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LIDAR, Episode IV THE PURSUIT OF DATA

LIDAR, Episode IV THE PURSUIT OF DATA. David Colucci Derek Burke. Laser fired into atmosphere Varied return based on backscatter from clouds/aerosol etc. Time measured from pulse fired to backscatter return is used to calculate cloud height and other values

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LIDAR, Episode IV THE PURSUIT OF DATA

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  1. LIDAR, Episode IVTHE PURSUIT OF DATA David Colucci Derek Burke

  2. Laser fired into atmosphere • Varied return based on backscatter from clouds/aerosol etc. • Time measured from pulse fired to backscatter return is used to calculate cloud height and other values • Return signal is diminished according to inverse square law and needs to be normalized Theory

  3. Valuable as a ceilometer at airports • Volcanic ash warning system for aircraft • Used to study atmospheric aerosol -> Applications

  4. Courtesy of NASA

  5. Time Lapse Photography

  6. Lidar Development: Phase I

  7. Op amp – 410 MHz • Gain increased by Resistor value • Amplifies signal from the diode • Photodiode connects to triport on back of board with use of 10nm filter Board for photodiode

  8. For the amplifier, a positive and negative voltage are pulled. • The signal out is shown as the white wire • Signal is read on the voltmeter Board in Operation

  9. Begin the full scale implementation of a lidar device. Lidar Development Phase II

  10. 100mm² active area photodiode with BNC mount • 532nm Filter with 2nm tolerance • SM tube assembly Photodiode/Filter UPGRADED

  11. 532nm, 100 mW output • Q-switched adjustable pulse frequency • Safety doesn’t take a vacation “LASER”

  12. We needed the scope to start acquiring when the laser fired • The external trigger on the laser driver gave a faint “square wave” that followed the laser • We amplified and filtered this signal to trigger acquisition • Circuit shown <- Triggering the Scope

  13. PHASE II COMPLETE

  14. Testfire Data

  15. DETAIL OF PULSE

  16. Larger Optics • Photomultiplier tubes • Dispersion of laser output FUTURE…

  17. AND BEYOND!

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