$LastChangedDate: 27-Juil-2011 $

# CL_ex_meanEckHech

Eckstein Hechler orbit propagation analytical model (mean elements)

## Calling Sequence

       [mean_cir] = CL_ex_meanEckHech(osc_cir [,er,mu,zonals])

## Description

- Computes the mean orbital elements mean_cir from the osculating elements osc_cir

- The orbital elements are the following:

- Warnings :

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

  - This function nominally works for eccentricities smaller than 5.e-3

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

  - This function does not work for eccentricities greater than 0.1

## Parameters

osc_cir:

  Osculating circular-adapted elements [sma;ex;ey;inc;raan;pom+anm] (6xN)

er:

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

mu:

  (optional) 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)) (Nz x 1)

mean_cir:

  Mean circular-adapted elements [sma;ex;ey;inc;raan;pom+anm] (6xN)

## Authors

- CNES - DCT/SB

## Bibliography

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

## See also

- CL_ex_lyddane

- CL_ex_eckHech

## Examples

    osc_cir = [42166712;2.9e-3;1.2e-3;CL_deg2rad([97.2;125;5])];
    mean_cir = CL_ex_meanEckHech(osc_cir)
    // check
    [mean_cir2,osc_cir2] = CL_ex_eckHech(0,mean_cir,0)