facing challenges with new techniques: southeast alaska to
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Facing Challenges with New Techniques: Southeast Alaska to the Aleutian Islands
Bob Richards, Andy Orthmann, Dean Moyles and Carol Lockhart Project thanks to JOA and Assoc.
Fugro Pelagos, Inc. San Diego, CA
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Past Alaska Surveys
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NOAA 2007
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Survey Platforms
• Davidson– Mother Ship– Reson 8111– Bottom Samples
Davidson
D2R2
• R2/D2– Reson 8101– Bottom Samples– Capable of Shoreline
Verification
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Concept
• Due to the magnitude of the project and the areas to be surveyed, we thought this could be the right environment for a tilted head.– Survey Plan and Breakdown (Chatham Strait and Krenitzin Islands):
• Total of 22 Survey Sheets.• Approx. 700 Sq NM area to survey.• Approx. 350 NM of coastline to survey and verify.
• Fugro Pelagos, Inc. (FPI) has been conducting surveys with a rotated MB head since 1999.– Normally used for :
• Breakwater Surveys - where data is require to the water line.• Reservoir Surveys - volume computations.• Navy Surveys (vertical profile of berthing walls).
– Survey Technique.• Conventional method we use is to always stay on our data in near shore
areas.
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Shoreline Skiff (a.k.a. Lil’ Dude)
• Reson 8125 (rotated ~30 degrees to starboard)• 4m survey work• Shoreline Verification• Transit @ 25-30 knots (with pole up)
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Tilting the sonar head
NO ROLL ANGLE15° ROLL ANGLE30° ROLL ANGLE
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As depth increases, more data is lost than gained
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Survey Operations
• Triton ISIS for data acquisition• Bathy Pro for Real-time display• WinFrog (Navigation Software)
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Survey Operations
• Instead of having to run multiple lines to achieve the 4m contour, it usually took just one.
• Color coded DTM’s and NOAA charts were displayed as background layers in either ISIS (Bathy Pro) or WinFrog.
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Examples
• 8101 data from R2 (No Tilt).
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Examples
• Combined Data Set (8101 from R2 and Rotated 8125)
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Swath Editor
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Conclusions
• Pros:– The SAFETY factor.– Increased productivity on achieving the 4m contour.– Increased productivity for shoreline verification.
• Cons:– Could only run lines in one direction when conducting the nearshore
work.
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Need for LIDAR Recon Data
• 100% multibeamcoverage w/ shoreline verification required
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Need for LIDAR Recon Data
• 100% multibeamcoverage w/ shoreline verification required
• Existing chart data sparse
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Need for LIDAR Recon Data
• 100% multibeamcoverage w/ shoreline verification required
• Existing chart data sparse
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Need for LIDAR Recon Data
• 100% multibeamcoverage w/ shoreline verification required
• Existing chart data sparse
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Need for LIDAR Recon Data
• 100% multibeamcoverage w/ shoreline verification required
• Existing chart data sparse
• Complex ledges and rocks
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Need for LIDAR Recon Data
• 100% multibeamcoverage w/ shoreline verification required
• Existing chart data sparse
• Complex ledges and rocks
• Extreme tidal currents to 15 kts or more in narrow constrictions
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Need for LIDAR Recon Data
• 100% multibeamcoverage w/ shoreline verification required
• Existing chart data sparse
• Complex ledges and rocks
• Extreme tidal currents to 15 kts or more in narrow constrictions
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Need for LIDAR Recon Data
• 100% multibeamcoverage w/ shoreline verification required
• Existing chart data sparse
• Complex ledges and rocks
• Extreme tidal currents to 15 kts or more in narrow constrictions
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LiDAR Survey of Mitchell Bay
Spot Spacing 5m x 5m 3m x 3mAltitude 400 m 400 m
Swath Width 230 m 130 mFlying Speed 180 knots 127 knots
Coverage 100% 200%Survey Time ~ 6 hrs ~ 22 hrsSurvey Time ~ 6 hrs ~ 22 hrs
Spot Spacing 5m x 5m 3m x 3mAltitude 400 m 400 m
Swath Width 230 m 130 mFlying Speed 180 knots 127 knots
Coverage 100% 200%
PetersburgPetersburg
Mitchell BayMitchell Bay
KekuKekuStraitStrait
ChathamChathamStraitStrait
SitkaSitka
KakeKake
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SHOALS 3000-T LIDAR System
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Use of LIDAR Recon Data
• Geo-referenced photomosaics
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Use of LIDAR Recon Data
• Geo-referenced photomosaics
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Use of LIDAR Recon Data
• Geo-referenced photomosaics
• XYZ of LIDAR soundings used to create a DTM
LIDAR DTM
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Use of LIDAR Recon Data
• Geo-referenced photomosaics
• XYZ of LIDAR soundings used to create a DTM
• DTM color coded to differentiate between shallow and deeper areas
LIDAR DTM
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Use of LIDAR Recon Data
• Geo-referenced photomosaics
• XYZ of LIDAR soundings used to create a DTM
• DTM color coded to differentiate between shallow and deeper areas
• Survey crew used DTM to navigate in real-time, surveying from 4m out utilizing the rotated 8125
LIDAR DTM
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Use of LIDAR Recon Data
• Geo-referenced photomosaics
• XYZ of LIDAR soundings used to create a DTM
• DTM color coded to differentiate between shallow and deeper areas
• Survey crew used DTM to navigate in real-time, surveying from 4m out utilizing the rotated 8125
Multibeam DTM
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Use of LIDAR Recon Data
• LIDAR DTM at 5m resolution gave indication of shoals so they could be avoided
LIDAR DTM Multibeam DTM
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Use of LIDAR Recon Data
• LIDAR DTM at 5m resolution gave indication of shoals so they could be avoided
• Pinnacle-like features were not as obvious in LIDAR DTM
LIDAR DTM Multibeam DTM
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Benefits of LIDAR Recon Data
• Safety: We could avoid dangerous, uncharted features
Chart Chart with LIDAR DTM
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Benefits of LIDAR Recon Data
• Safety: We could avoid dangerous, uncharted features• Speed: We could increase our survey speed
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Benefits of LIDAR Recon Data
• Safety: We could avoid dangerous, uncharted features• Speed: We could increase our survey speed• Able to access and multibeam areas we otherwise might
not have attempted to reach
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Benefits of LIDAR Recon Data
• Safety: We could avoid dangerous, uncharted features• Speed: We could increase our survey speed• Able to access and multibeam areas we otherwise might not have
attempted to reach• Increased efficiency: Could open up line spacing and run lines more
directly
Normal “on data”approach
More direct approach
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Side-Looking Survey Ops
Cht’d Rk
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Aided with Shoreline Verification
RSD Item
Cht’d RkRSD Item
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Time Savings
Estimated: 36.4 days
Concerned if this was enough time because of the lack of data to plan on
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Time Savings
During Survey Ops forBoth areas:
Submitted 140 DTN’s
Documented 5228 Dp’s
Took 325 Bottom Samples
Estimated: 36.4 days
Actual: 15.3 days (cumulative)
Time Savings: 21.1 days
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Facing Challenges with New Techniques: Southeast Alaska to the Aleutian Islands
Bob Richards, Andy Orthmann, Dean Moyles and Carol Lockhart
Fugro Pelagos, Inc. San Diego, CA
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