Rapids and shoals in the channel have a huge impact on the safety of the ship navigation, Based on the principle of a rubber dam can always adjust the height of the dam and raise upstream water level, This thesis crea...Rapids and shoals in the channel have a huge impact on the safety of the ship navigation, Based on the principle of a rubber dam can always adjust the height of the dam and raise upstream water level, This thesis creatively proposed the principle which applied to rapids and shoals in the Channel. In order to achieve the purpose of assisting ship through the channel safely. In this paper, through theoretical calculations verified the rubber dam has characteristics of raising water level, increasing the depth of the shoals, reducing the flow velocity, reducing water surface slope and improving the conditions of navigation. Therefore, this study has a wide range of practical value and application prospects in the project展开更多
This research aims to elucidate the navigational situation of ships during the massive tsunami that occurred in the Tohoku district of Japan on March 11,2011. In particular, it focuses on the time the massive tsunami ...This research aims to elucidate the navigational situation of ships during the massive tsunami that occurred in the Tohoku district of Japan on March 11,2011. In particular, it focuses on the time the massive tsunami encountered ships. AIS （automatic identification system）, which is required to be fitted aboard large ships for identifying and locating vessels, was used for the analysis of the navigational status of ships. It was confirmed that a group of ships sailing off the coast suddenly changed course. It was also verified that the ships had been struck by the tsunami, and the time of the strike was identified. The novelty and importance of this research are as follows. First, the behaviour of many ships that encountered the massive tsunami was clarified. There are no earlier instances of simultaneous and detailed recording of the behaviour of many ships encountering a massive tsunami. Second, the movement of the ships that encountered the tsunami was analysed, and the time of the maximum wave of the tsunami was verified. The research presents, for the first time in ship history, the status of a ship at the time of a tsunami using objective navigational data.展开更多
The problem of navigation for the distributed satellites system using relative range mea- surements is investigated. Firstly, observability for every participating satellites is analyzed based on the nonlinear Kepleri...The problem of navigation for the distributed satellites system using relative range mea- surements is investigated. Firstly, observability for every participating satellites is analyzed based on the nonlinear Keplerian model containing J2 perturbation and the nonlinear measurements. It is proven that the minimum number of tracking satellites to assure the observability of the distributed satellites system is three. Additionally, the analysis shows that the J2 perturbation and the nonlinearity make little contribution to improve the observability for the navigation. Then, a quasi-consistent extended Kalman filter based navigation algorithm is proposed, which is quasi-consistent and can provide an on- line evaluation of the navigation precision. The simulation illustrates the feasibility and effectiveness of the proposed navigation algorithm for the distributed satellites system.展开更多
文摘Rapids and shoals in the channel have a huge impact on the safety of the ship navigation, Based on the principle of a rubber dam can always adjust the height of the dam and raise upstream water level, This thesis creatively proposed the principle which applied to rapids and shoals in the Channel. In order to achieve the purpose of assisting ship through the channel safely. In this paper, through theoretical calculations verified the rubber dam has characteristics of raising water level, increasing the depth of the shoals, reducing the flow velocity, reducing water surface slope and improving the conditions of navigation. Therefore, this study has a wide range of practical value and application prospects in the project
文摘This research aims to elucidate the navigational situation of ships during the massive tsunami that occurred in the Tohoku district of Japan on March 11,2011. In particular, it focuses on the time the massive tsunami encountered ships. AIS （automatic identification system）, which is required to be fitted aboard large ships for identifying and locating vessels, was used for the analysis of the navigational status of ships. It was confirmed that a group of ships sailing off the coast suddenly changed course. It was also verified that the ships had been struck by the tsunami, and the time of the strike was identified. The novelty and importance of this research are as follows. First, the behaviour of many ships that encountered the massive tsunami was clarified. There are no earlier instances of simultaneous and detailed recording of the behaviour of many ships encountering a massive tsunami. Second, the movement of the ships that encountered the tsunami was analysed, and the time of the maximum wave of the tsunami was verified. The research presents, for the first time in ship history, the status of a ship at the time of a tsunami using objective navigational data.
基金supported by the National Basic Research Program of China under Grant No.2014CB845303the National Center for Mathematics and Interdisciplinary Sciences,Chinese Academy of Sciences
文摘The problem of navigation for the distributed satellites system using relative range mea- surements is investigated. Firstly, observability for every participating satellites is analyzed based on the nonlinear Keplerian model containing J2 perturbation and the nonlinear measurements. It is proven that the minimum number of tracking satellites to assure the observability of the distributed satellites system is three. Additionally, the analysis shows that the J2 perturbation and the nonlinearity make little contribution to improve the observability for the navigation. Then, a quasi-consistent extended Kalman filter based navigation algorithm is proposed, which is quasi-consistent and can provide an on- line evaluation of the navigation precision. The simulation illustrates the feasibility and effectiveness of the proposed navigation algorithm for the distributed satellites system.
