Comparing Survey Results Between a

Multibeam Sonar and a Multi-Channel

Depth-Capable ADCP

PAT SANDERS, TECHNICAL DIRECTOR, HYPACK YSI

HAROLD ORLINSKY, GENERAL MANAGER, HYPACK YSI

CHC 2016 Conference

The SONTEK M9 Hydrosurveyor ADCP

• ADCP Current Measurements

• Bottom Track Navigation Data

• Echosounder Data

• Capable of measuring depths

as small as 10cm!

• Vertical transducer is 500kHz

• Four transducers at 3MHz

• Four transducers at 1MHz

• It switches automatically

between the 3MHz and 1MHz

transducers as you go from

shallow to deep water.

3MHz and 1MHz transducers are angled

outwards at 25˚ from nadir in a Janus

pattern

Coverage of the system

With the beams at 25 degrees on each side, we can achieve a

coverage of almost 1 times water depth

Coverage = 2 x tan(25) x water depth

In 10 meters of water, the system will give the user an effective

swath of 9.6 meters. Compared to a traditional single beam system

using a 3 degree transducer, and giving a footprint size of 0.5m,

there is a tremendous advantage using this tool

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Our Test Area: Providence, RI

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Surveyed on 1/22/2016 by

USACE with R2Sonic 2040

multibeam and Applanix

POS-MV

Surveyed on 1/29/2016 by

USACE with a SONTEK M9

ADCP and Applanix POS-

MV

Survey Hardware:

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R2Sonic

2040

Applanix

POS-MV

SONTEK

Castaway

HYPACK/HYSWEEP

SURVEY

Network Switch

Bluetooth

Multibeam Configuration

SONTEK

M9

Applanix

POS-MV

SONTEK

Castaway

HYPACK SURVEY

Network Switch

Bluetooth

M9 Configuration

RS-232

PROCESSING

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HSX

FilesMBMAX

XYZ

File

TIN

MODEL

LNW File

DXF

Contours

Sections

R2Sonic Multibeam Data

RAW

FilesMBMAX

XYZ

File

TIN

MODEL

LNW File

DXF

Contours

Sections

RAW

FilesSBMAX

Edited

Files

TIN

MODEL

LNW File

DXF

Contours

Sections

SONTEK M9 Data (MBMAX)

SONTEK M9 Data (SBMAX)

CSV

M9 Data in MBMAX

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M9 Data in SBMAX

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Contour Comparisons

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DREDGE

AREAS

Contoured every 5’ in HYPACK’s TIN MODEL

• Good agreement on slopes

• Noise in M9 data set generates multiple contour artifacts (unsmoothed data)

Multibeam Contours in Blue M9 - MBMAX Contours in Red

Contour Comparisons

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DREDGE

AREAS

Contoured every 5’ in HYPACK’s TIN MODEL

• Good agreement on slopes

• Noise in M9 data set generates multiple contour artifacts (unsmoothed data)

Multibeam Contours in Blue M9 - SBMAX Contours in BLACK

Comparison of Sections Through TIN MODELS

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Multibeam M9 from MBMAX M9 from SBMAX

Why it’s good to have complete coverage…

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Multibeam M9 from MBMAX M9 from SBMAX

Statistical Comparisons

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XYZ MB TIN

MODEL

XYZ

DifferencesMBMAX

M9

XYZ

MB TIN

MODEL

XYZ

DifferencesSBMAX

M9

Mean Difference (cm) Standard Dev. (cm)

MB vs. M9 MBMAX 9 21

MB vs. M9 SBMAX 11 26

The differences between the M9 data processed in MBMAX and SBMAX

is due to different treatments of Sound Velocity (MBMAX routine is better).

Summary

•The depths from the SONTEK

M9 Hydrosurveyor can meet

IHO Order 1A/B survey

standards when combined with

a quality positioning system.

• It’s not going to replace your

multibeam system, but for

hydrographers interested in

obtaining simultaneous current

and depth measurements, it

can reduce redundant systems.

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