Improving Overall Resolution of Bathymetric Survey

Integrated Use of Multi-beam Echo Sounder and Towed Interferometric Sonar
Designing offshore engineering facilities requires large amounts of information. To acquire it, suites of engineering and geophysical surveys are run, which as a rule include such techniques of seabed and sub-bottom investigation as seismic profiling, acoustic, magnetic and bathymetric surveys. Obtaining accurate and detailed seabed bathymetry is extremely important because the quality of other surveys depends on the quality of the bathymetry. One of the most accurate and cost-effective ways to acquire high-resolution bathymetric data is the use of shipborne bathymetric systems such as multi-beam echo sounders (MBES) or interferometers. The drawback of this method is that the resolution of... (read more)
2012-04-19 03:50:13

Global Navigation Satellite Systems

Infrastructure Status and Developments
The concept of GNSS was first introduced by the European Space Agency (ESA), the European Commission (EC) and Eurocontrol in the early nineties. They defined requirements for a European GPS augmentation system, GNSS-1, and a full European satellite navigation system, GNSS-2, later together renamed EGNOS (European Geostationary Navigation Overlay System) and Galileo. Satellite navigation infrastructure status and developments are described here. Nowadays the term GNSS is used for the system of systems comprising GPS and GLONASS, with the later addition of Galileo. Satellite-based and ground-based augmentation systems (SBAS and GBAS) were introduced to augment GPS and GLONASS. Hydrographers were early... (read more)
2008-01-01 01:00:00

Proliferation SeaSonde Coastal Current-Mapping Radars

HF interference to improve coverage performance
For several decades while coastal HF current-mapping radars were under development, they radiated rarely and only for a few weeks at a time. Now 120 commercial SeaSonde units have been sold and seventy operate continuously in permanent locations. Their numbers are presently increasing at a rate of about 35 per year and they are used for a variety of maritime purposes. Although emitting only 50 watts of power they can map currents to 200km on the lower frequencies; these signals may also travel half way around the world, thanks to overhead reflecting ionospheric layers. After all, these same layers have... (read more)
2008-01-01 01:00:00

The Advancing Technology of AUVs

A View of the Autonomous Underwater Vehicle Market
Since the last autonomous underwater vehicle (AUV) review in 2016, the market has continued to grow. The biggest market for AUV systems remains the military. The world’s most advanced Navies own and operate low-logistic AUV systems for mine countermeasures (MCM) in very shallow waters. These systems can operate in confined areas where MCM vessels cannot. The same systems can also be used in search and recovery operations, hydrography and salvage. This market used to be dominated by a handful of AUV providers. However, the number of manufacturers is increasing. Defence primes are also investing in these technologies through internal development... (read more)
2018-12-04 09:23:07

The Dawn of the Digital Age

How digital visual systems lower costs and improve efficiency
Traditionally, Video Inspection surveys have been performed by ROV using analogue CCD colour cameras, with the video pictures recorded to S-VHS videotapes. This technology has served the industry well for more than twenty years but technology moves on: the world watches films on DVD, digital video movie trailers can be viewed over the internet and 3G mobile phones allow digital video clips to be viewed on the move. We are about to witness the same paradigm shift in the way we handle video information as occurred twelve years ago when CD audio replaced analogue vinyl recordings. Digital video systems offer... (read more)
2008-01-01 01:00:00

GNSS: Hydrographic Perspectives (Part 2)

Developments in GNSS, Possibilities for Hydrography
Hydro International Interviews Gary Chisholm, Trimble, Paul Cross, UCL, Owen Goodman, Fugro and Peter Grognard, Septentrio<br /> <br /> When Hydro International interviewed a group of experts on developments in GNSS as related to the hydrographic profession, they responded with such enthusiasm that that we were forced by lack of space to publish the interview in two parts. Part 1, which concentrated on the new opportunities offered the surveyor by horizontal and vertical accuracy and the need for differential solutions, appeared in our October issue. We now present the second part of the interview. Can you briefly explain the possibilities/advantages... (read more)
2008-01-01 01:00:00

Hydrography Will Be Big Contributor Filling the Digital Aquarium

Hydro International Interviews Mathias Jonas, Secretary-General of the International Hydrographic Organisation
The new secretary-general of the International Hydrographic Organisation (IHO), Mathias Jonas, has had a long career, now culminating in the highest rank within the world’s leading organisation for hydrography. He took office this autumn, succeeding Robert Ward, after he was elected in spring this year by the Member States. 'Hydro International' of course wants to know what Dr Jonas envisions for hydrography and the wider world it influences. Mathias Jonas starts off by sharing how he was already in touch with IMO and IHO in the nineties. ‘Arriving at the German maritime administration as a young professional mariner and as one... (read more)
2017-12-05 01:50:23

RTK River Bathymetry in Africa

From Syledis and Tide Gauge to RTK GPS Water-level Corrected Survey
This article describes the installation of a hardware and software system for bathymetric surveys in the maritime part of the Congo River. The ‘Regie des Voies Maritimes’ (RVM) is a Congolese public administration in charge of an operational navigation river lane in the Congo maritime reach. The Congo River has the second lar­gest flow in the world and is 4,700km long. RVM maintains the conditions for commercial navigation in the so-called ‘maritime area’, from the mouth to Matadi harbour, over a distance of 150km. The estuary is the only maritime border of the Democratic Republic of the Congo (DRC), with... (read more)
2007-11-27 12:00:00

‘Killer’ AUV Sonar System

In January 2001, C&C Technologies (C&C), a company based in Lafayette (Louisiana, USA), introduced the first commercially successful autonomous underwater vehicle (AUV) to the offshore industry. The AUV’s survey sensor suite, which included an EdgeTech side-scan sonar and sub-bottom profiler, performed well in the Gulf of Mexico and Brazilian offshore environments. However, West Africa proved more challenging – particularly for the sub-bottom profiler. C&C soon began searching for alternative technologies to provide better sub-bottom profiler penetration and higher resolution side-scan sonar imaging.Jim Chance, C&C Technologies (USA) Art Kleiner, EdgeTech (USA)<P> Narrator: Fast forward to the early autumn of 2004… C&C... (read more)
2008-04-02 12:00:00

Global Navigation Satellite Systems

Infrastructure Status and Developments
The concept of GNSS was first introduced by the European Space Agency (ESA), the European Commission (EC) and Eurocontrol in the early nineties. They defined requirements for a European GPS augmentation system, GNSS-1, and a full European satellite navigation system, GNSS-2, later together renamed EGNOS (European Geostationary Navigation Overlay System) and Galileo. Satellite navigation infrastructure status and developments are described here. Nowadays the term GNSS is used for the system of systems comprising GPS and GLONASS, with the later addition of Galileo. Satellite-based and ground-based augmentation systems (SBAS and GBAS) were introduced to augment GPS and GLONASS. Hydrographers were early... (read more)
2008-01-01 01:00:00
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