geocradius

Convert from geocentric latitude to radius of ellipsoid planet

Since R2021b

Syntax

r = geocradius(lambda)

r = geocradius(lambda,model)

r = geocradius(lambda,f,Re)

Description

WGS84 Ellipsoid Planet

r = geocradius(lambda) estimates the radius, r, of an ellipsoid planet at a particular geocentric latitude, lambda.

r = geocradius(lambda,model) estimates the radius for a specific ellipsoid planet.

Custom Ellipsoid Planet

r = geocradius(lambda,f,Re) is another alternate method for estimating the radius for a custom ellipsoid planet defined by flattening, f, and the equatorial radius, Re, in meters.

Examples

Radius at 45 Degrees Latitude

This example shows how to determine radius at 45 degrees latitude.

r = geocradius(45)

r = 
6.3674e+06

Determine Radius at Multiple Latitudes

This example shows how to determine the radius at multiple latitudes.

r = geocradius([0 45 90])

r = 1×3
106 ×

    6.3781    6.3674    6.3568

Determine Radius at Multiple Latitudes with WGS84 Ellipsoid Model

This example shows how to determine the radius at multiple latitudes, specifying the WGS84 ellipsoid model:

r = geocradius([0 45 90], 'WGS84')

r = 1×3
106 ×

    6.3781    6.3674    6.3568

Determine Radius at Multiple Latitudes with Custom Ellipsoid Model

This example shows how to determine the radius at multiple latitudes, specifying the custom ellipsoid model.

f = 1/196.877360;
Re = 3397000;
r = geocradius([0 45 90], f, Re)

r = 1×3
106 ×

    3.3970    3.3883    3.3797

Input Arguments

lambda — Geocentric latitude

scalar

Geocentric latitude, specified as a double, in degrees.

Data Types: double

model — Ellipsoid planet model

'WGS84' (default)

Ellipsoid planet model, specified as 'WGS84'.

Data Types: double

f — Flattening

scalar

Flattening at each pole, specified as a scalar.

Data Types: double

Re — Equatorial radius

scalar

Equatorial radius, specified as a scalar in meters.

Data Types: double

Output Arguments

r — Radius

vector

Radius of an ellipsoid planet, returned as a double, in meters.

References

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

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

Version History

Introduced in R2021b