integrating autonomous underwater vehicle capability into ...€¦ · underwater transponder...

United States Fleet Forces Ready Fleet … Global Reach

Public Release; Distribution Unlimited

11

Integrating Autonomous Underwater Vehicle Capability into Hydrographic Operations

Susan Sebastian

Lawrence Haselmaier

R. Wade Ladner

Naval Oceanographic Office

Hydrographic Department

Canadian Hydrographic Conference

18 May 2016

The inclusion of names of any specific commercial product, commodity or service in this

presentation does not imply endorsement by the U. S. Navy or NAVOCEANO. The views

expressed in this presentation are those of the authors and do not necessarily reflect the

official policy or position of the Department of Navy, Department of Defense, nor the U.S.

Government.



2

Topics

1. Introduction to the Littoral Battlespace Sensing-

Autonomous Underwater Vehicle (LBS-AUV)

2. Operational methods required to meet

hydrographic standards

3. Understand the function of the onboard sensors

4. Horizontal and Vertical accuracy methods

5. Calibration and Mission Planning

6. Overall process flow

7. Conclusions



LBS-AUV REMUS 600

3

Emphasize bathymetric data collection to support hydrographic and

mine warfare survey requirements

Developed with the shallow water Kongsberg EM3002 multibeam sonar and

positioning capability to meet stringent accuracy requirements



Survey Operation

4



Parameters to consider include:

• the sortie duration (in time and distance)

• vehicle altitude and swath width

• number of lines and turns

• where and how many UTP transponders are needed (for

position updates)

• orientation of lines

• frequency of position updates

• speed of advance

• water depth

• vehicle altitude

• maximizing swath width, and other factors

Mission Planning Parameters



Acoustic Positioning

6

• Long Baseline multiple transponders

of known locations are pinged and

those slant ranges are used to

triangulate the vehicle position

• Ultra-Short Baseline (USBL) range and

bearing measurements are obtained

between a single transducer on a

surface vessel, such as the High

Precision Acoustic Positioning System

(HiPaP) and the vehicle multi-element

transducer



Underwater Transponder Positioning

7

• Complement to USBL acoustic positioning

• Key: tight integration between the range

measurements and the inertial navigation

system significantly improves the real-time

accuracy

• As few as one UTP transponder can be

deployed, centrally located

• Deploy multiple transponders to increase

range of survey area

• Position error increases between position

updates; drift limit controls line length

Covariance ellipse of

position error compresses in

vicinity of UTP transponderHegrenaes, et al. 2009



DVL-Aided INS

8

• Inertial navigation degrades, or drifts,

very rapidly with distance from the last

known location

• Inaccurate vehicle velocity and heading

are the primary obstacles to position

accuracy

• Doppler Velocity Log provides an

independent and reliable measurement

of the vehicle velocity to aid the INS in

detecting and mitigating the inertial

measuring unit (IMU) velocity error

http://www.rdinstruments.com/navigator.aspx

Teledyne RD

Instruments Workhorse

Navigator Doppler

Velocity Log



Position Drift Error Limit

9

Intended main line

Max.

allowable

drift error

• Vehicle must encounter a position update BEFORE exceeding the

allowable cross-track error

• Max. drift limit is primary parameter affecting length of the lines and

transponder placement

UTP

Transponder 1

UTP

Transponder 2

Last known

location

Acquire known

location after driftposition update

radius position update

radius



Mission Pattern

10

• Maneuvering has a significant impact on the drift

error

• Velocity error in the IMU becomes observable when

the measured acceleration can be compared to the

predicted centripetal acceleration

• Cancelling effect increases for shorter lines with

turns

Jalving, B., E. Bovio, Gade, K, 2003

Testing has demonstrated position drift of 0.1% of distance travelled

or 1m per kilometer! Remember this number!

7] Jalving Bjorn, Kenneth Gade, Kristian Svartveit, Are Willumsen, Robert Sorhagen, 2004,



UTP Transponder Layout

11

• Ensure 2km position update radius is commensurate with the

specific environmental conditions

• The transponders positioned with the HiPaP

• Position drift error bounds the survey line length (0.1% dist.

travelled, or 1m/km)



Real Time Position Accuracy: NavP

12

Jalving Bjorn, Kenneth Gade, Kristian Svartveit, Are Willumsen, Robert

Sorhagen, “DVL Velocity Aiding in the HUGIN 1000 Integrated Inertial

Navigation System,” 2004

• Rigorous real-time navigation

solution provided by Kongsberg

Navigation Processing Suite

(NavP)

• Provides complete time

synchronization and integration

of onboard navigation and

environmental sensors

• NavP can be remotely initialized,

monitored, and supplied with

surface position via modem

• Uses the tight coupling between

the INS with the UTP as well as

all navigation and environmental

sensor inputs

• Real-time Kalman filter improves

the best accuracy for position



Navigation Post-Processing NavLab

13

Backward/forward processing

can significantly improve the

final solution

Navigation Laboratory (NavLab)

is a powerful and versatile tool to

estimate the vehicle’s position,

attitude and velocity

NavLab uses all measurements

and applies the optimal

smoothing algorithm in the

NavLab Kalman filterGade, Kenneth “NAVLAB, a Generic Simulation and Post-processing

Tool for Navigation,” European Journal of Navigation, Volume 2,

Number 4, November 2004, The Netherlands



Navigation Post-Processing Result

14

Position accuracy data from the 2011 test period in Sidney, Canada show DVL-

aided INS (without UTP) before and after post-processing

Saw tooth pattern of error (blue line) is typical where position error ramps up

rapidly from known positions, and then falls sharply when an updated position is

obtained or as a result of vehicle maneuvers

[3] Cronin, Doug, Dave Small, Shannon Byrne, 20-24 February 2012, New Zealand



Tide Measurement Options

GPS Buoy: records changes in water levels relative to the

ellipsoid; tide data must be continuous throughout AUV operations

Liquid Robotics Wave Glider SHARC

(Sensor Hosting Autonomous Remote Craft): long-duration

Unmanned Surface Vehicle (USV) that utilizes wave energy

for propulsion and solar panels for energy;

in addition to sending position updates to AUV,

can act as a GPS buoy

15

Virtual Tide Corrector (VTC) from nearby

vessel: promising technique under

development

Challenge: Measure tides without

land-based tide gauge![11] Haselmaier, Lawrence, September 2015



Twofold Calibration

16

Cal1: Bias in pressures between vehicle

and deck-mounted barometer Calibrations required prior to

data collection!

Barotroll mounted at deck level

Weatherpak mounted on mast

Baro

me

tric

Pre

ss

ure

(m

b)

Time (days)

Cal2: Multibeam Patch

Test for sensor

alignment error



Constant Altitude & Swath Width

17

Advantage of the AUV data collection

• Vehicle stays at constant height

• Swath width remains the same whether the

depths grow deeper or shallower.

• Up and down slope vice parallel to depth

contours

• No data gaps between swaths; very

efficient

<50m

>200m

Entire swath constant 120m



Sortie and Mission Planning

Vehicle stamina: 24 hours

During 20 hours on-line, six lines of data can be acquired each sortie



Main-Line Development

19

• Multiple sorties may be stacked to reduce the amount of transponder

repositioning



Cross-Line Comparisons

20

• Cross-line data should be the most accurate available

• QC tool: collect first so routine processing of main-line data is evaluated

as the mission progresses

• Cross-line placement near the transponder(s) is the obvious location



Overall Process Flow

21

Increased survey manning to 3 Lead Positions from

Hydrographic Department



Conclusions

22

1. NAVOCEANO is flagship for implementing US Navy

unmanned capabilities

2. UTP tightly coupled with the DVL-Aided inertial allows

required position accuracy for hydrographic standards

3. Ellipsoid-referenced survey techniques show promise in

extracting the needed water level corrections

4. Large strides have been made and operational use now

needed to further define process and realize capability

5. LBS-AUV operations is an exciting new area for

hydrographic and mine warfare applications



Questions?

23



Cited References

[1] Nicholson, J. W., PhD., Capt., USN, et. al., “The Present State of

Autonomous Underwater Vehicle (AUV) Applications and

Technologies,” Marine Technology Society Journal, Vol. 42, Number

1, Spring 2008

[2] Purcell, Mike, “New capabilities of the REMUS Autonomous

Underwater Vehicle,” Woods Hole Oceanographic Institution, IEEE,

2000

[3] Cronin, Doug, Dave Small, Shannon Byrne, “REMUS 600

Autonomous Undersea Vehicle Planning, Acquisition, and

Processing Workflow,” Proceedings Shallow Survey 2012, 20-24

February 2012, New Zealand

[4] Long and ultra-short baseline acoustic positioning systems:

https://en.wikipedia.org/wiki/Long_baseline_acoustic_positioning_sy

stem and https://en.wikipedia.org/wiki/Ultra-short_baseline

[5] Hegrenaes, Oyvind, Kenneth Gade, Ove Kent Hagen, Per Espen

Hagen, “Underwater Transponder Positioning and Navigation of

Autonomous Underwater Vehicles,” Proceedings of The Mts/Ieee

Oceans Conference and Exhibition, Biloxi, 2009

[6] Jalving, B., E. Bovio, Gade, K., “Integrated Navigation for AUVs

For REA Applications,” NATO Underwater Research Center

Conference Proceedings from MREP2003, NATO Underwater

Research Center May 12-15, 2003, La Spezia, Italy, available

www.navlab.net

[7] Jalving Bjorn, Kenneth Gade, Kristian Svartveit, Are

Willumsen, Robert Sorhagen, “DVL Velocity Aiding in the

HUGIN 1000 Integrated Inertial Navigation System,”

Modelling, Identification and Control Journal, Norway, 2004,

Vol 25, No 4, pp. 223-236.

[8] Zhao, Lin and Wei Gao, "The Experimental Study on

GPS/INS/DVL Integration for AUV,” IEEE Xplore, October

2008, by, Automation College, Harbin Engineering

University.

[9] Fulton, Thomas F., “Navigation Sensor Data Fusion for

the AUV Remus,” Marine Technology Special Edition,

Volume 38, Number 1 (ISSN 0025-3316), January 2001

[10] Gade, Kenneth “NAVLAB, a Generic Simulation and

Post-processing Tool for Navigation,” European Journal of

Navigation, Volume 2, Number 4, November 2004, The

Netherlands

[11] Haselmaier, Lawrence, “Computation of a Virtual Tide

Corrector to Support Vertical Adjustment of AUV Multibeam

Data,” MS Thesis, University of New Orleans, New Orleans,

LA, September 2015

[12] RD Instruments, “Workhorse Navigator Doppler Velocity

Log (DVL),” http://www.dvlnav.com/pdfs/navbro.pdf, June

2003.

24

integrating autonomous underwater vehicle capability into ...€¦ · underwater transponder...

Documents