Underwater iceberg profiling and motion estimation using autonomous underwater vehicles

• Main Author: Zhou, Mingxi
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2017
• Subjects: North Atlantic
• Online Access: https://research.library.mun.ca/12666/; https://research.library.mun.ca/12666/1/thesis.pdf

Icebergs originating from high latitude glaciers have drawn much attention from scientists and offshore operators in the North Atlantic. Scientists are curious about the iceberg drift and deterioration, while the offshore industry is concerned about the potential risks and damages on offshore oil platforms and infrastructures. In order to provide information to improve the iceberg drift and deterioration model constructed by scientists, and to assess the threats posed by icebergs to offshore platforms, iceberg shapes need to be measured. For the above water portion, optical instruments such as a camera and a laser scanner/LIDAR can be used. However, measuring the underwater portion of an iceberg is more challenging due to navigational constraints and sensor limitations. One approach, commonly used, is to deploy a horizontal plane scanning sonar from a support vessel at several locations around the iceberg. There are many drawbacks to this method, including the cost, sensing trade-offs in resolution and coverage, as well as constraints because of weather conditions limiting safe operations. The technology of Autonomous Underwater Vehicles (AUVs) has been developing rapidly in the last two decades. AUVs are commonly chosen to carry scientific sensors for various oceanographic applications. Without human intervention, AUVs can accomplish pre-programmed missions autonomously and deliver scientific data upon the users’ request. With these advantages, AUVs are considered as potential candidates in underwater iceberg sensing operations because they can operate close to icebergs to measure shapes and collect environmental data of the surrounding water. Sonar is usually used for underwater mapping applications. Since AUVs are typically quieter acoustically than manned surface vessels, a low noise to signal ratio can be achieved on sonars carried by AUVs. In this research, a technology of AUV-based underwater iceberg-profiling is evaluated. An iceberg-profiling simulator is constructed to analyse underwater ...