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Scientific Arts

TroposphericAttenuation

•Functions and parameters contained in this package:

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•Package functions and their basic documentation along with simple examples

•AbsorptionCoefficientGasses

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The absorption coefficient expressed in is given by

To see an example of this we use the 1976 US standard atmosphere as a function of height and the Mid Latitude mean water vapor density as a funciton of height. Here is the value for a milimeter band frequency of 220 GHz:

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Of course at a higher elevation the attenuation is less:

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Here is a plot of the absorption coefficient as a function of frequency at sea level

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[Graphics:HTMLFiles/index_15.gif]

For comparison, here is the same plot at a height of 20 kilometers.s

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•AbsorptionCoefficientOxygen

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•AbsorptionCoefficientRain

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A plot for a particular rain rate as a funciton of frequency in GHz (in dB/km):

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Here is the corresponding plot for horizontal polarization:

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[Graphics:HTMLFiles/index_23.gif]

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(2387 13/582016301^(1/2) r^(13000 + 372 (1 - (1 + (2500 Log[5]^2)/(9 Log[10]^2))^(1/2)))/10000)/2400000

•AbsorptionCoefficientWater

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•AngleBiasError

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$AngleBiasError[30, 100, 1 Degree, IndexOfRefractionModelExponential]$

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•ElevationAngle

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$ElevationAngle[30, 100, 1 Degree, IndexOfRefractionModelExponential] - Degree$

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•GroundRangeRayTrace

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$Clear[iorModel] ; iorModel = IndexOfRefractionModelTropospheric[Temperature1976[#], Pressure1 ... aterVaporDensityToPartialPressure[WaterVaporDensityMidLatitudeMean[#], Temperature1976[#]]] &$

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$IndexOfRefractionModelTropospheric[Temperature1976[#1], Pressure1976[#1], WaterVaporDensityToPartialPressure[WaterVaporDensityMidLatitudeMean[#1], Temperature1976[#1]]] &$

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GroundRangeGeometric[TransmitterHeight, TargetHeight, SlantRange] gives the arclength from the ... [TransmitterHeight, TargetHeight, {ElevationAngle}], uses the elevation angle in radians as input.

•LensLoss

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$? IndexOfRefractionModelTropospheric$

$IndexOfRefractionModelTropospheric[Temperature, Pressure, PartialPressureH2O] gives the refrac ... and partialPressureH2O is the partial pressure of the water vapor content in millibars.$

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$Clear[iorModel] ; iorModel = IndexOfRefractionModelTropospheric[TemperatureCOSPAR[July, #, 45 ... tyToPartialPressure[WaterVaporDensityMidLatitudeMean[#], TemperatureCOSPAR[July, #, 45]]] & ;$

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{SphereRadius :> $AverageEarthRadius, AccuracyGoal -> ∞, Compiled -> True, Gaus ... rsion -> 0, PrecisionGoal -> Automatic, SingularityDepth -> 4, WorkingPrecision -> 16}