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Passive Ranging Using Atmospheric Oxygen Absorption Spectra (Paperback)
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Passive Ranging Using Atmospheric Oxygen Absorption Spectra (Paperback)
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The depth of absorption bands in observed spectra of distant,
bright sources can be used to estimate range to the source.
Previous efforts in this area have relied on measuring infrared CO2
bands, with disappointing results. A novel approach is presented
here and demonstrated using observations of the O2 absorption band
near 762 nm. Oxygen was chosen because its concentration is more
stable and predictable than CO2 or H2O, and this band is spectrally
isolated from other atmospheric bands, which enables direct
estimation of absorption. Range is estimated by comparing observed
values of band-average absorption, A, against curves derived from
either historical data or model predictions. Curves are based on
fitting a random band model to the data, which reduces average
range error by 67% compared to the Beer's Law model used in
previous work. An original model is presented based on a
traditional random band model, modified to account for variations
in absorber concentration over long, inhomogeneous paths. This mod-
ification further reduces error by over 50% in short-range
experiments, and can be used in conjunction with any band model. A
static rocket motor test was observed using a Bomem MR-254 Fourier
trans- form spectrometer at a range of 2.8 km. In this case,
observed values of A were com- pared against data simulated using
FASCODE, a validated atmospheric transport model. Detailed
atmospheric soundings were not required; a standard atmosphere was
used, and a simple correction, based on published meteorology data,
is presented. The resulting range estimate was accurate to within
0.5% (14 m). Similar accuracy was also achieved at shorter ranges
using a lamp as a surrogate target. Long-range performance is
predicted by using FASCODE and theoretical mod- els to extrapolate
observed short-range performance. Range error of 5% or less is
predicted at ranges up to 400 km for a representative target.
General
Imprint: |
Biblioscholar
|
Country of origin: |
United States |
Release date: |
November 2012 |
First published: |
November 2012 |
Authors: |
Michael R. Hawks
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Dimensions: |
246 x 189 x 8mm (L x W x T) |
Format: |
Paperback - Trade
|
Pages: |
138 |
ISBN-13: |
978-1-288-30723-4 |
Categories: |
Books >
Social sciences >
Education >
General
|
LSN: |
1-288-30723-3 |
Barcode: |
9781288307234 |
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