ANALISIS HASIL SURVEI BATIMETRI TEREFERENSI ELIPSOID METODE SIMPLE SHIFT

• Main Author: Afif Naufaldi, Muhammad
• Format: Final Project
• Language: Indonesia
• Subjects: Karya Umum
• Online Access: https://digilib.itb.ac.id/gdl/view/56815
• Institution: Institut Teknologi Bandung

The use of the ellipsoid as a vertical reference plane in the hydrographic survey also called the Ellipsoidally Referenced Survey (ERS), has the opportunity to replace the tidal reduction obtained using a tide monitoring device (tide gauge). The tidal reductions in ERS are obtained from the GNSS height data at the time of the survey which is reduced by a vertical distance from the ellipsoid to the vertical reference plane used. The tidal reductions obtained from tidal observation (tide gauge reduction) and tidal reduction obtained from GNSS observations at the sounding points (GNSS tide reduction) are respectively used to reduce the depth measurement data so that they are referenced to the same vertical reference plane. The difference between the tide gauge reduction and GNSS tide reduction values were calculated and resulted in an RMSE value of 0.034 m. Depth measurement data in this study were acquired using a Single Beam Echo Sounder (SBES) which was then reduced by tide gauge reduction and GNSS tide reduction, produces tide gauge reduced depth data and GNSS tide reduced depth data. Each reduced depth data will produce two different digital surface models. To see the difference between the two digital surface models, a raster/grid model is created that displays the difference in the depth values of the two digital surface models. The RMSE value of the difference in the depth value is 0.032 m. To determine the quality of the depth data, the Total Vertical Uncertainty (TVU) test was performed for tide gauge reduced depth data and GNSS tide reduced depth data, respectively. The TVU test was carried out on 78 areas of intersection of the mainline and the crossline with the number of samples of depth sample varies in every area. The TVU test results show that the tide gauge reduced depth data and GNSS tide reduced depth data meet the TVU tolerance of order 2 up to the exclusive order based on the S-44 IHO standard. From the small RMSE value of the tidal reduction and the RMSE value of the difference in depth of 0.034 m and 0.032, it was concluded that the GNSS tide reduction could replace the original tide gauge reduction. This conclusion is also reinforced by the TVU test results of the GNSS tide reduced depth that meets the TVU tolerance of order 2 to exclusive order.