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Relative position reference system, RADius

RADius is developed for applications in need for a robust and reliable relative positioning system. Many applications can benefit from RADius in operations, as there are different types of retro-reflective transponders, and different types of installation of the sensor heads, (Interrogators).

Innovative technology

The implementation is fully solid state and based on measurement of reflected radar signals from a number of passive transponders in the nearby area. Each reflected signal is mixed with a unique ID to separate different targets from each other. Advanced signal processing allows simultaneous and continuous measurements to any practical number of transponders. RADius is designed for multiple users leveraging the same transponders simultaneously.



  • Multiple sensor heads
  • Autodetection of transponders
  • Measuring and output of range and bearing
  • Wide opening angles secure close-by operations
  • No moving parts
  • Multi user feasibility
  • Multiple transponder capability
  • Operates in all weather conditions, also extreme cold
  • Complementary to existing GPS reference system
  • Designed to meet all IMO DP Class requirements
  • Both battery and fixed power operated transponders
  • Operates in license free radio band
  • ATEX certified transponders
  • Easy to deploy and adapt

System components

  • RADius 1000 - Interrogator The interrogator is mounted on the outside of the vessel. It contains antenna elements, a transmitter and a signal processing front end.
  • RADius Workstation The workstation contains RADius Processing unit, a graphical user interface and serial interface. The System is delivered in a 6U 19’’ rack with keyboard, video display unit and power/connection module.
  • RADius 600 and 700 transponder There are both low power (battery operated) and high-gain transponders available.
  • RADius 550x and 600X transponder ATEX certified intrinsically safe transponders in low-power (battery operated) and high gain versions.
  • User Terminal Application Software

Multiple sensor heads

RADius can be deployed as an omni directional system utilising four sensor heads, which can be placed on suitable locations on the vessel dependent on the construction and operation. This provides full 360° signal acquisition as well as avoidance of blind angles as there will be a sensor head at a receiving angle to transponders at all times, regardless of the vessels relative position to the RADius transponder.

Signal processing will effectively remove possible interference with other transmitting devices in the same frequency band. Accurate Doppler measurements allow for rapid and reliable determination of relative velocities between the manoeuvring vessel and transponders.

Application software makes configuration and monitoring of the RADius operation easy and effective, and interfaces to remote systems like Dynamic Position may either be serial lines or Ethernet based.

RADius is designed to fill the need specified by IMO for DP Class 2 vessels.

Operational features

RADius is capable of detecting and measuring accurate range and bearing to any transponder within the range of up to 550 metres. (Dependant on the targets transponder) The direction from the interrogator to each transponder is accurately determined by the use of interferometric methods. Due to use of open standards, deployment of the operator interface is very flexible.

Wide opening angles

RADius has a vertical and horizontal opening angle of 90°. This secure stabile operations in close by operations where the difference in mounted transponder and interrogator can be considerable. Due to this there is not necessary to tilt the sensor head in any direction to obtain signal.

A variety of transponders

Retro-reflective transponders are mounted on the target that are to be approached. A variety of transponders are available suitable for any operation that demands an robust and reliable relative positioning solution.

Services and support

  • 24/7 Technical support

    Our 24/7 technical support team is there to help at any time, day or night, wherever your vessel is.

  • Conversions, retrofit and refit

    We understand the importance of having the right parts, available in the right place, at the right time.

  • Training

    Ensure that your crew is properly and thoroughly trained. This will reduce operational risk, downtime and maximise return on asset investment.