In bathymetric survey a multibeam sonar system is placed on the hull of a survey vessel. The sonar system sends out multiple soundwaves that bounce off the sea floor and return to the ship. The delay between sending and receiving the signal provides a measurement of water depth. These measurements are then used to produce a map charting the sea floor.
Acquiring high resolution multibeam data is time-consuming because the survey vessel moves through the area in overlapping lines to capture the data in a systematic way. Overlapping the lines increases confidence in the data’s accuracy and helps to fill any gaps in the data caused by factors such as bad weather. Different frequencies are used to map different water depths. Overall, the higher is the frequency the better is the resolution of data produced. That’s because the high frequency soundwaves will reach the seafloor at more of an angle and will create better return signal. Corrections need to be made while processing multibeam bathymetry data in order to allow factors such as water salinity, sea temperature. That’s because these factors affect how quickly sonar signals travel through the water.
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