A new method for weakening the combined effect of residual errors on multibeam bathymetric data

Abstract

Multibeam bathymetric system (MBS) has been widely applied in the marine surveying for providing high-resolution seabed topography. However, some factors degrade the precision of bathymetry, including the sound velocity, the vessel attitude, the misalignment angle of the transducer and so on. Although these factors have been corrected strictly in bathymetric data processing, the final bathymetric result is still affected by their residual errors. In deep water, the result usually cannot meet the requirements of high-precision seabed topography. The combined effect of these residual errors is systematic, and it's difficult to separate and weaken the effect using traditional single-error correction methods. Therefore, the paper puts forward a new method for weakening the effect of residual errors based on the frequency-spectrum characteristics of seabed topography and multibeam bathymetric data. Four steps, namely the separation of the low-frequency and the high-frequency part of bathymetric data, the reconstruction of the trend of actual seabed topography, the merging of the actual trend and the extracted microtopography, and the accuracy evaluation, are involved in the method. Experiment results prove that the proposed method could weaken the combined effect of residual errors on multibeam bathymetric data and efficiently improve the accuracy of the final post-processing results. We suggest that the method should be widely applied to MBS data processing in deep water.

Reconstructing Seabed Topography from Side-Scan Sonar Images with Self-Constraint

“…The noise from the suspended solids has strong backscatter strengths. Thus, the reconstruction of the noise will differ obviously from those of its surrounding terrain and can be removed by the topographic trend filtering [7].…”

“…Using SBS to obtain high-resolution seabed terrain needs dense surveying lines, which are low-efficiency and high-cost. Using MBS, one can carry out a large-scale bathymetric measurement, but the interval of surveying points in a ping will be enlarged and the bathymetric resolution will be decreased with the increases of water depth and beam incident angle [6][7][8]. Side-scan sonar (SSS) is height from the SSS waterfall image, the SSS towfish depth provided by a built-in pressure sensor and GNSS tidal level observed by the GNSS receiver mounted in surveying vessel.…”

A Method for Weakening Residual Errors in Multi - beam Swath Joins based on Terrain Spectrum Analysis

“…In study [19][20], a method of weakening the residual errors based on terrain geometric rectification and the method of discrete Fourier transform (DFT) was proposed. Their model is based on Ping continuous matching process, and has difficulty weakening the residual errors in nonoverlapping areas.…”

“…The evaluation values of the DFT (discrete Fourier transform) method derived from the tab. 2 in the literature [20]. However, the DFT method is not to remove the gross errors and correct the system errors before correction, so the evaluation values are different between the experiment B and its method.…”

“…Note: Seabed DEM (digital elevation model) generated by Golden Surfer software using all of the swaths; The gridding is achived by the interpolation method of triangulation with linear; In order to meet the width of the text, and improve the aesthetics, This figure changes the font and size of the axis; Morever, the corrected DEM effect can be compared with the fig. 14(b) of the literature [20] (the source of original data is the same, just the coordinates are the value of Latitude and Longitude in fig.14(b)). the experimental results in this paper is obviously better than the result of the DFT ( discrete Fourier transform).…”