Study On The Vessel Traffic Statistic System Based On AIS And The Raster Chart

With the economic globalization, enhancement of commercial transaction and improvement of shipping industry, there are more and more vessels. And the safety of navigation is threatened by the increase of ship's size and the traffic flow on the sea. In order for the decrease of the traffic accident on the sea, improvement of the vessel traffic at the present and in the future, it is necessary to collect basic data of vessel traffic with effective methods for statistic and analysis, and to do some research. Based on the data and research, the actual state, the basic feature and the general rule of vessel traffic can be further studied, so as to make clear whether it necessary to establish the ship routing system or to take further management measure.This thesis mainly study on the follow aspects:(1) The build up of the display platform based raster chartThe statistic system uses chart in the JPG or BMP format. To be used as the base for the graphic display in the system, the raster charts were calibrated to makegeographical coordinates corresponded with the screen pixels.(2) Gathering the vessel traffic dataThere are two methods of gathering the data of the vessel traffic: observation of vessel traffic and computer simulation. The observation can be conducted through manual record and with some kinds of nautical devices. The thesis use AIS as the data source and solve the key problem as AIS decoding. By use of different methods for the difference of the AIS Parametric Sentences and the AIS Encapsulation Sentences, the dynamic state, the static state and the navigation information can be gathered.(3) Displaying the vessels' track and distribution of density on the raster chart. By displaying the vessel traffic data from AIS on the base of the raster chart andfurther calculating and drawing, the distribution of track and ship's density and so on...