PRZEGLĄD ELEKTROTECHNICZNY, ISSN 0033-2097, R. 91 NR 2/2015 27 Jolanta KOSZELEW 1 , Piotr WOŁEJSZA 2 Białystok University of Technology (1), Maritime University of Szczecin (2) doi:10.15199/48.2015.02.07 Anticollision manoeuvre optimization in the NAVDEC system Abstract. Authors presented the concept of improved time optimization algorithm of anticollision manoeuvre to be implemented in the NAVDEC system. The algorithm will play an important role in supporting the navigator in decision making process. Moreover implementation of the algorithm will reduce significantly fuel consumption. In conclusion, safety and economic efficiency of shipping will be improved. Streszczenie. Autorzy przedstawili ulepszony algorytm optymalizacji czasu manewru antykolizyjnego, który zostanie zastosowany w systemie NAVDEC. Algorytm odegra istotną rolę w procesie wspomagania decyzji nawigatora. Ponadto, implementacja algorytmu zredukuje znacznie zużycie paliwa. Reasumując, poziom bezpieczeństwa oraz efektywność ekonomiczna zostanie poprawiona. (Optymalizacja manewru antykolizyjnego w systemie NAVDEC). Keywords: decision support, anticollision, optimization, NAVDEC. Słowa kluczowe: wspomaganie decyzji, zapobieganie kolizjom, optymizacja, NAVDEC. Introduction Supporting the navigator in making decisions may significantly enhance the safety and effectiveness of the transport process. The navigational decision support system is to supplement the shipborne navigational equipment, while in the future it may be a part of Integrated Bridge System (IBS). The correct operation of the system requires co-operation with other devices and systems onboard ship and the external ones in order to acquire navigational information automatically. Apart from the presentation of navigational situation and information, the basic functions of the decision support system include: 1) navigational situation analysis; 2) solving collision situations; 3) interaction with the navigator via a user/operator interface. For a system to be effective and practically used, it has to present selected information in a readable manner and to be user-friendly. In this connection, a lot of attention is paid to the issues connected with building a proper user interface. One important requirement is the compatibility with present standards of information presentation in navigational information systems[1], [2]. NAVDEC – Navigational Decision Support System The known navigational systems in use and methods of navigational decision support perform information functions and as such are helpful in the process of safe conduct of a ship. However, none of these known systems provides a navigator with ready solutions of collision situations taking account of all the vessels in the proximity of own ship, where the Collision Regulations [3] apply. Another shortcoming of these systems is that they do not explain the assessment of a navigational situation and proposed manoeuvre parameters. Systems presently used on ships are information systems only. NAVDEC is not only information system. It’s also decision support system. Developed at the Maritime University of Szczecin NAVDEC system is a navigation tool that performs alongside providing information typical tasks for decision support systems. NAVDEC is an important complement to navigational equipment of the ship. Is a real-time system operated by the navigator. Its proper functioning requires interaction with devices and systems on the ship. The standard configuration of the ship include: log, gyrocompass, radar, echo sounder, ARPA, GNSS (Global Navigational Satellite System), such as GPS (Global Positioning System) or DGPS (Differential Global Positioning System). In addition, AIS, ECDIS, GNSS. In the version being developed following sources of information are in use: log, gyrocompass, radar / ARPA, GPS and DGPS, AIS and ENC (Fig.1). Fig. 1. Data sources for decision supporting system [4] Actual optimization in the NAVDEC system The purpose of optimization is the choice of minimally-time manoeuvre from all available solutions, leading to pass other targets at presumed CPA (Closest Point of Approach). To achieve this goal, the following optimization criteria were used in NAVDEC: energy optimization, time optimization. First step of the actual optimization method involves the determination of the courses leading to pass at presumed distance (Safe_Courses procedure). The courses are calculated on the basis of [5] for each pair: the own ship (number 1) and the target ship i (for i = 2 to n, where n is the number of target ship). Input data: - position (x1, y1), speed (V1) and course over ground (KDd1) of the own ship, - position (xi, yi), speed (Vi) and course over ground (KDdi) of target, - CPA – safe passing distance set up by navigator Output data: < gamma i 1, gamma i 2 >, <gamma i 3, gamma i 4> - sectors of safe courses for pair: the own ship and the target ship number i. Safe_Courses(i): { xwz=xi-x1; ywz=yi-y1; vxwz=vxi-vx1; vywz=vyi-vy1; vw=sqrt(vxwz*vxwz+vywz*vywz); D=sqrt((xwz*xwz+ywz*ywz) 2 ); Adcpa1=(xwz*ywz + CPA * sqrt(D 2 -(CPA) 2 )) /(xwz*xwz - (CPA) 2 ); Adcpa2=(xwz*ywz – CPA * sqrt(D 2 -(CPA) 2 )) /(xwz*xwz -(CPA) 2 ); vxi=Vi*sin(KDd2); vyi=Vi*cos(KDdi); Bdcpa1=Adcpa1*vxi-vyi;Bdcpa2=Adcpa2*vxi-vyi;