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2/23/21
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Web: http://oceanai.mit.edu/2.680
Email: Mike Benjamin, mikerb@mit.eduHenrik Schmidt, henrik@mit.edu
2.680Unmanned Marine Vehicle Autonomy,
Sensing, and Communications
Lecture 2: Applications and Lessons Learned
February 23rd 2021
2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
MIT Marine RoboticsAutonomous Underwater Vehicles
MIT Odyssey II (1995) Bluefin21 (2002, 2005)
Applications of Autonomous Underwater Vehicles:
• Mine countermeasures in shallow water
• Large-area Undersea Search and Surveilllance
• Deep-ocean oil exploration
• Autonomous Ocean Observation and Sensing Systems
• Under-ice environmental surveysBluefin Sandshark (2015)
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Mine Counter Measuresin the Littoral Ocean
• Proud and buried mines• Detection - POD/PFA
• Localization - Navigation
• Classification POC/PFA• High Area Coverage rate
Objectives
Constraints
• Eliminate Divers• Autonomy
• Clandestine operation
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Adaptive
Behavior
Cooperative
Behavior
Sonars
Uncertain Communication
Self-navigating
Network
Unknown Environment
No Maps
Mine Countermeasures withAutonomous Vehicle Networks
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Sensing in the Marine Environment
Point Measurements
• Physical
– Temperature
– Pressure
• Chemical
– Salinity
– Natural plumes
– Pollutants
• Biological
– Plankton samples
Remote Sensing
• Vision
– High Resolution
– Short range (0-20 m)
– Examples
• Photography
• Fluorescence
• Optical backscatter
• Sonar
– Low-resolution
– Long range (0-5000km)
– Examples
• Side Scan Sonar
• Multi-beam Sonar
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Seabed Mapping
Photo
Mosaic
675 kHz
Pencil-BeamSonar
Images Courtesy of H. Singh, WHOI
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Side Scan Sonar Imaging
Aspect 270o Aspect 000o
Frequency 200-800 kHz• High range resolution
Wide horizontal aperture • Narrow horizontal beam• High angular resolution
Range
Angle
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Dolphin Sonar -- Beampatterns
Figures from “The Sonar of Dolphins” by W. Au (Springer Verlag, 1993)
Wide beam -> Low angle resolution
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Dolphin Sonar -- transmitted signals
Figures from “The Sonar of Dolphins” by W. Au (Springer Verlag, 1993)
Wide frequency band=>
Accurate ranging
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Dolphin SonarReflection from Objects
Figures from “The Sonar of Dolphins” by W. Au (Springer Verlag, 1993)
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
GOATS’98
Odyssey II Bi-static Receiver Platform
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
GOATS’98 Experiment
Automated, Bistatic SAS Imaging
Super-critical Insonification
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Navigating in the Ocean
• No GPS
• Optics, Radar or LORAN
• Only for ranges < 10-100 m
• Acoustic
• Long Baseline Navigation (LBL)
• Short and Ultra-short Baseline
Navigation (USBL)
• Simultaneous Localization and
Mapping (SLAM)
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
The Sonar of Bats
Figures from “The Sonar of Dolphins” by W. Au (Springer Verlag, 1993)
Wide beam -> Range only
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
CML - SLAMConcurrent Mapping and Localization
a) b)
c)SLAM:
Simultaneous Localization
And Mapping
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
MIT AUV OperationsBP’02 – MASAI’02
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
MIT-SACLANTCEN SAS Sonar
Source and Acquisition Payload Section
2x8-element Linear Array (7.5kHz)
16-element Linear Array (15kHz)
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Target TrackingWide Beam Sonar
d
Horizontal
View
Vertical
View
Acceptable
Target Range
Time
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
BP’02 - MASAI’02SAS Zamboni Surveys
Navigation Sensors
•GPS (surface)
•Sonardyne LBL•DVL
•Compass
SAS Sonar
•4-16 kHz SBP Source
•2x8 element nose array
Klein 5000 (GESMA)
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
BP’02 – MASAI’02Simultaneous Localization and Mapping
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Bat SonarSearch, Detection, and Tracking of prey
Figures from “The Sonar of
Dolphins” by W. Au (Springer Verlag, 1993)
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3
4
1
5
4
3
2
1
5
Narrow band – Doppler Detection
Wide band – Range Tracking
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Range-Doppler Resolution of Matched Filter
Ambiguity function of
CW sonar pulse signal
Ambiguity function of
LFM sonar pulse signal
Ambiguity function of
HFM sonar pulse signal
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Detection Enhancement Using Adaptive Platform Control
Detectionmade
Adaptpath
Simulated Acoustic Data Signal to Reverb (SRR)
Adaptive
Planned
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Environmentally Adaptive Sensing,
Communication and Autonomy
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Acoustic Signaturesof Arctic Climate Change
• Sound speed profile
– Increased average sound speed
– Increased surface sound speed in open water creates efficient sound channel with
reduced surface interaction
– Recently observed warm water entering through Bering Strait at 100 m depth
creates very efficient duct without interaction with ice cover (‘Beaufort Lens’)
– Complex laterally inhomogeneous propagation environment in MIZ
• Ice cover
– Retreating ice cover
• Exposes environment to atmospheric interactions -> more temporal variability of acoustic environment
– Thinner ice with altered roughness statistics
• Changes in scattering loss for long-range propagation
• Changes in modal composition of long range propagation
– Changes in dominant ice fracturing processes
• More frequent, ice-mechanical events, e.g. ridging – 1D features in azimuth and range
• Less dominance of distributed floe boundary grinding – 2D azimuthally isotropic, homogeneous in range
– MIZ ambient noise characteristics becoming significant throughout Arctic.
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
WHOI ITP ProgramBeaufort Lens
MIT Laboratory forAutonomous Marine
Sensing Systems
ITP Locations Double DuctProfiles
ITP Buoy
ITP 84
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
The New Arctic Acoustic Environment
ITP 14Traditional Arctic SVP.
Monotonically increasing sound speed forces all paths to interact with ice
cover.
ITP 84New Arctic SVP
‘Beaufort Lens’
Dramatically improved
propagation conditions above 300 Hz in duct
isolated from surface and bottom interaction
New Arctic SSP, “Beaufort Lens” (ITP 84)
Range (km)
Tra
nsm
issio
n L
oss (
dB
)
10 20 30 40 50 60 70 80 90 100
Depth
(m
)
0
1000
2000
30001420 1460 1500
Sound Speed (m/s)
500
1500
2500
Traditional Arctic SSP (ITP 14)
Tra
nsm
issio
n L
oss (
dB
)
10 20 30 40 50 60 70 80 90 100
Depth
(m
)
0
1000
2000
30001420 1460 1500
500
1500
2500
Sound Speed (m/s) Range (km)
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Beaufort Sea Acoustics Ice Camps
ICEX’16March 2016
AUV w. 32-element arrayVLA and towed HLA configurations
SIMI’94 –TAP’94March 1994
32-element VLA32 Element Mill’s Cross Array
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
ICEX16 Objectives• Operations
– Demonstrate ability to deploy and recover AUV with towed array from
14’x3’ hole in Arctic ice cover.
– Demonstrate ability to navigate AUV using INS with updates from acoustic tracking range shared with manned submarines.
– Communication through acoustic communication infrastructure shared with
manned submarines
– Demonstrate autonomous operations of several hours for collecting
scientific and tactical data from towed array, CTD, and upward looking
DVL.
• Scientific Data
– Ambient noise with vertical, horizontal and hybrid apertures for
characterizing directional properties of the ambient noise field in the new
Arctic.
– Spatial characterization of acoustic propagation in the new Arctic
– Ice roughness statistics using upward-looking DVL
– Under ice imaging using GoPro camera on AUV.
– CTD during all missions.
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Arctic MIZ Reality
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Macrura Survey MissionMarch 15, 2016
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
ICEX’16Integrated Acoustic Navigation and Communication
Acoustic Tracking and Navigation
Integrated with existing ARL/UW submarine tracking
WHOI HF Micro-Modem on platform emits tracking pulse
1PPS 3.5 ms CW at 13.5kHz with doublet every 10 seconds
10.5Khz carrier, 3kHz bandwidth 10ms FM sweep (“platform”) every 30 seconds
Topside tracker for aggressive outlier rejection, before fixes are transmitted back UUV via acoustic communication to update onboard INS navigation solution
Upward-looking DVL fusion disabled due to ice motion of order .5 kn
Acoustic CommunicationHardware: WHOI MF Micro-Modem (3.5 kHz center, 1.25 kHz bandwidth), shared with NUWC Digital Acomms transmit transducer and receive hydrophone
Software: Goby/DCCL marshalling, queuing, medium access, and physical layer interface.
DVL
INS
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Untethered Survey MissionMarch 15, 2016
MIT Laboratory forAutonomous Marine Sensing Systems
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Tracking Range Performance• Tracking range performance inferior to previous ICEX’
– Tracking range aperture smaller than historical due to ice floe
constraints
– Depth of tracking hydrophones fixed at 33 m
– Tracking of shallow targets (<80 m) have increased uncertainty beyond a ~ 1 km range and no tracking beyond ~ 2 km
– No tracking of deep targets (>80 m) beyond 1-1.5 km range
– Sporadic tracking at ranges 6-7 km
– Modeling confirms the performance degradation associated with
Beaufort Lens.
• Tracking range performance constrained AUV operations
– Safe operations restricted to area within range aperture (~ 1 km)
– Outlier rejection required on topside to avoid wasting ½ min update
slot
– 1 sec period ‘unit’ tracking pulse performed significantly better than
20 sec period ‘platform’ pulse
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Acomms and Navigation in the Beaufort Sea Then and Now
RAP CorridorsHistorical Beaufort Sea
Shallow source/receiver provides direct paths to target at all operational
depths out to 6 km range. No reliance on slower
surface duct multipaths.
Present Beaufort Sea
Shallow source/receiver provides NO direct paths to shallow target.
Ice interaction degrades coherence beyond 0.5-1 km
range.Deeper CZ RAP paths at 6-7 km range.
Deep target reachable only at very short range.
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
pHelmIvPPlatform Autonomy
Acquisition
ArrayProcessing
Detection
Tracking
Classification
Localization
Data BusMOOSDB
pAcommsHandler
iFrontSeat
TDA
EmbeddedVirtual Ocean
pLamssMissionManagerMission Autonomy
pHelmIvPPlatform Autonomy
Acquisition
ArrayProcessing
Detection
Tracking
Classification
Localization
Data BusMOOSDB
pAcommsHandler
iFrontSeat
TDA
EmbeddedVirtual Ocean
pLamssMissionManagerMission Autonomy
Virtual Ocean Autonomy Testbed
‘
UUV Frontseat
Towed ArrayModel
µModem
Dynamic Model
pTDA
Topside C2
uSimINS uSimIDVL
pAcommsHandler
EmbeddedVirtual
Ocean
MOOS-IvP Payload Autonomy System
pHelmIvPPlatform Autonomy
Acquisition
ArrayProcessing
Detection
Tracking
Classification
Localization
Data BusMOOSDB
pAcommsHandler
iFrontSeat
pTDA
EmbeddedVirtual Ocean
pLamssMissionManagerMission Autonomy
GobyDCCL
‘Live’ Virtual Ocean
µModem
A/D-D/AA/D-D/A
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
ICEX2020 UUV Operations
Integrated Acoustic Tracking, Navigation and Communication
To ide
AUV
Ice B o
Ice- ackingDVL
30 m
90 m
- T an mi e an d ce , - Recei e h d o hone
GPS & f ee a eadio
2 km
Modem Range
• 3-4 ice moorings with 10 kHz µModemsabove and below Beaufort Lens
• UUV INS, upward-looking DVL
• CSAC/GPS synchronized modem TDMA
Integrated Navigation & Communication
• UUV Status Reports to topside
• 1-way travel times converted to range using embedded TDA
• Topside tracking solution• Autonomous selection of optimal
transmit modem
• Navigation drift and errors transmitted via Acomms to UUV together with
current ice motion• Onboard navigation fusion of INS,
modem range tracking and DVL,
constrained by UUV dynamic model.• Full system simulation using Virtual
Ocean Autonomy Testbed with HITL
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
ICEX2020 UUV Operations
Integrated Acoustic Tracking, Navigation and Communication
Acoustic tracking system (LBL):
• UUV transmits a time-stamped status reports on TDMA schedule
indicating its current position & vehicle status.• µModems receive the message, & calculate OWTT from UUV to
each modem.
µModem Systems 1 & 2
µModem Systems 3 & 4
• OWTT & GPS coordinates of each modem, and last
reported UUV position is
used to triangulate the new position of the UUV.
• Uses Virtual Ocean for converting OWTT to range
estimate.
• Triangulation uncertainty is computed with a particle
filter.• New position delta, position
stdev and ice-camp drift
information is sent back to UUV.
µModems translate and with the ice sheet
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Top-side (Ice camp)
AUV backseat (MIT's payload computer)
Micro modem
1
Topside Tracking
System
Acomms
Handler
Frontseat
interface
IXBlue PHINS INS
AUV frontseat
(manufacturer-side)
Teledyne RDi DVL
Navigation sensors
HydroMAN navigation system
ICEX Manager
Vehicle dynamic
model
Real-time model
calibration
Sensor fusion
DVL ice-drift
correction
LBL time lag
correction
Micro modem
2
Micro modem
3
Micro modem
4
IvP Helm
Vehicle-side acoustic
hardware
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
A sample LAMSS simulation run:
ICEX2020 UUV Operations
Integrated Acoustic Tracking, Navigation and Communication
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
Modem Performance Metrics
1500 2000 2500 300020
40
60
80
100
Range (m)
Packet success (
%)
1500 2000 2500 300030
40
50
60
70
80
SN
R (
dB
)
rx: 30mrx: 90mrx: 30mrx: 90m
1500 2000 2500 300020
40
60
80
100
Range (m)P
acke
t su
cce
ss (
%)
1500 2000 2500 300030
40
50
60
70
80
MP
P (
dB
)
rx: 30mrx: 90mrx: 30mrx: 90m
HITL-NETSIM Virtual Ocean Missions ICEX20 Modem Range
Maximum SNR Maximum SNR
Multipath Penalty SNR Multipath Penalty SNR
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
ICEX203-hour Submerged Survey Mission
ITP 2013 ICEX2020
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
ICEX2020 Recovery
Tuesday, March 17, 2020
• ‘Steep’ Macrura/Durip recovery
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2.680 Spring 2021 – Marine Autonomy, Sensing and Communications – Applications
LAMSS 1997 – 2017Lessons Learned
• Artificial Intelligence is critical to persistent and resilient operation of undersea distributed sensing systems
– Adaptation and collaboration may compensate for reduced sensor performance
– Communication channel inherently layered, highly band limited, latent and intermittent
– Integrated of sensing, modeling, and control required for sustained autonomous operation
• Nested, behavior-based autonomy is a key enabler – Nested modularity supports effective ’cloning’ of domain experts
– MOOS-IvP is open-source, highly portable autonomy software • Multi-objective optimization HelmIvP is key enabler for adaptive autonomy.• Provides 95%+ of leveraging autonomy software through nested repositories• Provides templates for efficient application and behavior development by domain experts
– Adaptive sensing, communication and autonomy supported by embedded environmental and tactical modeling
• Robust and Resilient Onboard Data Processing– Processing products suited for machine decision making
– False Alarm Control is critical. Ocean is random!
– Robustness more critical than resolution!
• Virtual Experiments key to deployment of robust and resilient field systems– Adaptive autonomy is inherently unpredictable. Robust and resilient performance requires extensive testing with
actual autonomy software
– Requires high-fidelity, physics-based environmental simulation (oceanography, acoustics, dynamics).
– 500-1000 times more hours spent in virtual experiments than real ones for distributed sensing concept development.
– Hardware-in-the-Loop support• Stimulation of embedded processing chain
• Analog modem transmit/receive support
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