Radius at Geocentric Latitude

Estimate radius of ellipsoid planet at geocentric latitude

  • Library:
  • Aerospace Blockset / Flight Parameters

  • Radius at Geocentric Latitude block

Description

The Radius at Geocentric Latitude block estimates the radius (rs) of an ellipsoid planet at a particular geocentric latitude (λs).

The following equation estimates the ellipsoid radius (rs) using flattening (f¯), geocentric latitude (λ¯s), and equatorial radius (R¯):

rs=R21+[1/(1f)21]sin2λs.

Ports

Input

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Geocentric latitude, specified as a scalar or vector, in degrees.

Data Types: double

Output

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Radius of planet at geocentric latitude, returned as a scalar or vector, in the same units as flattening.

Data Types: double

Parameters

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Output units, specified as:

UnitsEquatorial RadiusRadius at Geocentric Latitude
Metric (MKS) MetersMeters
English FeetFeet

Dependencies

To enable this parameter, set Planet model to Earth (WGS84).

Programmatic Use

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

Planet model to use, Custom or Earth (WGS84).

Programmatic Use

Block Parameter: ptype
Type: character vector
Values: 'Earth (WGS84)' | 'Custom'
Default: 'Earth (WGS84)'

Flattening of the planet, specified as a double scalar.

Dependencies

To enable this parameter, set Planet model to Custom.

Programmatic Use

Block Parameter: F
Type: character vector
Values: double scalar
Default: 1/298.257223563

Radius of the planet at its equator, in the same units as the desired units for ECEF position.

Dependencies

To enable this parameter, set Planet model to Custom.

Programmatic Use

Block Parameter: R
Type: character vector
Values: double scalar
Default: 6378137

References

[1] Stevens, Brian L., Frank L. Lewis. Aircraft Control and Simulation, New York, John Wiley & Sons, 1992.

[2] Zipfel, Peter H., Modeling and Simulation of Aerospace Vehicle Dynamics. Second Edition. Reston, VA: AIAA Education Series, 2000.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Introduced before R2006a