Aerospace Toolbox

atmospalt - Calculate pressure altitude based on ambient pressure

Syntax

h = atmospalt(p, action)

Description

h = atmospalt(p, action)computes the pressure altitude based on ambient pressure. Pressure altitude is the altitude with specified ambient pressure in the 1976 Committee on Extension to the Standard Atmosphere (COESA) United States standard. Pressure altitude is also known as the mean sea level (MSL) altitude.

Inputs for atmospalt are:

`P`	An array of `m` ambient pressures, in pascal
`action`	A string to determine action for out-of-range input. Specify if out-of-range input invokes a `'Warning'`, `'Error'`, or no action (`'None'`). The default is `'Warning'`.

Output is:

`h`	An array of `m` pressure altitudes or MSL altitudes, in meters

Examples

Calculate the pressure altitude at a static pressure of 101,325 Pa with warnings for out-of-range inputs:

h = atmospalt(101325)


h =

     0

Calculate the pressure altitude at static pressures of 101,325 and 26,436 Pa with errors for out-of-range inputs:

h = atmospalt([101325 26436], 'Error' )


h =

  1.0e+004 *

         0    1.0000

Assumptions and Limitations

Below the pressure of 0.3961 Pa (approximately 0.00006 psi) and above the pressure of 101,325 Pa (approximately 14.7 psi), altitude values are extrapolated logarithmically. Air is assumed to be dry and an ideal gas.

References