Construction and visualization of a seafloor backscatter database using naval “through the sensor” technology

This paper describes developments in the Sonar Active Boundary Loss Estimation project. The aim of the project is to produce high-resolution bottom backscatter and bottom-loss databases using combatant AN/SQS-53C sonar “through the sensor” data collection. The approach utilizes modified signal processing techniques developed specifically for naval sonar systems to automatically detect and identify features of interest in the recorded time series of each beam. The current implementation is able to process acoustic returns from a variety of sonar setups. For each ping, all beams are processed. Feature parameters are extracted from the sonar signals, automatically geo-referenced, and stored in a database along with supporting ship and sonar status information. Unique features inherent to the database, analysis tools, and visualization capabilities include use of MATLAB, a commercially available software package; on-the-fly creation of gridded data at arbitrary (user-specified) grid cell resolution; ships status, navigation, and sonar setup data; the ability to extract, analyze, and display parameters by azimuth of observation; and the ability to generate “images” of the ocean bottom along the ship´s track as seen by the actual sonar system. In this paper we present an overview of the signal and data processing from the sonar beamformer output to the production of a gridded geo-referenced database and provide several examples of data visualization and data filtering which are possible with this approach