Name

CL_ex_eckHech — Eckstein Hechler orbit extrapolation analytic model

Calling Sequence

   [mean_cir_t2, osc_cir_t2] = CL_ex_eckHech ( t1, mean_cir_t1, t2 [,er[,mu[,zonals]]])
   
   

Description

  • Computes the mean parameters mean_cir_t2 and the osculatory parameters osc_cir_t2 at dates t2 given mean parameters mean_cir_t1 at dates t1.

    Zonals coefficients up to J6 are taken into account

    This function is vectorized for mean_cir_t1 or t2; but not for both at same time. When size(mean_cir_t1)=6xN and size(t2)=1xM, M or N must be 1.

  • Warnings :

    - This function does not work for inclinations close (0.0022918 deg) to the critical inclinations (63.43494882 deg and 116.5650512 deg)

    - This function nominally works for eccentricities lower than 5e-3

    - This function works with a lesser precision for eccentricities between 5e-3 and 0.1

    - This function does not work for eccentricities greater than 0.1

  • Last update : 28/3/2008

Parameters

t1:

CNES julian date of initial parameter (1xN)

mean_cir_t1:

circular adapted mean parameters at date t1 [sma,ex,ey,inc,gom,pom+anm]' (6xN)

t2:

CNES julian date (1xM)

er:

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

mu:

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

zonals:

(optional) vector of zonals coefficients J1 to Jn (troncated to J6) to be used (default is %CL_j1jn(1:6)) (1 x N)

mean_cir_t2:

circular adapted mean parameters at date t2 [sma,ex,ey,inc,gom,pom+anm]' (6 x max(N,M))

osc_cir_t2:

circular adapted osculatory parameters at date t2 [sma,ex,ey,inc,gom,pom+anm]' (6 x max(N,M))

Authors

CNES - DCT/SB

Bibliography

1 CNES - MSLIB FORTRAN 90, Volume E (me_eck_hech)

See also

CL_ex_lyddane, CL_ex_meanEckHech

Examples

// Example 1 : one orbit extrapolated at several dates :
t1 = 12584
mean_cir_t1 = [42166712,2.9e-3,1.2e-3,CL_deg2rad(97.2),CL_deg2rad(125),CL_deg2rad(0)]'
t2 = 12587:0.2:12588;
[mean_cir_t2,osc_cir_t2] = CL_ex_eckHech(t1,mean_cir_t1,t2)

// Example 2 : several orbits extrapolated at one date :
t1 = 12584
mean_cir_t1 = [42166712,2.9e-3,1.2e-3,CL_deg2rad(97.2),CL_deg2rad(125),CL_deg2rad(0)]'
mean_cir_t1 = [mean_cir_t1,mean_cir_t1*0.95]
t2 = 12587;
[mean_cir_t2,osc_cir_t2] = CL_ex_eckHech(t1,mean_cir_t1,t2)