Bathymetric Difference Analysis using Multifrequency Multibeam Echosounder Khomsin (a), Mukhtashor (b), Danar Guruh Pratomo (a), Suntoyo (b)
(a) Geomatics Engineering Department ITS Surabaya
(b) Ocean Engineering Department ITS Surabaya
Abstract
The primary purpose of a bathymetric survey is to make a nautical chart used for navigational safety purposes. For the safety of the ship^s berth at the port, multitemporal and multifrequency bathymetry data can describe how much sedimentation occurs in the channel or port pool. The bathymetric survey equipment uses acoustic methods such as singlebeam echosounder (SBES) and multibeam echosounder (MBES). The last decades of the development of MBES are multifrequency MBES- the advent of multibeam echo sounders has enormously increased the efficiency, accuracy, and spatial resolution of coastal and ocean mapping. Multifrequency MBES, on a ping-by-ping basis, provides multifrequency data with a single survey platform. The purpose of multifrequency MBES is to get a better detection resolution of the subsurface. By conducting surveys with five modes simultaneously (200kHz, 250kHz, 300 kHz, 350 kHz, and 400 kHz), the user can reduce the effect of this subsidence to get an accurate picture of the seabed. This study aims to bathymetric analysis using multifrequency MBES in shallow coastal water. This study shows that the density of each frequency is 1/5 of the original data. Each frequency of the digital bathymetric model (DBM) is almost similar. Based on the formed DBM, the depth value of the study site ranges from -2.5 m to -11 m LWS. The maximum bathymetric difference is 35 cm between a depth of 200 kHz and 400 kHz. The difference in bathymetry between 250 kHz and 350 kHz is only in the range of -5 cm to 5 cm. The range dredging volume inter frequencies is between 0.015 m3/m2 and 0.080 m3/m2.
