Processing explorer ADCP data collected on slocum gliders using the LADCP shear method

Thurnherr, Andreas M.; Symonds, Darryl; Laurent, L. St.

doi:10.1109/cwtm.2015.7098134

Cited by 9 publications

(6 citation statements)

References 11 publications

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“…Sensors on autonomous platforms can also measure physical variables, such as current velocity. Acoustic Doppler Current Profilers (ADCP) are widely used on research vessels, moorings, and more recently on AUVs including gliders (Thurnherr et al, 2015) although they are not routinely installed on gliders because of power requirements and data processing challenges (Hall et al, 2019).…”

Section: Physical Oceanographic Sensorsmentioning

confidence: 99%

Future Vision for Autonomous Ocean Observations

Whitt¹,

Pearlman²,

Polagye

et al. 2020

Front. Mar. Sci.

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Whitt et al. Future of Autonomous Ocean Observations reductions. Cost reductions could enable order-of-magnitude increases in platform operations and increase sampling resolution for a given level of investment. Energy harvesting technologies should be integral to the system design, for sensors, platforms, vehicles, and docking stations. Connections are needed between the marine energy and ocean observing communities to coordinate among funding sources, researchers, and end users. Regional teams should work with global organizations such as IOC/GOOS in governance development. International networks such as emerging glider operations (EGO) should also provide a forum for addressing governance. Networks of multiple vehicles can improve operational efficiencies and transform operational patterns. There is a need to develop operational architectures at regional and global scales to provide a backbone for active networking of autonomous platforms.

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Section: Physical Oceanographic Sensorsmentioning

confidence: 99%

Future Vision for Autonomous Ocean Observations

Whitt¹,

Pearlman²,

Polagye

et al. 2020

Front. Mar. Sci.

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“…For the velocity inversion method [34], a set of linear equations is solved to estimate absolute water velocities from a combination of velocity-referencing constraints (navigational data, shipboard ADCP measurements, bottom tracking, etc.). The shear method [35][36][37] is based on the assumption that glider speed is constant for each profile and can, therefore, be eliminated. After reconstructing the shear of the current over the whole water column, its integration allows to obtain a relative water velocity profile.…”

Section: Water Velocity Estimatesmentioning

confidence: 99%

Glider-Based Active Acoustic Monitoring of Currents and Turbidity in the Coastal Zone

et al. 2020

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The recent integration of Acoustic Doppler Current Profilers (ADCPs) onto underwater gliders changes the way current and sediment dynamics in the coastal zone can be monitored. Their endurance and ability to measure in all weather conditions increases the probability of capturing sporadic meteorological events, such as storms and floods, which are key elements of sediment dynamics. We used a Slocum glider equipped with a CTD (Conductivity, Temperature, Depth), an optical payload, and an RDI 600 kHz phased array ADCP. Two deployments were carried out during two contrasting periods of the year in the Rhone River region of freshwater influence (ROFI). Coastal absolute currents were reconstructed using the shear method and bottom tracking measurements, and generally appear to be in geostrophic balance. The responses of the acoustic backscatter index and optical turbidity signals appear to be linked to changes of the particle size distribution in the water column. Significantly, this study shows the interest of using a glider-ADCP for coastal zone monitoring. However, the comparison between suspended particulate matter dynamics from satellites and gliders also suggests that a synoptic view of the processes involved requires a multiplatform approach, especially in systems with high spatial and temporal variability, such as the Rhone ROFI area.

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“…Aided by the development of very high frequency ADCPs (1 MHz) specifically for autonomous underwater gliders, the two main lowered ADCP processing frameworks-the shear method and the inversion method-have been modified to estimate depth-varying current profiles from gliders by [9] and [10], [11] respectively. A related, but distinctly different method based on non-linear objective mapping of ADCP shear has been also developed by [12].…”

Section: Introductionmentioning

confidence: 99%

“…A related, but distinctly different method based on non-linear objective mapping of ADCP shear has been also developed by [12]. In all implementations ( [9], [11], [12]), the authors needed to contend with the limitation of Slocum and Spray glider ADCPs that only collect data during one half of the dive (either ascending or descending).…”

Section: Introductionmentioning

confidence: 99%

Preliminary Results in Current Profile Estimation and Doppler-aided Navigation for Autonomous Underwater Gliders

Jonker

Shcherbina

Krishfield

et al. 2019

OCEANS 2019 - Marseille

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This paper describes the development and experimental results of navigation algorithms for an autonomous underwater glider (AUG) that uses an on-board acoustic Doppler current profiler (ADCP). AUGs are buoyancy-driven autonomous underwater vehicles that use small hydrofoils to make forward progress while profiling vertically. During each dive, which can last up to 6 hours, the Seaglider AUG used in this experiment typically reaches the depth of 1000 m and travels 3-6 km horizontally through the water, relying solely on dead-reckoning. Horizontal through-the-water (TTW) progress of AUG is 20-30 cm/s, which is comparable to the speed of the stronger ocean currents. Underwater navigation of an AUG in the presence of unknown advection therefore presents a considerable challenge. We develop two related formulations for post-processing. Both use ADCP observations, through the water velocity estimates, and GPS fixes to estimate current profiles. However, while the first solves an explicit inverse problem for the current profiles only, the second solves a deconvolution problem that infers both states and current profiles using a state-space model.Both approaches agree on their estimates of the ocean current profile through which the AUG was flown using measurements of current relative to the AUG from the ADCP, and estimates of the AUGs TTW velocity from a hydrodynamic model. The result is a complete current profile along the AUGs trajectory, as well as over-the-ground (OTG) velocities for the AUG that can be used for more accurate subsea positioning. Results are demonstrated using 1 MHz ADCP data collected from a Seaglider AUG deployed for 49 days off the north coast of Alaska during August and September 2017. The results are compared to ground truth data from the top 40 meters of the water column, from a moored, upward-facing 600 kHz ADCP. Consequences of the state-space formulation are discussed in the Conclusions section.

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Processing explorer ADCP data collected on slocum gliders using the LADCP shear method

Cited by 9 publications

References 11 publications

Future Vision for Autonomous Ocean Observations

Future Vision for Autonomous Ocean Observations

Glider-Based Active Acoustic Monitoring of Currents and Turbidity in the Coastal Zone

Preliminary Results in Current Profile Estimation and Doppler-aided Navigation for Autonomous Underwater Gliders

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