Research On The Method For Tracking And Locating The Pollution Source In River Channels For Emergency Monitoring

Tracking and locating the source of water pollution is one of the important functions for water quality monitoring. Fast and reliable locating method for pollution source combined with convenient and efficient mobile monitoring equipment will play an important role in controlling the sewage discharge and disposing the water pollution incidents.In this thesis, the tracking methods for the pollution source in the river channels were firstly studied, including the directional strategy, step length strategy, motion path planning algorithm and so on. Then a kind of mobile platform for water quality monitoring was developed. The overall performance was tested by the simulation and experiment.The main works and innovation points of the paper are as follows:(1) In terms of the features of pollutant diffusion model in natural rivers, a tracking method for the pollution source in the river channels with the constraint of boundary conditions was proposed. Based on the behavior planning strategy and the concentration gradient strategy, the boundary conditions were introduced to accommodate the complex environment for actual river channel. Its performance of applicability, efficiency, and position accuracy were validated in two-dimensional pollutant diffusion simulation of river channels.(2) According to the characteristics of boundary conditions and obstacles distribution in river channels, a motion path planning algorithm was put forward based on the standard Improved Genetic Algorithm. The way of encoding, the producing mode of the initial population, the selection and variation algorithm of evaluation function were deeply analyzed. And then, a kind of inserting operator and an optimization algorithm of path smoothing were applied in path planning. The proposed algorithm, which was combined with the tracking method mentioned above, was also tested in two-dimensional pollutant diffusion simulation with and without the obstacles along the motion path.(3) In order to simulate the actual river channels, an experimental platform was established. It can be used to construct various experimental scenarios of pollutant diffusion with different outfall locations, emissions and obstacle conditions to verify the proposed method. The advantages and the deficiencies of the proposed method were discussed by analyzing the results of the experiment.(4) A mobile platform for water quality emergency monitoring was successfully developed. The platform consists of three parts as mobile ship for water quality monitoring, remote-monitoring & control center, and handheld remote controller. It has five basic functions as real-time location monitoring with differential GPS, autonomous navigation, three-dimensional sampling, online measurement of water quality parameters (now just for several specific parameters), wireless remote control and data transmission. The mobile platform was tested in the Qiantang River, and several preliminary emergency monitoring experiments were carried out.