Transcript Semester Project Underwater Optical Communication

Underwater Optical Communication
Semester Project
López Estepa, Pedro
Assistant: Konstantinos Karakasiliotis
Professor: Auke Jan Ijspeert
Final presentation
13 January 2009
Summary
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Goals
Initial Problems
Wireless Communication Technologies
Designed System
Experiments
Conclusions
Future work
Underwater Optical Communication - Pedro López Estepa
Goals
Project Description
video and data
accompanying
vehicle control
Radio
[receiver]
Blue light
[transmitter]
Underwater Optical Communication - Pedro López Estepa
Goals
Goals of the Project
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Develop a communication system to transmit video
between underwater robot and surface platform
Decrease size due to space restrictions.
Find a good combination of communication speed and
robustness.
Underwater Optical Communication - Pedro López Estepa
Initial Problem
Initial Problem
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Most of the current underwater optical communication
systems can be clasified in two groups in terms of their
limitations.
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Size Limitations
Power Limitations
We are not included in only one of them!
Size Limitations
Power Limitations
Optical
Communication
System
Underwater Optical Communication - Pedro López Estepa
Wireless Communication Technologies
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31.09.2008 – 16.10.2008
High frequency radio wave is highly absorbed in water.
Acoustic communication systems are relatively low
bandwidth.
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Optical communication with LASER is monidirectional.
Optical communication in Visible Spectrum
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1.
Omnidirectional
Bandwidth up to some MHz
Minimal light absorption
in water is usually achieved
for blue light around 400-450 nm.
Felix Schill , Uwe R. Zimmer , and Jochen Trupf. “Visible Spectrum Optical Communication and Distance Sensing For Uncerwater Applications”. The Australian National
University, ACT 0200.
Underwater Optical Communication - Pedro López Estepa
Designed System
16.10.2008 – 20.12.2008
System Designed
TX
16.10.2008 – 20.12.2008
Video signal
CLK
Vdd
Modulation
XOR
LED Driver
LED
GND
Water
Lens
Demodulated
signal
RX
Demodulation
Filtering
Amplification
Underwater Optical Communication - Pedro López Estepa
Photodiode
Vdd
GND
Designed System
16.10.2008 – 20.12.2008
Transmitter
LED Driver
Modulation XOR
Underwater Optical Communication - Pedro López Estepa
Designed System
Transmitter
Underwater Optical Communication - Pedro López Estepa
16.10.2008 – 20.12.2008
Designed System
Transmitter
LUXEON III Blue
700 mA - 3W
Underwater Optical Communication - Pedro López Estepa
16.10.2008 – 20.12.2008
Designed System
16.10.2008 – 20.12.2008
Receiver
Signal Treatment
Amplification
Filtering
Underwater Optical Communication - Pedro López Estepa
Designed System
Receiver
Underwater Optical Communication - Pedro López Estepa
16.10.2008 – 20.12.2008
Experiments
09.12.2009
Air experiments
Underwater Optical Communication - Pedro López Estepa
20.12.2008-
Experiments
09.12.2009
Air experiments
Underwater Optical Communication - Pedro López Estepa
20.12.2008-
Experiments
09.12.2009
Underwater experiments-Hardware Setup
Underwater Optical Communication - Pedro López Estepa
20.12.2008-
Experiments
09.12.2009
Underwater experiments
Underwater Optical Communication - Pedro López Estepa
20.12.2008-
Experiments
09.12.2009
Underwater experiments
Underwater Optical Communication - Pedro López Estepa
20.12.2008-
Experiments
09.12.2009
Underwater experiments
Underwater Optical Communication - Pedro López Estepa
20.12.2008-
Conclusions
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The experiments have shown that the range is not decreased while working
in underwater
The wide angular coverage of 30º, due to the used lens, doesn’t allow more
than 10 cm range around the perpendicular point of movement
To obtain omnidirectional coverage it’s necessary to include an improved
lens system in the receiver with several photo diodes to increase the
detection range
Underwater Optical Communication - Pedro López Estepa
Conclusions
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It’s necessary to try to decrease the power consumption after the lenses
analysis is finished.
The experiments show that the system has a good response in the range of
500 kHz to 1.50 MHz, which could be increased to 2 MHz by using a better
lens system.
According to the initial project requirements
 We have completed the electronic hardware fabrication, which means,
design and build the physical layer for an underwater communication
system.
 Even if we didn’t manage to get the transmitter underwater, the setup
we used resembles in a good way the final one.
 A systematic analysis to determine the most efficient lenses system is
not completed.
Underwater Optical Communication - Pedro López Estepa
Time Frame
W. Communication technologies
Communication type selection
Completed task
Actual task
Preliminary experiments
Fast optical communications
Trasmitter design
Transmitter build
Receiver design
Receiver build
Air experiments
Underwater experiments
Improvements
Underwater Optical Communication - Pedro López Estepa
Time
Future work
Improvements
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Analyze and improve lenses system
High Frequency amplification in receiver
PCB Reduce
Build platform
Enchance harware for underwater emplacenment
Implement Software demodulation
…
Underwater Optical Communication - Pedro López Estepa
Questions
Underwater Optical Communication - Pedro López Estepa