1. An Embedded Linux Based Navigation
System for an Autonomous Underwater
Vehicle
Presented By:
Priyanka Katkar
Under the Guidance of
Mr. B.G. Patil
1

2. Outline
 Introduction
 Interfacing With SBC
 System Architecture
 Hardware Development
 Software Development
 Conclusion and Future Work
2

3. Introduction
• AUVs are unmanned and untethered submarine vehicles, used to
gather ocean data.
• Find applications in the area of mines clearing operation, feature
tracking, cable or pipeline tracking and deep ocean exploration.
• HUGlN 3000 was the world's first AUV used in commercial survey
operations.
3

4. Use of the AUV
• Search and Recovery of Government
Property.
• Prediction of Waves and Currents.
• Readings for depth, salinity, pressure
and temperature.
• Pictures of visual light,
bioluminescence.
• Discovery of never seen before
species and footage.
4

5. UUV Research
5

6. 6

7. Nomenclature
• Unmanned Underwater Vehicle (UUV): Self propelled
unmanned submersible
• Remotely Operated Vehicle (ROV): controlled and
powered from the surface by an operator/pilot via an
umbilical or using remote control
• Autonomous Undersea Vehicle (AUV): Un-tethered
UUV operating with no or very limited operator control.
• Two paddle wheel thrusters are installed on AUV, one for
horizontal motion and other for vertical motion
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8. Navigation Techniques
• AUV: The benefits of offered by autonomous data gathering
• Examples include the Theseus AUV, developed by Interna-
tional Submarine Engineering, the DARPA UUVs, developed
by Draper Laboratories, the LDUUV and 21UUV developed
by the Naval Undersea Warfare Centre in Newport.
• The three primary methods for navigation of AUVs are:
1. Inertial navigation systems
2. Acoustic navigation
3. Geophysical navigation techniques.
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9. System Architecture
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10. INS KF
DGPS +USBL UTP
Pressure
Sensor
Compass
DVL
Bottom-Track
Velocity
Altitude
Depth
Smoothing
Position
Error
estimates
Inertial Measurement Unit
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11. Outline of Conventional Aided INS
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12. The Complete System Setup
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13. Interfacing With SBC
• Single Board Computers (SBC) like Kontron E2Brain
EB8540, Gumstix, Inhand Fingertip- Elf, AMD GX SOM-144
and TS-7200
• TS-7200 SBC selected due to its features, good support by the
manufacturer and a huge user community. TS-7200 is based on
200MHz Strong ARM processor.
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14. TS-7200 Hardware
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15. The CirrusLogic EP9302 and TS-7200
• The EP9302 features an advanced ARM920T processor design
with a memory management unit (MMU) .
• Supports Linux & many other operating systems.
• Contains 16Kbyte instruction cache and 16Kbyte data cache.
• supports both the 32-bit ARM and
16-bit Thumb instruction set.
• The core can operate in big
and little endian mode
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16. (Cont...)
• The TS-7200 is a compact full-featured (SBC) based upon the Cirrus
EP9302 ARM9 CPU
• The TS-7200 SBC runs on a 200MHz EP9302 ARM9 processor with
power as low as 0.5Watts.
• includes a compact flash interface which allows booting from large
flash drives to the different Linux distros.
• fast boot from the on-board Strata Flash memory using a compact TS-
Linux distribution.
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17. Interfacing of INS with SBC
Block Diagram of Integrated Sensor Pack
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18. Tracking Algorithm
Calculation of object
centroid in the image
Separation of moving
objects from the
stationary objects
Identification of moving
objects based on change
in centroid values
Comparison of centroid
values in all subsequent
frames
Calculation of trajectory
for all moving objects
Calculation of speed and
direction of moving
objects
Block diagram of the complete model
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19. Kalman filter
• The Kalman Filter is an estimator for the linear-quadratic
problem, estimating the instantaneous ‘state’ of a linear
dynamic system perturbed by white noise.
• The Kalman filter is a set of mathematical equations that
provides an efficient computational (recursive) means to
estimate the state of a process, in a way that minimizes the
mean of the squared error.
• Various Kalman filter configurations applied to a low-cost
inertial navigation system (INS) for AUV.
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20. Kalman Filtering Algorithm
 Time Update ( Predict ) equations:
• Step 1: Project the state ahead:
𝑋 𝑘
−
= A 𝑋 𝑘−1 + 𝑊𝑘
• Step 2: Project the error covariance ahead:
𝑃𝑘= A 𝑃𝑘−1 𝐴 𝑇+ Q
 Measurement Update ( Correct ) equations:
• Step 3: Compute the Kalman gain:
𝐾𝑘 = 𝑃𝑘 𝐻 𝑇(H 𝑃𝑘 𝐻 𝑇 + R)
−1
• Step 4: Update estimation with measurements:
𝑋 𝑘= 𝑋 𝑘
−
+ 𝐾𝑘 (𝑍 𝑘 - H 𝑋 𝑘
−
)
• Step 5: Update the error covariance:
𝑃𝑘 = (I - 𝐾𝑘 H) 𝑃𝑘
−
• Step 6: Go to Step 1. 20

21. GPS Receiver
• To provide the absolute positioning of any object, GPS uses a
constellation of 24 satellites.
• Four satellites are visible at all times from any point on the earth’s
surface.
• GPS receiver supports NMEA 0183 data protocol.
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22. Software Development
• TS-Linux embedded distribution is installed on the on-board Flash
memory of the TS-7200.
• TS-Linux is a compact distribution, which is based on Busy Box
• The GPS receiver is interfaced to the TS-7200 through the serial port
• Linux distinguishes devices into three fundamental device types: a
char module, a block module, or a network module.
• Developing a serial class is classified.
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23. Results
Output from the ADC and the GPS Receiver.
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24. Future Scope
• The exact position of the vehicle can be determined by
processing the logged sensor data using the Kalman filter.
• Current version does not have a driver for the digital I/O port.
• This can be implemented to increase the no of sensors that
can be interfaced with SBC.
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25. Applications
• Pipeline inspection and intervention.
• Under ice surveys (transponders may be deployed from
an ice breaker or along the ice ridge).
• Mines clearing operation, feature tracking, cable or pipeline
tracking and deep ocean exploration.
• Autonomous surveys where surfacing or support from a
surface ship are infeasible due to e.g. heave traffic.
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26. Pros And Cons
 Pros
• Smaller, Lighter and less expensive equipment became
available, the access to operational vehicles which made more
affordable AUVs.
• TS7200 has on board Apaches web server therefore data logged
from SBC can be displayed on a web page.
 Cons
• Limited number of DIO ports available on SBC board.
• loss of controllability at low speeds, 26

27. Conclusion
• The SBC with Linux setup and the development tools form the
embedded Linux development system.
• Provides lower development cost with interfaces such as Ethernet and
USB and have made AUVs more affordable.
• As a data logger/analyzer of various sensor measurements for Marine
research.
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28. References
• Grenon, G., Edgar, P., Smith, S., and Healey, A., “Enhancement of the inertial
navigation System for the Morpheus Autonomous underwater Vehicles”,
IEEE Journal of Oceanic Engineering, Vol. 26, No. 4, October, 2012.
• Yun, X.; McGhee, R.; Whalen, R.; Roberts, R; Healey, A, and Zyda, M.,
“Testing and Evaluation of an Integrated GPS/INS System for Small AUV
Navigation” IEEE Journal of Oceanic Engineering, Vol. 24, Issue 3, pp.396–
404, 19-20 July, 2007.
• B. Jalving, K. Vestgkd, N. Sterkersen, “Detailed seabed surveys with AUVs” in
TechnologV and Apphcurions of Autonomous Underwater Vehicles. Edited
by Gwyn Grifiths. Tavlor & Francis. London and New York. 2008. pp. 179-201
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29. Thank You
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