944 research outputs found
Low cost underwater acoustic localization
Over the course of the last decade, the cost of marine robotic platforms has
significantly decreased. In part this has lowered the barriers to entry of
exploring and monitoring larger areas of the earth's oceans. However, these
advances have been mostly focused on autonomous surface vehicles (ASVs) or
shallow water autonomous underwater vehicles (AUVs). One of the main drivers
for high cost in the deep water domain is the challenge of localizing such
vehicles using acoustics. A low cost one-way travel time underwater ranging
system is proposed to assist in localizing deep water submersibles. The system
consists of location aware anchor buoys at the surface and underwater nodes.
This paper presents a comparison of methods together with details on the
physical implementation to allow its integration into a deep sea micro AUV
currently in development. Additional simulation results show error reductions
by a factor of three.Comment: 73rd Meeting of the Acoustical Society of Americ
Advances in Decentralized Single-Beacon Acoustic Navigation for Underwater Vehicles: Theory and Simulation
This paper reports the theory and implementation
of a decentralized navigation system that enables simultaneous
single-beacon navigation of multiple underwater vehicles. In
single-beacon navigation, each vehicle uses ranges from a single,
moving reference beacon in addition to its own inertial navigation
sensors to perform absolute localization and navigation. In this
implementation the vehicles perform simultaneous communication
and navigation using underwater acoustic modems, encoding
and decoding data within the acoustic broadcast. Vehicles calculate
range from the time of flight of asynchronous acoustic
broadcasts from the reference beacon. Synchronous clocks on
the reference beacon and the vehicles enable the measurement
of one-way travel-times, whereby the time of launch of the
acoustic signal at the reference beacon is encoded in the acoustic
broadcast and the time of arrival of the broadcast is measured
by each vehicle. The decentralized navigation algorithm, running
independently on each vehicle, is implemented using the
information form of the extended Kalman filter and has been
previously shown to yield results that are identical to a centralized
Kalman filter at the instant of each range measurement. We
summarize herein the architecture and design of the acoustic
communications (Acomms) system consisting of an underwater
acoustic modem, synchronous clock, and the software necessary
to run them, and salient results from the validation of the
decentralized information filter using a simulated data set.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86057/1/swebster-4.pd
Closedâloop oneâwayâtravelâtime navigation using lowâgrade odometry for autonomous underwater vehicles
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of FIeld Robotics 35 (2018): 421-434, doi:10.1002/rob.21746.This paper extends the progress of single beacon oneâwayâtravelâtime (OWTT) range measurements for constraining XY position for autonomous underwater vehicles (AUV). Traditional navigation algorithms have used OWTT measurements to constrain an inertial navigation system aided by a Doppler Velocity Log (DVL). These methodologies limit AUV applications to where DVL bottomâlock is available as well as the necessity for expensive strapâdown sensors, such as the DVL. Thus, deep water, midâwater column research has mostly been left untouched, and vehicles that need expensive strapâdown sensors restrict the possibility of using multiple AUVs to explore a certain area. This work presents a solution for accurate navigation and localization using a vehicle's odometry determined by its dynamic model velocity and constrained by OWTT range measurements from a topside source beacon as well as other AUVs operating in proximity. We present a comparison of two navigation algorithms: an Extended Kalman Filter (EKF) and a Particle Filter(PF). Both of these algorithms also incorporate a water velocity bias estimator that further enhances the navigation accuracy and localization. Closedâloop online field results on local waters as well as a realâtime implementation of two days field trials operating in Monterey Bay, California during the Keck Institute for Space Studies oceanographic research project prove the accuracy of this methodology with a root mean square error on the order of tens of meters compared to GPS position over a distance traveled of multiple kilometers.This work was supported in part through funding from the Weston
Howland Jr. Postdoctoral Scholar Award (BCC), the U.S. Navy's Civilian
Institution program via the MIT/WHOI Joint Program (JHK),W. M.
Keck Institute for Space Studies, and theWoods Hole Oceanographic
Institution
Preliminary Deep Water Results in Single-Beacon One-Way-Travel-Time Acoustic Navigation for Underwater Vehicles
This paper reports the development and experimental
evaluation of a novel navigation system for underwater
vehicles that employs Doppler sonar, synchronous clocks, and
acoustic modems to achieve simultaneous acoustic communication
and navigation. The system reported herein, which is
employed to renavigate the vehicle in post-processing, forms the
basis for a vehicle-based real-time navigation system. Existing
high-precision absolute navigation techniques for underwater
vehicles are impractical over long length scales and lack
scalability for simultaneously navigating multiple vehicles. The
navigation method reported in this paper relies on a single
moving reference beacon, eliminating the requirement for
the underwater vehicle to remain in a bounded navigable
area. The use of underwater modems and synchronous clocks
enables range measurements based on one-way time-of-flight
information from acoustic data packet broadcasts. The acoustic
data packets are broadcast from the single, moving reference
beacon and can be received simultaneously by multiple vehicles
within acoustic range. We report experimental results from
the first deep-water evaluation of this method using data
collected from an autonomous underwater vehicle (AUV) survey
carried out in 4000 m of water on the southern Mid-Atlantic
Ridge. We report a comparative experimental evaluation of the
navigation fixes provided by the proposed synchronous acoustic
navigation system in comparison to navigation fixes obtained by
an independent conventional long baseline acoustic navigation
system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86040/1/swebster-7.pd
Toward a Platform-Independent Acoustic Communications and Navigation System for Underwater Vehicles
This paper presents a platform-independent
acoustic communication (Acomms) system that enables multiple
nodes (any combination of underwater vehicles, surface
ships, and fixed beacons) to simultaneously exchange data
and calculate inter-node ranges with O(1m) accuracy. The
Acomms system supports two types of communications: standard
asynchronous acoustic communication and synchronous
communication, which enables navigation based on inter-node
ranges derived from the one-way travel-times of acoustic
messages between nodes. The Acomms system hardware is
implemented with a dedicated software program, Linux host
computers, Woods Hole Oceanographic Institution (WHOI)
Micro-Modems, and precision reference clocks. The acoustic
communications software configures the modem, manages all
acoustic communication traffic, and acts as an interface between
the vehicle-specific software and the modems and clocks. The
software and related hardware have been installed on theWoods
Hole Oceanographic Institution vehicles Puma, Jaguar, and
Nereus, and deployed in sea trials in the North Pacific and
South Atlantic.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86048/1/swebster-8.pd
Efficient AUV Navigation Fusing Acoustic Ranging and Side-scan Sonar
This paper presents an on-line nonlinear least
squares algorithm for multi-sensor autonomous underwater
vehicle (AUV) navigation. The approach integrates the global
constraints of range to and GPS position of a surface vehicle
or buoy communicated via acoustic modems and relative pose
constraints arising from targets detected in side-scan sonar images.
The approach utilizes an efficient optimization algorithm,
iSAM, which allows for consistent on-line estimation of the
entire set of trajectory constraints. The optimized trajectory
can then be used to more accurately navigate the AUV, to
extend mission duration, and to avoid GPS surfacing. As iSAM
provides efficient access to the marginal covariances of previously
observed features, automatic data association is greatly
simplified â particularly in sparse marine environments. A
key feature of our approach is its intended scalability to
single surface sensor (a vehicle or buoy) broadcasting its GPS
position and simultaneous one-way travel time range (OWTT)
to multiple AUVs. We discuss why our approach is scalable
as well as robust to modem transmission failure. Results are
provided for an ocean experiment using a Hydroid REMUS
100 AUV co-operating with one of two craft: an autonomous
surface vehicle (ASV) and a manned support vessel. During
these experiments the ranging portion of the algorithm ran online
on-board the AUV. Extension of the paradigm to multiple
missions via the optimization of successive survey missions (and
the resultant sonar mosaics) is also demonstrated.United States. Office of Naval Research (Grant N000140711102
Synchronous-clock range-angle relative acoustic navigation: a unified approach to multi-AUV localization, command, control, and coordination
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rypkema, N., Schmidt, H., & Fischell, E. Synchronous-clock range-angle relative acoustic navigation: a unified approach to multi-AUV localization, command, control, and coordination. Journal of Field Robotics, 2(1), (2022): 774â806, https://doi.org/10.55417/fr.2022026.This paper presents a scalable acoustic navigation approach for the unified command, control, and coordination of multiple autonomous underwater vehicles (AUVs). Existing multi-AUV operations typically achieve coordination manually by programming individual vehicles on the surface via radio communications, which becomes impractical with large vehicle numbers; or they
require bi-directional intervehicle acoustic communications to achieve limited coordination when submerged, with limited scalability due to the physical properties of the acoustic channel. Our approach utilizes a single, periodically broadcasting beacon acting as a navigation reference for the group of AUVs, each of which carries a chip-scale atomic clock and fixed ultrashort baseline array of acoustic receivers. One-way travel-time from synchronized clocks and time-delays between signals received by each array element allow any number of vehicles within receive distance to determine range, angle, and thus determine their relative position to the beacon. The operator can command different vehicle behaviors by selecting between broadcast signals from a predetermined set, while coordination between AUVs is achieved without intervehicle communication by defining
individual vehicle behaviors within the context of the group. Vehicle behaviors are designed within a beacon-centric moving frame of reference, allowing the operator to control the absolute position of the AUV group by repositioning the navigation beacon to survey the area of interest. Multiple deployments with a fleet of three miniature, low-cost SandShark AUVs performing closed-loop acoustic navigation in real-time provide experimental results validated against a secondary long-baseline positioning system, demonstrating the capabilities and robustness of our approach with real-world data.This work was partially supported by the Office of Naval Research, the Defense Advanced Research Projects Agency, Lincoln Laboratory, and the Reuben F. and Elizabeth B. Richards Endowed Funds at WHOI
Synchronous-Clock, One-Way-Travel-Time Acoustic Navigation for Underwater Vehicles
This paper reports the development and deployment of a synchronous-clock acoustic navigation system suitable for the simultaneous navigation of multiple underwater vehicles. Our navigation system is composed of an acoustic modemâbased communication and navigation system that allows for onboard navigational data to be broadcast as a data packet by a source node and for all passively receiving nodes to be able to decode the data packet to obtain a one-way-travel-time (OWTT) pseudo-range measurement and navigational ephemeris data. The navigation method reported herein uses a surface ship acting as a single moving reference beacon to a fleet of passively listening underwater vehicles. All vehicles within acoustic range are able to concurrently measure their slant range to the reference beacon using the OWTT measurement methodology and additionally receive transmission of reference beacon position using the modem data packet. The advantages of this type of navigation system are that it can (i) concurrently navigate multiple underwater vehicles within the vicinity of the surface ship and (ii) provide a bounded-error XY position measure that is commensurate with conventional moored long-baseline (LBL) navigation systems [i.e., ] but unlike LBL is not geographically restricted to a fixed-beacon network. We present results for two different field experiments using a two-node configuration consisting of a global positioning systemâequipped surface ship acting as a global navigation aid to a Doppler-aided autonomous underwater vehicle. In each experiment, vehicle position was independently corroborated by other standard navigation means. Results for a maximum likelihood sensor fusion framework are reported.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86046/1/reustice-2.pd
Recent Advances in Synchronous-Clock One-Way-Travel-Time Acoustic Navigation
This paper reports recent results in the development
and deployment of a synchronous-clock acoustic navigation
system suitable for the simultaneous navigation of multiple
underwater vehicles. The goal of this work is to enable the
task of navigating multiple autonomous underwater vehicles
(AUVs) over length scales of 0(100 km), while maintaining
error tolerances commensurate with conventional long-baseline
transponder-based navigation systems (0(1 m)), but without the
requisite need for deploying, calibrating, and recovering seafloor
anchored acoustic transponders. Our navigation system is comprised
of an acoustic modem-based communication/navigation
system that allows for onboard navigational data to be broadcast
as a data packet by a source node, and for all passively receiving
nodes to be able to decode the data packet to obtain a one-way
travel time pseudo-range measurement and ephemeris data. We
present field results for a two-node configuration consisting of a
surface ship acting as a global navigation aid to a Doppler-aided
AUV.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86042/1/reustice-26.pd
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