1. Operation principle - Multibeam Sounding System
The working principle of the multi-beam sounding system is to use the transmitting transducer array to transmit the sound wave covered by the wide sector to the seabed, and use the receiving transducer array to receive the sound wave with a narrow beam, a footprint of the seabed topography is formed through orthogonality pointed by transmit and receive sectors. By properly processing these footprints, the water depth values of hundreds and more soundings on the seabed in the vertical plane perpendicular to ship heading direction can be obtained through one time detection, thus the system can accurately and quickly Measure the size, shape and height changes of underwater targets within a certain width along the route, as a result the three-dimensional characteristics of the seabed terrain can be reliably rendered.
2. Hydro-Tech MS400 Applying to Artificial Reef Survey
The feature of Hydro-Tech MS400 multibeam echo sounder is portable, high precision and resolution performance, it's suitable for pre-observation and evaluation of the underwater topography in the area where artificial reefs were placed, recording the layout of artificial reefs, and scanning the placing scales, calculate empty volume of artificial reefs with the help of GIS software. The variation trend of slippage, overturning, subsidence and burial of reefs is examined through continuous observation records.
MS400 multibeam sounding system has achieved the results of artificial reef measurement as follows:
(1) As shown in the figure below, a 0.2-meter grid is used to form a point cloud map of the artificial reefs. According to this point cloud map, the length, width, and height of fish reefs can be measured, and the position distribution of fish reefs, the amount of placement and the size of each reef group can be calculated.
(2) Import the multibeam measurement data to Google Maps or Baidu Maps, which can visualize the position and distribution of fish reefs. As shown below:
By using multibeam sounding system for periodic observations, it is possible to accurately grasp the changes in reefs and reef groups, the placing results, etc., thus provide data supports for scientific management of artificial reefs.