Name

CL_cw_ballisticPropa — Ballistic propagation of a chaser relatively to a target

Calling Sequence

   [rel_dates,rel_pos_vel]=CL_cw_ballisticPropa(rel_date_ini,rel_pos_vel_ini,alt,rel_date_end,delta_t,ballistic_coef_chaser,ballistic_coef_target,er,mu)
   
   

Description

  • This function computes (with no maneuvers) positions and velocities of a chaser relatively to a target. rel_dates contains time in seconds, rel_pos_vel contains positions and velocities of the chaser relative to target's LVLH reference frame (described in CL_fr_lvlhMat). If ballistic coefficients are not given, the function does not take into account acceleration due to drag.
  • Last update : 20/10/2009

Parameters

rel_date_ini:

initial date in seconds [seconds] (1x1)

rel_pos_vel_ini:

initial position and velocity of chaser in target's LVLH frame [rx;ry;rz;vx;vy;vz] [m;m/s] (6x1)

alt:

altitude of target [m]

rel_date_end:

relative end date in seconds [seconds] (1x1)

delta_t:

(optional) time step [s] (default is 100)

ballistic_coef_chaser:

(optional) Ballistic coefficient of chaser : S*cx/m S=equivalent drag surface, cx = drag coefficient, m = mass [m^2/kg] (default is 0)

ballistic_coef_target:

(optional) Ballistic coefficient of target : S*cx/m S=equivalent drag surface, cx = drag coefficient, m = mass [m^2/kg] (default is 0)

er:

(optional) equatorial radius [m] (default is %CL_eqRad)

mu:

(optional) geocentric gravitational constant [m^3/s^2] (default value is %CL_mu)

rel_dates:

dates in seconds [seconds] (1xN)

rel_pos_vel:

positions and velocities of chaser in target's LVLH frame at corresponding dates [rx;ry;rz;vx;vy;vz] (6xN)

Authors

CNES - DCT/SB

See also

CL_cw_impulPropa, CL_cw_diffDrag, CL_cw_Mmatrix, CL_cw_Nmatrix, CL_cw_circularDrift, CL_cw_twoImpulse

Bibliography

Mecanique spatiale, CNES - Cepadues 1995, Tome II

Examples

rel_date_ini = 0;
rel_pos_vel_ini = [0;0;0;0;0;0] ;  // target and chaser have the same initial position and velocity
alt = 450.e3;
ballistic_coef_chaser = 100 * 1 / 20.e3;
ballistic_coef_target = 200 * 1 / 400.e3;
rel_date_end = 4*3600; // 4 hours of ballistic propagation
delta_t = 100; // 100 seconds time step
[rel_dates,rel_pos_vel] = CL_cw_ballisticPropa(rel_date_ini,rel_pos_vel_ini,alt,rel_date_end,delta_t,ballistic_coef_chaser,ballistic_coef_target)

//see 'CelestLab> Demos> RELATIVE MOTION> CW_propagation' for more examples