponding class notations.

The DP-21 system provides a direct interface to the thrusters and includes the necessaryinterfaces to power plant, position-reference systems and sensors (see Figure 7).

Figure 7 DP-21

The DP-22 system is designed for integration with the KONGSBERG K-Thrust andK-Chief systems. In this configuration, the interface to the propulsion and power systemsis via a dual data network to the other parts of the integrated system.

385603/C 37


K-Pos DP-31 and DP-32The DP-31 and DP-32 are triple-redundant DP control systems comprising atriple-redundant DP controller unit (DPC-3) and three identical operator stations (K-PosOS). The controller unit and the operator stations communicate via a dual high-speeddata network. Both systems satisfy the requirements of IMO Equipment Class 2 andcorresponding class notations.

The DP-31 system provides a conventional interface to the vessel's propulsion and powersystems, while the DP-32 system is designed for integration with the KONGSBERGK-Thrust and K-Chief systems.

Figure 8 DP-31

38 385603/C


Integrated Control System (ICS)Integrating all the functions for monitoring and control of a vessel provides a real benefitboth technically and economically. Functions can be integrated in order to reduce theoverall need for hardware and software functions and to reduce interfacing requirements.This in turn leads to less demand for special software, cabling and testing. Furthermore,integrated systems offer a far greater degree of redundancy, and therefore increasedsystem availability and operational performance.

K-Chief - Marine AutomationK-Chief is a distributed vessel automation and control system covering functions such as:• Power management• Machinery monitoring and alarm system• Auxiliary monitoring and control• Ballast monitoring and control• Cargo monitoring and control• Vessel-wide mode control

K-Thrust - Thruster ControlThe thruster control system monitors and controls the vessel’s propulsion and thrustersystem. The system includes the following functions:• Individual control of propulsion/thruster units• Joystick control• Station-keeping• Monitoring and control of propulsion/thruster prime power units• Monitoring and control of propulsion/thruster auxiliary units• Emergency stop of propulsion/thruster unitsIn an integrated system K-Thrust operator stations may also act as backup for any of theK-Pos operator stations, thereby increasing the system availability.

Heading reference systemsGood heading reference is crucial for a DP system. The heading reference is not onlyused for the heading control of the vessel, but also used to correct the position-referencesystem for its offset to the center of the vessel. For systems measuring angles relative tothe hull of the vessel, the heading reference will correct for the orientation of the vessel.Without heading reference, the DP system will not accept any position-reference systems.Inaccuracies, fluctuations or drift in the heading reference will affect all position-referencesystems. Firstly, the measurements from the position-reference systems relative to thesensor head or antenna, are calculated back to the center of the vessel. The heading

385603/C 39


measurement will affect this. Secondly, it will have great impact on short range Artemis(beacon) and FanBeam because their measured relative bearing is corrected with theheading to get true bearing. It may also directly affect all systems using vertical anglemeasurements such as SSBL HPR/HiPAP and Taut Wires, dependent on the angles.

A commonly used heading-reference system is the gyrocompass. There are normallytwo or three gyrocompasses installed for a redundant DP system.

Vertical reference sensors (VRS)The vertical-reference sensor measures the vessel's pitch and roll angles. These areused to correct the position measurements for the motion of the antennas and sensorheads. Without a good VRS, the effect of pitch and roll would look like noise on thereference systems.

Position-reference systemsThe position-reference systems used for dynamic positioning must have good accuracy,preferably within a few meters. The required positioning accuracy may vary fromoperation to operation. For example, a vessel positioning ten metres from an installationrequires much more accurate position measurements than a drill ship operating at 2000meters water depth, and allowed to move inside a circle of 50 meters without anyconsequences for the operation.

The position-reference systems used are either accurate navigation systems, systems usedfor surveying or systems specially designed for measuring a vessel's position locally.The most common types are global satellite navigation systems (GPS/DGPS/DARPS),hydro acoustic position-reference systems (HPR/HiPAP), microwave surveying system(Artemis), laser surveying system (FanBeam), taut wire systems (LTW).

Various types of position-reference systems are described in the sections that follow.

Hydro Acoustic Position-Reference systems (HPR)Hydro Acous

kongsbergk-posdp(os) dynamicpositioningsystem ......documenthistory documentnumber:385603 rev.a...

Documents