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The intrinsic length- and time-scales of variability in the ocean are too small and short, respectively, for it to be possible to observe the ocean in any truly comprehensive sense. This paper describes the approach being taken by the Bluelink project to combine the strengths of various in-situ observing arrays, various types of satellite data, and various types of ocean models, to produce our closest...
A novel time series client is described along with the supporting infrastructure required. The need for such a client comes from the lack of uptake of time series data generated by sensor network projects such as the Great Barrier Reef Ocean Observing System project. Central to the client is the need for a Registry of available data sets that can be used by the client to discover what data is available...
The Bekker Theory of Locomotion has long been the leading applied theory when it comes to calculating and predicting soil-tyre interaction for terrestrial wheeled and tracked vehicles. Whilst the theory is applicable for terrestrial systems, there is no evidence to suggest it also applies under water. Furthermore, the complications of measuring the required soil parameters in marine substratum makes...
A reference frequency stabilised DFB fibre laser is used to reduce the interferometric detection system noise within optical fibre laser sensor (FLS) SONAR arrays by up to 20-30 dB.
The anchor mooring profile monitoring buoy can obtain the long-term, fixed-point and high vertical resolution vertical profile monitoring data of the specific sea area. To guarantee the communication reliability and the safety of the profiler, an underwater non-contact wireless communication system based on electromagnetic induction coupling is presented in this paper. This system can realize the...
The Norwegian company CodarNor A/S, with funding from the Norwegian Clean Seas Association for Operating Companies (NOFO) and from Innovation Norway through an industrial research and development contract, is developing a self-contained rapid deployment HF radar which can be deployed by helicopter or other means to remote and rugged locations along the Norwegian coast and operate autonomously, communicating...
A preliminary resource assessment is made for three forms of Ocean Renewable Energy in Australia. The wave energy incident on the south coast of Australia constitutes Australia's principal resource of ocean renewable energy. Integrating the total energy flux crossing the 25m isobath between Geraldton WA and the southern tip of Tasmania, we estimate the total size of this resource to be 1329TWh/yr...
An ocean magnetometer detecting near seafloor can reveal more information for geologists and geophysics. A new design of Ocean Bottom Magnetometer was proposed in the paper. The sensor error compensation and circuit design was given in detail. The data logger was elaborately designed for data acquisition, data storage and data readout. The first sea trial for this system was described and a data analysis...
A calibration problem for log sensor of UUV is established and the problem can be divided into two separate parts: misalignment angle and scale factor of log sensor. Instead of using the conventional least square algorithm, a fine calibration approach based on M-estimate is used to suppress the effect of non-white noise. The adaptive factor relation to calibration precision is brought forward which...
Alamouti space-time coding is investigated in conjunction with OFDM modulation for high-rate underwater acoustic communications over time varying channels. The scheme's diversity gain is exploited using a low-complexity adaptive multichannel receiver. Performance is demonstrated using experimental data transmitted in a 10 kHz bandwidth over a 1 km shallow water channel south of the Martha's Vineyard...
Glider data collected along a sawtooth section crossing Storm Bay in south east Tasmania, show high spatial and temporal variability in temperature, salinity, fluorescence and dissolved oxygen . A Slocum glider was used to repeat 6 transects from the mouth of the Derwent Estuary to the continental shelf in autumn 2009. The instrument was deployed for 25 days, travelled 974 km and dived to within 10...
Underwater acoustic communication systems usually operate at frequencies below 40 kHz, which have low absorption rates that in turn enable long link distances. These links suffer from channel effects including multi-path, fading and doppler. Cellular and multi-hop strategies have been proposed that would use shorter path lengths, so would tolerate much higher absorption rates, and hence could work...
An Autonomous Underwater Vehicle (AUV) equipped with rare-earth (Sm-Co) magnets was used to sample suspended particles during its transects of the Derwent estuary in Tasmania. Mineral characterization was then performed in the laboratory using 57Fe Mössbauer spectroscopy (MB) and X-ray diffractometry (XRD). Results indicate the sources of the suspended particles to be both natural and industrial.
The scattering of high frequency electromagnetic waves from the ocean surface is considered for the case of the radiation source being a vertical pulsed antenna mounted on a floating platform while the receiving antenna is fixed on the shore. This represents a small extension to an earlier analysis by Walsh in which both the transmitting (TX) and receiving (RX) antennas were co-located on a floating...
We are developing a magnetic tensor gradiometer for underwater unexploded ordnance (UXO) detection using high-Tc SQUID planar gradiometers. The system will use signals from six planar gradiometers, located on the faces of a hexagonal pyramid, to calculate the full gradient tensor. It will be towed underwater and will need to deal with noise caused by ocean waves, sensor motion and the measurement...
The present paper deals with new approaches concerning pressure tolerant submerged technology. Different designs of pressure tolerant systems, which are characterized by the absence of pressure hulls, are discussed. Advantages and disadvantages of this novel technology are demonstrated. The overall pressure tolerant test platform DNS Pegel is introduced along with the main vehicle components and subsystems...
In this study, we show the results of applying two automated data processing methods to a set of videos previously used to manually monitor the period and the phase of activity rhythms of the deep-water Norway lobster, Nephrops norvegicus, a species of elevated commercial fishery value. Present data are consistent with published findings on Nephrops norvegicus activity rhythms both in the laboratory...
This paper reported modeling and theoretical characterization of circular piezoelectric micromachined ultrasonic transducer (pMUT) for immersion applications. Zinc oxide (ZnO) was employed as piezo active material and nickel aluminum bronze alloy UNS C63000 (CuAl10Ni5Fe4) also known as “sea bronze”, was introduced as electrodes. First, virtual fabrication process was carried out within software environment...
Seabed topographic match is a very important work for fulfilling the blend of different-source sounding data and the underwater positioning and navigation. Contour match is a classic method for the seabed topographic match. However, the traditional contour match algorithm will lead to obvious time consuming and mismatch, especially in the longer contour match. Thus, a kind of contour match algorithm...
The stability of the conductivity sensor is a key consideration for the long-term deployments of the instruments on mooring and observatories, because the conductivity measurement is very sensitive to the accumulation of organisms (bio-fouling) inside the sensor. We tested the performance of a conductivity sensor, the ALEC CTW, which features a simple but effective wiper mechanism to keep the sensing...
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