The main difference
In the space of the device is oriented with built-in sensors, they determine the distance to the ground and the depth of immersion, which can reach up to 1,000 meters. The structure of "Gavia" is hydroacoustic modem to accurately determine the location of the device and its location.
The device can be used in research, such as oceanography, geodesy and archeology. And military purposes for the survey and exploration of the underwater environment.
During the construction of hydraulic structures on large water areas, especially in the difficult climate and hydro-morphological conditions, performed a wide range of topographical, hydrological surveys and inspections at each stage of the design.
Getting information on terrain, geology, physical and geological phenomena, the strength of soils, the composition and nature of the groundwater can make a proper assessment of the conditions of building structures and provide the basis for the design.
This process is accompanied by a large complex of works involving specialized staff and equipment, however, is one and the most modern and the most promising application may be considered for this purpose autonomous unmanned underwater vehicles.
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Autonomous unmanned underwater vehicles (AUV) have the potential to change the existing principles of underwater work and successfully demonstrate its capabilities as effective tools for a wide range of applications. Using autonomous means reduces the cost of operations and increases the efficiency.
AUV successfully applied in the fields of hydrology, geology of the seabed. The class of problems using AUV in marine exploration is searching for oil, gas and gas hydrates. AUV can be used successfully in harsh environments for under-ice operations, cable installation, and inspection of underwater structures. With a number of advantages over other types of subsea hardware, modern underwater vehicles have the ability to make precise measurements in combination with high precision navigation bindings allow real-time monitoring and documentation of information for the underwater situation. Stand-alone devices are programmable adaptive systems that have several advantages over remote-controlled (tethered) systems. The main advantages are the absence of the functional dependence of the AUV from the carrier providing the vessel, a large area coverage and speed of inspection, data collection, in close proximity to the object of study. Access to the goals and mission accomplishment AUV carries out with the program drawn up by the operator. The optimal parameters of the movement, the sequence of the drives, etc., in the course of operations, are chosen according to the current environmental conditions and parameters of the internal state of the AUV.
Currently, the following areas should be made use of AUV:
— Surveying the seabed;
— Examination and inspection of underwater structures and gas installations
oil, gas and oil pipelines, cable ducts;
— Subglacial research.
Also AUV is used to perform the following tasks:
— Search operations;
— Operative and long-term monitoring of the aquatic environment;
— Measurement of hydro-biological, hydro-chemical and hydro-
environmental parameters, followed by mapping data;
— Studies of seafloor topography and the biosphere in shallow water, deep water, in the under-ice conditions.
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AUV GAVIA — ice conditions
Currently, there are about 400 projects of autonomous underwater unmanned vehicles. A number of major manufacturers, such as: Kongsberg Maritime AS, Hydroid Inc., Teledyne Gavia, ECA SA, Saab Underwater system AB, Bluefin Robotics, OceanServer Technology, Inc., ATLAS ELEKTRONIK GmbH manufactured devices in series.
In 2011, for the first time in Russia appeared autonomous unmanned underwater vehicle of Teledyne Gavia — one of the world’s largest manufacturers of AUV. Gavia is widely used worldwide in the oil and gas complex of works, has successfully established itself in the course of underwater and under-ice research.
To understand the principle of the AUV consider the structure of the device as an example AUV «GAVIA».
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Modularity AUV «GAVIA»
Underwater vehicle has a modular construction of the system, thereby allowing the configuration and adjustment in accordance with the requirements for performing the work.
Basic systems that are part of the AUV: PA management system, power supply system, propulsion and steering system, navigation system, information-measuring system, data transmission system, a complex vision.
The control module and communication is the "core" system, is a system management software includes a main computer system, control electronics, software, control device, installed on the PC. The module also includes a standard communication equipment: for communications on the surface — a wireless local area network (Wi-Fi), a wired local area network (Ethernet), the Iridium satellite communications, data underwater — sonar communication system (SSIA) implemented by acoustic modem pair. Information-measuring system implemented in this module contains the basic parameters of the medium gauges — temperature, pressure (depth), conductivity, speed of sound, etc.
The system power supply unit is implemented in the battery module, consisting of lithium-ion batteries, chargers, power controls. Autonomy of the PA depends on the type of power system. With a minimum amount involved during the passage of the mission equipment, with capacity of one battery module of 40 Ah, AUV «GAVIA» can go the distance of about 45 km at a speed of stroke 1.53 m / s.
Propulsion and steering system is located in the propulsion module. As the propulsion system uses an electric motor propulsion. Course management, roll, pitch, carried out by independent steering systems.
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Inspection of structures jackup offshore drilling rigs
Vision system, represented by the apparatus in question consists of a side-scan sonar (SSS), cameras, sonar lookout for avoiding collisions. Thus, the system receives data from the survey and survey the bottom, and information necessary for control. The complex of the system may include a circular sonar survey, multibeam sonar, interferometric HBO, profilers.
Navigation system consists of a flatbed, sonar, satellite navigation systems. The airborne system is complexed Doppler-inertial reference system consisting of a high-precision strapdown inertial navigation system (INS). ANN adjusted data Doppler log, which measures the velocity of the vehicle over the ground or through the water. Using data on the height above the ground, provided the Doppler lag allows the AUV to keep equidistance from the bottom, you need to take a picture of HBO or photographic shoot. To get the position on the surface is used receiver DGPS. Sonar navigation system provides a definition of the position of the AUV with installed onboard tracking beacon relatively transceiver or antenna mounted on the bottom of the lighthouse.
The modular architecture allows integration of the submersible in new modules developed as equipment manufacturers and end users. The base configuration provides a platform for various applications of AUV, the specific requirements are implemented in the form of additional modules.
The user interface is the primary tool for managing AUV. With the software, it becomes possible to carry out:
— Mission planning — development of user-mission plan for AUV;
— operation and management — you monitor the work of the AUV and has the ability to intervene in his work;
— view of the mission and analysis — Data collection, processing and presentation, the user works with the data colle
cted during the mission AUV.
Recently conducted by the company of "Tethys Pro" test Gavia in Gelendzhik shown success using AUV when working at depths of up to 1,000 m the results of developed mission, during which he analyzed the work and management of Gavia, were found the remains of a sunken airplane.
Detection of the aircraft during the test in Gelendzhik
In the future, further development of autonomous vehicles in the service area of hydraulic structures, offshore platforms, subsea pipeline routes and construction sites for underwater objects, the difference between the AUV and ROV will decrease. AUV is planned to equip workers actuators used as a means of moving goods, the slave machine while doing some work ROV. The main requirements for the AUV will be: working depth up to 3,000 m, greater autonomy associated with a higher capacity battery power supply system, the accuracy of position navigation system, security and speed of tripping operations for different weather conditions.
Thus, the range of tasks assigned to autonomous unmanned underwater vehicles, will continue to expand.