Name

CL_fr_inertial2qsw — Inertial to local orbital frame (q,s,w) vector transformation

Calling Sequence

   [vect_qsw] = CL_fr_inertial2qsw(pos_car,vel_car,vect_geo)
   
   

Description

  • Given the vector vect_geo expressed in a geocentric inertial frame, this function computes its coordinates vect_qsw in the local orbital frame (q,s,w) defined by satellite's position (pos_car) and velocity (vel_car) in the geocentric inertial frame.
  • The QSW local orbital frame is defined as follows:

    origin: center of gravity of the satellite

    q: a unit vector from the planet center towards the satellite

    w: a unit vector in the direction of the osculating orbit's kinetic moment

    s: a unit vector chosen so that qsw is a direct orthonormal frame

  • Last update : 07/11/2007

Parameters

pos_car:

satellite's cartesien position in a geocentric inertial frame [m] (3xN)

vel_car:

satellite's cartesien velocity in a geocentric inertial frame [m/s] (3xN)

vect_geo:

vector cartesien coordinates in a geocentric inertial frame [m] (3xN)

vect_qsw:

vector vect_geo in the local orbital frame (q,s,w) [m] (3xN)

Bibliography

1 Mecanique spatiale, CNES - Cepadues 1995, Tome I, section 10.2.2.3 (Definition du Repere orbital local)

2 CNES - MSLIB FORTRAN 90, Volume O (mo_geo_qsw)

Authors

CNES - DCT/SB

See also

CL_fr_qsw2inertial, CL_fr_qswMat, CL_fr_tnwMat, CL_fr_inertial2tnw, CL_fr_tnw2inertial

Examples

// Example 1
pos_car = [- 700700.,5.325E-11,6.718E-11;- 700700.,5.325E-11,6.718E-11]'
vel_car = [- 2.919E-12,- 14807.462,- 18682.367;- 2.919E-12,- 14807.462,- 18682.367]'
vect_geo = [1,0,0;1,1,1]'
[vect_qsw] = CL_fr_inertial2qsw(pos_car,vel_car,vect_geo)