CL_gm_stationVisiLocus

Description

• Computes the position of the satellite on a sphere (with a given radius) given the direction of the satellite in the local frame of some location.

  station is a location defined by its elliptical (geodetic) coordinates.

  azim (azimuth, posive towards West) and elev (elevation) define the direction of the satellite in the local (topocentric North) frame. The corresponding unit vector in spherical coordinates is [azim; elev; 1].

  pos_sat is the position on the sphere of radius rsat in cartesian coordinates.

• Notes:

  This function can be used to compute "visibility circles".

Parameters

station:

Station position, in elliptical (geodetic) coordinates [long,lat,alt] [rad,m] (3x1 or 3xN)

azim:

First spherical coordinate of the pointing direction in the topocentric North frame [rad] (1x1 or 1xN)

elev:

Second spherical coordinate of the pointing direction in the topocentric North frame [rad] (1x1 or 1xN)

rsat:

Satellite radius (= distance from body center) [m] (1x1 or 1xN)

er :

(optional) Equatorial radius (default is %CL_eqRad) [m] (1x1)

obla :

(optional) Oblateness (default is %CL_obla) (1x1)

pos:

Satellite position (cartesian coordinates) [m] (3xN)

See also

• CL_gm_stationPointing

Authors

• CNES - DCT/SB

Examples

station = [10 * %pi/180; 45 * %pi/180; 0]; azim = linspace(0, 2*%pi, 100); rsat = 8000.e3; // Elevation = constant value elev = 10 * %pi/180; pos_sat = CL_gm_stationVisiLocus(station, azim, elev, rsat); // Elevation = f(azimuth) elev = 10 * (%pi/180) * (1+sin(4*azim)); pos_sat2 = CL_gm_stationVisiLocus(station, azim, elev, rsat); scf(); CL_plot_earthMap(color_id=color("grey60")); CL_plot_ephem(pos_sat, color_id=2); CL_plot_ephem(pos_sat2, color_id=5);