Real-time detectors based on stochastic resonance

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Real-time detectors based on stochastic resonance
Aditya Saha University of Alberta
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Stochastic resonance(SR)

• Stochastic resonance is a phenomenon by which the
  presence of noise enhances signal content
• Counter-intuitive!!!
• Seen only in nonlinear, complex systems
• Difficult to analyze

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Signal Detection
Signal noise/
Is a signal present?
Detection Technique
Or absent?
Noise

• The objective of any detector is to detect the
• presence of target i.e. subs
• Classical optimal detectors are difficult to
• implement (WW-II era, N. Atlantic theatre)
• SR provides suboptimal detectors that are easy
• to implement

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Applications of SR

• Sonar arrays
• Tracking whales and dolphins
• Cochlear implants
• Self-guided torpedoes (fantasy??)

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Sonar Applications I

• To detect underwater targets (i.e. submarines)
• A typical submarine emits signals at
• - propeller frequency (5 Hz) - relatively
  strong
• - electrical machinery (50/60 Hz)
  relatively weak
• - cavitation noise (wideband) very weak
• (due to bubbles collapsing on subs hull)

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Sonar Applications II

• The input to the SR detector includes
• - signal (propeller frequency)
• - random noise (passing ships, biological
• noise, waves etc)
• The objective is to detect only the propeller
• frequency.

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Schematic of SR detector in Sonar
Marine sounds
Detection Hypothesis
Present/ Absent
Sensor
Electrical Signal
Marine sounds
SR Device
Detection Hypothesis
Present/ Absent
Sensor
Electrical Signal
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Layout of proposed SR device
Global Optimization
Perturbation Correction
Marine noise pdf
Values of Gamma Integrals
Roots of
pdf parameters of input noise
G.O. finds the global optimum of the gain
function
ROM
Roots of fx
Control Circuitry
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Whats special

• Entire operations done in real-time
• on existing chip (Texas Instruments
  TMS320C6000)
• Robust, economical (100)
• Easy to upgrade isolated sonar platforms
• Working prototype exists (ECE, UofA)

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Alternatives

• Topologically matched filters (US)
• Satellite based measurements (US/NATO)
• Magnetic anomalies (US/ Russia)

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Other Labs/ RD groups

• SPAWAR group (San Diego)
• Office of Naval Research (Baltimore)
• DRDC (Halifax)
• French naval labs (Toulon)
• Companies Thomson CSF, Massa, Reson,
• Thales underwater systems, C-MAQ

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Collaborators

• Dr. J. Tuszynksi, Dr. M. Mandal, M. Lu,
• G. Guo (U of A)
• Dr. M. McDonnell (Adelaide, Australia)
• Dr. F. Chapeau-Blondeau (Angers, France)