Research And Implementation On Ship Draft Automatic Detection Technology Based On Multi-beam Bathymetry Sonar

With annual growth of shipping volume of Yangtze River, the phenomenon of ultra-draft vessels becomes frequent every year. In order to pursuing personal interests, some offenders often load cargo which is not in accordance with the provisions. This has resulted in overloading of ship, ship grounding and destruction of channel, and disturbing channel order, even affecting the economy.The key of governance of ship draft lies in the effective draft detection. In this dissertation, ship draft detection requirements in Yangtze River are analyzed, ship draft detection method based on the multi-beam sonar is proposed, the related technologies has been researched and its implementation and the field experiment has been carried out, which can detect ship draft in time and does not affect the normal navigation of ships, the detection accuracy meets the requirements, and it has important significance to protect the Yangtze River waterway navigation safety.The main working content includes the following five aspects:(1) By analyzing the environmental conditions of the Yangtze River, including the feature of ship and the channel of Yangtze River, the aggregate damand of the ship draft detection platform based on multi-beam sonar has been put forward; By analyzing the method and principle of multi-beam sonar, the ship draft real-time detection platform and system framework has been designed.(2) The multi-beam sonar data transmission way, message format and the transmission protocol has been researched, the method to transmit the data and analyse the message has been designed, and the multi-beam sonar real-time data has been received successfully.(3) The data preprocessing methods based on multi-beam sonar has been studied, incuding the correction and compensation method of multi-beam sonar data and filtering method of the abnormal data. The correction and compensation method of the draft data based on the environmental fators(attitude and velocity) has been researched; The characteristics of the abnormal data of multi-beam sonar have been analyzed, which has been divided into the discrete abnormal data and the continuous abnormal data, the discrete abnormal data has been deal with by the single frame and the multi-frame processing methods, the continuous abnormal data has been processed from the maximum draft data of the single frame, these algorithms have been analyzed by the experiment which use the measured data and simulated data.(4) The dynamic identification method and the process of the ship draft in the Yangtze river have been researched, including the start and end recognition of ship draft detection, the identification of the single and parallel ship draft. The multiple parallel ship data segmentation method is proposed. The detection precision and error range of the ship draft recognition algorithm have been calculated by field experiments.(5) The ship draft detection based on the multi-beam bathymetry sonar application software is implemented preliminarily, including the data communication, data analysis, data playback, data display and ship draft detection functions.Preliminary experiments showed that the system is technically feasible, and laid a solid foundation for the subsequent related technology research and engineering implementation.