Implement International Standard Atmosphere (ISA)
The ISA Atmosphere Model block implements the mathematical representation of the international standard atmosphere values for ambient temperature, pressure, density, and speed of sound for the input geopotential altitude.
The ISA Atmosphere Model block icon displays the input and output metric units.
Select to customize various atmospheric parameters to be different from the ISA values.
Selecting this check box enables the parameters .
Enter acceleration from gravity in m/s2.
Enter a ratio of specific hits.
Enter the characteristic gas constant in J/Kg/K.
Enter the lapse rate in K/m.
Enter the height of the troposphere in m.
Enter the height of the tropopause in m.
Enter the air density at mean sea level in Kg/m3.
Enter the ambient pressure at mean sea level in N/m2.
Enter the ambient temperature at mean sea level in K.
Enter the lowest altitude in m.
|Contains the geopotential height.|
|Contains the temperature.|
|Contains the speed of sound.|
|Contains the air pressure.|
|Contains the air density.|
Below the geopotential altitude of 0 km and above the geopotential altitude of 20 km, temperature and pressure values are held. Density and speed of sound are calculated using a perfect gas relationship.
 U.S. Standard Atmosphere, 1976, U.S. Government Printing Office, Washington, D.C.