Egil Pedersen

Simulator Studies on a Collision Avoidance Display that Facilitates Efficient and Precise Assessment of Evasive Manoeuvres in Congested Waterways

This paper is based on two articles by the authors that were published in the March and September 2002 issues of the Journal of Japan Institute of Navigation. The collision risk to multiple targets and identification of feasible evasive manoeuvres can be assessed simultaneously in true motion by judging the tip of own ships velocity vector in relation to the display of cone-shaped collision danger regions to acquired targets. Simulator test programmes composed of scenarios with various traffic densities and different speed ranges of own ship have been carried out in order to evaluate the performance of this collision avoidance display versus ARPA (true and relative motion) displays. Experienced navigators and maritime university students with license participated as test subjects. It is shown that the proposed display is capable to facilitate more homogeneous, precise and safe evasive manoeuvres than utilising conventional judgement techniques. The superiority increases with the excess speed of own ship, traffic density and complexity.

On the development of guidance system design for ships operating in close proximity

An international joint-industry research project for studies of hydrodynamic, control and operational aspects related to ship-to-ship (STS) operations has been initiated by the Norwegian Marine Technology Research Institute and received the funding from the Norwegian Research Council and industrial partners. The background for the project is an anticipated future demand for STS studies and the necessity to improve the mathematical models for multiple ship maneuvering in close proximity in order to further enhance quality of training on ship-handling simulators of operative key personnel involved in STS operations. A major objective with the ongoing research is to develop a decision support and guidance system for the ship navigation officers that can contribute to the operational safety and efficiency. Experienced Mooring Masters conducting lightering operations suggest that accurate information of relative distance and speed would assist in conducting a safe approach of the service ship towards the ship-to-belightered. The short-range distance measurement system RADius developed by Kongsberg Seatex AS of Norway has been proposed as one suitable technology platform towards a decision-support and guidance system for STS operations. A control strategy is proposed based on the availability of a relative distance sensor which can provide sufficient measurement accuracies.

On the Effect of Plotting Performance by the Errors of Pointing Targets in the ARPA System

The effect of different measurement points on an acquired target is theoretically investigated with respect to the ARPA (radar-computed anti-collision) plotting performance. The target is described by simple geometrical figures and the echo is simplified. The actual measurement position is generally not at the centre of the target. This may cause errors in the standard plotting results. The characteristics of these errors are discussed from a nautical viewpoint.

Modelling and Control of Towed Marine Seismic Streamer Cables

Summary Full-scale measurement data have revealed that slowly varying fluctuations in the course of survey vessels performing marine seismic data acquisition with towed recording (streamer) cables are capable of forcing the in-sea hardware in longitudinal and transverse directions. This may give rise to undesired low-frequency oscillations in the depth of streamer cables. The interaction between the transverse and longitudinal motions takes place at the location of the depth-control devices that are mounted along the streamers. A quasi-static model that describes the low-frequency dynamics of streamer cables is proposed for the purpose of controller design and analysis. The simulation study showed that the overall depth-control performance is sensitive to appropriate tuning of controller gains, selection of sampling period and application of dead bands. A successful depth control will rely on the number and lift capability of the mounted depth-control devices.

Experimental Results of Ship-To-Ship Lightering Operations Applied Velocity Information GPS

A ship-to-ship (STS) lightering operation takes place in order to transfer cargo (e.g. crude oil or petroleum products) between an ocean-going ship...

Study on an Automatic Ship Detection System and Its Information Display

Abstract An Automatic Ship Detection System (ASDS) and its information display system are introduced in an effort to provide effective navigational aids to helmsmen, such as collision avoidance support, which require detailed information of ships in the vicinity. The information is usually obtained from RADARJARPA (Automatic Radar Plotting Aids), but is not gathered automatically. Automatic information detection and its effective display are essential for One Person Bridge Operation (OPBO). These functions are realized by using Automatic Identification System (AIS) and Multi Sensor Image Processing of front view. The information display system for OPBO has been tested on a ship handling simulator.