The article presents a brief overview of methods for ensuring the navigation safety of vessel traffic, which are divided into three categories: methods of early detection of the collision possibility of ships, methods of maneuvering to avoid a collision and planning trajectory methods of the ship. A detailed theoretical review of methods for assessing the risk of a dangerous approach of ships, associated with ensuring the navigation safety of ship traffic, is carried out in detail. The representation of ship domains is disclosed to assess the risk of a dangerous approach of ships. The work provides links to sources that clarify the presented material.
The science of ensuring safe navigation in the civil and military spheres is in the process of improvement. A global issue in this scientific area is prevention of groundings and collisions of ships. This science examines the aspect of the problem of navigation safety from all sides. Navigation figure 1, since antiquity, as a result, has created problems of navigation safety. Ensuring navigational safety is a task that is a complex multi-level complex.
To solve this problem, the forces are united:
manufacturers of maritime navigation aids,
international organizations, administrations of
states participating in world shipping. The
cooperation of these entities forms a system for
ensuring safe navigation. Despite such
cooperation, a high percentage of ship accidents
at sea is an objective reality that cannot be denied
and is primarily due to the peculiarities of external
and internal factors accompanying navigation,
which will always be present regardless of the
human factor. The level of state and reliability of
navigation in modern conditions, the real
accuracy of navigation and the quality of
navigation problems is about twice worse than
expected. It follows that the complete elimination
of the accident rate of ships has no chance. But it
is quite possible to influence the number of
accidents with the help of various measures and
try to achieve its relative maximum reduction for
a period that is limited. Such a drop in the accident
rate can be achieved up to a certain level, after
which the accident rate will inevitably grow again
or temporarily stabilize [
Experimental studies show that the largest
number of accidents in water transport occur in
the areas of responsibility of ports and on the
approaches to them. In this regard, the problem of
safe movement at sea becomes most acute in
limited waters and cramped navigation conditions
[
One of the seven ancient man-made wonders
of the world - the Pharos lighthouse, and the
miraculous miracle - the Pillars of Hercules were
navigational landmarks on the approaches to
Alexandria and Gibraltar and helped mariners
prevent their ships from aground. And this is one
of the proofs that at that time the knowledge,
experience and intuition of the navigator was not
enough to guarantee the safety of navigation. In
modern conditions when the main cause of
maritime accidents is breakdown, damage, or
equipment failure. The worst regions in terms of
maritime accidents, according to the AGCS
report, are the waters of southern China,
Indonesia, and the Philippines. Every fourth
incident occurs in those areas. Even though Asia
remains the most unfavorable region due to the
busiest routes and the old fleet. Next come the
Eastern Mediterranean and the Black Sea and the
British Isles. From the analysis of catastrophes,
the existing problems of the safety of navigation
becomes acute in limited waters and cramped
navigation conditions. As a result, special
methods of preventing collisions of ships,
introduced into complex technical navigation
systems, are in great demand [
Method 1. On-board radio and computer
systems, which are called on-board collision
avoidance systems, have been recognized as
highly effective means of preventing collisions in
shipping. The English name for these complexes
is Collision Avoidance System. The on-board
collision avoidance system is a proven system
based on the use of surveillance radar signals and
other navigational aids. It operates independently
of ground equipment and provides information on
situations that other vessels can create in various
navigational conditions. The collision avoidance
system provides information to the officer of the
watch on the situation in the navigation area
through the provision of visual and voice
information, ensures the timely detection of
threatening vessels, classifies vessels according to
their degree of danger, and issues
recommendations for the appropriate maneuver.
The collision avoidance system monitors vessels
in the surrounding water area within a radius of up
to 24 miles from own vessel [
Method 2. The problem of divergence of vessels in the water area is a priority in the management of the vessel. Without disregarding the increasing intensity of traffic on all international water communications, it is possible to ensure a satisfactory level of traffic safety in recent years using innovative means of radio navigation. For this reason, the problem of divergence of ships should be considered only in accordance with the section "Use of automatic radar plotting means".
The main document among the normative ones
that determine the reliability of the divergence of
ships is the "International rules for preventing
collisions of ships at sea" (IRPCSS-72) [
These Rules oblige each vessel to carry the appropriate lights and signs, to sound the appropriate sound signals, to use all available means in accordance with the prevailing circumstances and conditions to enable each of them to:
1. To detect in advance the presence of other vessels;
2. To determine the degree of danger in order to identify the existence of a collision hazard; 3. Take into account the mutual obligations when maneuvering the gap;
4. Ensure safe divergence in all visibility conditions.
Method 3. The lack of a quantitative description of the concept of "limited visibility" in the IRPCSS-72 causes a contradiction between R. 19 ("Swimming with limited visibility") and R. 15 ("Situation of intersecting courses in sight of each other") in cases where the visibility range is of the same order of magnitude with D. Having detected in such conditions with the help of the radar an approaching vessel from the right side, a prudent navigator will make way for him, without waiting for this vessel to come within the distance of visual visibility and he will have to act in conditions: the short period of time and minimal space.
In addition, the International Maritime Organization at the United Nations (IMO) in 1978 adopted the Convention on the Training, Certification and Watchkeeping of Seafarers. This Convention defines the minimum requirements for the knowledge and practical skills of boat masters in relation to ship divergence and the use of radar information. IMO has also formulated requirements for programs for radar surveillance, laying and use of automatic radar laying facilities. All this is aimed at increasing the reliability of the divergence of ships.
Method 3. Get answers to the questions:
determination of the current coordinates of the
vessel in the coordinate system - bearing and
distance relative to a given point; determination of
the actual trajectory of the vessel's movement, the
actual elements of movement, is possible with the
help of navigation methods for monitoring the
position and movement of the vessel. Evaluation
of the trend of the vessel's movement to predict
the current coordinates in time, control of the
lateral deviation of the vessel from and calculation
of the course correction. The listed monitoring
tasks are referred to as “Real-time tasks”. The
more difficult the navigation conditions are, the
shorter the “real time clock” should be. The
advantage of each navigation method is
determined by the main features of the
characteristics: the accuracy of determining the
current coordinates of the vessel, the duration of
navigation determination and the discreteness of
the definitions [
The area around a ship of a certain radius, shape, and size, not considering geometry, actual dimensions, the current course, into which the oncoming ship should not enter is called the ship's domain. The ship's heading is determined by evaluating the speed vector from radar observations during several turns of the antenna. This definition indicates that the information is not received in real time, but nevertheless this area is called the "navigation safety zone". In methods for assessing the risk of dangerous approach by the foundation, there is a point of the shortest approach of ships (closest point of approach). For navigational safety, the shortest distance is greater than the critical value. The following values are provided: "time of movement to the point of the shortest approach of ships" (time of closest point of approach), "distance to the point of the shortest approach of ships" (distance to closest point of approach).
Research groups that study the issue of ship collision avoidance use a variety of domains: circular, elliptical, and other complex shapes. The domain boundary is interpreted as a function of the ship's heading angle. At this point in time, to use the security domain, each domain is analyzed separately. Based on this, we can conclude that the domain cannot fully solve all the problems of discrepancy due to strictly defined domain boundaries.
The Goodwin domain model is divided into 3 sectors. The dimensions of the free zone from other objects are different. Depends on the situation in a certain period. The radius of the sectors corresponds to the critical values of the closest approach of ships for each scenario Figure 2.
Deepening the idea of Goodwin is carried out by the Davis domain, presented in the form of an ellipse with an offset center, divided into sectors. For the navigator, this is an indicator for deciding to perform an evasive maneuver when other objects intrude into the active domain Figure 3.
Caldwell's ship domain is a different configuration depending on the ship's approaching scenario. With oncoming traffic in the domain, the stern part is completely absent. When overtaking, the domain has an ellipsoidal shape.
Tszyu's ship domain is based on neural
networks trained by the backpropagation method,
which makes it possible to partially consider the
influence of the external environment without
resorting to complex classical deterministic
mathematical models of its description [
The ship domain proposed by
S. V. Smolentsev, A. E. Filyakov considers the
navigation features of the navigation area and the
hydrometeorological situation. Eliminates the
occurrence of false alarms when a vessel enters
the safety domain that is moving in the opposite
direction in its lane [
There are groups of our and foreign researchers who are working towards assessing the risk of collision and improving ship domains. An unconventional method for clarifying the situation of approaching ships at sea based on information from an automatic identification system was proposed by Bukaty Vitaly Mikhailovich, Morozova Svetlana Yurievna. Titov A.V., Zaikova S.N., Volynskiy I.A., Khmelnitskaya A.A. in their work the current state and problems of using inland waterways (on the example of the Volga-Caspian Sea shipping canal) and Nitsevich A.A., Melnikov N.V., Khristich D.Yu., Lebedev V.P. in work Collision of ships use the method of M.A. Konoplev, who presents the risk assessment in the form of a fuzzy system.
One of the main problems of navigation, namely the navigation safety, remains unresolved, although the work is carried out by all groups according to the law of a conical spiral.
The article presents a brief overview of methods for ensuring the navigation safety of vessel traffic, which are divided into three categories: methods of early detection of the possibility of collision of ships, methods of maneuvering to avoid a collision and methods of planning the trajectory of the safe movement of the ship. A detailed theoretical review of methods for assessing the risk of a dangerous approach of ships, associated with ensuring the navigation safety of ship traffic, is carried out in detail. To assess the risk of a dangerous approach of ships, the presentation of ship domains of complex figures is given - a dangerous approach of ships.
The work provides links to sources that clarify the presented material.
We wish to thank V. Kychak, prof., I. Trotsyshyn, prof., O. Punchenko, prof., G. Bortnyk, prof. for their insightful comments on earlier drafts.
We would also like to thank Vinnitsa National Technical University for the application of theoretical and practical research in the R&D "Development of the theory and methodology of digital radio signal processing in real time" (Ministry of Education and Science of Ukraine, Vinnitsa National Technical University);
R&D "Development of methods for designing a fiber-optic transmission system" (Ltd "Budivelnik-3", Vinnitsa National Technical University).