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Uniform linear array is a kind of very important underwater acoustic detection equipment, it mainly divided into two kinds: rigid array and flexible array. Rigid array is the best means to obtain ideal detection result, but the layout and recovery is difficult. Flexible array is used more popular for its easy to operation, but the array shape is difficult to maintain. Shape distortion of the flexible...
After the nuclear accident in Fukushima, Japan, marine radioactivity monitoring has received more and more international attention. According to China's needs for marine radioactivity monitoring in the North Pacific Region, this paper introduces the design of a special system for deep-sea environmental radioactivity (DSER) online monitoring in the γ-ray energy spectrum. The system uses an improved...
Based on the scattering of dual-frequency transmission pulses and frequency-domain data processing, Philip R. Atkins has proposed a new method for standard-target phase calibration of sonar systems. This approach reduces the impact of unknown range and sound speed parameters upon phase calibration accuracy. However, since solutions to the phase of scattering of targets underwater are not offered,...
Vision system is the important equipment for Unmanned Surface Vehicle (USV) to find obstacles and monitor surrounding environment. There are popular calibration methods for vision system used indoor and outdoor on land. However, the USV has to be transported, hoisted and deployed, and calibrated parameters may be changed in the process. Consequently, it is desired to calibrate the vision system in...
Conductivity, temperature and depth (CTD) are the most essential physical properties of sea water. CTD instrument is one of the most efficient approaches for collecting the accurate ocean information. However, traditional CTD instruments are not best suited for applications that require high resolution data by a large number of sensors because of their large size and high cost. This paper describes...
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...
Acoustic systems are used widely to provide quantitative estimates of biomass for fisheries and ecosystem assessments. Traditionally, these systems are attached to surface vessels, but increasingly they are being fitted to remote operated vehicles, autonomous vehicles and towed platforms. These platforms allow the acoustic transducer to get closer to targets, and provide increased resolution and,...
Underwater multispectral images are disturbed by water absorption, dispersion and scattering etc. Previous conducts have been made to model the underwater multispectral imaging process and to restore underwater multispectral images based on water attenuation estimation. In this paper, optimization is done to determine the least number of distances (or images) which is adequate for accurate compensation...
An in-situ calibration method to accurately and precisely constrain the pH of deep sea environments is reported. This method involves the pre-evaluation of the Ir-IrOx|Ag-AgCl electrode in the laboratory, followed by the in situ calibration using pH buffers at the ocean bottom. The standard potential E° and in situ slope are derived by the calibration process. This calibration method was implemented...
High-resolution bathymetric sidescan sonar system (HRBSSS) is a kind of acoustic detection equipment for the micro-topography of the seafloor. This paper briefly introduces the working principle, the main error sources, the data processing and error calibration method of HRBSSS at first. On this basis, a sounding data quality assessment method including one part for the sonar and the other for the...
Offshore oil and gas industry has been active in the North Sea for more than half a century, contributing to the economy and facilitating a low oil import rate in the producing countries. The peak production was reached in the early 2000s, and since then the oil production has been decreasing while the water cut has been increasing rapidly. The water dominates some of the wells and a water cut of...
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