Estimating random errors due to shot noise in backscatter lidar observations
- 20 June 2006
- journal article
- Published by Optica Publishing Group in Applied Optics
- Vol. 45 (18), 4437-4447
- https://doi.org/10.1364/ao.45.004437
Abstract
We discuss the estimation of random errors due to shot noise in backscatter lidar observations that use either photomultiplier tube (PMT) or avalanche photodiode (APD) detectors. The statistical characteristics of photodetection are reviewed, and photon count distributions of solar background signals and laser backscatter signals are examined using airborne lidar observations at using a photon-counting mode APD. Both distributions appear to be Poisson, indicating that the arrival at the photodetector of photons for these signals is a Poisson stochastic process. For Poisson- distributed signals, a proportional, one-to-one relationship is known to exist between the mean of a distribution and its variance. Although the multiplied photocurrent no longer follows a strict Poisson distribution in analog-mode APD and PMT detectors, the proportionality still exists between the mean and the variance of the multiplied photocurrent. We make use of this relationship by introducing the noise scale factor (NSF), which quantifies the constant of proportionality that exists between the root mean square of the random noise in a measurement and the square root of the mean signal. Using the NSF to estimate random errors in lidar measurements due to shot noise provides a significant advantage over the conventional error estimation techniques, in that with the NSF, uncertainties can be reliably calculated from or for a single data sample. Methods for evaluating the NSF are presented. Algorithms to compute the NSF are developed for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations lidar and tested using data from the Lidar In-space Technology Experiment.
Keywords
This publication has 9 references indexed in Scilit:
- Cloud Physics Lidar: instrument description and initial measurement resultsApplied Optics, 2002
- Simulation study for cloud detection with space lidars by use of analog detection photomultiplier tubesApplied Optics, 2002
- High-spectral-resolution lidar using an iodine absorption filter for atmospheric measurementsOptical Engineering, 1999
- An overview of LITE: NASA's Lidar In-space Technology ExperimentProceedings of the IEEE, 1996
- Fundamentals of low-noise analog circuit designProceedings of the IEEE, 1994
- Methodology for error analysis and simulation of lidar aerosol measurementsApplied Optics, 1979
- The distribution of gains in uniformly multiplying avalanche photodiodes: TheoryIEEE Transactions on Electron Devices, 1972
- Thermal and quantum noiseProceedings of the IEEE, 1965
- Coherence Properties of Optical FieldsReviews of Modern Physics, 1965