JPH0431439B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for setting a predictive collision risk range for ships.

(Prior Art) Various automatic collision prevention techniques have been put into practical use in order to avoid collisions between a ship and other objects such as ships or offshore structures in the sea area in which the ship is navigating. These can be roughly divided into (a) a track display method that displays the past tracks of other targets (see Figure 4); (b)
A vector display method that displays the predicted future course of other targets and the current ship speed as vectors (see Figure 5); (c) Added the predicted danger range to the above vector display method. It is classified into three types: expected danger range display method (see Figure 6).

Methods (a) and (b) above input the planned course and speed of the own ship, calculate the relative course to each target, and calculate the DCPA.
(point of closest approach), TCPA (time to point of closest approach), etc. to determine the course and ship speed that allows for avoidance.
This is a method of finding out through trial and error.
In order to find out the course and ship speed, it is necessary to repeat the above calculation for each target being tracked, which is complicated. Furthermore, since the ship's own ship's avoidance course cannot be immediately determined, effective avoidance maneuvers are difficult.

The above method (c) is a method that displays a uniform predicted collision risk range on the predicted course of each target based on a preset avoidance distance (cruising distance) between the own ship and the target. Regarding the above-mentioned setting of the avoidance distance, the vessel operator determines the avoidance distance and manually sets it from the outside, and the setting of the avoidance distance largely depends on the intuition of the vessel operator.

(Problems to be Solved by the Invention) In the conventional method of setting the predicted collision risk range shown in FIG. (2) It is difficult for ship operators to take appropriate avoidance maneuvers, especially in the Habaminato area. (3) The predicted collision risk range is displayed on the extension of the current course of other targets, and changes in course due to influences from other targets or land/water depth are not considered. This is not taken into account at all, and therefore there is a risk that dangerous areas may exist due to changes in direction of other targets even in areas that are determined to be safe.

(Means for Solving the Problems) The predicted collision risk range setting method according to the present invention is a method for setting a predicted collision risk range on a collision risk line determined by the position and speed of the own ship and targets such as ships around the own ship that are detected by radar. ,
Avoidance is based on the position information (position and course) of the target obtained from the above radar, the position/direction measurement error that occurs when measuring with the radar or gyroscope, and the maneuverability of the own ship and the target. This is to set a predicted collision risk range for ship maneuvering.

To explain in detail based on FIG. 1 according to the embodiment, the collision danger line 3 (the trajectory of the point at which the arrival time of the own ship and the target object are equal) is determined based on the positions and speeds of the own ship 1 and the target object 2. It's decided.

The course of own ship 1 is within the range of the measured course obtained from the gyro compass plus the position/direction measurement error (±α). Similarly, the course of the target object 2 is a range obtained by adding position/direction measurement errors (±α) to the measured course based on position information obtained from the radar.

Therefore, region Z ₁ in the figure is the region with the highest risk of collision, and regions Z ₂ and Z ₃ are regions with relatively high risk of collision.

The range in which own ship 1 can change its course based on the kinematic maneuverability of own ship 1 is an area of ±β, and based on the kinematic maneuverability of target 2 predicted from the size of target 2, etc.
is the range ±β' in which the course can be changed.

Therefore, the area _Z4 , which is included in both the area of own ship's course ±β and the area of target course ±β', is an area where there is a risk of collision. Note that areas other than the above areas Z ₁ to _{Z 4} are areas where there is no risk of collision.

Although the description has been given here with respect to one target 2 around the own ship 1, the predicted collision risk range is set every moment for all the targets 2 around the own ship 1.

(Function) As explained above, in the predicted collision risk range setting method according to the present invention, a target object is located on the collision danger line based on the position information of the target with respect to own ship, the error in position/direction measurement, and the maneuverability. Since the predicted collision risk range is set, it is possible to accurately set the predicted collision risk range where there is a risk of actual collision, and by navigating around this predicted collision risk range, the risk of collision can be reliably avoided. I can do it.

(Effects of the Invention) According to the predicted collision risk range setting method according to the present invention, as explained above, it is possible to set and display the predicted collision risk range according to the degree of danger, so that the vessel operator can select an appropriate avoidance target. The predicted collision risk range is set by taking into account the motion control performance of other targets and the possibility of a change in course. By taking into consideration the fact that the danger range will not appear in the collision danger line and limiting it to a predetermined time, it is possible to omit the setting of the danger range for distant targets where there is no risk of collision. , advantages can be obtained in terms of data arithmetic processing and ship maneuvering.

(Embodiments) Hereinafter, embodiments of a predictive collision risk range setting method and an embodiment of a predictive collision risk range setting device according to the present invention will be described in order based on the drawings.

First, a method for setting a predicted collision risk range will be explained based on FIG. 1.

Based on the position and speed of own ship 1 and the positions and speeds of ships and marine structures around the own ship (hereinafter referred to as other ships 2) detected by radar (these are obtained from data from radar). Then, the collision risk line 3 between own ship 1 and other ship 2 is determined.

The collision danger line 3 is a circular locus of a point where the own ship 1 and the other ship 2 arrive at the same time, and is determined as follows.

That is, the position of own ship 1 is the reference origin (0, 0), the position of other ship 2 is (x ₁ , y ₁ ), the position of own ship 1 is V ₀ , and the speed of other ship 2 is V ₁ . Then, the center coordinates (X ₀ , Y ₀ ) of the collision danger line 3 and the radius R of the collision danger line 3 can be determined by the following equation.

(X ₀ , Y ₀ )=[(1/2)(A+B),(1/2)(C
+D) ] R = (1/2) √ (-) ² + (-) ² However, A = V ₀ x ₁ / (V ₀ + V ₁ ), B = V ₀ x ₁ / (V ₀
−V ₁ ), C=V ₀ y ₁ /(V ₀ +V ₁ ), D=V ₀ y ₁ /
(V ₀ −V ₁ ), If the ship speeds of own ship 1 and other ship 2 are equal,
Collision danger line 3 is the perpendicular bisector of the line connecting both ships.

Next, on the course (straight line L ₀ ) of own ship 1, lines E ₁ and E ₂ that make an angle of ±α with respect to the bow direction and lines F ₁ and F ₂ that make an angle of ±β are set, and ship 2
On the course (straight line L ₁ ) of the ship, lines G ₁ and G _{2 make an angle of ±α with respect to the bow direction, and lines H 1 and G 2} make an angle of ±β′ with respect to the bow _direction .
Set _H2 .

The above-mentioned angle α is an angle corresponding to a measurement error (sensing error) that occurs when measuring a position or direction using a radar, a gyro compass, or the like. The above-mentioned angle β is the maximum angle at which the own ship 1 can change course in a short time, but this angle β is determined according to the maneuverability of the own ship 1. The above angle β' is the maximum angle at which the other ship 2 can change its course in a short time, taking into account the size of the other ship 2.
It is determined according to the maneuverability of the vehicle.

An area included between straight lines E ₁ and E ₂ and between straight lines G ₁ and G ₂ on the above-mentioned collision danger line 3
Z ₁ is the area with the highest risk of collision and is
Area Z ₂ between E ₁ and E ₂ (excluding area Z ₁ ) and area Z ₃ between straight lines G ₁ and G ₂ (excluding area Z ₁ )
is an area with a relatively high risk of collision, and
Area Z ₄ included between F ₁ and F ₂ and between straight lines H ₁ and H ₂ (excluding areas Z ₁ , Z _2, and Z ₃ ) is an area where there may be a risk of collision. , areas other than areas Z ₁ to _{Z 4} are areas where there is no risk of collision.

As mentioned above, after determining the collision danger line 3, an area Z ₁ is created as a predicted collision danger range on this collision danger line 3.
~ Z ₄ is set, and the area Z ₁ , areas Z ₂ and Z ₃ , and area Z ₄ are separated and set.

Collision with another vessel 2 can be prevented by maneuvering to avoid the predicted collision risk range.

Next, a predicted collision risk range setting device for implementing the above predicted collision risk range setting method will be described.

The predictive collision risk range setting device for this vessel is
As shown in the figure, there is a radar device 4 that detects the direction and distance of ships and marine structures (hereinafter referred to as other ships) in the sea area where the own ship is sailing relative to the own ship, and a gyroscope 5 that detects the bearing of the own ship. A log 6 for detecting the speed of own ship and a ship position measuring device 7 for detecting the position of own ship
and a predicted collision risk range setting control unit 8 which receives information and signals from these and sets a predicted collision risk range in which there is a risk of collision between the own ship and another ship, and a predicted collision risk range setting control unit 8. It is composed of a display device 9 equipped with a CRT that displays the set predicted collision risk range, etc.

As the radar device 4, in addition to a normal marine radar device, it is also possible to use a pulse width compression radar device, a beam width compression radar, etc.
Furthermore, in order to detect the target object size more accurately, it is also possible to use a synthetic aperture radar or the like.

The ship position measuring device 7 is a device that measures the ship's position by receiving signals from an artificial satellite or a device which measures the ship's position by receiving radio waves from a plurality of transmitting stations on the ground.

The predicted collision risk range setting control unit 8 includes own ship position calculation means 10, other ship position calculation means 11, other ship acquisition and tracking means 12, other ship predicted course/collision danger line calculation means 13, and other ship position calculation means 11. Size identification means 14 and predicted collision risk range calculation means 15
and collision danger line arrival time calculation means 16.

Own ship position calculation means 10 uses own ship position signals from ship position measuring device 7, azimuth signals from gyro 5, and ship speed signals from log 6 to determine the own ship's position (in a stationary coordinate system common to the nautical chart). position) is calculated.

The other ship position calculation means 11 receives other ship signals representing the ever-changing bearings and distances of each other ship relative to the own ship from the pulse transmitter/receiver 4a of the radar device 4, and also receives the own ship's bearing signal from the gyro 5. In response to the own ship position signal from the own ship position calculation means 10, the positions of each other ship (positions in the same stationary coordinate system as the nautical chart) are calculated.

The other ship tracking means 12 receives the other ship position signal from the other ship position calculation means 11 and individually detects all other ships that can be detected by the radar device 4 in the navigation area of the own ship from time to time. At the same time as being captured, the positions of other ships that are within a predetermined radius of the own ship and are at risk of colliding with the own ship are updated while memorizing their positions from the past times when they were captured by radar, for example, about 10 times. By doing so, the other ships are tracked, and their speeds are calculated from the positions of the other ships being tracked.

The other ship predicted course/collision danger line calculation means 13 receives the own ship position signal from the own ship position calculation means 10 and the ship speed signal from the log 6, and also receives the other ship position signal from the other ship position calculation means 11. In response to the other ship speed signals from the other ship acquisition and tracking means 12, the predicted course of each other ship from time to time with respect to the own ship and the collision risk line between each other ship and the own ship are calculated.

In the other ship size identification means 14, the size of each other ship is identified by receiving the other ship signal from each other ship from the radar device 4 and the other ship position signal from each other ship position calculation means 11. Ru.

The predicted collision risk range calculation means 15 receives the own ship position signal from the own ship position calculation means 10, the other ship position signal from the other ship position calculation stage 11, and the other ship predicted course/collision danger line calculation means 13. A predicted collision danger range is calculated on the collision danger line by receiving the other ship predicted course signal, the collision danger line signal, and the other ship size signal from the other ship size identification means 14.

In this case, the preset and input values are used for the position and orientation measurement errors (±α) by the radar device 4 and the gyro 5, and the preset and input values are used for the own ship's maneuverability (±β). For the other ship's maneuverability (±β'), a value calculated based on the other ship size signal is used.

In the collision danger line arrival time calculation means 16,
Receives the own ship speed signal from the log 6, the other ship speed signal from the other ship acquisition and tracking means 12, and the danger range signal from the predicted collision danger range calculation means 15, and reaches the predicted collision danger range. The time it takes to reach the collision danger line is calculated.

The CRT control means 9a of the display device 9 receives various signals as shown in the figure, and displays the own ship's position, own ship's course, other ships' positions for other ships not far from the own ship, and other information as shown in FIG. The ship's course, the collision danger line, the predicted collision danger range (regions Z ₁ to _{Z 4} ), the arrival time to the predicted collision danger range, etc. are displayed moment by moment on the CRT 9b.

In this case, since the predicted collision risk range is displayed according to the degree of danger, the vessel operator can easily determine the course to avoid based on the information displayed on the CRT 9b.

Each calculation means constituting the predictive collision risk range setting control unit 8 can be composed of a digital computer and an AD converter provided as necessary.

The predictive collision risk range setting control unit 8 may be constructed using a digital computer and an AD converter for AD converting each detection signal from each detection means, in which case reference numerals 10 to 1 are used.
Each function performed by each means of 6 is executed by each program input and stored in the computer.

In the above case, a schematic flowchart of the calculations etc. executed by the predictive collision risk range setting control unit 8 is shown in FIG.

The series of operations shown in the above flowchart is
It may be executed every predetermined minute time when the radar scanner 4b of the radar device 4 rotates by a predetermined minute angle, or
Alternatively, it may be executed each time a signal indicating that another ship has been captured is output.

[Brief explanation of drawings]

The drawings relate to an embodiment of the present invention, and FIG. 1 is an explanatory diagram for explaining a predicted collision risk range setting method, FIG. 2 is an overall configuration diagram of a predicted collision risk range setting device,
Fig. 3 is a schematic flowchart showing each step of setting a predicted collision risk range, Figs. The relative course, b, indicates the true course, and FIG. 5a shows the relative course with respect to own ship, and b indicates the true course. 1...Own ship, 2...Other ships, 3...Collision danger line,
Z ₁ to _{Z 4} ...Predicted collision risk range.

Claims (1)

[Claims] 1. Position information of the target obtained from the radar on the collision danger line determined by the position and speed of the own ship and targets such as ships around the own ship detected by the radar;
A method for setting a predicted collision risk range, comprising setting a predicted collision risk range for an avoidance maneuver line based on position/azimuth measurement errors and motion maneuverability between own ship and a target.