MBES data simulation: Assessment by direct comparison with a high-resolution multi-settings wreck survey.

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Blachet A., Plets R., Sacchetti F., Austenga A., Huntera A.J., Hansena R.E. MBES data simulation: Assessment by direct comparison with a high-resolution multi-settings wreck survey. UACE 2019

 

Abstract:    

Simulation is a valuable tool when investing new sonar designs or survey strategies. By avoiding expensive and time-consuming sea trials it helps to test and identify the optimum acquisition settings when dealing with complex bathymetry.

We have previously introduced a simulator that can compute synthetic raw sonar data. The user can specify any array geometry, pulse type and point-based seabed model. Furthermore, the package includes fully flexible swath sonar processing.

In this contribution we evaluate the simulator by comparing real and synthetic Multi-Beam Echo-Sounder (MBES) water-column data. To this end, we take advantage of an exceptionally high resolution MBES dataset. In 2015 a 92 meters WWI wreck (SS Polwell) located in the Irish Sea was mapped using various multibeam acquisition settings, such as multiple frequencies, modes, pulse rates, angular sectors, beam spacing, bandwidth and bottom detection modes  . 

We replicate the survey configuration and provide a ready to use framework for generating the data. The array imitates a Kongsberg EM-2040 and the scenario encapsulates the effects of key acquisition settings. The input model is an ultra dense point cloud of the wreck (gridded to 15cm) created from a combination of all  MBES data acquired in 2015. Moreover, the signal processing is designed to match the embedded system.  

We display examples of synthetic water-column images and compare these with the original survey measurements. Finally, system-specific artifacts such as sidelobes will be examined in more detail . 

Based on the outcome of the modeling experiment, we will be able to advise hydrographers and researchers on the optimum survey strategy to image objects exposed on the seabed .