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How can teams of artificial agents localize and position themselves in GPS-denied environments? How can each agent determine its position from pairwise ranges, own velocity, and limited interaction with neighbors? This paper addresses this problem from an optimization point of view: we directly optimize the nonconvex maximum-likelihood estimator in the presence of range measurements contaminated with...
An automated docking system is presented for an autonomous underwater vehicle utilizing light-field imaging for navigation guidance. This article focuses on three major components of the system: docking position acquisition with light-field imaging, optimal docking trajectory planning, and nonlinear trajectory tracking control. With the camera sensor data of each photographic exposure, depth maps...
In order to accurately control the portable AUV, a dynamic modeling method based on computational fluid dynamics (CFD) and a improved Generalized Predictive Control (GPC) method were presented. First, the whole modeling process was described from two aspects: dynamic model derivation and model parameter identification. Second, the validity of the model and modeling method were tested by comparing...
In this paper, we present an approach for producing side scan sonar image mosaicking under a robust SLAM scheme. A Pose Graph based SLAM algorithm is used to perform a correction over the sensor trajectory for enabling image registration, using observation constraints extracted from the images. However, due to the operational context, the available odometry data carries a high degree of uncertainty...
This paper studies an optimal autonomous underwater vehicule (AUV) path planning method for both reducing average delay before pollutants detection in underwater mining, oil or gas fields and reducing AUV occupancy time. The proposed technique, based on the bayesian search theory framework and multi-objective optimization, extracts optimal boustrophedon paths for leak detection in complex environment...
Closest Point of Approach (CPA) calculations are fundamental calculations for determining the utility and safety of a candidate maneuver of a marine vessel with respect to another vessel, i.e., contact. In certain kinds of path planning, a set of CPA calculations is made for thousands of candidate maneuvers, perhaps several times per second. Furthermore, with multiple contacts, multiple sets need...
The possibility of increasing flight duration, particularly for small and micro fixed-wing Unmanned Aerial Systems (UAS), is typically hindered by the payload and size of the platform. In maritime missions, Atmospheric Energy Harvesting (AEH) near the Marine Atmospheric Boundary Layer (MABL), is a low-cost solution, with very promising results, that may allow drastic increases in flight duration by...
This paper focuses on the inspection for sloping dam wall by a remotely operated vehicle (ROV). First, a dedicated ROV for dam inspection is described. Second, a fixed-distance tracking control strategy is proposed to guarantee the fixed camera-to-subject distance in sloping dam inspection, which is instrumental in sonar image fusion for the large-scale dam wall with a certain inclination. In addition,...
This paper addresses the heterogeneous data registration problem, which is one of the key features for any scene reconstruction and representation, especially for the underwater environment. In this study, we propose a registration method built around a 2D-to-3D feature-based approach that registers high-resolution side-scan sonar images with bathymetric data (topographic 3D point cloud) obtained...
During an oil spill, an accurate assessment of the trajectory of oil is important for a quick and effective remediation response. In the remote Arctic, oil fate and transport models are critical; especially during winter months when darkness and ice presence hamper visual detection of oil. A set of equations to describe the transport of oil in ice-covered waters and an environmental database were...
A new algorithm for a compact mobile four-hydrophone array “RAPID Array” that displays the dolphin's real-time direction data on a graphical user interface (GUI) was proposed to accurately estimate the number of Ganges river dolphins from acoustic data recorded during the census. By considering the trajectory changes in dolphins' click data depending on the time (t) and azimuth (θ) in the coordinate...
The underwater vehicle-manipulator system (UVMS) generally has more degrees of freedom than those required to perform a given task. Because of these extra of degrees of freedom, UVMS has infinite combinations of joint velocities. In this paper, in order to generate the joint angle trajectories of the manipulator, a redundancy resolution is performed to minimize the distance between the position of...
Focusing on detection technology for autonomous underwater detection device which found marine target which radiated noise signal submerged in background noise, chaotic detector based on Duffing oscillator is researched. In this paper, the Duffing oscillator and chaotic detector based on Duffing oscillator are described. Through numerical simulation and theoretical analysis, it is proved that the...
A novel anomaly detection algorithm is proposed to detect anomalies in trajectory data of autonomous underwater vehicles (AUVs). Compared to existing work, the proposed algorithm estimates vehicle speed (i.e., through-water speed) from trajectory data and detect abnormal motion with estimated vehicle speed by a threshold technique. The influence of ocean flow on AUVs is significant and must disturb...
Harbor protection systems detect unauthorized harbor entry by intruders such as divers, mini-submarines, and small boats. These systems typically consists of a sensor network array to detect harbor entry, a messaging system to communicate status, and a response system to react to any perceived threat. This system falls under the general problem of detecting a moving target through an array of stationary...
A software tool has been developed to simulate the entanglement of leatherback sea turtles (Dermochelys coriacea) in fishing and aquaculture gear. Entanglements are well documented and are increasing in frequency due to greater fishing effort and with the use of synthetic materials in marine applications. However relatively little is known about how entanglements occur and how they might be prevented...
Underwater mobile sensor node localization is a key enabling technology for several subsea missions. A novel scalable underwater localization scheme, called Best Suitable Localization Algorithm (BLSA), is proposed to dynamically fuse multiple position estimates of sensor nodes using fuzzy logic, aiming at improving localization accuracy and availability along the whole trajectory in missions. Numerical...
Reading is one of the main paths to acquire knowledge, either done traditionally on paper media or practiced on electronic devices. Efficiency varies when different reading patterns are involved. It is the objective of this research to classify reading patterns from fixation data using machine learning techniques in an attempt to understand and evaluate the reading and learning process. In our experiment,...
With the growth of crowd phenomena in the real world, crowd scene understanding is becoming an important task in anomaly detection and public security. Visual ambiguities and occlusions, high density, low mobility and scene semantics, however, make this problem a great challenge. In this paper, we propose an end-to-end deep architecture, Convolutional DLSTM (ConvDLSTM), for crowd scene understanding...
Self-organized flocking behavior is often seen in nature in the form of flocks of sheep, herds of cow, fish schools, and swarms of insects. The shepherding problem is concerned with the control of such a group by a small number of guides and has useful applications. The present paper focuses on two unrelated control methods and the similarities between them. Based on these two control methods, we...
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