Design And Research Of Emergency Water Quality Monitoring Buoy System

Marine data buoys are an important tool for realizing long-term online monitoring of the marine environment.Existing large-scale buoys are difficult to use for rapid emergency response to marine pollution due to size and weight limitations,while small-scale buoys have poor stability and safety,and are prone to data quality problems due to the impact of complex marine environments.Therefore,this paper relies on the demonstration project of Tianjin Marine Economic Development Region to conduct research on high-stability miniaturized buoy structure design,wind speed and direction measurement correction method,outlier processing method,and emergency water quality monitoring buoy data collection and control system.Then,a water quality monitoring buoy designed for emergency response to offshore marine pollution was designed,and field experiments were completed.The main work is as follows:1 、 In response to the demand for rapid emergency response to marine environmental pollution,with miniaturization and high stability as the design goals,a cylindrical buoy structure suitable for my country’s offshore environment was designed,and an anchor-cable hybrid mooring system was designed.Then,a three-dimensional model of the floating body is established,and the hydrodynamic characteristics of the floating body are numerically simulated based on the three-dimensional potential flow theory.The results show that the natural period of the structure avoids the main period of offshore waves,and the stability and follow-up properties are good.2 、 Aiming at the problem that wind speed and wind direction measurement results are affected by the buoy tilt and sway,a correction method for wind speed and wind direction measurement based on buoy attitude calculation is proposed.Based on the quaternion method,the buoy attitude is solved,and the fourth-order Runge-Kutta methods are used to complete the quaternion update,by calculating the wind speed components introduced by the buoy space movement and space rotation,the true wind speed and true wind direction correction calculation is completed.Experimental results show that the calculation results of this method are consistent with the measurement results on a fixed platform.3、Aiming at the problem of outliers in water quality monitoring data,an outlier processing method based on multiple interpolation has been developed.The extreme value characteristic criterion,Pau Ta criterion,Dixon criterion,etc.are used to judge and eliminate the outliers in the data,and then the multiple interpolation method based on Bayesian theory is used to interpolate the missing values.Finally,based on the water quality monitoring data,the root mean square error is used to evaluate the interpolation effect of different methods.4 、 An emergency water quality monitoring buoy data collection and control system was developed.A sensor identification scheme based on serial communication and a remote data transmission scheme based on CDMA are designed.It realizes the plug and play of the sensor,remote firmware update and low power dynamic power management.Developed shore station receiving software based on Visual Basic.5、Conducted on-site testing experiments of emergency water quality monitoring buoys,including instrument cabin air tightness experiment,buoy static water attitude experiment,system high and low temperature experiment and offshore experiment,etc.Then through a comparative experiment,the rationality of the design scheme of the emergency water quality monitoring buoy structure and control system was verified.