Low Energy, Multimodal Sensing for Wireless Underwater ......2019/11/03 · FIELD TRIAL –BIOGRAD...
Transcript of Low Energy, Multimodal Sensing for Wireless Underwater ......2019/11/03 · FIELD TRIAL –BIOGRAD...
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Low Energy, Passive Acoustic Sensing
for Wireless Underwater Monitoring
Networks
Gavin Lowes
Jeff Neasham, Richie Burnett, Charalampos Tsimenidis
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INTRODUCTION TO PROJECT
• EPSRC sponsored £1.3m three year project in
collaboration with Newcastle University, Heriot-Watt
University and the University of York
• Development of affordable technology for large
scale, smart wireless sensing networks to be
deployed in the oceans.
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PROJECT DATA COMMUNICATION ENABLER
Low power, low cost miniature underwater
acoustic modem developed by Newcastle
University Sensors, Electromagnetics and
Acoustics Laboratory (SEALab)
Supply Voltage 3 – 6.5V
Supply Current Listening: 2.5mA
Receiving: 5mA
Transmitting: max 300mA
Standby/sleep: < 100uA
Acoustic
directivity
Near omnidirectional
Acoustic data
rate
640 bits/s, unicast and broadcast
data messages up to 64 bytes
Max range 3.6 km
Addressing Up to 256 units
Range variance ~10 cm
RS232
interface
9600 Baud, 8-bit, no parity, 1
stop bit, no flow control
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AIMS AND OBJECTIVES
Research and develop the SENSOR PAYLOAD for the USMART project
• Detect acoustic signals of interest reliably and at low-power
• Classify successfully detected signals of interest
• Transmit compressed data through an underwater network of nodes
• Maintain a low-power, low-cost development approach
Signals of Interest include… Cetaceans, VESSEL DETECTION, Underwater Threats, Subsea Assets, Noise Pollution
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LOW POWER VESSEL DETECTION
DETECTION SOURCE MOTIVATION
(1)Propeller Cavitation - Formation and
collapse of bubbles in water at or on the
surface of a rotating propeller, occurring
when the pressure falls below the
vapour pressure of water.
(1) https://www.maritime-executive.com/article/us-japan-and-germany-join-australian-stealth-research
(2) https://www.bbc.co.uk/news/uk-england-kent-46679414
(2)
• Detection of vessels which are being used
to carry out dangerous and illegal functions.
• Examples include – Drug trafficking,
defence related threat detection, border
control.
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwi2g46EgpTlAhVCzoUKHVDxCuMQjRx6BAgBEAQ&url=https://www.logolynx.com/topic/bbc%2Bnews%2B24&psig=AOvVaw3opsn5rZbkf2CQIvW8BYV3&ust=1570876739478845https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwi2g46EgpTlAhVCzoUKHVDxCuMQjRx6BAgBEAQ&url=https://www.logolynx.com/topic/bbc%2Bnews%2B24&psig=AOvVaw3opsn5rZbkf2CQIvW8BYV3&ust=1570876739478845
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SIGNAL DETECTION METHOD
Cavitation Signal
Band Pass Filter
Rectifier
Envelope Tracker
Fast Fourier Transform
DEMON Spectrum
Detection of Envelope Modulation on Noise (DEMON)
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VESSEL DETECTION CRITERIA
• The vessel detection algorithm searches for consistent DEMON spectral peaks.
• A linear fit is applied to the frequency peak history over a user defined time frame.
• Standard Error Of the Estimate (SEOE) is calculated to determine how well the actual recorded samples 𝑦 relate to the estimated samples ො𝑦.
• 𝑆𝐸𝑂𝐸 = σ( ෝ𝑦 −𝑦)2
𝑛 −2
• The acceptable SEOE value is one of a variety of user defined system thresholds to tune the algorithm to specific applications.
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RECEIVE AND TRANSMIT SYSTEM DIAGRAM
VESSEL SIGNAL
DATA TRANSMITTED
DETECTION
ALGORITHM
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DESIGN CHARACTERISTICS
• Integrated with existing acoustic
communication device via add-on signal
processing PCB
• Shared Transducer for Receive and Transmit
• Power consumption - 11.4mW using a 6V
supply.
• Cost - less than £40 in quantities of 200 units.
• Cable Connection to Depth Rated Battery
Pack
• Encapsulated in Acoustically Favourable
Polyurethane for Underwater Applications
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DATA TRANSMISSION
RECEIVED SIGNALDATA TRANSMISSION
• Once the algorithm decides a vessel has been
detected, data is sent acoustically through the water
using the acoustic communication device developed by
Newcastle University.
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FIELD TRIAL – BIOGRAD NA MORU, CROATIA
Positive detection
of RHIB at approx.
1.6km.
Detection data
transmitted
acoustically over a
200m range back
to the receiver
station.
DECODED DETECTION DATA
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NORTH SEA DEPLOYMENT – NOVEMBER 2019
WIFI LINK University Marine Station Newcastle University CampusDATA BUOY
HYDROPHONE 1
HYDROPHONE 2
ACOUSTIC MODEM 1
ACOUSTIC MODEM 2
Newcastle University - Acoustic Network GatewaY (ANGY)
1km (potential for up to 3.6km in single hop)10m from
sea floor
Battery Pack
Vessel Detector/
Acoustic Modem
30
m d
ep
th
Acoustic Data Transmission
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NORTH SEA DEPLOYMENT – NOVEMBER 2019
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CONCLUSIONS
This presentation had demonstrated the following:
• Ability to detect propeller cavitation signals using DEMON methodology.
• Implementation of DEMON methodology using analogue electronics.
• The vessel detection criteria to decide whether a vessel is present.
• Low-power, low-cost project ethos has been maintained.
• Data communication using integrated underwater acoustic modem.
• Field trial results proving the system for vessel detection and communication.
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FUTURE WORK
• Use Low-Power vessel detector to wake-up a higher power classification mode.
• Classification mode will perform time-frequency analysis on full spectrum signal.
• Spectral feature extraction will be used to classify specific vessels based on their
acoustic signature.
• Expand the current system to also detect divers.
• Explore other applications such as cetacean whistle detection/classification and
subsea asset monitoring.
• Research the feasibility of adding other sensors to the system (magnetometer,
temperature etc) to offer more data to the end user application.
• Test the system as part of the USMART underwater network.
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THANK YOUhttps://research.ncl.ac.uk/usmart/ [email protected]