Side scan sonar grid map for Unmanned Underwater Vehicle navigation

Underwater operating platforms face difficulties regarding power supply and communications. To overcome these difficulties, this study proposes a hybrid surface and underwater vehicle (HSUV) and presents the development of the platform, control algorithms, and results of field tests. The HSUV is capable of supplying reliable power to the unmanned underwater vehicle (UUV) and obtaining data in real time by using a tether cable between the UUV and the unmanned surface vehicle (USV). The HSUV uses global positioning system (GPS) and ultra-short base line sensors to determine the relative location of the UUV. Way point (WP) and dynamic positioning (DP) algorithms were developed to enable the HSUV to perform unmanned exploration. After reaching the target point using the WP algorithm, the DP algorithm enables USV to maintain position while withstanding environmental disturbances. To ensure the navigation performance at sea, performance tests of GPS, attitude/heading reference system, and side scan sonar were conducted. Based on these results, manual operation, WP, and DP tests were conducted at sea. WP and DP test results and side scan sonar images during the sea trials are presented.

This manuscript considers a team of Unmanned Underwater Vehicles (UUVs) such that each UUV measures the arrival time of sound signal generated from the evader. The purpose of the UUV team is to intercept the underwater evader based on the arrival time measurements. We present both the motion control for the UUV team and the algorithm to estimate the evader position in real time. In this manuscript, the UUVs chase the evader while preserving a 3D spherical formation. Moreover, the formation size is controlled adaptively to assure the convergence of the evader estimation. Our tracking approach doesn't require global localization of every UUV. The proposed approach only requires that the central UUV measures the relative position of any other UUV using proximity sensors. Simulations are utilized to verify the effectiveness of the proposed method.

In this chapter, the receding horizon Kalman filter is applied to underwater navigation systems. The ocean covers about two-thirds of the earth and has a great effect on human beings. However, the ocean is overlooked while we focus our attention on land and atmospheric issues; we have not been able to explore the full depths of the ocean, its abundant livings and non-living resources. For example, only recently we have discovered, by using manned submersibles, that a large amount of methane and carbon dioxide comes from the seafloor and extraordinary groups of organisms live in hydrothermal vent areas. However, a number of complex issues due to the unstructured and hazardous undersea environment make it difficult to survey in the ocean even though today’s technologies have allowed humans to land on the moon and robots to travel to Mars. Unmanned underwater vehicles (UUVs) can help us better understand marine and other environmental issues, protect the ocean resources of the earth from pollution, and efficiently utilize them for human welfare. The UUV is a platform for a variety of sensors: acoustic, magnetic, gravimetric and chemical ones. Most commercial UUVs are tethered and remotely operated, referred to as remotely operated vehicles (ROVs). Extensive use of manned submersibles and ROVs are currently limited to a few applications because of very high operational costs, operator fatigue and safety issues. The demand for advanced underwater vehicle technologies is growing and will eventually lead to fully autonomous and reliable underwater vehicles. Autonomous underwater vehicles (AUVs) were initially developed to perform missions that were not easy for ROVs and manned underwater vehicles. Since the autonomy allows AUVs to be used for risky missions such as a mine countermeasure (MCM) or under-ice operations, AUVs are replacing ROVs towed vehicles as well as manned underwater vehicles (Whitcomb, 2000). For detailed ocean surveys, an AUV acts as a more stable platform for precision sensors than ROVs or towed vehicles because an AUV is not subject to physical disturbances transmitted along the cable to the surface vessel. This absence of physical attachment also allows AUVs to measure ocean characteristics at specific depths and perform bottom-following missions as owing to its autonomy. In short, An AUV provides marine researchers with a new form of access to deeper ocean. For an AUV to successfully complete a typical survey mission, it must follow a path specified by the operator as closely as possible and arrive at a precise location for collecting data. When an AUV is not able to follow the path accurately during the mission, critical Source: Kalman Filter, Book edited by: Vedran Kordic, ISBN 978-953-307-094-0, pp. 390, May 2010, INTECH, Croatia, downloaded from SCIYO.COM

Unmanned underwater vehicles (ROV/AUV) are autonomous or remotely controlled robotic systems that can move underwater at any desired angle. Unmanned underwater vehicles; It is used in areas such as underwater image taking, ship maintenance and repair, coast guard, examination of shipwrecks, underwater cleaning. In this study, the software design of the balance control of underwater vehicles was carried out using the PID algorithm. For the PID algorithm trial, a two-motor test setup with an IMU sensor was prepared. After the data from the sensor were recorded in MATLAB using the Kalman filter, the transfer function of the system was obtained using the System Identification Toolbox. With the obtained transfer function, the stable operation of the system is provided in real time. As a result of the research on software and hardware integration, microcontroller ARM-based STM32 was used.

Beam-Based Tether Dynamics and Simulations using Finite Element Model

Many modern imaging sensors must obtain multiple looks or “views” of a target at different orientations to automatically classify it with high confidence. Therefore, when tasked with classifying many targets, a mobile sensor may need to travel a long distance to change its position and orientation relative to every target, resulting in costly and time-consuming operations. This article presents a novel and general approach, referred to as informative multiview planning (IMVP) that simultaneously determines the most informative sequence of views and the shortest path between them. The approach is demonstrated on an underwater multitarget classification problem in which a sidescan sonar installed on an unmanned underwater vehicle must classify all targets in minimum time. Simulation and experimental results show that IMVP can achieve the same, or better, classification performance in half the time of existing multiview path planning methods. Also, by determining the most informative views and the shortest path between them, IMVP significantly improves classification efficiency, classification confidence level, as well as performance robustness.

The paper addresses the development of an artificial intelligence algorithm implemented for maximum power point tracking control of a unmanned underwater vehicle. It is shown that this algorithm tracks the optimum operation point and provides fast response even in the presence of faults. The strategy implements the tracking algorithm by using real—time measurements, while providing maximum power to the grid without using online data training. The solution is simulated in the Matlab and Simulink to verify the effectiveness of the proposed approach when fault–free and faulty conditions are considered. The simulation results highlight efficient, intrinsic and passive fault tolerant performances of the algorithm for general unmanned underwater vehicles with low inertia.KeywordsFault diagnosisNeural networksActuator faultHigh–fidelity simulationAutonomous underwater vehicle

In this study, real-time online body detection under water was conducted using an unmanned underwater observation tool. According to the underwater position of the vehicle, data from the vehicle camera is provided to identify different body parts of a body in a real-time video stream. Here we present an approach for underwater human body detection based on the use of highly educated classifiers. The algorithm's performance in real time video shooting of the car is optimized to reduce the false positive rate by aiming to identify a corpse part of each picture frame. According to the results obtained, it was ensured that the corpse parts were successfully detected under changing conditions with incorrect positive perception. Algorithms were developed using the Pyhton program.

The growing need for underwater observation and subsea monitoring systems have stimulated considerable interest in advancing the technologies of underwater wireless communication. This communication technology is expected to play an important role in investigating climate change, monitoring biogeochemical, ecological and biological change in the ocean and lake environments, which helps to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), ships, buoys, and submarines. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environmental factors. To overcome this problem, Optical wireless communication has been proposed as the best alternative to meet this challenge. In this paper, optical communication using LEDs is presented as an advancement over acoustic modems for scenarios where high speed but only limited access applications is required and also lower power, less complex communication systems are desired. On the basis of Beer-Lambert's law it was deduced that blue light (470 nm) of the visible spectrum suffered the least attenuation underwater. We attempt to design an ultra-bright blue LED based transmitter system by optimizing it with opto-coupler and an enhanced photodiode based receiver system are developed with the goal of transmitting data at higher rates by using On-Off keying technology. The objective was to transmit the data at a rate of at least 1 Mbps over a distance of 30 meters. Here, real time data could be sent or received with the help of simulation results.

This work presents an improvement of an inertial-Doppler underwater navigation system for unmanned underwater vehicles (UUV) using a complementary range sonar. The inertial-Doppler navigation system is generally based on an inertial measurement unit (IMU) and a Doppler velocity log (DVL) accompanying a magnetic compass and a depth sensor. Although conventional navigation systems update bias errors of the inertial sensors, scale effects of the DVL, the estimated position slowly drifts as time passes. This paper proposes a measurement model with additional range sonar to improve the performance of the IMU-DVL navigation system for underwater vehicles. The proposed navigation model based on inertial navigation systems includes the scale effects, the bias errors of the DVL, and the error model of the range sonar, where the order of the system states is 21. An extended Kalman filter was adopted to propagate the error covariance, updated the measurement errors and correct the state equation when the external measurements are available. Simulation conducted with the 6-d.o.f. equations of motion of an AUV in lawn-mowing survey mode illustrates the effectiveness of the IMU-DVL navigation system assisted by the additional range measurement.

In Alzheimer disease, amyloid beta, a 39-43-residue peptide produced by cleavage from a large amyloid precursor protein, undergoes conformational change to form amyloid fibrils and deposits as senile amyloid plaques in the extracellular cerebral cortices of the brain. However, the mechanism of how the intrinsically linear amyloid fibrils form spherical senile plaques is unknown. With total internal reflection fluorescence microscopy combined with the use of thioflavin T, an amyloid-specific fluorescence dye, we succeeded in observing the formation of the senile plaque-like spherulitic structures with diameters of around 15 microm on the chemically modified quartz surface. Real-time observation at a single fibrillar level revealed that, in the absence of tight contact with the surface, the cooperative and radial growth of amyloid fibrils from the core leads to a huge spherulitic structure. The results suggest the underlying physicochemical mechanism of senile plaque formation, essential for obtaining insight into prevention of Alzheimer disease.

Side-scan sonar is very important in marine survey such as seafloor exploration, topography, underwater pipeline investigation and so on. SSS-echograms classification and mosaicking are essential during those tasks. Initial side-scan sonar images have uneven brightness distribution. Mosaicking proved difficult due to grayscale gradients on sonar echograms. Brightness equalizing is necessary prior to processing of SSS-echograms. This article discusses methods for brightness equalizing of the echogram images from side-scan sonar in order to identify local inhomogeneities of the seafloor. It provides results of comparative experiments using different approaches to solve this problem. The paper also evaluates the possibility of using these methods on board autonomous underwater robots in real time.

The lack of information on what constitutes suitable habitat for native freshwater mussels can limit restoration efforts. While many species reside in silt–sand–gravel substrates, species such as the Spectaclecase ( Cumberlandia monodonta ) and Salamander ( Simpsonaias ambigua ) mussels are thought to be associated with rock structures (e.g., wing dams and rock outcrops) in rivers. Our objective was to assess if hydroacoustic technology could be used to quantify physical habitat features for C. monodonta and S. ambigua . Multibeam echosounder, acoustic Doppler current profiler, sidescan sonar and underwater videography were used to quantify water depth, substrate hardness, bed roughness and bed slope of the riverbed, water velocity, shear velocity and the degree of rock clustering at six sites in the Saint Croix River, Minnesota. The sites varied in type of rock structures and relative abundances of both species. The strength of the associations among physical habitat features and mussel abundance was weak; R 2 values were typically < 0.5. However, species‐specific differences in microhabitat were observed. For example, C. monodonta was typically observed at sites with higher velocity and shear velocity compared to S. ambigua . Mussel abundance was greatest at sites that contained crevices of sand surrounded by boulders and bedrock. Future refinements in hydroacoustic methods and post‐processing computations could improve predictions. Information on habitat features from occupied and unoccupied sites could help resource managers characterize existing occupied habitats, identify potential reintroduction areas and implement restoration programmes.

This research was conducted on inseptisol soils, especially for plantations, with the aim of not only restoring the health and fertility of the soil due to the use of chemical fertilizers and pesticides as well as seeing the pattern of EC distribution at each depth from the center of the biohole based on the time of observation. Through controlled microbial activity, its spread through two types of biohole, namely horizontal and vertical biohole. This research observes in real time through soil parameter sensors connected to the micro controller to changes in soil acidity, infiltration rate, conductivity electrolyte level and porosity level through soil infiltration rate. Through simulations with 2 types of biohole, it can be seen the increase in EC in each depth to the time of observation in real time. From the observations of graphs and EC standards, it can be seen that the ability of the soil to provide nutrients in the root growth zone to support the schedule and distribution patterns of planting both during vegetative growth and generative growth periods. So that we will know the proper biohole distance and spacing in order to be able to provide vegetative and generative mass nutrition based on nutrient values monitored through sensors that change the analogue parameters in the micro possessor into digital information transmitted by Wi-Fi in real time. Inseptisol soils fertility simulation based on the number of microbial populations=108/cfu with variable 1: The effective depth for providing root nutrition to a depth of 30 cm with a soil fertility value or Electrolyte Conductivity/ EC 1000 uS/cm to 1900 uS/cm is reached on the 10 to 60th day. Variable 2: The effective depth for providing root nutrition is up to a depth of 24 cm with a soil fertility value or Electrolyte Conductivity/EC 1000 uS/cm to 2350 uS/cm achieved on the 10th to 60th day.

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