VTS를 위한 상황별 충돌위험도 연구

경상대학교

컴퓨터과학과

Contents

Problem statement Proposed System Introduction and Background study

▫ Calculation of DCPA

▫ Calculation of TCPA

▫ Calculation of VCD

Multi-vessel collision risk calculation▫ Fuzzy inference system

▫ Utilization of Fuzzy Inference for collision risk calculation

Application▫ Simulator Development

▫ Techniques , tools

Results Future Work

Problem Statement

▫ Due to brisk industrial growth, the marine traffichas become an imperative subject in the open sea.

▫ The crew inside the vehicle traffic service (VTS)centre is facing challenging issues due toc o n t i n uo u s g r ow t h i n v e s s e l s n u m b e r .

▫ Most of VTS centers are using the ARPA RADARbased conventional vehicle traffic managementsystem.

▫ VTS staff has to carry out most of thingsmanually.

▫ Strong need to develop RADAR operated, multi-vessel collision detection system.

Proposed System (Salient Features)

▫ Fuzzy inference based intelligent collision detection system.

▫ Using the DCPA, TCPA and VCD to calculate collision risk.

▫ Development of multi-vessel graphical simulator

can calculate degree of collision risk among vessels from VTS centre.

has RADAR filtration algorithm.

Flexible development approach based on MFC, VC++ and openGL

Flow chart to calculate

the degree of collision risk

Calculation of DCPA•DCPA is considered the closet point of approach between the two vessels.

•The blue line in the following figure is displaying the DCPA between A & B.

Projection Vectors

Resultant Vector

Mathematical Calculation of DCPA

0°< θ < 90° Then m = tan (90°- θ) (1)

90°< θ < 180° Then m = -tan(θ - 90°) (2)

180°< θ < 270° Then m = tan(270°- θ) (3)

270°< θ < 360° Then m = -tan(θ - 270°) (4)

Where θ is the angle between the vessels, calculated from VTS centre and x, y ,m are the coordinates and the slope respectively.

mx - y - mtx + ty = 0 (5)

2)1(2m

ytmxtDCPA

(6)

Suppose ‘V’ is the vessel and ‘I’ denotes the number of vessels which comes in the range of RADAR. If the total number of vessel in particular scenarion=6. Then, mathematically we can calculate,for how many times, we have to calculate the DCPA using the following calculation.

=

Ship 1 case: 1 2, 1 3, 1 4, 1 5, 1 6Ship 2 case: 2 3, 2 4, 2 5, 2 6

. . . . . .

. . . . . .

Calculation of DCPA among vessel from VTS

Calculation of TCPA

• TCPA is the time to closet point of approach. According to figure (mentioned in the previous slide) the TCPA is the time, which the vessel A takes to reach the vessel B.

For reference

222 )( DCPAytxtTCPA

(7)

Where x and y are the co-ordinates and DCPA is the distance to the closet point of approach

송재욱, 1995. PC를 이용한 ARPA RADAR SIMULATOR의 개발에 관한 연구, 한국해양대학교

Calculation of VCD

• VCD is the variance of a compass direction which can bemeasured with the difference of two consecutive bearing.

Calculation of VCD among vessel from VTS centre

Calculation of VCD

• For the calculation of VCD, first we have to calculate thebearings among all the vessels from VTS centre using RADARinput.

Calculation of VCD

Calculation of degree of collision risk

Input arrays to calculate the degree of collision risk among vessels from VTS centre

Calculation of degree of collision risk

• To calculate the degree of collision risk. We used fuzzy inference system.

Fuzzy Inference System

Fuzzy inference is the process of formulating the mapping from a given input to an

output using fuzzy logic.

Fuzzy Logic

Fuzzy logic is based on fuzzy set theory which is introduced by Lotfi A. Zadeh and

Dieter Klauain 1965

Fuzzy set theory

Fuzzy sets are sets whose elements have degrees of membership.

an extension of the classical notion of set.

In classical set theory, the membership of elements in a set is assessed in binary terms.By contrast, fuzzy set theory permits the gradual assessment of the membership of elements in a setfuzzy set theory can be used in a wide range of domains in which information is incomplete or imprecise.

Simulation and scenario

To validate the accuracy of our algorithm. We developed a simulator.

In simulation we took 11 vessels

Each vessel is considered as an autonomous object which means; each have its own

Position (x,y)

Speed (we can derive velocity from speed)

Angle (course)

DCPA (can be measured from VTS)

TCPA (can be measured from VTS )

We supposed in our scenario that ships are moving randomly.

Vessels Statistics Display Module

DCPA, TCPA and VCD Module

Simulation Panel

RADAR Filtration

ModuleCollision Risk Calculation

Module

What is inside the ship simulator code !!

Simulator code Snippet

Code view of DCPA inference engine

19

PS PMS PM PMB PB

0 0.5 1 1.5 2 2.50

1

DCPA의 소속함수 (nmile)

Code view of TCPA inference engine

20

-16 -8 0 8 16 24 32

NB NM NS PS PMS PM PMB PB

0

1

TCPA의 소속함수 (min)

Code view of VCD inference engine

21

PS PMS PM PMB PB

0 7.5 15 22.5 300

1

VCD의 소속함수 ( 도, º)

▫ 장애물과 자선 사이의 충돌위험도를 1과 -1 사이의 값으로 표현

▫ 음수는 장애물이 지나갔음을 의미

22

0

1

-1 -0.6 -0.2 0 0.2 0.4 0.6 0.8 1

NB NM NS PS PMS PM PMB PB

충돌위험도의 소속함수

Collision Risk

• VCD가 PM일 때 추론규칙

• VCD가 PMB일 때 추론규칙

23

NB NM NS PS PMS PM PMB PB

PS NB NB NB PM PM PMS PMS PS

PMD NM NB NB PMB PMS PMS PS PS

PMD NS NM NB PM PMS PS PS PS

PMB NS NS NM PMS PS PS PS PS

PB NS NS NS PS PS PS PS PS

D

C

P

A

T C P A

NB NM NS PS PMS PM PMB PB

PS NB NB NB PM PMS PMS PMS PS

PMD NB NB NB PMS PMS PMS PS PS

PMD NM NB NB PMS PMS PS PS PS

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PB NS NS NM PS PS PS PS PS

D

C

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충돌위험도 추론규칙

• VCD가 PB일 때 추론규칙

24

NB NM NS PS PMS PM PMB PB

PS NB NB NB PMS PMS PMS PS PS

PMD NB NB NB PMS PMS PS PS PS

PMD NB NB NB PMS PS PS PS PS

PMB NM NB NB PS PS PS PS PS

PB NS NM NB PS PS PS PS PS

D

C

P

A

T C P A

• VCD가 PS일 때 추론규칙

• VCD가 PMS일 때 추론규칙

25

NB NM NS PS PMS PM PMB PB

PS NS NM NB PB PMB PM PMS PS

PMD NS NS NM PMB PM PMS PS PS

PMD NS NS NS PM PMS PS PS PS

PMB NS NS NS PMS PS PS PS PS

PB NS NS NS PS PS PS PS PS

D

C

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A

T C P A

NB NM NS PS PMS PM PMB PB

PS NM NB NB PMB PMB PM PMS PS

PMD NS NM NB PMB PM PMS PS PS

PMD NS NS NM PM PMS PS PS PS

PMB NS NS NS PMS PS PS PS PS

PB NS NS NS PS PS PS PS PS

D

C

P

A

T C P A

Code Snippet of inference tables

Collision risk calculation

Radar Filtration

The simulation area shows the results after 1800 milli-

second delay. (It can be decreased by using multi-core processor)

The filtration module filters the vessel which come in

5 NM radius of selected vessel.

This module create easiness to filter the degree of

collision risk around specific vessel.

Radar Filtration

This area display the vessel which come in radar range.

Degree of collision around a specific vessel.

Many Thanks