59 research outputs found
Mapping Complex Marine Environments with Autonomous Surface Craft
This paper presents a novel marine mapping system using an Autonomous
Surface Craft (ASC). The platform includes an extensive sensor suite for mapping
environments both above and below the water surface. A relatively small hull size
and shallow draft permits operation in cluttered and shallow environments. We address the Simultaneous Mapping and Localization (SLAM) problem for concurrent
mapping above and below the water in large scale marine environments. Our key
algorithmic contributions include: (1) methods to account for degradation of GPS
in close proximity to bridges or foliage canopies and (2) scalable systems for management of large volumes of sensor data to allow for consistent online mapping
under limited physical memory. Experimental results are presented to demonstrate
the approach for mapping selected structures along the Charles River in Boston.United States. Office of Naval Research (N00014-06-10043)United States. Office of Naval Research (N00014-05-10244)United States. Office of Naval Research (N00014-07-11102)Massachusetts Institute of Technology. Sea Grant College Program (grant 2007-R/RCM-20
Towards three-dimensional underwater mapping without odometry
This paper presents a method for the creation of three-dimensional maps of underwater cisterns and wells using a submersible robot equipped with two scanning sonars and a compass. Previous work in this area utilized a particle filter to perform offline simultaneous localization and mapping (SLAM) in two dimensions using a single sonar [11]. This work utilizes scan matching and incorporates an additional sonar that scans in a perpendicular plane. Given a set of overlapping horizontal and vertical sonar scans, an algorithm was implemented to map underwater chambers by matching sets of scans using a weighted iterative closest point (ICP) method. This matching process has been augmented to align the features of the underwater cistern data without robot odometry. Results from a swimming pool and an archeological site trials indicate successful mapping is achieved
The Malta cistern mapping project : expedition II
This paper documents the second of two
archeological expeditions that employed several
underwater robot mapping and localization
techniques. The goal of this project is to explore
and map ancient cisterns located on the islands of
Malta and Gozo. Dating back to 300 B.C., the
cisterns of interest acted as water storage systems
for fortresses, private homes, and churches. They
often consisted of several connected chambers,
still containing water. A Remotely Operated
Vehicle (ROV), was deployed into cisterns to
obtain video and sonar images. Using a variety of
sonar based mapping techniques, two-dimensional
maps of 18 different cisterns were created.peer-reviewe
Mapping and visualizing ancient water storage systems with an ROV - an approach based on fusing stationary scans within a particle filter
This paper presents a new method for construct-
ing 2D maps of enclosed underwater structures using an
underwater robot equipped with only a 2D scanning sonar,
compass and depth sensor. In particular, no motion model or
odometry is used. To accomplish this, a two step offline SLAM
method is applied to a set of stationary sonar scans. In the
first step, the change in position of the robot between each
consecutive pair of stationary sonar scans is estimated using
a particle filter. This set of pair wise relative scan positions
is used to create an estimate of each scan’s position within
a global coordinate frame using a weighted least squares fit
that optimizes consistency between the relative positions of the
entire set of scans. In the second step of the method, scans and
their estimated positions act as inputs to a mapping algorithm
that constructs 2D octree-based evidence grid maps of the site.
This work is motivated by a multi-year archeological project
that aims to construct maps of ancient water storage systems,
i.e. cisterns, on the islands of Malta and Gozo. Cisterns, wells,
and water galleries within fortresses, churches and homes oper-
ated as water storage systems as far back as 2000 B.C. Using a
Remotely Operated Vehicle (ROV) these water storage systems
located around the islands were explored while collecting video,
still images, sonar, depth, and compass measurements. Data
gathered from 3 different expeditions has produced maps of
over 60 sites. Presented are results from applying the new
mapping method to both a swimming pool of known size and
to several of the previously unexplored water storage systems.peer-reviewe
Underwater robots with sonar and smart tether for underground cistern mapping and exploration
This paper describes the application of using a submersible remotely operated vehicle (ROV) to map and explore
underground water cisterns during a series of expeditions to Malta and Gozo. The purpose of this project was to
create maps of ancient cisterns located under private homes, churches, and fortresses where passageways leading
to the cisterns are too narrow and dangerous for humans to enter. These cisterns were used as water storage
systems for hundreds of years, and many still contained water. The small ROV that was lowered into these cisterns
was equipped with a sonar module to enable the creation of maps, two cameras to record live video, a grabber-arm
for interacting with objects in the environment, and a Smart Tether to record additional positioning data of the ROV.
Each of these components are discussed in terms of functionality and appropriateness for use by archaeologists
wishing to explore and extract mapping information from narrow water-filled caverns. Additionally, three different
mapping and localization techniques are presented including 1) Sonar image mosaics using stationary sonar
scans, 2) Sonar image mosaics using stationary sonar scans with Smart Tether position data, and 3) Simultaneous
Localization and Mapping (SLAM) using stationary sonar scans. Each of the algorithms used in this project have
benefits in certain applications. During two expeditions in Malta and Gozo, 2-dimensional maps of 32 cisterns
were successfully constructed.peer-reviewe
Toward autonomous exploration in confined underwater environments
Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Journal of Field Robotics 33 (2016): 994-1012, doi:10.1002/rob.21640.In this field note we detail the operations and discuss the results of an experiment conducted
in the unstructured environment of an underwater cave complex, using an autonomous underwater vehicle (AUV). For this experiment the AUV was equipped with two acoustic
sonar to simultaneously map the caves’ horizontal and vertical surfaces. Although the
caves’ spatial complexity required AUV guidance by a diver, this field deployment successfully demonstrates a scan matching algorithm in a simultaneous localization and mapping (SLAM) framework that significantly reduces and bounds the localization error for fully
autonomous navigation. These methods are generalizable for AUV exploration in confined
underwater environments where surfacing or pre-deployment of localization equipment are
not feasible and may provide a useful step toward AUV utilization as a response tool in
confined underwater disaster areas.This research work was partially sponsored by the EU FP7-Projects: Tecniospring-
Marie Curie (TECSPR13-1-0052), MORPH (FP7-ICT-2011-7-288704), Eurofleets2 (FP7-INF-2012-312762),
and the National Science Foundation (OCE-0955674)
Archaeology via underwater robots : mapping and localization within Maltese cistern systems
This paper documents the application of several
underwater robot mapping and localization techniques used
during an archaeological expedition. The goal of this project was
to explore and map ancient cisterns located on the islands of
Malta and Gozo. The cisterns of interest acted as water storage
systems for fortresses, private homes, and churches. They often
consisted of several connected chambers, still containing water. A
sonar-equipped Remotely Operated Vehicle (ROV) was deployed
into these cisterns to obtain both video footage and sonar range
measurements. Four different mapping and localization
techniques were employed including 1) Sonar image mosaics
using stationary sonar scans, and 2) Simultaneous Localization
and Mapping (SLAM) while the vehicle was in motion, 3) SLAM
using stationary sonar scans, and 4) Localization using previously
created maps. Two dimensional maps of 6 different cisterns were
successfully constructed. It is estimated that the cisterns were
built as far back as 300 B.C.peer-reviewe
Surface Reconstruction of Maltese Cisterns Using ROV Sonar Data for Archeological Study
Abstract. We present a methodology and algorithm for the reconstruc tion of three dimensional geometric models of ancient Maltese water stor age systems, i.e. cisterns, from sonar data. This project was conducted as a part of a four week expedition on the islands of Malta and Gozo. During this expedition, investigators used underwater robot systems ca pable of mapping ancient underwater cisterns and tunnels. The mapping included probabilistic algorithms for constructing the maps of the sonar data and computer graphics for surface reconstruction and visualization. This paper presents the general methodology for the data acquisition and the novel application of algorithms from computer graphics for surface reconstruction to this new data setting. In addition to reconstructing the geometry of the cisterns, the visualization system includes methods to enhance the understanding of the data by visualizing water level and texture detail either through the application of real image data via pro jective textures or by more standard texture mapping techniques. The resulting surface reconstructions and visualizations can be used by ar chaeologists for educational purposes and to help understand the shape and history of such water receptacles
Past, Present, and Future of Simultaneous Localization And Mapping: Towards the Robust-Perception Age
Simultaneous Localization and Mapping (SLAM)consists in the concurrent
construction of a model of the environment (the map), and the estimation of the
state of the robot moving within it. The SLAM community has made astonishing
progress over the last 30 years, enabling large-scale real-world applications,
and witnessing a steady transition of this technology to industry. We survey
the current state of SLAM. We start by presenting what is now the de-facto
standard formulation for SLAM. We then review related work, covering a broad
set of topics including robustness and scalability in long-term mapping, metric
and semantic representations for mapping, theoretical performance guarantees,
active SLAM and exploration, and other new frontiers. This paper simultaneously
serves as a position paper and tutorial to those who are users of SLAM. By
looking at the published research with a critical eye, we delineate open
challenges and new research issues, that still deserve careful scientific
investigation. The paper also contains the authors' take on two questions that
often animate discussions during robotics conferences: Do robots need SLAM? and
Is SLAM solved
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