Dynamic Positioning System


The Mega-Guard Dynamic Positioning System (DP) automatically controls a vessel’s heading and position


The Mega-Guard Dynamic Positioning System (DP) automatically controls a vessel’s heading and position by activating thrusters based upon data as received from position reference systems, gyrocompasses, wind sensors and motion reference units. The Auto Track mode allows the ship to move along a pre-defined track at low speed as defined by the operator.

The Mega-Guard Joystick Control System (JC) is a basic version of the Mega-Guard DP system and allows the operator to automatically control the heading and manually position the vessel based upon data as received from gyrocompasses and wind sensors.

The Mega-Guard DP and JC system are based upon the field-proven products of the Mega-Guard product line and the experience as gained on the design and delivery of joystick control systems as supplied on many different kind of vessels since 1980 (see reference list).

The Mega-Guard DP and JC system are suited for e.g. supply vessels, tug boats, dredgers, cable and pipe laying vessels, FPSO’s, heavy lift vessels and mega-yachts in full accordance with the applicable classification and IMO rules (DP1, DP2 and DP3).

Main advantages of the Mega-Guard Dynamic Positioning System:

  • Accurate positioning with better then 0.5 meter accuracy in combination with DGPS and MRU (inclinometer). Higher position accuracies can be achieved with e.g. a laserbeam positioning system.
  • Sea trial tuning and testing can be limited to three days maximum. Parameter tuning is already done before shipment out of our factory by modelling of the ship and testing with a ship simulator.
  • Extremely reliable hardware by using only solid state components and 24VDC power supply for all components within the DP system. All Mega-Guard DP hardware and software is designed and manufactured by Praxis Automation Technology and is applied in other Mega-Guard products as well (AMCS, VCMS, PMS, PCS, INS, etc).
  • Various language options are available including Chinese, Japanese and others.
  • Supports third party and own (Mega-Guard brand) position reference systems: Mega-Guard DGPS/Glonass with NTRIP (DGN), Hydroacoustic Position Reference (HPR) and Taut wire Position Reference (TPR).
  • Cost effective DP solution. Reliable hardware that is field proven on hundreds of vessels, allows for efficient off the shelf manufacturing in large quantities. As a result, we can offer our advanced Mega-Guard Dynamic Positioning System, including navigation sensor package, at a very attractive price level. In addition, customer’s investment is supported by a world wide service network.

Reference and models


  • Cable and pipe laying vessels (DP2)
  • Offshore supply vessels (DP1 and DP2)
  • Ocean salvage vessels (DP2)
  • Tug and work boats (DP1)
  • Multi purpose vessels (DP1 and DP2)
  • Platform crew boats (DP1)
  • Passenger ferries (DP1)
  • Jack-up platforms (DP1)
  • Mega-yachts (DP0)

Applicable classification: DNV,BV,LRS,GL,ABS, CCS, RMRS, IR, JG.

Joystick and Trackball panel

Control mode selection is executed with pushbuttons on the Joystick panel. Step adjustments of position and heading setpoints can be made on the Joystick panel as well. Larger size widescreen TFT’s also allow for absolute entering of position (northings/easting or UTM) and heading (degrees) setpoints through the Trackball panel. Vessel behavior, sensor data and thruster data (setpoint and feedback) are shown on mimic diagrams on the widescreen TFT’s.

The following main Control Modes can be selected on the Joystick panel:

  • Auto Position- Minimum Power Mode ; Weather Vane Mode
  • Auto Position- Minimum Power Mode ; Positioning Circle Mode
  • Auto Position-Joystick Manual Surge Mode
  • Auto Position-Joystick Manual Sway Mode
  • Auto Position-Joystick Manual Surge/Sway Mode
  • Auto Track (low and high speed) Mode
  • Track Follow Mode

In addition, the DP system can be used as a training system by entering the Simulator-Trainer mode. The Simulator mode can only be selected on the DP Operator Workstation when the DP and JC system are not active (thrusters in individual mode). The built-in Simulator-Trainer mode fulfills the rules of a Nautical Institute Class C simulator.


  • Mega-Guard JC: Joystick Control System with optional position holding capability
  • Mega-Guard DP0: Dynamic Positioning System
  • Mega-Guard DP1: Dynamic Positioning System with independent JC System
  • Mega-Guard DP2: Dual redundant Dynamic Positioning System with independent JC System
  • Mega-Guard DP3: Triple redundant Dynamic Positioning System with independent JC System

DP Operator Workstation

Operator mimics

The DP Operator Workstation contains user friendly mimic diagrams so that the ship’s crew can execute DP operations in an accurate and safe way. The following main mimic diagrams are available:

  • Map (North pointing upwards)
  • Diagram (bow pointing upwards)
  • Capability
  • Positioning sensors
  • Other sensors

The following sections describe the various functions available within the mimic diagrams.

Diagram section

  • Heading indication with rotating compass and rotating decimal degrees
  • HDG (°) and ROT (°/min)
  • Latitude / Longitude
  • COG (°) and SOG (knot)
  • Error X (m) surge and Error Y (m) sway
  • Wind and current vectors relative
  • Total thrust vector with thrust amplitude and direction
  • Individual thrust indication for each thruster with amplitude and direction

Map section

  • Heading indication with compass slider
  • HDG (°) and ROT (°/min)
  • Latitude / Longitude; map indication
  • COG (°) and SOG (knot)
  • Error North (m) and Error East (m)
  • Vessel orientation, heading and movement
  • SOG vector (green)
  • Wind vector (yellow)
  • Force vector (white); controller output

Thruster section

  • Bargraph and numeric value for each thruster: setpoint and feedback
  • An icon for each thruster showing thrust angle setpoint and feedback
  • Thruster ready indication
  • Heading controller output
  • Station in control and Operating mode

Alarm area

  • 6 rows for alarm display with alarm acknowledgement for each alarm
  • Day/night vision selection


Capability section

  • Online X-Y plot of wind capability with selected thrusters and selected current value
  • Capability plot with 80% thrust, 100% thrust and with worst case thruster failure
  • Wind vector; direction and speed; if this vector reaches the capability boundries the vessel is out of capability
  • Current settings

Sensor section

  • Supports multiple position reference systems: DGPS, laser, radar, hydroacoustic, taut wire and winch
  • Supports multiple sensors: gyro, wind and motion reference unit (MRU)
  • Absolute (Northings and Eastings) or relative coordinates Sensor validation and weighing

Heading setting

  • Heading setpoint (°) and ROT (°/min) maximum
  • Alarm limit (°)
  • Steer limit (°)
  • Heading gain (%)

Environmental setting

  • Wind compensation setting in between 0% and 100%
  • Current direction (°)
  • Current speed (knot)
  • Check box to select or de-select automatic current compensation

Position setting

  • Step (m) adjustment
  • Bearing (°) adjustment
  • Relative (X/Y) or absolute (N/E )
  • Position setpoint mode
  • Alarm limit (m)
  • Set new position
  • Up/down and Left/right step (m)
  • Position gain

Joystick setting

The following parameters can be set:

  • Joystick gain
  • Display of thrust vectors to the thruster controller



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