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Other Requirements for Estbalishing a Seafloor Observatory Network
Pages 79-94

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From page 79...
... technology are also essential for the success of an observatory network. This chapter outlines currently available technology and future developments needed to establish both moored and cabled observatories.
From page 80...
... , many critical water-column measurements are similar to those for coastal regions, but they also include sensors for pressure and horizontal electric field, inverted echo sounders, hydrophores, and bioacoustic profilers. In the case of benthic experiments (see Chapter 2, sections titled "Fluids and Life in the Oceanic Crust" and Although gene chip technology currently exists, it will need significant refinement to be suitable for wide use in oceanographic research.
From page 81...
... Thus, to maximize the potential for biological and chemical research at a seafloor observatory network, sensor development needs to be a high priority. Sensors that are commonly used only in laboratory settings will require substantial development before these instruments can make accurate measurements while being left unattended for long periods of time.
From page 82...
... POWER GENERATION TECHNOLOGY CURRENTLY AVAILABLE TECHNOLOGY As described previously, the power requirements for a moored-buoy observatory span a range of a few lOs of watts up to several kW. A 50 W output can be achieved with solar or wind power generation, or both, coupled to rechargeable batteries.
From page 83...
... The satellite communications industry is currently undergoing rapid change as part of the worldwide explosion in wireless communication. The communi2 Corona (discharge)
From page 84...
... Such a system could be mounted on either a disk or spar buoy, but for full-time operation of the satellite telemetry system, the power requirements would necessitate the use of a diesel generator. In addition, tariffs for global coverage are high, making continuous, real-time data telemetry prohibitively expensive.
From page 85...
... FUTURE DEVELOPMENTS NEEDED The satellite communications industry is currently undergoing rapid change, and the systems that will be available in 3 or 5 years are difficult to predict. Market forces outside the academic community will drive the pace of technical development in this industry.
From page 86...
... are a class of relocatable observatory in which mobile platforms supported by a communications network provide a nested observational capability. This program has developed a significant fraction of the technologies that in the future could support the inclusion of Autonomous Underwater Vehicles (AUVs)
From page 87...
... and power consumption by onboard computers and sensors, which can range up to hundreds of watts depending on the payload. The docking capability thus provides the means to extend the AUV presence in the ocean, while at the same time retaining the ability to retrieve data and exert control over AUV missions.
From page 88...
... Seafloor observatories will place significant navigation demands on AUVs, but they also could provide an unparalleled navigation infrastructure to support AUV operations. A common navigation technique used in the deep ocean is long-baseline acoustic navigation.
From page 89...
... One problem with this technique is that the AUV must remain sufficiently close to the seafloor for the Doppler velocity log to have bottom lock a few hundred meters for current systems on the small vehicles discussed here. A correlation velocity log can provide a similar function to the Doppler velocity log at distances much greater from the bottom; however, such systems are not readily available commercially.
From page 90...
... Inclusion of one or more AUVs in an observatory can substantially impact the design of the observatory. Not only do AUVs have significant power needs, but the data produced by AUVs can impose substantial demands on observatories relying on satellite communications for data transfer.
From page 91...
... Marine survey companies are driven by the desire to gain a competitive edge in acquiring oil industry contracts, AUV manufacturing companies are motivated by the sales prospects, and sensor and subsystem supplier companies also want a share of the new market. While this has seeded a wide range of technology development, it is important to note that the economic drivers for offshore operations are very different from those of a seafloor observatory network as discussed here.
From page 92...
... Higherresolution seafloor maps are obtained by placing mapping sonar systems on platforms flying relatively close to the seafloor. While towed vehicles are routinely used for producing these surveys, the highest quality maps are produced from vehicles capable of flying precision tracks, such as ROVs and AUVs.
From page 93...
... Standard methods of mounting instrumentation and connector protocols can make instrument replacement routine using a variety of ROVs. There is currently an American Petroleum Institute standard for ROV intervention that should be reviewed for applicability to seafloor observatories.
From page 94...
... ROVs are becoming mature enough that, with proper design of observatory hardware, there should be little risk in using ROVs to service observatory systems. The oceanographic community has already demonstrated the use of ROVs in various aspects of observatory work, such as the Woods Hole Oceanographic Institution (WHOI)


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