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.
robotic ship, automatic mooring, navigation system, reference positioning, phase rangefinder, homodyne detection
1. Ahmed Y. A., Hasegawa K. Artificial neural network based automatic ship berthing combining PD controlled side thrusters - A combined controller for final approaching to berth // 13th International Conference on Control, Automation, Robotics & Vision, Singapore, 10-12th December 2014. S. 1304-1309.
2. A Study on Automatic Ship Berthing System Design / Bui V. P., Kim Y. B., Choi Y. W., Kawai H. // IEEE Proceedings of the 2009 International Conference on Networking, Sensing and Control, Japan, March 26-29, 2009. S. 181-184.
3. Russell D. DGNSS Position Quality Information for DP Applications // Dynamic Positioning Conference, October 9-10, 2007. S. 1-10.
4. Miles R. Performance modelling for local position reference sensors applied to RadaScan // Dynamic Positioning Conference, October 15-16, 2013. S. 1-15.
5. Shirokov I. B. Precision Indoor Objects Positioning based on Phase Measurements of Microwave Signals // Evaluating AAL Systems Through Competitive Benchmarking, Indoor Localization and Tracking. Berlin: Springer-Verlag, 2012. S. 80-91.
6. Shirokov I. B. The Multitag Microwave RFID System // IEEE Transactions on Microwave Theory and Techniques. 2009. T. 57, vyp. 5, ch. 2. S. 1362-1369.
7. Shirokov I. B. Pat. 2584976 (RF). Sposob izmereniya dal'nosti. Opubl. v Byul. № 14, 2016.
