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Data Retrieval Algorithms for Validating the Optical Transient Detector and the Lightning Imaging SensorA linear algebraic solution is provided for the problem of retrieving the location and time of occurrence of lightning ground strikes from an Advanced Lightning Direction Finder (ALDF) network. The ALDF network measures field strength, magnetic bearing, and arrival time of lightning radio emissions. Solutions for the plane (i.e., no earth curvature) are provided that implement all of these measurements. The accuracy of the retrieval method is tested using computer-simulated datasets, and the relative influence of bearing and arrival time data an the outcome of the final solution is formally demonstrated. The algorithm is sufficiently accurate to validate NASA:s Optical Transient Detector and Lightning Imaging Sensor. A quadratic planar solution that is useful when only three arrival time measurements are available is also introduced. The algebra of the quadratic root results are examined in detail to clarify what portions of the analysis region lead to fundamental ambiguities in sc)iirce location, Complex root results are shown to be associated with the presence of measurement errors when the lightning source lies near an outer sensor baseline of the ALDF network. For arbitrary noncollinear network geometries and in the absence of measurement errors, it is shown that the two quadratic roots are equivalent (no source location ambiguity) on the outer sensor baselines. The accuracy of the quadratic planar method is tested with computer-generated datasets, and the results are generally better than those obtained from the three-station linear planar method when bearing errors are about 2 deg.
Document ID
20000032975
Acquisition Source
Marshall Space Flight Center
Document Type
Other - Reference Materials
Authors
Koshak, W. J.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Blakeslee, R. J.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Bailey, J. C.
(Raytheon STX Corp. Huntsville, AL United States)
Date Acquired
September 7, 2013
Publication Date
March 1, 2000
Publication Information
Publication: Journal of Atmospheric and Oceanic Technology
Publisher: American Meteorological Society
Volume: 17
Subject Category
Optics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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