Results of the RV Simon Stevin EM2040 Sea Acceptance Test ... SURVEY 23/07/2012 @ 300 kHz CROSS SECTION

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  • http://economie.fgov.be

    Results of the RV Simon Stevin EM2040 Sea Acceptance Test and comparison with EM3002D data from

    the HS Ter Streep and RV Belgica.

    Cattrijsse Andre, Degrendele Koen, De Mol Lies, Naudts Lieven, Roche Marc, T’Jampens Michiel, Vanparys Kris, Versteeg Wim and Verstraeten

    Johan

    http://www.vliz.be/NL/HOME

  •  A new research vessel, the

    Simon Stevin

     A new project to map the

    entire Belgian Continental

    Shelf

     And troubles with the

    EM2040 on board the Simon

    Stevin

    Why do we always

    have problems with

    multibeams?

    A mix of the following topics:

  • • Flag: Belgium

    • Port of registry: Ostend

    • Length: 36 m • Beam: 9.4 m • Draught: 3.5 m • Maximum speed: 12 kn

    • Area of operations: Southern Bight of the North Sea & eastern part of the English Channel

    • Physical oceanography

    • Fisheries research

    • Marine geology

    • Microbiology

    • Chemical oceanography

    • Geochemistry

    • Maritime archaeology

    • Marine pollution

    • Year of construction: 2012

    • Shipbuilder: Damen Shipyards Group

    May 2012: the new RV Simon Stevin

    http://economie.fgov.be

  • http://economie.fgov.be

    Research Facilities Vlaams Instituut voor de Zee vzw Flanders Marine Institute VLIZ – InnovOcean site

    Acoustic equipment

    • EM2040 Single Head

    • Draught sensor : ATM

    • SV profiler : Valeport

    • Mini SV sensor : Valeport

    • Octans IV from IXSEA

    • RTK GPS MGB Tech (LRK-RTK)

    • ADCP : RDI instruments, 600kHz

    • Odom CV300 : 200 & 33kHz

    • Singlebeam (navigation) : 50kHz (JRC, jfe-380/200)

    • Speedlog : 2 MHz (JRC, jln-205)

    May 2012: the new RV Simon Stevin

    http://www.vliz.be/NL/HOME

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    SAT area 1: flat gravel area

    Belgica EM3002D SAT area 1 reference model Min depth = -27.6 m Max depth = -29.3 m

    ~ 200 m

    SURVEY 23/07/2012 @ 300 kHz CROSS SECTION (x and y in m) Along nadir of line 1, across lines 3, 4 and 5

    1

    4 3

    5

    Without tide reduction

    0 50 100 150 200 250 300 350 400 450

    -32.6

    -32.4

    -32.2

    -32

    -31.8

    -31.6

    -31.4

    July 2012: SAT of the Simon Stevin EM2040

  • http://economie.fgov.be

    With tide reduction

    0 50 100 150 200 250 300 350 400 450 500

    -28.6

    -28.5

    -28.4

    -28.3

    -28.2

    -28.1

    -28

    -27.9

    -27.8

    CROSS SECTION (x and y in m) Along nadir of line 1, across lines 3, 4 and 5

    = 0.3 m

    Complete inability to model a coherent surface from this data!

    SAT area 1: flat gravel area

    Belgica EM3002D SAT area 1 reference model Min depth = -27.6 m Max depth = -29.3 m

    ~ 200 m

    SURVEY 23/07/2012 @ 300 kHz

    1

    4 3

    5

    July 2012: SAT of the Simon Stevin EM2040

  • http://economie.fgov.be

    Real-time HEAVE (in m) statistics:

    -0.4

    -0.3

    -0.2

    -0.1

    0

    0.1

    0.2

    0.3

    1

    3 4

    5

    + ? heading and vessel speed dependent

    0 m

    SAT area 1: flat gravel area

    Belgica EM3002D SAT area 1 reference model Min depth = -27.6 m Max depth = -29.3 m

    ~ 200 m

    SURVEY 23/07/2012 @ 300 kHz

    1

    4 3

    5

    July 2012: SAT of the Simon Stevin EM2040

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    August 2012: dynamic draught and heave tests

    Influence of heading and vessel speed?

     Impact of speed and heading on pitch and heave

    -0.5

    -0.4

    -0.3

    -0.2

    -0.1

    0.0

    0.1

    0.2

    0.3

    0.4

    0.5

    5 kt 7 kt 8 kt 9 kt 10 kt 11 kt

    Pitch (mean, °)

    Vessel speed

    0.0

    0.1

    0.2

    0.3

    0.4

    0.5

    0.6

    0.7

    5 kt 7 kt 8 kt 9 kt 10 kt 11 kt

    Heave (range, m)

    Vessel speed

    E N S W -0.2

    -0.1

    0.0

    0.1

    0.2

    Heave (mean, m)

    Vessel heading

     Can dynamic draught explain the large differences in bathymetry?

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    50 sec

    Heave signal:

    slowly undulating during a single track (with constant speed and heading)

     Problem with the motion sensor?

    August 2012: dynamic draught and heave tests

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    September 2012: Comparison of 3 multibeam systems

    Part of the project to chart the entire surface of the BCS with high resolution. Two federal agencies: • MUMM • FPS Economy

    RV Belgica EM3002D

    Two regional agencies • MDK - Afdeling Kust

    Ter Streep EM3002D • Flanders Marine Institute – VLIZ

    Simon Stevin EM2040

     Quality assessment and regular comparison between systems

    From Vera Van Lancker, MUMM

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    18/09/2012: measurements in a lock (Vandammesluis)

    HV Ter Streep EM3002D RV Belgica EM3002D RV Simon Stevin EM2040

    Zeebrugge harbor

    EM2040

    paving 4x2m

    September 2012: Comparison of 3 multibeam systems

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    16.57 m 16.57 m

    15.11 m

    -16,8 -16,6 -16,4 -16,2 -16,0 -15,8 -15,6 -15,4 -15,2 -15,0 -14,8 -14,6 -14,4

    27 32 37 42 47 52 57 62 67

    D e

    p th

    ( m

    )

    Distance (m)

    reference

    Ter Streep 18/09/2012

    Belgica 18/09/2012 shift 0.40m

    Simon Stevin 18/09/2012

    September 2012: Comparison of 3 multibeam systems

    Along track profile

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    16,2

    16,3

    16,4

    16,5

    16,6

    16,7

    16,8

    16,9

    D e

    p th

    ( m

    )

    “real” depth 16.57

    IHO SO

    Ter Streep Belgica

    mean ± 2 std

    Simon Stevin

    mean ± 2 std

    “real” depth 15.11

    IHO SO

    Ter Streep

    Belgica

    Simon Stevin

    14,8

    14,9

    15,0

    15,1

    15,2

    15,3

    15,4

    D e

    p th

    ( m

    )

     Only the central part of the swath is compared

    Bathymetry results

    September 2012: Comparison of 3 multibeam systems

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    full swath

    Stable gravel area:

    L0 (speed ~ 5 kt)

    EM2040 measurements: SURVEY 18/09/2012 @ 300 kHz

    L3 (speed ~ 10 kt) Same Heading Tide corrected

    -22.5

    0 500 1000 1500 2000 2500 3000 -25.5

    -25

    -24.5

    -24

    -23.5

    -23

    CROSS SECTION (x and y in m)

    L0 L3

    Medium dunes area Gravel area

    Locally, Z = 25 cm

    September 2012: EM2040

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    September 2012: EM2040

    Real-time heave low frequency fluctuations:

    SURVEY 18/09/2012 @ 300 kHz ANALYSIS OF THE L3 REAL-TIME HEAVE:

    0 500 1000 1500 2000 2500 3000 -1

    -0.5

    0

    0.5

    1

    1.5

    L3 (speed ~ 10 kt)

    1: Raw heave

    2: Filtered heave (moving average on 150 pings)

    3:  BATHY

    L3-L0

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    September 2012: EM2040

    Correlation with low frequency fluctuations of real-time heave:

    0 500 1000 1500 2000 2500

    -0.15

    -0.1

    -0.05

    0

    0.05

    0.1

    0.15

    0.2

    0.25

    0.3

    0.35

    Filtered heave (moving average on 150 pings, m) and  BATHY L3-L0 (m)

     Line by line correction of the bathymetry with the low

    frequency real-time heave signal…

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    September 2012: EM2040

    0 500 1000 1500 2000 2500 3000

    -24.5

    -23.5

    -22.5

    -25.5

    -25

    -24

    -23

    Line by line correction of the bathymetry with the low frequency real-time

    heave signal after tide correction:

    SURVEY 18/09/2012 @ 300 kHz line 0 (5 kt) and line 3 (10 kt)

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    November 2012: SAT part 2

    Visit and installation of different software for the OCTANS IV:

    SURVEY 22/11/2012 @ 300 kHz

    • No apparent bias (all median ~ 0 m) • All distributions symmetrical

     Heave low frequency artifact problem looks solved

     But still inconsistent bathymetry

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    -0,15

    -0,10

    -0,05

    0,00

    0,05

    0,10

    0,15

    -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

    ∆ m

    ea n

    ( m

    )

    Beam pointing angle (°)

    line 0 line 1 line 2 line 3 li