JPS62297910A - Method for deciding navigable area against underwater obstacle - Google Patents

Abstract

PURPOSE:To improve the sailing safety of ships by calculating both the most approximate distance TCPA and the time DCPA against all underwater obstacles in case a ship veers in all directions at 360 deg. and comparing these TCPA and DCPA with the limit TCPA and limit DCPA respectively to obtain a navigable sea area including plural underwater obstacles in the form of the azimuth information. CONSTITUTION:The time DCPA needed for targets P1-P4 have their shortest distances and the most approximate distance TCPA are plotted by means of a variable phi. Then the limits DCPA and TCPA are set and plotted. If it is decided that a dangerous target exists in the present navigation course, a veering enable azimuth area having a range exceeding the limit DCPA is pointed out. In case no azimuth is obtained to exceed the limit DCPA of each target, the target having the margin of the TCPA in a certain azimuth is temporarily neglected. Then an azimuth is set again in the next step. Thus all simulating actions are performed when the dangerous position information is obtained to decide a navigable azimuth in a sea area including the underwater obstacles.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application This invention relates to a method for determining a navigable area in a sea area where a plurality of fixed underwater obstacles exist.

Prior Art Conventionally, when navigating in a sea area where multiple underwater fixed obstacles exist, TCPA (time to closest distance) for each obstacle is calculated based on dangerous position information of underwater fixed obstacles based on nautical charts. ) and DCPA (nearest distance)
Using this as a guideline for the degree of risk, avoidance courses were set in descending order of TCPA, and when the avoidance course for - fixed targets was completed, a new avoidance course was set for the next target, and avoidance maneuvers were performed one after another. .

Problems to be Solved by this Invention For this reason, when there are a large number of underwater fixed obstacles, setting a avoidance course requires a large number of tasks and is complicated, making it difficult to set a avoidance course for all fixed targets. It is. In addition, there were cases where there were delays when starting the evacuation route.

Therefore, this invention improves the above-mentioned disadvantages of the conventional technology when determining the navigable area of a ship in a sea area where there are multiple fixed underwater obstacles, and solves the problem of determining the navigable area of a ship in a sea area where there are multiple fixed underwater obstacles. This allows you to easily determine the navigable area for your own ship.
The purpose of the present invention is to provide a method for determining a navigable area that can improve the stability of ship maneuvering.

Structure of the Invention The method of determining the navigable area for underwater obstacles according to the present invention expresses the TCPA and DCPA for underwater obstacles, which are used as safety indicators during avoidance maneuvers, as a variable of azimuth φ from the own ship. The TCPA and DCPA when changing course in any direction are calculated for all underwater obstacles, and compared with the set limit TCPA and limit DCPA, the navigable area in sea areas where multiple underwater obstacles exist is calculated as azimuth information. It is characterized by the way it is generated.

EMBODIMENTS The following describes embodiments of the present invention shown in the drawings. This invention consists of the following three algorithms.

(1.) TCPA and DCPA calculation algorithm The TCPA and DCPA for underwater fixed obstacles used as an index of risk during avoidance maneuvers are expressed as a variable of azimuth φ from the own ship.

(Figure 1) TCPA and IICPA are as follows.

TOPA = r cos (φ+φo)/'v...
(1) DCPA = r sin (φ+φo)
-・-f2] r: Distance between own ship and fixed target, ■: Ship speed of own ship [2] T when own ship changes course in any direction of 360° (:! PA and DCPA characteristic calculation algorithm .

TCPA when own ship changes course from formulas (1) and (2)
Characteristics are obtained with the direction φ of the DCPA as a variable (Figs. 2 and 3) From the above Figs. 2 and 3, the following equation can be obtained for the state of own ship.

[3] Risk judgment and navigable direction determination algorithm limit TCPA and limit DCPA are set and plotted in FIGS. 2 and 6.

If the current course and DCPA (or T C! FA) at the time of course change are within the limit DCPA (or TCPA), it is determined to be dangerous, and the range of azimuth φ that exceeds the limit DCPA (or TCIPA) is extracted. When obtaining the position information of a plurality of fixed obstacles, a simulation based on the above is performed for all the obstacles, and the navigable direction for all the obstacle groups is determined at once.

Next, the effect will be explained based on the sea area having fixed obstacles P1 to P4 as shown in FIG.

(2) Plot the DCPA and TCPA of each target P1 to P4 using φ as a variable as shown in FIGS. 5 and 6.

(2) Set the limit DCPA1 and the limit TCPA and plot them as shown in FIGS. 5 and 6.

■ Check whether there are any targets judged to be dangerous on the current course. In Figures 5 and 6, D (φ) and T (φ) when φ = 0 are DC on the current course! FA and TCP-A are shown. ) If there is a dangerous target, the limit DC! on Figure 5! P
Extract the azimuth range in which the course can be changed beyond A.

■ Limit DC of all targets for multiple fixed targets
If a bearing exceeding PA is not given, the TCPA characteristics shown in Fig. 6 are used, and for a target with a margin for TCPA in a certain bearing, the limit TC! Until the PA,
The relevant target is temporarily ignored and the direction is reset in the next step.

■ The processes from ■ to ■ are all simulated when dangerous position information is obtained, and the navigable direction in the sea area where underwater obstacles are present is determined.

Effects of the Invention The embodiments of the method for determining a navigable area for underwater obstacles according to the present invention are as described above, and the following effects can be achieved.

This is a navigable area determination method that can process multiple underwater fixed obstacles at once, easily determine the navigable area of your own ship, and improve the stability of ship maneuvering.

[Brief explanation of the drawing]

Figure 1 shows the TCPA and l) C! Figures 2 and 3, which express PA as a variable of azimuth φ from own ship, are TCPA when own ship changes course
and a characteristic diagram with the direction φ of DCPA as a variable, Figure 4 is a positional relationship diagram between own ship and fixed targets P1 to P4, Figures 5 and 6
The figure is a characteristic diagram with DCPA and TCPA of each target as variables of φ.

Claims (1)

[Claims] TCPA (time to closest approach distance) and DC for underwater obstacles used as safety indicators during avoidance maneuvers
Expressing PA (nearest distance) as a variable of azimuth φ from own ship, TCP when own ship changes course in any direction of 360°
Navigation against underwater obstacles that calculates A and DCPA for all underwater obstacles and compares them with the set limit TCPA and limit DCPA to generate the navigable area in sea areas where multiple underwater obstacles exist as azimuth information. Possibility range determination method.