Towards Autonomous IndustrialScale Bathymetric Surveying Both higher efficiency and cost reduction can be gained from automating bathymetric surveying for offshore applications such as pipeline, telecommunication or power cables installation and inspection on the seabed. We present a SLAM system that optimizes the georeferencing of bathymetry surveys by fusing the deadreckoning sensor data from the surveying vehicle with constraints from the maximization of the geometric consistency of overlapping regions of the survey. The framework has been extensively tested on bathymetric maps from both simulation and several actual industrial surveys and has proved robustness over different types of terrain. We demonstrate that our system is able to maximize the consistency of the final map even when there are large sections of the survey with reduced topographic variation. The framework has been made publicly available together with the simulation environment used to test it and some of the datasets.

SVIn2: An Underwater SLAM System using Sonar, Visual, Inertial, and Depth Sensor This paper presents a novel tightlycoupled keyframebased Simultaneous Localization and Mapping (SLAM) system with loopclosing and relocalization capabilities targeted for the underwater domain.Our previous work, SVIn, augmented the stateoftheart visualinertial state estimation package OKVIS to accommodate acoustic data from sonar in a nonlinear optimizationbased framework. This paper addresses drift and loss of localization xe2x80x93 one of the main problems affecting other packages in underwater domain xe2x80x93 by providing the following main contributions: a robust initialization method to refine scale using depth measurements, a fast preprocessing step to enhance the image quality, and a realtime loopclosing and relocalization method using bag of words (BoW). An additional contribution is the addition of depth measurements from a pressure sensor to the tightlycoupled optimization formulation. Experimental results on datasets collected with a custommade underwater sensor suite and an autonomous underwater vehicle from challenging underwater environments with poor visibility demonstrate performance never achieved before in terms of accuracy and robustness.