geocradius

Convert from geocentric latitude to radius of ellipsoid planet

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

Determine radius at 45 degrees latitude

Determine radius at 45 degrees latitude.

r = geocradius(45)

r =

  6.3674e+006

Determine radius at multiple latitudes

Determine radius at multiple latitudes.

r = geocradius([0 45 90])

r =

  1.0e+006 *

    6.3781    6.3674    6.3568

Determine radius at multiple latitudes with WGS84 ellipsoid model

Determine radius at multiple latitudes, specifying WGS84 ellipsoid model.

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

r =

  1.0e+006 *

    6.3781    6.3674    6.3568

Determine radius at multiple latitudes with custom ellipsoid model

Determine radius at multiple latitudes, specifying custom ellipsoid model.

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

r =

  1.0e+006 *

    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.