Design And Implementation Of Wireless Underwater Topographic Mapping System Based On Broadband Ultrasonic Distance Measurement

In recent years, due to lack of terrestrial resources, exploring and exploiting marine sources becomes hottest topic. Underwater topographic mapping technology developed quickly at the same time and is widely used in seabed mineral exploration, lake ecosystem protection, reservoir flood control, Urban waterway dredging and so on.The difficulty in underwater topographic mapping is how to use ultrasonic distance measurement to collect terrain surface height coordinate data and how to reconstruct terrain surface and display in three dimensions according to the collected coordinate data of 3D discrete points. In traditional mapping system, Ultrasonic distance measurement module mainly builds with full hardware circuit, which has complex structure, low accuracy, and poor mobility and the terrain reconstruction module is not suitable for modeling complex 3D terrain surface, especially for details. In order to improve the deficiencies in functionality and performance in underwater topographic mapping system, this article designs and implements a wireless underwater topographic mapping system based on broadband ultrasonic distance measurement. This system is relatively simple, intelligent, user-friendly with high accuracy and good mobility.The main work of this paper is as follows:1.Use software instead of hardware to achieve main function based on software radio concepts. Except the front-end detection module built with simple hardware circuit, all the other modules like signal generation, signal processing, signal analysis and results display are developed in software, which simplifies the hardware system. The front-end detection module and background analysis processing module separate in real time and interconnect wirelessly. It extends the system usage and achieve the motion detection and remote control.2. Use chirp signal instead of single-frequency pulse signal for detection to increase signal bandwidth and increase anti-interference performance. This system can be applied on different detection depth and different detection range. Users can configure signal detection parameters according in different scenarios.3. According to the three-dimensional coordinate data of underwater terrain surface collected by ultrasonic distance measurement, constructd the 3D triangular mesh to approximate the surface of the terrain by using the scattered point cloud triangulation algorithm and simulated curved surface model reconstruction based on three-dimensional discrete data points and three-dimensional dynamic display.4.Conducted underwater ultrasonic ranging experiment and underwater topographic mapping experiment indoor. Tested the functionalities of underwater ranging and terrain surface reconstruction. The results show that the system can reconstruct the 3D feature of the underwater terrain surface according to the 3D discrete point coordinate data reduction based on the ultrasonic distance measurement. This system was shown to have high accuracy, and stability from the experiments and proved to be feasible.