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Superdirectivity is a very attractive option in array aperture constrained applications due to its high directivity and good angular discrimination. However, it is hardly applied in practice because of its extreme sensitivity to small random array errors. In this paper, we propose an online calibration method for superdirective arrays with gain-phase errors. Unlike the currently well-known robust...
Computer vision has become the tool of two-dimensional image recognition and analysis, which mainly means extracting image features. But the problem of robustness and real-time property in complex scenarios makes feature extraction become a challenging task. Visual attention is an important psychological adjustment mechanism in the process of human visual information management, under the guidance...
This paper proposes a novel diving plane control scheme for autonomous underwater vehicle (AUV) based on tracking differentiator (TD) and cascade control (CC). The outer loop controller and inner loop controller adopt PI and P, respectively. Firstly, the mathematical model of AUV is established. The model consists of two parts: one is the depth model, and the other is the pitch model. Then, both controllers...
A nonlinear H∞ measurement feedback control algorithm is exploited for the control of Autonomous Underwater Vehicle in the Dive Plane. Here, the control algorithm is designed with the combination of a nonlinear H∞ state feedback law along with a nonlinear observer. The control problem of measurement feedback is formulated in terms of two Hamilton-Jacobi-Isaacs inequality by using the dissipative theory...
Ocean ambient noise mainly includes uncorrelated noise and correlated noise. The uncorrelated noise only affects the diagonal elements in the noise covariance matrix, and it can be suppressed by subtracting a value on the diagonal elements. Utilizing this feature, a high array-gain beamforming based on diagonal reducing is presented. Meanwhile, the robustness becomes poor. So, the array weight norm...
Matched-field processing (MFP) is an underwater acoustic signal processing method for passive source localization. It works by matching the measured field with the full-field solution for sound wave propagation in an oceanic waveguide. The popular Minimum Variance Distortionless Response (MV-DR) algorithm is known to be highly sensitive to environmental mismatch, which is one of the main obstacles...
Autonomous Underwater Vehicle (AUV) is a typical system which is characterized by nonlinearity, uncertainty of system parameters, and it is also affected by many external disturbances. Therefore, it is difficult to achieve the accurate AUV motion control, which includes depth control, heading control and so on. In order to improve the stability and robustness of depth control system of AUV, this paper...
Model-based passive source localization is known to be quite sensitive to model mismatch. In this paper, we present a new implementation based on matched-mode processing. Specifically we formulate mode filtering as a convex optimization problem, and ℓ1-regularized least squares is applied, which is robust in terms of the numerical implementation. Simulations with respective full-depth and partially-spanned...
In shallow water, loud surface ships can mask the weak signal of the underwater target. In this case, the localization of the target is difficult due to side-lobes of the interferers. By incorporating the prior knowledge of the uncertain parameters, we have proposed a robust localization method [Liu, et al. Robust source localization using predictable mode subspace in uncertain shallow ocean environment...
One of the main recent research trends of the Italian Interuniversity Research Center on Integrated Systems for Marine Environment (ISME) is the use of marine cooperative teams of autonomous robots within the fields of security, prevention and management of emergencies at sea. Such fields are of worldwide interest for obvious reasons, but they have recently gained relevance in the current historical...
Traditional matched-field processing (MFP) techniques for underwater source localization such as Bartlett and Minimum variance Distortionless Response (MVDR) suffer from low resolution and sensitivity to environment/system mismatch respectively. This paper considers the problem of underwater source location estimation using a combination of sparsity imposed reconstruction method with newly proposed...
Formation control of autonomous underwater vehicle (AUV) team based on adaptive high order sliding mode is studied in the paper. First, the kinematics control law is given based on the guidance function. Then, as sliding mode controller (SMC) is widely used in motion control of underwater vehicles, a robust and continuous controller using high order sliding mode method is proposed to achieve leader-follower...
We describe the implementation of a protocol stack for multi-modal underwater networks, where multiple physical layer technologies are available to each node. This condition implies greater flexibility, by allowing each node to decide how to serve specific transmissions and traffic classes depending on system, quality-of-service, and application-specific policies implemented in a controller. In this...
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