scholarly journals Performance Analysis of Ice-Relative Upward-Looking Doppler Navigation of Underwater Vehicles Beneath Moving Sea Ice

2021 ◽  
Vol 9 (2) ◽  
pp. 174
Author(s):  
Laughlin D. L. Barker ◽  
Louis L. Whitcomb
Keyword(s):  
Sea Ice ◽  
Underwater Vehicles ◽  
Operating Conditions ◽  
Estimate Error ◽  
Ice Velocity ◽  
Robotic Vehicle ◽  
Ice Navigation ◽  
Navigation Accuracy ◽  
Estimate Uncertainty ◽  
Range Sensors

This paper addresses the problem of ice-relative underwater robotic vehicle navigation relative to moving or stationary contiguous sea ice. A review of previously-reported under-ice navigation methods is given, as well as motivation for the use of under-ice robotic vehicles with precision navigation capabilities. We then describe our proposed approach, which employs two or more satellite navigation beacons atop the sea ice along with other precision vehicle and ship mounted navigation sensors to estimate vehicle, ice, and ship states by means of an Extended Kalman Filter. A performances sensitivity analysis for a simulated 7.7 km under ice survey is reported. The number and the location of ice deployed satellite beacons, rotational and translational ice velocity, and separation of ship-based acoustic range sensors are varied, and their effects on estimate error and uncertainty are examined. Results suggest that increasing the number and/or separation of ice-deployed satellite beacons reduces estimate uncertainty, whereas increasing separation of ship-based acoustic range sensors has little impact on estimate uncertainty. Decreasing ice velocity is also correlated with reduced estimate uncertainty. Our analysis suggests that the proposed method is feasible and can offer scientifically useful navigation accuracy over a range of operating conditions.

scholarly journals Sea-floor and sea-ice conditions in the western Weddell Sea, Antarctica, around the wreck of Sir Ernest Shackleton's Endurance

2020 ◽  
Vol 32 (4) ◽  
pp. 301-313 ◽  
Author(s):  
Julian A. Dowdeswell ◽  
Christine L. Batchelor ◽  
Boris Dorschel ◽  
Toby J. Benham ◽  
Frazer D.W. Christie ◽  
...  
Keyword(s):  
Sea Ice ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Weddell Sea ◽  
Energy Conditions ◽  
Mass Wasting ◽  
Sea Floor ◽  
Fine Grained ◽  
Ice Conditions ◽  
Sedimentary System

AbstractMarine-geophysical evidence on sea-floor morphology and shallow acoustic stratigraphy are used to examine the substrate around the location at which Sir Ernest Shackleton's ship Endurance sank in 1915 and on the continental slope-shelf sedimentary system above this site in the western Weddell Sea. Few signs of turbidity-current and mass-wasting activity are found near or upslope of the wreck site, and any such activity was probably linked to full-glacial higher-energy conditions when ice last advanced across the continental shelf. The wreck is well below the maximum depth of iceberg keels and will not have been damaged by ice-keel ploughing. The wreck has probably been draped by only a few centimetres of fine-grained sediment since it sank in 1915. Severe modern sea-ice conditions hamper access to the wreck site. Accessing and investigating the wreck of Endurance in the Weddell Sea therefore represents a significant challenge. An ice-breaking research vessel is required, and even this would not guarantee that the site could be reached. Heavy sea-ice cover at the wreck site, similar to that encountered by Agulhus II during the Weddell Sea Expedition 2019, would also make the launch and recovery of autonomous underwater vehicles and remotely operated vehicles deployed to investigate the Endurance wreck problematic.

scholarly journals Cooperative Localization Method for AUV Using Acoustic Communication Measurement

2012 ◽  
Vol 4 ◽  
pp. 227-231 ◽  
Author(s):  
Li Chuan Zhang ◽  
Ming Yong Liu ◽  
Fu Bin Zhang
Keyword(s):  
Acoustic Communication ◽  
Navigation System ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Cooperative Localization ◽  
Relative Location ◽  
Navigation Problem ◽  
Cooperative Navigation ◽  
Acoustic Device ◽  
Navigation Accuracy

In this paper, we propose an algorithm based on double acoustic measurement for cooperative navigation of multiple autonomous underwater vehicles. Research on cooperative navigation of AUV is an important topic to solve the navigation problem in long range and deep sea. We investigate the improvement in navigation accuracy. In the Leader-follow structure, the leader AUV is equipped with high precision navigation system, and the follow AUV is equipped with low precision navigation system. They all are equipped with acoustic device to measure relative location. Traditionally geometry triangulation method is used to calculate the position of follow AUV, the method may cause fault error solution. Double acoustic communication measurement method was designed, which fused the proprioceptive and exteroceptive sensors. The research results prove that the navigation accuracy has been improved effectively.

Thick and deformed Antarctic sea ice mapped with autonomous underwater vehicles

2014 ◽  
Vol 8 (1) ◽  
pp. 61-67 ◽  
Author(s):  
G. Williams ◽  
T. Maksym ◽  
J. Wilkinson ◽  
C. Kunz ◽  
C. Murphy ◽  
...  
Keyword(s):  
Sea Ice ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Antarctic Sea Ice

scholarly journals The Statistical Properties of Sea Ice Velocity Fields

2017 ◽  
Vol 30 (13) ◽  
pp. 4873-4881 ◽  
Author(s):  
Sahil Agarwal ◽  
John S. Wettlaufer
Keyword(s):  
Sea Ice ◽  
White Noise ◽  
Time Scales ◽  
Velocity Fields ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Noise Characteristics ◽  
Noise Structure ◽  
Spatial Correlation Structure ◽  
Ice Velocity

By arguing that the surface pressure field over the Arctic Ocean can be treated as an isotropic, stationary, homogeneous, Gaussian random field, Thorndike estimated a number of covariance functions from two years of data (1979 and 1980). Given the active interest in changes of general circulation quantities and indices in the polar regions during the recent few decades, the spatial correlations in sea ice velocity fields are of particular interest. It is thus natural to ask, “How persistent are these correlations?” To this end, a multifractal stochastic treatment is developed to analyze observed Arctic sea ice velocity fields from satellites and buoys for the period 1978–2015. Since it was previously found that the Arctic equivalent ice extent (EIE) has a white noise structure on annual to biannual time scales, the connection between EIE and ice motion is assessed. The long-term stationarity of the spatial correlation structure of the velocity fields and the robustness of their white noise structure on multiple time scales is demonstrated; these factors (i) combine to explain the white noise characteristics of the EIE on annual to biannual time scales and (ii) explain why the fluctuations in the ice velocity are proportional to fluctuations in the geostrophic winds on time scales of days to months. Moreover, it is shown that the statistical structure of these two quantities is commensurate from days to years, which may be related to the increasing prevalence of free drift in the ice pack.

Impact of Sea Ice Compression on Navigation Performance

2017 ◽  
Author(s):  
Genki Sagawa
Keyword(s):  
Numerical Model ◽  
Sea Ice ◽  
Static Condition ◽  
Performance Estimation ◽  
The Arctic ◽  
Dynamical Processes ◽  
Speed Reduction ◽  
Ship Navigation ◽  
Arctic Ice ◽  
Ice Navigation

Ship navigation performance in the Arctic ice-covered sea was investigated from various kinds of satellite data and a numerical model of sea ice. The effect of dynamical processes of ice on the performance was especially examined, for it was not focused enough in previous studies. As a result, it was found that ice stress can explain some parts of the navigation when high amount of speed reduction occurred in thin ice area, and vice versa. The result indicates an importance of considering dynamical processes of ice in addition to static condition of ice, to improve an accuracy of an ice navigation performance estimation.

scholarly journals Towards an automatic ice navigation support system in the Arctic area

2021 ◽  
Author(s):  
Shahram Sattar
Keyword(s):  
Sea Ice ◽  
Voronoi Diagram ◽  
Support System ◽  
The Arctic ◽  
Navigation Systems ◽  
Viable Solution ◽  
Navigation Support ◽  
Northern Regions ◽  
Ice Navigation ◽  
Arctic Area

Conventional ice navigation through sea ice is manually operated by well-trained navigators, whose experiences are heavily relied upon to guarantee the ship's safety. Despite increasingly available ice data and information, little has been done to develop automatic ice navigation systems to better guide ships in sea ice. In this study firstly navigable sea areas for different types of ships were identified according to the navigation codes in northern regions. Secondly, three algorithms of path planning were adopted to automatically compute the safest-and-shortest ship routes based on the concepts of the Voronoi diagram, Visibility graph, and Visibility-Voronoi diagram, respectively. These algorithms and results were compared and evaluated in terms of different application scenarios. Results show that the Visibility-Voronoi approach seems to be the best viable solution in terms of computing performance and navigation safety. The work will provide a basis for further development towards an automatic ice navigation support system

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