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Jason Gobat

Senior Principal Oceanographer

Email

jgobat@apl.washington.edu

Phone

206-543-2439

Research Interests

Sensor-Platform Integration, Towed Vehicles, Autonomous Vehicles, Moorings, Cable Dynamics, Instrumentation, Data Telemetry

Department Affiliation

Ocean Physics

Publications

2000-present and while at APL-UW

Multi-month dissipation estimates using microstructure from autonomous underwater gliders

Rainville, L., J.I. Gobat, C.M. Lee, and G.B. Shilling, "Multi-month dissipation estimates using microstructure from autonomous underwater gliders," Oceanography, 30, 49-50, doi:10.5670/oceanog.2017.219, 2017.

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1 Jun 2017

Ocean turbulence is inherently episodic and patchy. It is the primary mechanism that transforms water mass properties and drives the exchanges of heat, freshwater, and momentum across the water column. Given its episodic nature, capturing the net impact of turbulence via direct measurements requires sustained observations over extended temporal and/or broad spatial scales.

Towards real-time under-ice acoustic navigation at mesoscale ranges

Webster, S.E., L.E. Freitag, C.M. Lee, and J.I. Gobat, "Towards real-time under-ice acoustic navigation at mesoscale ranges," Proc. IEEE International Conference on Robotics and Automation, 26-30 May, Seattle, WA, 537-544, doi:10.1109/ICRA.2015.7139231 (IEEE, 2015).

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26 May 2015

This paper describes an acoustic navigation system that provides mesoscale coverage (hundreds of kilometers) under the ice and presents results from the first multi-month deployment in the Arctic. The hardware consists of ice-tethered acoustic navigation beacons transmitting at 900 Hz that broadcast their latitude and longitude plus several bytes of optional control data. The real-time under-ice navigation algorithm, based on a Kalman filter, uses time-of-flight measurements from these sources to simultaneously estimate vehicle position and depth-averaged local currents. The algorithm described herein was implemented on Seagliders, a type of autonomous underwater glider (AUG), but the underlying theory is applicable to other autonomous underwater vehicles (AUVs). As part of an extensive field campaign from March to September 2014, eleven acoustic sources and four Seagliders were deployed to monitor the seasonal melt of the marginal ice zone (MIZ) in the Beaufort and northern Chukchi Seas. Beacon-to-beacon performance was excellent due to a sound duct at 100 m depth where the transmitters were positioned; the travel-time error at 200 km has a standard deviation of 40 m when sound-speed is known, and ranges in excess of 400 km were obtained. Results with the Seagliders, which were not regularly within the duct, showed reliable acoustic ranges up to 100 km and more sparse but repeatable range measurements to over 400 km. Navigation results are reported for the real-time algorithm run in post-processing mode, using data from a 295-hour segment with significant time spent under ice.

Preliminary results in under-ice acoustic navigation for Seagliders in Davis Strait

Webster, S.E., C.M. Lee, and J.I. Gobat, "Preliminary results in under-ice acoustic navigation for Seagliders in Davis Strait," Proc., OCEANS 2014, 14-19 September, St. John's Newfoundland, doi:10.1109/OCEANS.2014.7003070 (IEEE, 2014).

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14 Sep 2014

This paper presents an under-ice acoustic navigation system developed for Seaglider, a buoyancy-driven autonomous underwater vehicle (AUV), and post-processed navigation results from one of fourteen glider deployments between 2006 and 2014 in Davis Strait. Seagliders typically receive all geolocation information from global positioning system (GPS) signals received while they are at the surface, and perform dead reckoning while underwater. Extended under-ice deployments, where access to GPS is denied due to the inability of the glider to surface, require an alternative source of geolocation information. In the deployments described herein, geolocation information is provided by range measurements from mooring-mounted acoustic navigation sources at fixed, known locations. In this paper we describe the navigation system used in Davis Strait and present navigation results from a six degree-of-freedom Kalman filter using post-processed navigation data.

More Publications

Transport estimate of the Western Branch of the Norwegian Atlantic Current from glider surveys

Høydalsvik, F., C. Mauritzen, K.A. Orvik, J.H. LaCasce, C.M. Lee, and J. Gobat, "Transport estimate of the Western Branch of the Norwegian Atlantic Current from glider surveys," Deep-Sea Res. I, 79, 86-95, doi:10.1016/j.dsr.2013.05.005, 2013.

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1 Sep 2013

The northernmost limb of the Atlantic Meridional Overturning Circulation (AMOC), so relevant for understanding decadal climate variability, enters the Nordic Seas as the Norwegian Atlantic Current and continues on to recirculate in the Arctic Ocean. The strength of the Eastern Branch of the Norwegian Atlantic Current has been systematically monitored for over 15 years at the Svinøy section off southern Norway, whereas the strength of the Western Branch has not. We therefore used autonomous gliders to monitor and quantify the strength of this broader branch at the Svinøy section, located 500 km downstream from the Iceland–Scotland Ridge, and at the Station Mike section 300 km further downstream. The gliders' diving depth is 1000 m, spanning the warm Atlantic Water. The current encompasses more than warm Atlantic Water; we find that the transport peaks in two distinct temperature ranges, one around 7.5–8°C (Atlantic Water, carrying 7 Sv (1x106 m3/s)) and another around –0.5°C (Norwegian Sea Deep Water, carrying 12 Sv). Contrary to earlier expectations, our results indicate that the Western Branch carries as much water of Atlantic origin (temperature>7.5°C) as the Eastern Branch. It should therefore be included in future monitoring plans for this region.

Acoustic navigation and communications for high latitude ocean research (ANCHOR)

Lee, C.M., and J.I. Gobat, "Acoustic navigation and communications for high latitude ocean research (ANCHOR)," J. Acoust. Soc. Am., 123, 2990, doi:10.1121/1.2932529, 2008.

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1 May 2008

Recent community reports on autonomous and Lagrangian platforms and Arctic observing identify the development of under-ice navigation and telemetry technologies as one of the critical factors limiting the scope of autonomous (e.g. floats, AUVs and gliders) high-latitude measurement efforts. These platforms could provide persistent, high-resolution, basin-wide sampling in ice-covered regions and collect measurements near the critical ice–water interface. Motivated by the dramatic advances in temporal and spatial reach promised by autonomous sampling and by the need to coordinate nascent efforts to develop navigation and communication system components, an international group of acousticians, platform developers, high-latitude oceanographers and marine mammal researchers gathered in Seattle, U.S.A. from 27 February – 1 March for an NSF Office of Polar Programs sponsored Acoustic Navigation and Communication for High-latitude Ocean Research workshop.

Workshop participants summarized the current state of knowledge concerning Arctic acoustics, navigation and communications, developed an overarching system specification to guide community-wide engineering efforts and established an active community and steering group to guide long-term efforts and ensure interoperability between elements developed by disparate teams. This presentation will summarize workshop findings and provide an update on recent developments stemming from the EU DAMOCLES and US NSF Arctic Observing Network programs.

Time-domain numerical simulation of ocean cable structures

Gobat, J.I., and M.A. Grosenbaugh, "Time-domain numerical simulation of ocean cable structures," Ocean Eng., 33, 1373-1400, doi:10.1016/j.oceaneng.2005.07.012, 2006.

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1 Jul 2006

This paper describes the numerical features of WHOI Cable, a computer program for analyzing the statics and dynamics of oceanographic cable structures. The governing equations include the effects of geometric and material nonlinearities, bending stiffness for seamless modeling of slack cables, and a model for the interaction of cable segments with the sea floor. The program uses the generalized-α time integration algorithm, adaptive time stepping, and adaptive spatial gridding to produce accurate, stable solutions for dynamic problems. The nonlinear solver uses adaptive relaxation to improve robustness for both static and dynamic problems. The program solves surface and subsurface single-point mooring problems, multi-leg and branched array systems, and towing and drifting problems. User specified forcing can include waves, currents, wind, and ship speed.

Cruise Report: DOLCE VITA 1 and 2, 31 January - 24 February and 26 May - 15 June, 2003

Lee, C., and J. Gobat, et al., "Cruise Report: DOLCE VITA 1 and 2, 31 January - 24 February and 26 May - 15 June, 2003," APL-UW TR 0409, February 2005.

28 Feb 2005

An Observational Array for High-Resolution, Year-Round Measurements of Volume, Freshwater, and Ice Flux Variability in Davis Strait: Cruise Report for R/V Knorr 179-05, 22 September - 4 October 2004

Lee, C.M., B. Petrie, J.I. Gobat, V. Soukhovtsev, J. Abiel, K. Van Thiel, and M. Scotney, "An Observational Array for High-Resolution, Year-Round Measurements of Volume, Freshwater, and Ice Flux Variability in Davis Strait: Cruise Report for R/V Knorr 179-05, 22 September - 4 October 2004," APL-UW TR 0408, November 2004

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30 Nov 2004

As part of the Freshwater Initiative sponsored by the National Science Foundation Office of Polar Programs, a team of scientists from the Applied Physics Laboratory of the University of Washington and the Bedford Institute of Oceanography are investigating freshwater exchange through Davis Strait. This 300-km-wide strait sits between Baffin Island and the west coast of Greenland and acts as the gateway for waters passing between the Canadian Arctic Archipelago and the subpolar North Atlantic. In autumn 2004 the R/V Knorr cruise 179-05 undertook the first of three one-year mooring deployments. Six subsurface moorings, one off-axis sound source, eight bottom landers, and two Seagldiers were deployed successfully slightly north of the Davis Strait sill. Four cross-strait hydrographic lines, complete with sampling for chemical tracers, characterized water mass variability from the southern end of Baffin Bay to the northern tip of the Labrador Sea. The moored array will be recovered, serviced, and redeployed annually for a period of at least three years.

Inventions

Integrated RF Relay-GPS Board for Seaglider

Record of Invention Number: 48007

Jason Gobat

Disclosure

22 Mar 2017

Temperature Microstructure Instrument Controller Logger

Record of Invention Number: 47906

Luc Rainville, Jason Gobat, Adam Huxtable, Geoff Shilling

Disclosure

6 Dec 2016

Passive Miniature Acoustic Recorder for Seaglider

Record of Invention Number: 47208

Ben Brand, Jason Gobat, Adam Huxtable, Geoff Shilling

Disclosure

22 Jan 2015

More Inventions

Seaglider Systems Testbed

Record of Invention Number: 46641

Jason Gobat

Disclosure

27 Aug 2013

Buoyancy Engine Improvements for High-Pressure FIrst Stage and Higher Efficiency

Record of Invention Number: 46492

Frederick Stahr, Jason Gobat, Adam Huxtable, Mike Johnson, Ben Jokinen

Disclosure

1 May 2013

Science Processor for Seaglider

Record of Invention Number: 46344

Peter Sabin, Geoff Shilling, Jason Gobat

Disclosure

4 Jan 2013

Seven DOF Attitude Sensor for Seaglider

Record of Invention Number: 46345

Jason Gobat

Disclosure

4 Jan 2013

Single Voltage Battery Architecture for Seaglider

Record of Invention Number: 46343

Adam Huxtable, Fritz Stahr, Ben Jokinen, Jason Gobat

Disclosure

4 Jan 2013

ARM Processor Based Motherboard for Seaglider

Record of Invention Number: 46329

Peter Sabin, Chris Siani, Geoff Shilling, Jason Gobat

Disclosure

10 Dec 2012

Control Software for Deepglider

Record of Invention Number: 45824

James Bennett, Jason Gobat, Geoff Shilling

Disclosure

15 Oct 2011

Multi-stage Buoyancy System for an Underwater Vehicle

Record of Invention Number: 45456

Jason Gobat, Jim Osse, Frederick Stahr

Disclosure

10 Dec 2010

Ogive Fairing, Cover Hatch, and Wing Drawings

Record of Invention Number: 4149-Reg-0009

Jason Gobat, Adam Huxtable, Craig Lee, Charles Eriksen, Jim Osse

Disclosure

25 Mar 2010

Autonomous Logger Sensor Architecture for Seaglider

Record of Invention Number: 4273-Reg-0001

Jason Gobat, Geoff Shilling

Disclosure

27 Jan 2010

Integrative Observational Platforms (IOP) Mission Control WEb Software

Record of Invention Number: 4257-Reg-0001

Jason Gobat

Disclosure

12 Aug 2009

Seaglider Improvements (motherboard revisions and associated software support)

Record of Invention Number: 4149-Reg-0008

Jason Gobat, Peter Sabin, Geoff Shilling, Keith Van Thiel

Disclosure

23 Jun 2009

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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