taking the multibeam jump a rough guide based on experiments with reson multibeam echosounders 2011...
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Taking the Multibeam JumpA rough guide based on experiments
with RESON multibeam echosounders
2011 RESON User Conference
Jean-Guy Nistad & Mathieu Rondeau
Introduction
Example of survey well suited for small enterprises: bridge pier mapping
Introduction
Integrated (IMU + MBES), portable, pole-mounted solutions used on vessels of opportunity
RESON Hydrobat (source: RESON)
WASSP(source: ENL Electronic Navigation Ltd.
Introduction
• Problem: multibeam integration is complex• Solution: share lessons from experiences
with Seabat 7125 integration
Three requirements are of importance:
1. Measure all relative locations and sensor orientations2. Be aware of the sensor connection layout3. Anticipate the data processing workflow
Lever arms & orientations
Scenario 1
Y
X
-1.902m
X
Z
0.674m
-2.604m
0.596m
-3.512m
1.648m
0.665m-1.835m
-0.207m
SeaBat 7125POS/MV 320Reference Point
Y
X
Y
Z
Lever arms & orientations
Y vessel
Z vessel
R
+
X vessel
Z vessel
T
Defining the Ship Reference Frame
Pitch
Roll
+
Lever arms & orientations
Scenario 2
Y
YX
Z
X
Y
Z
X
-0.658m
-4.109m
-0.895m
-0.456m
-0.975m
0.275m-0.817m
Centre of gravity
Lever arms & orientations
X vessel
Y vessel Az
Y vessel
Z vessel
R
+
+
X vessel
Z vessel
T
+
Measuring the IMU mounting angles
Heading
Pitch
Roll
Lever arms & orientationsMeasuring the sonar mounting angles
Heading
Pitch
Roll
X vessel
Y vessel
Az
+
X vessel
Z vesselT
+
Y vessel
Z vessel
+
R30° starboard tilt
Lever arms & orientations
X vessel
Y vessel
Incidence of 90° starboard rotation of the IMU
X IMU
Y IMUAz+
Only detected with the 30° sonar tilt!
Lever arms & orientations
Roll stabilization issue with 30° sonar tilt
Quay side wall
Seabed
?
Missed side wall
No roll stabilizationRoll stabilization
Lever arms & orientations
• Almost same as scenario 2• Simulating an integrated pole-mounted system
Scenario 3
For integrated systems, IMU – MBES are factory aligned. How then should they relate to the SRF?
Y sonar
X sonar
Az+
X sonar
Z sonar
T
+
Y sonar
Z sonar
R
+
Heading
Pitch
Roll
Lever arms & orientations
Scenario 3
Connection Layouts
• Many different possible inter-sensor connection layouts
How does the chosen layout affect timing latency issues?
Connection Layouts
Full serial (RS232, RS422) + Sonar PC
+ =
Connection Layouts
Serial + USB between sonar and PC
+ =
Processing Box
USB
Connection Layouts
Serial + LAN between sonar and PC
+ =
Processing Box
LAN
Connection Layouts
Serial + LAN between sonar and PC
+ =
Processing Box
LAN
Connection Layouts
• Latencies will vary depending on chosen layout• The conventional patch-test will solve for GPS –
sonar latency but not IMU – sonar latency• 1 PPS is mistakenly seen as the ultimate solution to
all latency issues
How does one solve for IMU latencies?
Source: Lockhart, Arumugan, Precise Timing and TrueHeave® in Multibeam Acquisition and Processing
Timing latencies
Source: GeoSwath Plus Operation Manual
Data Processing Workflow
RESON Seabat 7125
QINSy
Hypack
CARISHIPS & SIPS
RESON Seabat 8101 HSX
XTF
PDS2000
S7KPDS
Raw bathymetry
More control in post-processing but harder to setup
Corrected bathymetry
Easier to setup but less control in post-processing
Conclusion
Other helpful tips:• Get familiar with standard hydrographic practices• Get friends in the Support department!
Many thanks toRESON, Applanix, CARIS & QPS