Automatic Radar Plotting Aids Research Articles

The role of information technology in maritime education for hazard avoidance

Maritime transport is an important aspect of the economy of every maritime state and this needs safety and efficiency. It is well known that one of the major factors of accident prevention is perfect theoretical and practical knowledge, which can help reduce accidents at sea and in harbours, ship collisions and sinking and loss of human lives and protects the environment. There are many different tools and systems used to satisfy these demands. Our forefathers have sailed using paper charts and sextants; today we use radar, Automatic Radar Plotting Aid (ARPA), Global Positioning System (GPS), nautical charts and publications. This study provides an experience of teaching graduate students how new technologies and techniques (Petri nets, genetic algorithms) have been applied. All these are very effective for improving engineers' and officers' management experiences and operational skills in emergency situations. But the cadets who lack practical experience have to spend most of their time learning theoretical courses on land. To meet the challenge of modern maritime development, the responsibility of education is to produce a great number of talents with ideas and work abilities. This paper's conclusion is that the use of interactive computer simulations in maritime education results in increased emergency preparedness, which consequently leads to hazard mitigation and reduces the risk of human error in the operation and maintenance of marine equipment.

COMPARISON BETWEEN ARPA RADAR AND AIS CHARACTERISTICS FOR VESSEL TRAFFIC SERVICES

Recently most maritime countries in the world have fitted automatic identification system (AIS) in vessel traffic services (VTS) in compliance with regulations of International Convention in order to identify ship name and collect ship information. Traditionally VTS operators use automatic radar plotting aids (ARPA) to get ship maneuvering information for preventing ships from navigational faults. Although the two equipments can provide similar functions for VTS, the operational theory of them is quite different. In this study an experimental observation was carried out by means of ARPA radar and AIS fitted in the building of Merchant Marine Department, NTOU. The detected information was analyzed for comparison of their difference on characteristics. Results reveal that AIS can detect target ships with wider area coverage, larger quantity and more voyage information than ARPA radar. The latter can provide an active monitor to detect small ships that can not be done by AIS. Consequently for navigation safety VTS operators must concentrate on ARPA radar in priority and use AIS as supplementary installation for identification of ships.

Assessing Risk of Collision

Edmund Hadnett writing in his article AIS at the Front Line in the May 2005 issue of the Journal, attributes to me the argument that ‘the automatic radar plotting aid (ARPA) should remain the principal means of assessing a risk of collision’. ARPA has never been the principal means of assessing a risk of collision and I have never argued that it has been and should remain so. My argument concerns the merits respectively of ARPA and AIS as navaids or a fusion of data from both.

Cost-Benefit Analysis for Ship Automation Retrofit: The Case of Icebreaker Frej

A detailed cost-benefit analysis of a retrofit of the Advanced Technology to Optimise Maritime Operational Safety (ATOMOS) platform on board icebreaker Frej is presented. After accurately determining the relationship between the costs and benefits, an analysis is implemented in order to assess the most basic advantages and disadvantages of the suggested retrofitting action in monetary terms. A two-step approach is adopted. The first step is to define the major categories of the ship operational aggregate costs and benefits (for example, the actual cost of the ATOMOS platform and of equipment not part of the ATOMOS platform but still necessary for its installation and operation, or the expected crew decrease because of the higher degree of automation). The second step is to examine the various basic components of these categories (for example, administration and training cost, required automatic radar plotting aid [ARPA] and electronic chart display and information system [ECDIS] equipment acquisition cost, fuel benefits, and insurance benefits). The cost-benefit analysis performed is followed by a sensitivity analysis of the most important factors affecting the net present value of the investment. It is shown that it takes about 5 years for the ATOMOS retrofit to be fully paid back by the annual savings it offers and it takes about 6.5 years for the net present value of the investment to turn positive. This coupled by the increased vessel safety justifies the decision to retrofit Frej with the ATOMOS platform. Furthermore, it is found that the cost of the ATOMOS platform, the benefits from crew decrease, and the interest rate are those factors that essentially determine the profitability of the investment. In the case of Frej, it is concluded that the retrofit is worth undertaking for the majority of future scenarios.

Capability Prediction: An Effective Way to Improve Navigational Performance

The potential benefit of predictive information for navigation support was investigated in a simulator study. Twelve participants had to guide a medium-size vessel across a traffic separation scheme. In the simulator, critical vessel traffic scenarios were created, where participants were provided with: (i) baseline Automatic Radar Plotting Aid (ARPA) information, and (ii) baseline ARPA information supplemented with capability prediction information. This is information that shows the predicted manoeuvring margins of the vessel, indicating the predicted boundaries of safe operation. Results of the experiment indicate that capability prediction allows better anticipation by the navigator, significantly improving ship navigation performance.

Neural network classifier for ship domain assessment

The article presents an attempt to apply an artificial neural network in anti-collision systems at sea. Such systems determine safe trajectory for a ship by, most frequently, processing the information sourced from an automatic radar plotting aids (ARPA) type arrangement. In this research work the use of neural classifier has been proposed as an element supporting a navigator in the process of determining the ship’s domain, i.e., the area around a ship which, for safety reasons, should remain free from navigational obstacles. Neural classifier has a form of a multilayer feed-forward network of a perceptronic nature. It has been assigned a task to represent the evaluation of a navigational situation provided by an experienced navigator functioning as a teacher in the process of the network learning phase. Programs designed in the MATLAB language have been applied for the simulation of the network and also for the illustration of a navigational situation. Testing of the correctness of classification of the collision situations by the network have been also conducted. In the final part of the article conclusions have been formulated with regard to the application of the neural classifier in the process of determining a safe trajectory of a ship.

Evolutionary Guidance System for Ship in Collisions Situation at Sea

The structure has been worked out of an autonomous guidance system of the ship motion in collision threat regions at the presence of fixed navigational constraints. For the computations, the navigational data were obtained from the ARPA (Automatic Radar Plotting Aids) automatic radar echo tracing system and from an electronic map. The problem of the safe trajectory planning was solved as a dynamic optimisation task using evolutionary algorithms. As an example, the evolutionary solution of a ferry trajectory is presented for the case when the ferry meets other moving ships and fixed navigational constrains on its way.

ARPA情報の精度に関する研究-III

Automatic Radar Plotting Aids (ARPA) is one of the instruments effective for safe navigation. ARPA information is caluculated using target's position (ARPA position) and own ship's course and speed. It is assumed that the fluctuation of ARPA position has an influence on the accuracy of ARPA information. So the authors have tackled this problem. In this report we show distance characteristic of ARPA position's fluctuation and performed a Monte-Carlo analysis to find the effect of 4 different target positions on the accuracy of ARPA information. The results are as follows. 1. The radar echo signals of T. S.FUKAE MARU were collected at the three distances of 2, 4 and 6 nautical mile. 2. The distance dependence of the fluctuation of the echo position was found at the 18 aspect angles from the 63 scan radar echo signal data of FUKAE MARU. 3. Monte-Carlo simulation was carried out for four IMO's scenarios and used to evaluate the effect of the distance of four ARPA positions on ARPA information.

海上における物標の視認と見張り

The visual perception of the targets at sea is the most important factor for safety and for a good lookout in preventing marine disasters. The International Regulation for Preventing Collision at Sea, 1972 gives rules for a proper look-out (rule 5). What is a proper look-out? This study shows the conditions for the visual perception of the targets at sea in connection with the luminance difference threshold which is referred to the luminance of the sky (about 2 degrees over horizon). Author shows the visual conditions and factors thereof ; they are as follows ; 1. There is a physiological factor which masters and navigation officers on duty can't perceive by sight. 2. The condition for visual perception of the targets is more difference between the luminance of the sky and that of the target than the luminance difference threshold. 3. There are two psychological factors for a good lookout by sight. (1) Masters and navigation officers on duty should remember that there should be existing some targets in case of no sights of them. (2) They should have previous informations of the targets by using ARPA (Automatic Radar Plotting Aids) or RADAR (RAdio Detection And Ranging). 4. There are three physiological factors relating to the luminance difference threshold for a good lookout by sight. (1) They should maintain a proper look-out as long as possible. (2) In daytime, they had better use their sunglasses also in case of not feeling glaring, because of perceiving targets easily by sight. (3) They should use actually the binocular and compass for getting more informations with relative changing direction of targets.

ARPA Accuracy Testing

In this paper, methods and formulas for testing ARPA (Automatic Radar Plotting Aid) equipment according to IMO requirements are developed. The International Maritime Organization (IMO) and International Electrotechnical Commission (IEC) requirements for tracking accuracy are also discussed.

Analysis of Radar PAD Information and a Suggestion to Reshape the PAD

Potential points of collision (PPC) and predicted areas of danger (PAD) are used in marine radars for assessment of risk of collision and of action to avoid collision. Both are useful concepts for automatic radar plotting aids (ARPA) which lead to a better understanding of collision avoidance. The PAD display, developed by Sperry Ltd, is a graphic form3 alternative to the vector display. More information can be obtained from the PAD display than from the vector display but additional knowledge is necessary for the mariner to correctly interpret and use the information. The IMO Resolution on ARPA Performance Standards emphasizes the need for deck officers to understand the basic principles involved in the use of the equipment. In this paper consideration will be given to the information obtained from the PAD display and a suggestion will be made for possible improvement of the shape of the PAD.

海上交通調査におけるレーダ利用方法の改善について

Authors improved the marine traffic survey system using radar and developed an automatic processing system using ARPA (Automatic Radar Plotting Aids) for analysis of marine traffic. These systems provide a hard copy of an image on a radar PPI on real time at an arbitrary time interval and semi-automatically analyze a marine traffic situation. The proposed traffic survey system consists of a color radar, a video printer and modulate and demodulate equipments to record raw radar signals into VTR. The automatic processing system consists of a personal computer and ARPA linked with the survey system. These systems were applied to the marine traffic survey in Akashi channel in order to realize its validity. Then there were much improvement on increasing the accuracy of observed data and significantly reducing working time on the steps of the analysis comparing with the conventional way. The data in a personal computer linked with ARPA make us easy to analyze the marine traffic from various points of view.

A Handheld Collision Avoidance Aid

Collision avoidance aids used in conjunction with marine radar range from plotting sheets and special plotters to computer based “Automatic Radar Plotting Aids” (ARPA). One device, which has received very little attention is the hand-held or pocket calculator. The potential of the calculator for use in radar tracking is explored. The use of calculators with differing capabilities are examined respecting their possible use for distance/velocity/time computations, vector arithmetic to determine relative and true motion and, with the more advanced programmable variety, solutions for closest point of approach (CPA) information as well as an aid in maneuvering to avoid targets whose CPA's are too close. An example of an algorithm for a programmable calculator is presented. The limitations of calculators as a collision avoidance aid are discussed. The conclusion is that the available hand-held calculators will not replace ARPA's but could be useful as a backup to ARPA and as an aid on ships not equipped with ARPA when traffic density is not so great that the operator becomes overloaded.

Risk of Collision-A Sequel

An international performance standard for Automatic Radar Plotting Aids (ARPA), frequently referred to as collision avoidance aids, has been approved. This paper briefly reviews the domestic and international actions that led to development of the ARPA standard. The main features of the international ARPA standard are examined and compared to the United States statutory requirements which require compliance with the Maritime Administration (MARAD) specification. The differences between the international standard and the MARAD specification are highlighted and the implications of these differences addressed. Domestic implementation of the ARPA standard requires Coast Guard rulemaking action. The background, applicability, and time frame for regulatory action is presented. The potential alternative rulemaking actions are touched on. The implementation of requirements for a major new system are not without potential problems. Some of these potential problems that have been raised in international fora, but have not been fully considered, include development of equipment reliability standards and determination of necessary training requirements. The author's thoughts on these issues are presented. The opinions or assertions contained herein are the private views of the writer and are not to be construed as official or reflecting the views of the Commandant or the Coast Guard at large.

Estimation of Ship Domain Zone

The paper discusses the ship domain zone or ship navigationsafety area. The navigation safety area around the ship hasbeen the object of research of many authors. Different variantsand algorithms have been suggested and the most popularamong them are as follows:- navigation safety area around the ship being observed by herown devices, presenting information of the danger of possiblecollision directly on the bridge;- navigation safety area around the ship when regulating hermovement by means of Vessel Traffic Se1vices.The article presents an algorithm for determination andplotting of the navigation safety area, which has the followingadvantages:- the algorithms give an instant solution to the problem ofevading one or more dangerously moving targets;- the calculation may apply the ARPA (Automatic RadarPlotting Aids) algorithm, which does not prevent the navigatorfrom keeping watch.The above mentioned algorithm allows simultaneous plottingof information about the situation around the ship and thedata for probable manoeuvring.