side scan sonars t alavosus klein associates
TRANSCRIPT
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
1/38
Marine & PowerSystems Group
Recent Developments in Side ScanSonar with Combined
Interferometric Bathymetry
Oceanology International 2010London, England
Timothy J. Alavosus, Ph.D.Director of Sales and Marketing
Sonar Products
L-3 Klein Associates
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
2/38
Marine & PowerSystems GroupIts All About the (Underwater) Image
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
3/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
The Benefits of Side Scan Sonar:
Excellent imagery (resolution, shadow detail) often not
possible with optics due to sea conditions
Long-range scanning possible (>1 km swath) Shallow, deep configurations available
AUV, ROV compatible
Can be easily deployed
CAD/CAC possible
The wreck of the Bungsberg; note how SSS shadow imagery
helps reveal important additional information
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
4/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
S5000 V2 Range = 150m
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
5/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
S5000 V2 Range = 150m
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
6/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
The Downside of Side ScanSonar:
SSS is two-dimensional.The images are great, and
give us a wealth of
information; but even with
good shadow imagery,
essentially the side scan
world is flat.
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
7/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
The Downside of SideScan Sonar:
Without bathymetricdata, and thus it can
be almost impossible
to determine the
relative spatial
orientation of the
bottom. This can be
important for many
applications.
Bottom appears completely flat
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
8/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
The Benefits of Adding Bathymetry: Bathymetry gives you the third dimension. Instead of
guessing about topography, it gives us contour lines and
excellent imagery, different than, yet complimentary to, SSS.
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
9/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
The Benefits of AddingBathymetry:
The benefits extend
further than
topographical issues.Bathymetry also
provides the z-axis
measurement of objects
on the ocean floor.
With side scan alone,
this had to be done by
making an estimation
from shadow heights.
The shadow method
often requires multiple
passes on an object. Shadow z measurement Bathy z measurement
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
10/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
The Benefits ofBathymetry :
Back to our firstimage; still looks
pretty flat, yes?
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
11/38
Marine & PowerSystems Group
Combining Side Scan Sonar
with Bathymetry
The Benefits of Bathymetry:
Looks can be deceiving,
especially in a 2-
dimensional world. In fact,
theres quite a differencebetween the port and
starboard sides of our
image.
Even with good chart
data, we could not have
interpreted this from SSS
data alone.
>10m difference in slope not discernable from SSS alone
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
12/38
Marine & PowerSystems GroupInterferometric Bathymetry
Why Interferometry?
Classic Multi-beam
echosounder bathymetry is
an excellent tool for deep
water measurements.
However, in shallow water
environments, it is limited by
the width at which it can take
readings. Its a simple
geometry problem, limiting
swath width to 3-5 times
water depth.1Image courtesy NOAA Coast Survey
Multi-beam echosounder Towed Side Scan Sonar
1. Gostnell, C. et al., NOAA Test and Evaluation of Interferometric Sonar Technology, Proceedings of the 2006
Canadian Hydrographic Conference, 15 May 2006
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
13/38
Marine & PowerSystems GroupMulti-beam Bathymetry Geometry
Great in Very Deep Environments: Misses a lot in Shallow Environments:
Angle =
Angle =
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
14/38
Marine & PowerSystems GroupInterferometry Bathymetry Geometry
Limited in Deep Environments: Excellent in Shallow Environments:
(Just not feasible for great depths)
Provides excellent Coverage Rate
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
15/38
Marine & PowerSystems GroupInterferometry Geometry: Stand-Off
Interferometry has much wider area forrecognition:
Multi-beam has trouble ensonifyingstand-off targets:
Object must be within beam spread;
usually close to z-axis; results in
poorer imagery. This can also be a
dangerous hazard to navigation.
Interferometry naturally allows better
stand-off ensonification, especially
farther away from z-axis; results in
better imagery and safer surveys.
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
16/38
Marine & PowerSystems GroupInterferometric Bathymetry
Why Interferometry?
In contrast,
interferometric
bathymetry (also
known as PhaseDifferencing
Bathymetric Sonar,
PDBS) provide
high-resolution
wide-swath
bathymetry inshallow water with
swaths of 10-15
times system
altitude.2Shallow-water interferometric bathymetry (max. depth 18m)
2. Ibid
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
17/38
Marine & PowerSystems Group
The Klein System 5000 V2
With Bathymetry
A combined system:
Chirp, true Multibeam, Side Scan Sonar
Interferometric Bathymetry
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
18/38
Marine & PowerSystems Group
System 5000 v2 with
Interferometric Bathymetry
AUV, Pole, Vessel, or Towed Mount Configurations: Vessel or Pole mount best for hydrographic survey
Topography augments side scan in towed operation
AUV 5000 v2 BATHY 5000 v2 BATHY Pole-Mount AUV 5000 v2 Towfish
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
19/38
Marine & PowerSystems Group
Specifications: Side-Scan Sonar:Multi-beam
5 Beams/side
FM Chirp
InterferometricBathymetry:
Frequency 455 kHz 455 kHz
Along Track Res 10 cm to 38m
20 cm at 75m
37 cm at 150m
50 cm at 250m
0.4
Across Track Res 3.75 cm 5.5 cm
Tow Speed 2 to 10 knots 5-6 knots (typical)
Depth Rating 500m 200m
Max Range 250m/side 125m/side
The Klein System 5000 V2
With Bathymetry
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
20/38
Marine & PowerSystems Group
The Klein System 5000 V2
With Bathymetry
Towfish System
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
21/38
Marine & PowerSystems GroupKlein 5000 v2 Interferometric Bathymetry
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
22/38
Marine & PowerSystems GroupKlein 5000 v2 Interferometric Bathymetry
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
23/38
Marine & PowerSystems GroupKlein 5000 v2 Interferometric Bathymetry
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
24/38
Marine & PowerSystems GroupKlein 5000 v2 Interferometric Bathymetry
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
25/38
Marine & PowerSystems GroupKlein 5000 v2 Interferometric Bathymetry
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
26/38
Marine & PowerSystems GroupKlein 5000 v2 Interferometric Bathymetry
The Wreck of the Empire Knight
Th Kl i S t 5000 V2
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
27/38
Marine & PowerSystems Group
The Klein System 5000 V2
With Bathymetry
Bow/Hull-Mount System:
IHO-Quality Bathymetry
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
28/38
Marine & PowerSystems GroupKlein S5000 V2 Bathymetry Bow Mount
UNH R/V Coastal Surveyor
Bow mounted underwater
component
Applied Microsystems Micro SVarray sound speed probe
Applanix POS/MV combined GPS
navigation, motion and heading
ODOM Digibar Pro sound speed
profiler
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
29/38
Marine & PowerSystems GroupKlein S5000 V2 Time Synchronization
Time synchronization of sonar, motion andnavigation data is critical to producing
accurate hydrographic data
Hardware in TPU used to precisely
synchronize time tagging ofsonar/sensor/navigation data to 1PPS
pulse from navigation system (or external
time reference)
Some motion sensors provide time taggeddata referenced to GPS time
Resultant total timing errors < 50 seconds
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
30/38
Marine & PowerSystems GroupKlein S5000 V2 Bathymetry Test Area
Portsmouth Harbor Survey
1500 x 600 meter area
Speed 5 6 knots
Calm sea, low tide
7 north south lines
Focused on sandy area northeast
Depth 10 25 meters
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
31/38
Marine & PowerSystems Group
Both SDF range / angle and raw(complex stave) data were collected
(Data can be logged in SDF, GSF or
XYZ format)*
Range / angle (roll stabilized), motionand sound speed profile data were
processed using Hypack 9.0 software
Line spacing was set to range scale
(75m) to facilitate viewing nadir area andprovide complete overlap of adjacent
swath data
*In addition to processed data, raw stave data can be logged
together with all motion, navigation, and heading and sound
speed data. This permits reprocessing of both side scan and
bathymetry data in a post processing environment
Data Collection and Processing
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
32/38
Marine & PowerSystems Group
Data in image was cut and joined to
show excellent agreement in data,
both in depth and position
Sand waves 40 to 120 cm high
Spot check of grid cells to either
side of cut were within 20 cm of
each other
Sand waves between lines
2 and 3
0.5 x 0.5 m grid
Data Collection and Processing
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
33/38
Marine & PowerSystems GroupKlein S5000 V2 Bathymetry XYZ Data
Data from lines 2 4
Inner regions cut and joined
Outer regions single swaths
Sand waves at left can be seen to
edge, although noise is increasing
Feature at lower left is about 1 meter
high by 10 meters across
Upper right region used for depthvariation analysis
There is intentionally a Nadir Gap in this
image, for our testing purposes.
Si l S h D h V i i
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
34/38
Marine & PowerSystems GroupSingle Swath Depth Variation
Hypack cell editor used for
standard deviation
measurement
Variation is for all pointswithin a grid cell
Data was gridded at 0.5 x 0.5 m and 1 x 1 m for
comparison (negligible difference)
Since no surface reference, variation attributed to sonar
0 10 20 30 40 50 60 70 800
10
20
30
40
50
S5000 V2 two-sigma depth variation
Meters from nadir
Depthvariation(cm.)
Kl i S 000 V2 P f
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
35/38
Marine & PowerSystems GroupKlein S5000 V2 Performance
At 15 meters altitude, with vessel
mount and proper calibration, the
S5000 V2 provides IHO Special
Order data to about 40m from the
nadir on each side.3
3. M. C. Moser, M.C., Bathymetric Uncertainty Model for
the L-3 Klein 5410 Sidescan Sonar MS Thesis, UNH
Ocean Engineering, 2009. Note: Nadir is assumed to be
20 from center on either side.
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
36/38
Marine & PowerSystems GroupKlein 5000 v2 Bathymetry Summary
The Klein S5000 V2 System is a
hydrographic survey system whichhas the ability to simultaneously
collect IHO quality swath bathymetry
and high resolution multi-beam side
scan sonar data in a fully corrected
and geo-referenced data set System demonstrated to meet IHO
Special Order requirements up to 12X
water depth
The dual functionality of the Klein
S5000 V2 effectively allows two
surveys to be accomplished in one
pass saving significant ship time and
expense
AUV 5000 pipe inspection surveyImage courtesy of SHOM, GESMA & ECA
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
37/38
Marine & PowerSystems GroupKlein 5000 v2 Bathymetry Live
-
7/28/2019 Side Scan Sonars T Alavosus Klein Associates
38/38
Marine & PowerSystems Group
For More Information,Please Contact
Tim Alavosus
Director of Sales and MarketingL-3 Klein Sonar Products
(+1) 603.339.1928
Thank You!