Showing papers on "Collision avoidance published in 1973"

A statistical study of ship domains

Abstract: The thesis is an attempt to establish the water area required by any one ship for safe and efficient navigation. The concept of a ship domain has been considered, which may be defined as the effective area around a ship which a navigator would like to keep free with respect to other ships and stationary objects. This area will not be the same for all ships but will depend on a variety of factors such as speed, size of ship and density of traffic among others. The first part of the project was concerned with the collection of data from two separate sources: one being the performance of ships' officers in collision avoidance exercises on a marine radar simulator and the second being marine traffic surveys conducted in the Sunk area of the North Sea, The collection of data on ship movements and their processing for analysis by computer comprised the early work of the thesis. The next section of work was concerned with the development of a technique for evaluating the size of the domain and in particular the range of the domain boundary from the ship referred to as the domange. Very little work appears to have been done on this topic previously so several possibilities were considered before a decision was made as to the most suitable technique. Once this had been established results were obtained for a variety of conditions such as different sea area, length of ship and experience of the navigator as well as those previously mentioned and others. The final part of the thesis considers possible applications of the results in a variety of situations which are of current and future interest in marine traffic studies.

Optimal evasive maneuvers in maritime collision avoidance

Abstract: Evasive maneuvers are determined for each of two potentially colliding ships, such that their miss distance is maximized, these maneuvers are frequently contrary to the established rules of the road. It is assumed that the ship speeds are constant during the encounter, and that the turn-rates of the ships are bounded between symmetrical limits, corresponding to hard right and hard left turns. The optimal turn directions are found to be explicit functions of the range, bearing and heading between the two ships. The cooperative case, when both ships maneuver, and the noncooperative, when only one ship maneuvers, are both analyzed. Examples of the optimal maneuvers for two identical ships are presented in detail.

Radar anti-collision system for ships in waters adjacent land areas

Abstract: The radar signals of a vessel navigating on a given course are supplied to a data processing unit connected to an input of a computer. An auxiliary memory is connected to an input of the computer and has stored therein data with respect to land areas adjacent the course of the vessel, and these data are supplied to the computer progressively in accordance with a preset program for comparison with the data supplied by the processing unit. If the comparison indicates that the vessel is at a greater distance from land areas than limits defined by the stored positional data, the processed positional data corresponding to scanned land areas is deleted from the data supplied to a collision avoidance program, so that the processing by this collision avoidance program is made more reliable. After processing by these programs, data are displayed on a display unit.

Synchronizing techniques for an aircraft collision avoidance system

Abstract: A system for avoiding collision between a group of aircraft within range of a ground-controlled radar beam that is cyclically moved so that the beam sequentially strikes the aircraft Identical radio transmitting and receiving equipment is carried on each aircraft The equipment is arranged so that an aircraft transmits an interrogating signal only upon receipt of the leading edge of the radar beam, but responds to an interrogating signal at any time By synchronizing the transmission of interrogating signals with the radar beam, the collision avoidance information transmitted between the airplanes within range of the radar beam is sequenced in an orderly fashion to avoid confusion between the signals

Collision avoidance in a traffic system

Abstract: The chief criticism which has always been made against the existing Collision Regulations and is now being made against the revised ones, is that, except for the end-on encounter, no directives are given as to how the vessel should manoeuvre to 'keep out of the way'. The work done in the early nineteen-sixties showed that if miss distances and contributions were given positive and negative signs depending on the rotation of the physical and computed sight-lines, then, as far as the mathematics were concerned, a uniform treatment was in fact possible. However this early work did not lead to a set of directives acceptable to mariners in general. The present paper takes this method of attack further, and shows that if the return to course is included in the treatment, then all close-quarter encounters between two vessels can be covered by one simple formula. This formula not only clarifies what may be called the 'mechanism' of avoidance; it can also be used to provide operational information (as opposed to directives), which may turn out to be more useful than the maneuvering diagrams which were the practical outcome of the early work.

Anticipatory sensors for collision avoidance and crash protection as applied to vehicle safety research.

Abstract: Considerable effort has been expended in recent years to develop anticipatory crash sensors-effective means of detecting motor vehicle collisions immediately prior to occurrence. If the potential crash is sensed early enough, evasive action may be instituted to avoid the accident. If technical or dynamic considerations limit the warning time to a very short interval, benefits can still be obtained through initiation of passive restraint deployment significantly earlier than would otherwise be the case, extending the effectiveness of such systems to higher impact speeds than are now tolerable. The latter case-restraint system deployment- is more readily defined, and is discussed here in terms of research directed toward delineation of operational requirements, optimal means of realization, and performance characteristics. Research which has been reported by a number of investigators will be described. Collision avoidance is a more complex topic, in that no consensus yet exists as to explicit performance objectives. Research into possible operating modes and technical realizations will be discussed, with emphasis on inherent sensor requirements in each case. Topics appropriate to future research will be indicated. /Author/

Collision Avoidance and the Future of Air Traffic Control

Abstract: This paper is a report on some early findings of a long-term study which has the ambitious objective of suggesting better alternative solutions to the general problem of controlling a collection of aircraft. The study aims to answer questions about the optimum division of responsibility between the aircrew and ground A.T.C., about the way in which the A.T.C. tasks are shared between a number of controllers and A.T.C. computers, and about the fundamental principles on which traffic flow is organized.

Optimum Collision Avoidance for Merchant Ships

Abstract: The paper describes a special combination of high resolution, high accuracy, solid-state radar equipment with a sophisticated computer operated automatic acquisition automatic plot collision avoidance indicator. Technical characteristics and special features that make this equipment particularly suitable for the newer higher speed Merchant Marine vessels are described. A description is given of the separate displaying of high resolution radar and automatic navigational data. Information is also presented concerning application and performance features that make it particularly well suited for service aboard ships.

Realization of a horizontal collision avoidance system

Abstract: For a two-aircraft encounter, the computer realization of a cooperative horizontal collision avoidance system is analyzed. The system is based on range, relative bearing, relative heading and speed ratio information, and the realization accounts for the turn dynamics of both aircraft.

Driving under the influence of electronics

Abstract: ACCIDENTS RESULTING FROM UNSAFE DRIVER ACTIONS MAY BE SUBSTANTIALLY REDUCED BY A PROPOSED NEW SYSTEM CALLED DRIVER ALERT AND INHIBITION (DAI). THE DUAL-MODE RESPONSE IS A KEY ELEMENT WHICH ALLOWS FOR FLEXIBILITY AND TOLERANCE WITHOUT SACRIFICING EFFECTIVENESS. TWO SYSTEMS WITHIN THE FRAMEWORK OF DAI ARE DESCRIBED - SPEED CONTROL AND REAR-END COLLISION AVOIDANCE. IMPLEMENTATION CAN PROCEED ON THE BASIS OF DEVICES AND SUBSYSTEMS THAT EXIST TODAY.