Signal Averaging Limitations in Heterodyne- and Direct-Detection Laser Remote Sensing Measurements

  • N. Menyuk
  • D. K. Killinger
  • C. R. Menyuk
Part of the Springer Series in Optical Sciences book series (SSOS, volume 39)


The use of laser remote sensing to determine the concentration of molecular species in the atmosphere by differential-absorption LIDAR (DIAL) requires the measurement of the average transmission of laser signals through the atmosphere at two or more different wavelengths. The accuracy with which the average transmission value, and hence the molecular concentration, may be determined is limited in many cases by the presence of large atmosphere-induced pulse-to-pulse fluctuations in the LIDAR returns.


Temporal Correlation Average Transmission lIDAR Signal Heterodyne Detection Lidar Return 
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    When the measurement accuracy limitation due to the fluctuations of the signal returns is significantly greater than the limitations due to the detection capability of the system, as is the case in the measurements presented here, the signal-to-noise ratio is defined as the mean value of the LIDAR return signals divided by the standard deviation of those signals. This is equivalent to the inverse of the normalized standard deviation values used throughout this paper. The ratio of the mean value of the signal to the mean value of the noise (defined as the carrier-to-noise ratio in Ref. 10) is an equally important factor in establishing system capabilities. In general, for a given energy level, this ratio for a heterodyne-detection system can be expected to be 3 to 4 orders of magnitude greater than for a direct-detection system.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1983

Authors and Affiliations

  • N. Menyuk
    • 1
  • D. K. Killinger
    • 1
  • C. R. Menyuk
    • 2
  1. 1.Lincoln LaboratoryMassachusetts Institute of TechnologyLexingtonUSA
  2. 2.Laboratory for Plasma and Fusion Energy StudiesUniversity of MarylandCollege ParkUSA

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