Yukito Iijima

RESULTS OF COLLISION AVOIDANCE MANOEUVRE EXPERIMENTS USING A KNOWLEDGE-BASED AUTONOMOUS PILOTING SYSTEM

One of the most important factors for the safety of navigation is to ensure proper collision avoidance manoeuvres in a congested traffic area. There are many aids for this purpose; for example, an ARPA, which is mandatory for certain ships and which is expected to be effective.

STUDY TOWARDS A 21ST-CENTURY INTELLIGENT SHIP

Recent technological developments and the emergence of new, high-tech materials have led to the concept of a new type of ship and to innovations in ship operation. A Japanese research team is studying ways of designing a ship for the future. This paper focuses on the optimum automatic operation system for oceanic navigation in a future ship. See also the following abstract.

The use of soundings for navigation in the mid-20th century

Many ingenious mechanical methods were used by hydrographic surveyors for measuring the depth of water in the early part of the 20 th Century. These were superseded by echo-sounding and sonar techniques in the later decades. Relatively few of the mechanical methods were used by merchant ships but, in the years before radar and satellite navigation, they, and the increasingly popular echo sounder, had a useful place in the navigators armoury of navigation aids. This paper is not intended to provide a detailed description of the development of sounding devices. Sections 1 to 5 simply outline the principles of the sounding devices with which the authors were familiar during their time at sea. In Sections 6 to 9 the authors recount their anecdotal experiences of the way in which they, personally, used depth measuring devices during the middle years of the 20 th century.

A PROCESSING METHOD OF RADAR SIGNAL TO DETECT DRAGGING ANCHOR

The authors have studied the possibility of detecting the dragging of a ships anchor by using a technique of radar image processing. The video signal was converted to an 8 bits digital signal at a 40 nanosecond sampling rate and stored in the 1 megabyte memory of a personal computer in order to measure the 2-D distribution of echoes. Using this data, the position, attitude and change of attitude of the ship were examined. It was concluded that a large number of further observations will be needed to establish a more accurate processing method. See also Abstracts Nos. 89013076, 89013082 in this issue.