Name

CL_fr_inertial2tnw — Inertial to local orbital frame (t,n,w) vector transformation

Calling Sequence

   [vect_tnw] = CL_fr_inertial2tnw(pos_car,vel_car,vect_geo)
   
   

Description

  • Given the vector vect_geo expressed in a geocentric inertial frame, this function computes its coordinates vect_tnw in the local orbital frame (t,n,w) defined by satellite's position (pos_car) and velocity (vel_car) in the geocentric inertial frame.
  • The TNW local frame is defined as follows:

    origin: center of gravity of satellite

    t: unit vector in the direction of satellite's velocity

    w: unit vector of the kinetic moment of the osculating orbit

    n: unit vector chosen so TNW is a direct orthonormal frame

  • Last update : 25/07/2007

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 (3xN)

vect_tnw:

vector vect_geo coordinates in the local orbital frame (t,n,w) (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_tnw)

Authors

CNES - DCT/SB

See also

CL_fr_qsw2inertial, CL_fr_qswMat, CL_fr_tnwMat, CL_fr_inertial2qsw, 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_tnw] = CL_fr_inertial2tnw(pos_car,vel_car,vect_geo)