| Chart Plotter units is one of the important equipments using in the ocean vessel and the maritime operations. The working principle and the system composition of Chart Plotter units were researched, the overall structure of the system was proposed, at the same time, the hardware and software platform were selected in this paper. ARM-Linux embedded developing platform and QT graphic editor are adopted in the design, and the traditional plotting system has been improved and upgraded aiming at the advantages and the disadvantages of it. Functional requirements of Chart Plotter units were analyzed in the part of overall design in this paper, including the achievement of functions such as the position picking up of the paper charts; track plotting; network communication; screen display and so on. Dividing the Chart Plotter units into the power module, digital module, drawing chassis, information processing and controlling module. Solutions of the system modular of Chart Plotter units were proposed by detailing and analyzing the each module one by one, and then the basis of developments of the hardware and software were provided, in where, the power module will power supply for other modules; the digital module mainly to realize the picking up of paper charts; the drawing chassis is the executing agency of realizing the drawing track plotting function of Chart Plotter units; the focus of the work of the information processing and controlling module which is also the core part of Chart Plotter units is to realize functions of information processing,network communication,human-computer interaction and tracking plotting. In the hardware, the selection of the minimum system (core board) and the expansion board design were completed according to various indicators, and the designs of the hardware interface of the power circuit, the serial circuit, Network Communication, the stepper motor and the LCD screen were solved in this paper. In the software, the establishment of cross-compilation chain was achieved, completed the embedded ARM Linux system in the transplant; programmed the driver of serial port and realized the serial communication of Chart Plotter units by using the RS232 standard; programmed the driver of network chips and realized the network communication between Chart Plotter units and navigation network by using the UDP agreement of TCP/IP; realized the track plotting by timing the counter to control the stepper motor; analyzed the QT graphic editor systematically and accomplished the realization of the signal, dialog and window layout in Qt, accomplished the analysis of the signal and slots at the same time. All of the analyses above have laid a foundation for the follow-up realization of the human-machine interface of Chart Plotter units. In the part of system debugging, used the serial debugging tools to test the serial communication; used the network coverage to simulate the network communication of Chart Plotter units to test; tested the plotting accuracy of Chart Plotter by formulating the plotting of the paper charts. Finally, a feature-rich, easy to use, and reliable interface of human-machine interaction was designed by using the QT graphic editor. The Chart Plotter units meet the design requirement of the paper, is able to realize functions such as the position picking up of the paper charts, track plotting, network communication, screen display and so on. |
