| The Navigation Satellite Timing And Ranging/Global Position System has been widely used in many fields such as Position, Navigation and accurate Timing. By integrating GPS-OEM board with computer and communication techniques, users can develop various GPS application system freely and expediently to satisfy their special need. In this paper, a marine navigation system is designed using GPS-OEM board and computer technique. At first, based on the requirements of GPS marine navigation system, the whole system framework is designed. Then the main factors that affect navigation precision are investigated deeply. Secondly, corresponding solutions are putted forward based on the results of investigation. To solve reference frame error, the conversion methods among different preference frames are analyzed and mathematic models are established. As to position error, the normal and improved Kalman filter models are used to deal with position coordinates flatness. And the method of curve fitting position data is used to do velocity flatness. When the position information is invalid, the model of position calculation is considered. To get more accurate navigation parameter, the method of normal intercept arc is used to calculate earth-line-length instead of the traditional big circular navigation method. At last, the main functions of the navigation software are implemented using Visual C++ development environment and database under Windows. Especially, the design and implementation of the information receiver module of software, database module and interface module are analyzed and described in detail. In this part, the key techniques are as follows: the data communication between GPS-OEM board and computer COM port using MSCOMM controller, the design of Access database and the interface between the database and the other three modules, the implementation of the application of timing used at interface, the showing of preplanned sea routes, and the real-time showing of navigational tracks.
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