Marine Radar Research Articles

Experimental study of the radar cross-section of maritime targets

A comprehensive set of results are presented for a variety of surface targets. The targets chosen range from −40 dBm2 to + 70 dBm2 and results of the smaller ones have been compiled from trials that have taken place over a variety of environmental conditions. These illustrate the variability experienced at sea in the radar performance of targets, which, in a free-space environment, may exhibit neither fading nor variability with the aspect viewed. The necessary statistical treatment for fading targets has been used to describe the targets examined in a manner which is directly applicable to the estimation of radar range and detection probabilities. Most of the results are appropriate to the bulk of marine radars using a wavelength of 3.2 cm and horizontally-polarised transmission and reception

Microwave Air Strip Transmission Line forS-Band

A low-loss microwave shielded air strip transmission line has been fabricated using a dielectric material Tellite and 3 cm waveguide as a substitute for waveguides in the 5-Band 10 cm region. This has made it possible to use strip line transmission for long distances, such as used in marine radars. It has the added advantage of reduced cost and size over waveguides normally used in 10 cm region.

AN OIL RECOVERY SYSTEM FOR SAN FRANCISCO BAY AREA

ABSTRACT In May of 1974, Clean Bay, Inc., acquired a recovery system which is designed specifically for oil spill cleanup operations in the San Francisco Bay Area. Operational constraints for the Bay Area, such as large amplitude, short-period waves, debris, a long and varied multiuse shoreline, and large variations in potential spill sizes, locations and properties of spilled products strongly influenced Clean Bay's performance specifications for this system. The system can respond quickly and effectively to spills anywhere within the bay area. Special features of the system include oil recovery rates up to 1,000 gpm, high oil-water recovery efficiency, the ability to recover and effectively process oil soaked debris, 90 barrels of onboard storage capacity, the ability to recover and transfer high viscosity products, a water jet propulsion system for high maneuverability, transit speeds approximating 10 knots, an elevated pilot house to improve visual observation of the spill area, marine radar, radio transceiver, and an onboard hydraulically operated crane. The paper will describe in detail the performance specifications for the recovery system; compare wave tank predictions of hull performance with operating experience, discuss the impact on design and operations of the requirements for tank vessel certification by the U.S. Coast Guard, and describe Clean Bay's operating experience with the system.

Marine Instrumentation Developments

The National Maritime Research Center, Kings Point, N.Y., is conducting projects dealing with the “new technology” in the field of navigation. This paper consists of a survey of this area of activity of the Center. The intent is not only to disseminate information to the wide community of navigators but also to structure a mutually beneficial communications link between the NMRC and the Institute of Navigation. The paper will cover the following projects, some innovative, others extensions of previous programs: —RAPS (Radar Automatic Plotting System) —MASS (MarAd Anti-Stranding Sonar) —TRANSIM (Simplified Transit) —MARINE RADAR TRANSPONDER —MARSCAN (Maritime Satellites Communication and Navigation System) —INTEGRATED CONNING SYSTEM

Marine Radar Automatic Plotter Display Philosophy

The object of any kind of marine radar plot when ships are in fog is to synthetize as much data on the current traffic situation as affects or will affect the safety of own ship and so to produce a plan picture of the area around the ship and the vessels moving on it, more or less as it would appear to the eye in clear weather. The plot will be expected to show, not only the current position of each ‘target’ vessel, but also the expected forward movement of each and the risk of collision which this involves.The word synthetize is used because it so completely implies the building up of separate elements of information into a whole; in this case, a continually changing whole. The word whole is also worth emphasizing, because only if the situation is so presented can the mariner appreciate the form which its development is taking both between own ship and those target ships which present a direct threat and between target vessels whose mutual evasive manœuvres may indirectly endanger own ship. The needed synthesis cannot be attained unless the predicted future positions of target ships are coordinated in time, so that the relative positions at the future time may be compared with the current relative positions.

Systems Engineering Aspects of the Proposed Channel Navigation Information Service

This paper, by the head and the deputy head of the Civil Marine Navigational Aids Division of the Admiralty Surface Weapons Establishment, deals with certain problems relating to the proposed Channel Navigation Information Service, including radar coverage, the transmission of information, computer assistance and information display. The paper was read at a meeting of the Institute held in London on 30 January 1974 with the President in the Chair.Much of the background to marine traffic problems in the Dover Strait has already been discussed in previous issues of this Journal. It was decided in 1971 that some radar surveillance of the area would be appropriate. The first steps were taken when a radar trial was conducted by A.S.W.E. in the St. Margaret's Bay area near Dover in 1971. As a result of these trials the Coastguard station at St. Margaret's was fitted with a standard marine radar as an interim solution.

A New Approach to the Presentation of Marine Radar Information

This paper describes a new radar system which aims to give the Master of a vessel, on a television screen, the kind of information which could be obtained visually from a wheelhouse window in daylight in clear weather. The system was described by Mr. P.O. Prior at a meeting of the Institute held on 17 January and an account of the discussion will be given in the next number of the Journal. S. R. Parsons is Chief Engineer of Kelvin Hughes and Captain J. P. Stewart a Marine Consultant.The early history of marine radar when the phrase ‘radar assisted collision’ was coined, the setting up of radar simulator schools to assist in teaching the interpretation of the radar picture, and more recently the increased number of collisions at sea, particularly in congested areas like the English Channel and the approaches to major harbours, all call into question the adequacy of the presentation of radar data on conventional relative and true-motion radar sets.

舶用レーダによる船体反射強度の方向性について-I

舶用レーダによる船体反射強度の方向性について-I

The Extraction and Presentation of Collision Avoidance Data from Marine Radar

Radar was fitted to merchant ships after the last war in the belief that, amongst other things, it would help to reduce collision casualties. However, by the early 1950s people were talking about ‘radar assisted collisions’ and today, in spite of improved radar equipment and training facilities, we read all too often of collisions between radar equipped ships. The question remains why such collisions occur; in part the answer lies in the fact that modern merchant ships have limited manpower so that the officer of the watch is often the only man on the bridge for long periods, and plotting ships' tracks from radar information is a time consuming business. The result is that, although radar provides the information required to avoid a collision, it is not in a form readily assimilated by the operator and incorrect interpretations can occur. The obvious solution is automatic extraction and processing of the radar information so that it can be presented to the operator in a form which will enable him to assess the situation rapidly. This would eliminate the tedious process of plotting, but retain the information normally obtained from a plot.

Some Thoughts on Marine Radar

The Man/machine interface. People who design motor cars also drive them, but whoever heard of a radar design engineer who also had a Master's ticket? Of course, the designers of marine instruments do go to sea occasionally, but not for longer than they can help; sea-time is apt to interfere with the weekend. So it happens that the people who make marine radars are rather remote from those who use them, and from the environment in which they work, the sea. The engineer might argue that no two seamen ever seem able to agree on what they want, so the easiest thing is to decide for them, and that, in any case, it is only a matter of ergonomics. On the other hand, it may be that the people who write books on ergonomics have not been to sea either. Radars are used in the dark, as are motor cars, but the darkness of the bridge is not the same as night driving.

Radar at Sea

As one of the authors of Marine Radar and How to Use It which was reviewed by Captain Cockcroft in the October 1971 issue of this Journal I feel it necessary to reply to some of his comments. Though he and I may disagree on a few points the authors can only be pleased to have had someone so well known take the time and effort to review our book.

Collision Avoidance Systems and the Rules of the Nautical Road

The International Regulations for Prevention of Collisions at Sea (33 U.S.C. 1051), the Inland Rules (33 U.S.C. 154), the Pilot Rules, Great Lakes Rules, Western Rivers Rules and the Admiralty Court decisions which interpret them, form a real and complex system of constraints upon the mariner in the navigable waters of the United States and on the open sea. These Rules are law, both international and U. S., and are used by the Courts in the determination of liability in case of collision. Admiralty Court decisions have modified and clarified the Rules of the Road in many cases. They have also added to the difficulty of the watch officer on the bridge of a ship at sea who must know not only the Rules but the Court interpretations in order to comply with them. The nature of the constraints imposed by these Rules is examined as they apply to the information furnished to the mariner from marine radar and radar based collision avoidance systems. The rules which apply when the vessels are in sight of each other and when they are not are discussed. The information needed to comply with the rules in each case is compared to the information available from radar and collision avoidance systems. The informational short comings of these systems are identified and an ideal collision avoidance system to aid the mariner in maneuvering under the constraint of the Rules of the Road is described.

Reviews of Recent Books

NAVIGATIONVolume 18, Issue 3 p. 350-351 Reviews of Recent Books First published: Fall 1971 https://doi.org/10.1002/j.2161-4296.1971.tb00106.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Book reviewed in this article: For Mariners: MARINE RADAR AND HOW TO USE IT, by Gilbert C. Fonda and Hilliard Lubin For Aviators: SYSTEMES HYPERBOLIQUES DE LOCALISATION, April 1970. Volume18, Issue3Fall 1971Pages 350-351 RelatedInformation

A Fully Automatic Marine Radar Data Plotter

Digiplot is a marine radar aid for automatic anti-collision navigation which processes signals from conventional radar and presents computed information on a separate screen to give at-a-glance situation appreciation. The company's origin is touched on and conception and design are described as they evolved to meet operational requirements.The majority of sophisticated radar equipments and devices available today have evolved from successive shipborne radar developments over a considerable period of years. With Digiplot it is otherwise. The Iotron Corporation was established in 1969 by a few men whose background had been information technology in the realms of fire control and navigational systems for submarines, aircraft, missiles and spacecraft, and reconnaissance systems using electronic and optical techniques; in all these systems digital electronics played a key role. The choice of the navigational functions of marine radar as the most appropriate subject for attention by the group was made after a general study of the commercial field, because of the revolution apparent in ships, their equipment and their operations.

レーダ装置を利用する左右舷識別装置の試作について(日本航海学会第45回講演会)

The port and starboard discrimination device is composed of a marine radar with some adaptor and a simple receiver. The system of the device is undermentioned ; (1) The port and starboard discrimination is limited among the ships with this device. (2) p.r.f. is changed when scanner pass over fore and aft line. (3) The receiver accepts this change of p.r.f. and discriminate port and starboard of another ship. Foundamental field tests at sea were performed between "Taisei Maru" and "test boat", and the effect of the device was confirmed. The tested device has some shortcoming, however, the authors believe that if the defects of this device are improved, it may contribute to collision avoidance.

Marketing a New Radar

Marketing a marine radar may not sound the most promising subject for a navigational paper. But in an age when almost anything is technically feasible, the direction of progress will be governed by many considerations which, if they are not themselves navigational, are nevertheless of great interest to those concerned with the subject. A new range of equipment for example must be related to the level of skill and training which actually prevails at sea; research and development costs must be seen in relation to the cost-effectiveness of the system; and finally purely operational factors such as traffic separation schemes may have to be taken into account. In this paper, originally presented in Paris to the French Institute of Navigation, some of these considerations are discussed in relation to the new Decca anti-collision radar.Just over 25 years ago, in the summer of 1944, a United Kingdom conference on radio for marine transport concluded that radar would be of great value to merchant ships. They asked the Royal Navy to draw up a specification for the average ship. Discussion with various shipping interests confirmed that there was in fact a requirement for a radar set ‘for navigation and pilotage as distinct from a collision warning set, which would, of course, be a much simpler and cheaper device’. The later 1946 Ministry of Transport Specification referred to the requirement ‘to provide warning of the proximity of other surface craft and obstructions which will enable collision to be avoided’. Now of course, after 25 years of hard experience, we know that the matter of avoiding collision at sea is not apparently so simple.

An Investigation into the use of Radar for Collision Avoidance

The introduction of marine radar into the general market immediately after the last world war, offered the promise of reducing the many economic losses sustained through failure to keep schedules during periods of reduced visibility. These promises have been only partially fulfilled. Initially it was accepted that radar needed little introduction—that it established the range and bearing of targets in the vicinity and no more was required. With radar available on only a small proportion of vessels, this limited information was sufficient to enable these few to avoid other, slower-moving craft which were not so fitted. Radar is now fitted on almost all vessels and speeds have increased, while manoeuvring characteristics have changed because of increased tonnage of vessels. The situation is now far more complex.

Pilotage or Conning Radar

The paper by Captain J. P. Stewart in the July issue of the Journal, entitled as above, presents a wealth of evidence and argument for the obvious sense of designing marine radars in such a way that they can:(a) present compass stabilized radar pictures in the natural ship's-head-up orientation. This avoids the mental stress of trying to correlate the radar view and the eye-ball view of the same situation when the two may be presented in completely different orientations;and(b) simultaneously allow true bearings of targets to be read off directly.

Marine Collision Avoidance: Human Factor Considerations for the Development and Operation of an Effective Merchant Marine Radar

The objective of this paper is to identify problem areas in the use of radar and to show the implication of these problems to those involved in ship operations and radar development. The discussion includes the operating procedure for radar, the philosophy of radar use in the merchant service and the modification thereto required by increased speeds and traffic, the relevance of basic operator capabilities, and operator information requirements versus current display capabilities. These problem areas and requirements were identified as one aspect of a study of “Human Factors in Ship Control” conducted for the Maritime Administration (MA-4221). The paper emphasizes the need for research designed to develop a radar system which meets the deck officer's requirements yet which is compatible with his capabilities and the cost constraints of the merchant service.

レーダ波の複合体反射強度について(日本航海学会第40回講演会)

レーダ波の複合体反射強度について(日本航海学会第40回講演会)