eagle ray corporation

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eagle ray corporation
A High PrecisionLaser Distance SensorFor
Measurements on Natural Surfaces

• is proud to present

DMR RANGEFINDER(Differentially Modulated
Receiver)
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OVERVIEW

• Optical distance sensing on natural surfaces can
  provide fast and accurate data
• Most existing techniques deliver 1mm or lower
  accuracy at working distances beyond a few m
• Many applications require greater accuracy, but
  current options are few and expensive

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OVERVIEW

• DMR configuration enhances the performance of an
  established technique by up to 100x without major
  cost escalation
• DMR sensors have the potential to achieve
  commercial success in a broad spectrum of
  applications

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OPPORTUNITY

• Outperforms existing systems by up to 100x
• Based on established, robust optical technique
• Low/moderate cost hardware
• Compatible with mass produced telecom emitters
  and modulators
• Creation of new markets

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OPPORTUNITY

• Surveying using optical rangefinding
• Precise measurement of components or assemblies
  (alternative to contacting coordinate measuring
  machines)
• Robotics, machine vision and guidance
• Industrial sensors

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PRIMARY TECHNIQUES

• Geometrical/Triangulation
• Interferometric
• Time of Flight of Optical Pulse
• Phase Shift of Modulated Beam

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PHASE SHIFT of modulated beam
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PHASE SHIFT of modulated beam

• Robust and fast
• High accuracy, even at long range, using remote
  reflector
• Distance measurements for surveying using prism
  targets
• Poor performance on natural surfaces

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CURRENT CAPABILITIES with remote reflector

• Short Range (10m) Laser Tracker
• Accuracy ? 20 microns (1 result per second)
• S1 and S2 at 300MHz (1mW power)
• Medium Range (120m) GBT Metrology
• Accuracy ? 50 microns (5 results per second)
• S1 and S2 at 1.5GHz (1mW power)

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CURRENT TECHNOLOGY electronic down-mixing
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CURRENT CAPABILITIES with natural surfaces

• Accuracy ? 0.3mm to ? 3mm at working distance of
  3m
• S1 and S2 at frequencies between 14MHz and 700MHz
• Emitted beam power typically 20-50mW
• Scanning systems generating 1k-500k results per
  second

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FUNDAMENTALTECHNOLOGY LIMITS received
power

• Weak reflected beam limits available S/N ratio
  and achievable phase measurement accuracy
• Typical received beam power from rough surface at
  10m range is 100pW, assuming a safe, 1mW emitted
  beam

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FUNDAMENTALTECHNOLOGY LIMITS photon
statistics

• Photon statistics impose physical limit on
  available S/N ratio
• 100pW ? random arrival of 4 x 108 photons per
  second (for wavelength 800nm)
• For 1 measurement per second, best achievable S/N
  ratio is (4 x 108)1/2 2 x 104
• Limiting ranging accuracy ? 7.5?m using 1GHz
  modulation

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CURRENT TECHNOLOGYLIMITS fast optical detectors

• PIN photodiode low-cost and very stable, but very
  low S/N ratio at 1GHz
• Avalanche PIN photodiode moderate cost and
  stability S/N ratio better but still low
• PMT high cost and low stability S/N ratio good
  but still well below physical limit practical
  frequency limit lt1GHz

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FAST OPTICAL DETECTOR
not required
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OPTICAL DOWN-MIXING
schematic
F 1GHz, F? 0.95GHz, ? ?/2 radians
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DMR CONFIGURATION sidestepping limitations

• DMR configuration permits a huge difference
  between the optical modulation and optical
  detection frequencies, without loss of phase
  information
• Can use a stable, small area photodiode with low
  noise trans-impedance amplifier and 1kHz
  bandwidth to measure the phase shift on a 10GHz
  sensing beam

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DMR CONFIGURATION sidestepping limitations

• 1 kHz photodiode can provide S/N ratio of 10,000
  in a bandwidth of 0.5Hz with a rough surface at
  10m, using a 1mW beam
• Corresponding ranging accuracy ? 15?m using 1GHz
  modulation
• Achievable ranging accuracy ? 1?m using 15GHz
  modulation

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COMMERCIALIZATION
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eagle ray corporation

• Contact
• Dr. Andy Barker(403) 247-9939abarker_at_eagleray.ca