Research On Data Fusion For Position Reference System Of DP Ship

With the development of ocean exploitation, many large ocean projects appeared, so we need more and more vessels work on the ocean, and the request is higher. The vessel developed from hooker to large DP vessel, such as deepwater pipelay crane vessel, semi submersible drilling platform and so on. The request of DP ship from DP1 to DP3. DP3 ship has higher request to safety and dependability, so DP3 needs three or four set of position reference systems to get redundancy. This paper mostly aims at studying on position reference system of DP3 vessel, the major work is designing a data fusion system for position information in order to improve the positioning precision and the ability of disposing error.Firstly, we introduced some kinds of position reference system used in DP ship, then established its mathematics model. For the ship motion parameters the base of the position reference system, so we first established the ship model, wind model, wave model and current model under reasonable suppose. Then we established the position reference system model by the coordinate switching under the analysis of the measure theory of the position reference system, we also do some experiment to validate the correctness of the model.Secondly, we divide the data fusion into two parts in this paper, data dispose and fusion arithmetic. In the study of the data dispose we do some study on the filter and the outlier checking, we can get the dependable data by this disposal. Then we transform the data from different position reference system to a uniform reference frame and make the data rate of different position reference system to a uniform data rate by a self adaptive data adjust method. In the fusion arithmetic we judge the measure data from different position reference system by computing the confidence measure of them, in the paper we also improved the arithmetic according to the actual request. In the end we do some experiment, the result of the experiment indicates that the fusion system really can improve the measure precision and the ability of disposing error.Finally we do some experiments on the four DOF flat with three compasses, the result of the experiment ulteriorly validate the validity of the fusion arithmetic.