Abstract
Autopilots are an integral part of modern ships. However, at present, many tasks are emerging, including the ones in the unmanned navigation field, requiring the use of new control algorithms and new means of monitoring navigation parameters. In particular, to solve such problems as keeping a vessel on a given trajectory, automating the ships’ divergence and similar tasks, it is necessary to have means of continuous monitoring of the ship’s location. For this purpose, receivers of global navigation satellite systems can be applied. To model control processes, it is necessary to know the distribution of positioning errors of modern devices. Some works show that over long time intervals (a day or more), positioning errors can be considered a random process with a Gaussian distribution. This paper presents the experimental study results of the distribution of positioning errors of a ship navigation receiver operating in the GPS and GLONASS systems, in a combined GPS/GLONASS mode, as well as in the indicated modes with differential corrections. The paper shows that at time intervals of seconds – minutes (characteristic of ship’s control systems), positioning errors of the navigation receiver cannot be represented by a random process with a Gaussian distribution law. The paper presents the results of a mathematical modelling of the process of holding a ship on a given trajectory using experimental values of positioning sensor errors. For the research, a mathematical model of an innovative ship with a wheel-propulsion steering complex is used. An algorithm is created that makes it possible to keep a vessel on a given trajectory with an accuracy acceptable for a practical use, commensurate with deviations determined by the design features of the ship’s hull and its propulsors.
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