Local navigation system for automatic ship berthing

This paper shows that it is necessary to solve the problem of accurate ship positioning to provide automatic ship berthing. It is impossible to solve this problem using global positioning systems since they do not provide the proper precision. The principles and methods of development of a local navigation system are discussed. The system operation is based on measurement of the distance between the antennas of radio equipment installed on a ship and at the quay. Microwave propagation analysis is used for distance measurements. It is followed by a homodyne procession of microwave signals and the phase difference measurements on low-frequency signals. The block diagram of the rangefinder and its operation principles are described. The main equations that determine functioning of the system are given. The procedure of the range finding by measuring the phase difference between signals is analyzed; some limitations of the method are shown. Some aspects of system operation concerning selection of its operating frequencies are discussed. It is shown that using the proposed block diagram gives possibility to create an effective local navigation system to provide automatic ship berthing.