Georeferencing and Spatial Representation of Two-Dimensional SONAR Images

Abstract

The presented thesis deals with the augmented visualization from a two- to three-dimensional scene of visualised backscattered signals, captured by a two-dimensional multi-beam BlueView P900-130 Sound Navigation And Ranging (SONAR), as well as its georefencing, against the background of harbour risk management and sheet pile wall examination. Alongside the data acquisition and preparation a simple methodology for combining depth values, motion parameters, underwater positioning data and two-dimensional SONAR images is presented, in order to provide an economically priced alternative to high-quality, but also upscale three-dimensional multi-beam SONAR. By means of the provided sensors systems by the German Aerospace Center DLR, Institute for the Protection of Maritime Infrastructures, a measurement trial in the Fischereihafen 1 (Bremerhaven, Germany), was realised using concrete reference objects in the accuracy range of the SONAR. The resulting program structure of data acquisition, preprocessing and final visualization is concerted to the utilized systems and can be handled by instructed person with a minimum of programming knowledge. Regarding the outcome of the measurement trial a lack of precision in the three-dimensional representation along the depth, due to the large vertical coverage of the SONAR, can be observed. Also a floating of the sensor carriers acoustic position occurred throughout the trial, on account of interferences between the acoustic sensors.