$LastChangedDate: 27-Juil-2011 $

# CL_co_ell2car

Elliptical coordinates to cartesian coordinates

## Calling Sequence

       [pos_car[,jacob]] = CL_co_ell2car(pos_ell [,er,obla])

## Description

- Converts elliptical ("geodetic") coordinates into cartesian coordinates.

  Elliptical coordinates are longitude, latitude and altitude with respect to some reference ellipsoid.

  The reference ellipsoid is an ellipsoid of revolution around the Z axis. It is then characterized by 2 parameters:

  - semi-major axis of the ellipse obtained as the intersection of the ellipsoid with any plane containing the Z axis,

  - oblateness (or flattening) of this ellipse.

- Notes:

  - The transformation jacobian is computed if the corresponding output argument exists.

  - Be careful that the 3rd elliptical coordinate is an altitude and not the distance to the planet center.

## Parameters

pos_ell :

  [lon;lat;alt] Position vector in elliptical ("geodetic") coordinates [rad,m] (3xN)

er :

  (optional) Equatorial radius of reference ellipsoid [m] (default is %CL_eqRad)

obla :

  (optional) Oblateness of reference ellipsoid (default is %CL_obla)

pos_car :

  [x;y;z] Position vector in cartesian coordinates [m] (3xN)

jacob :

  (optional) Transformation jacobian (3x3xN)

## Authors

- CNES - DCT/SB

## Bibliography

- 1) Mecanique Spatiale, Cnes - Cepadues Editions, Tome I, section 3.2.3 (Les reperes de l'espace et du temps, Relations entre les coordonnees)

- 2) CNES - MSLIB FORTRAN 90, Volume T (mt_geod_car)

## See also

- CL_co_car2ell

- CL_co_sph2car

- CL_co_car2sph

## Examples

    // Example 1 :
    pos_ell = [ CL_deg2rad(12.125) ; CL_deg2rad(108.2) ; 110.0];
    [pos_car,jacob1] = CL_co_ell2car(pos_ell);