Dredger Using The Ultrasonic Sounder

During the dredging, dredgers must always measure the depth of work fields such as rivers and lakes to see the effect of the dredging and to figure out the workload which stands for the sullage removed by the dredgers. The traditional depth sounder is mainly aimed at work fields characterized by big depth and relatively clean water. However the work fields of dredgers marked by shallow water, turbidity and submerged floating miscellany is not included. Depth measurement in the dredger's working field is not just a problem of anti-interference; the true-echo-picking is the key point which is caused by two factors following as below. First fake echo produced by the turbidity and submerged floating. Second multi-echo caused by the shallow water and the conversion between the big-depth water and the shallow water.And there is no such a depth sounder aim at work fields of dredger or the similar environment. For this demand, a depth sounder target at the dredger's work field or similar environment is designed mainly considering the fluctuation, the time-varying of the channel and some specific conditions. The feature of water in the dredger's working field and the characteristic of the echo has been carefully studied in this thesis. According to this feature, a time-delay estimation algorithm has been designed using the correlation between envelopes of echo and standard echo, which highly raises the accuracy and stability. Experiments carried out in the thesis have proved the effect of the algorithm, which shows the applicability of the algorithm in the dredger's working field.This thesis consists of seven chapters.Chapter 1 mainly represents the current status of ultrasonic depth measure and development, especially the dredger-using ultrasonic depth measure or the similar conditions, a brief introduction of the time-delay technology, the character of the working field, difficulty in the depth measurement of the dredger's working field and the current status of dredger-using depth sounder included.Chapter 2 the character of ultrasonic, the basic principle of ultrasonic depth measure and the specialty of dredger-using ultrasonic depth measure is discussed in detail and the structure of the depth sounder has been given out.Chapter 3 discusses the time-delay algorithm of the ultrasonic measure considering the fluctuation and some specific conditions in the work field of dredger. Some simulations have been done to visualize the effect of the algorithm.Chapter 4 represents the structure of hardware of ultrasonic depth measure system including ultrasonic launching and picking circuit, controlling circuit and anti-noise measures. Ant-interference in electric has been done to reinforce stability of the depth sounder.Chapter 5 represents the structure of software, realization of the sub-module and the correlation of those modules. Some measurement has been taken in the software to enhance the ant-interference.Chapter 6 includes some experiment result and the analysis of the result which were done to prove the effect of the design.Chapter 7 gives the conclusion of the work, some advice for the further work included.