Pressure Altitude

Calculate pressure altitude based on ambient pressure

  • Library:
  • Aerospace Blockset / Environment / Atmosphere

Description

The Pressure Altitude block computes the pressure altitude based on ambient pressure. Pressure altitude is the altitude in the 1976 Committee on the Extension of the Standard Atmosphere (COESA) United States with specified ambient pressure.

Pressure altitude is also known as the mean sea level (MSL) altitude.

The Pressure Altitude block icon port label change based on the input and output units selected from the Units list.

Limitations

  • Below the pressure of 0.3961 Pa (approximately 0.00006 psi) and above the pressure of 101325 Pa (approximately 14.7 psi), altitude values are extrapolated logarithmically.

  • Air is assumed to be dry and an ideal gas.

Ports

Input

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Static pressure, specified as a scalar or array.

Data Types: double

Output

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Pressure altitude, returned as a scalar or vector.

Data Types: double

Parameters

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Input units, specified as:

Units

Pstatic

Alt_p

Metric (MKS)

Pascal

Meters

English

Pound force per square inch

Feet

Programmatic Use

Block Parameter: units
Type: character vector
Values: 'Metric (MKS)' | 'English'
Default: 'Metric (MKS)'

Out-of-range block behavior, specified as follows.

ActionDescription

None

No action.

Warning

Warning in the MATLAB® Command Window, model simulation continues.

Error (default)

MATLAB returns an exception, model simulation stops.

Programmatic Use

Block Parameter: action
Type: character vector
Values: 'None' | 'Warning' | 'Error'
Default: 'Warning'

References

[1] U.S. Standard Atmosphere, 1976, U.S. Government Printing Office, Washington, D.C.

Introduced before R2006a