Name

CL_op_ssoJ2 — Semi major axis, eccentricity or inclination for a sun synchronous orbit (J2)

Calling Sequence

   [output] = CL_op_ssoJ2(type_output,par1,par2[,er[,mu[,j2[,om_sun]]]])
   [sma] = CL_op_ssoJ2('a',ecc,inc[,er[,mu[,j2[,om_sun]]]])
   [ecc] = CL_op_ssoJ2('e',sma,inc[,er[,mu[,j2[,om_sun]]]])
   [inc] = CL_op_ssoJ2('i',sma,ecc[,er[,mu[,j2[,om_sun]]]])
   
   

Description

  • This function computes orbital parameters (semi major axis, eccentricity or inclination) ensuring a sun synchronous orbit. This means that the orbit's ascending node precession rate is equal to the sun's inertial pulsation om_sun .(See equation (1))

    - If type_output='a', par1 is eccentricity, par2 is inclination and semi major axis is computed (output).

    - If type_output='e', par1 is semi major axis, par2 is inclination and eccentricity is computed (output).

    - If type_output='i', par1 is semi major axis, par2 is eccentricity and inclination is computed (output)

    Note : If there is no solution, %nan is returned.

  • Last update : 8/4/2008

Parameters

type_output:

string defining parameter to compute (output). It can be 'a' for semi major axis, 'e' for eccentricity or 'i' for inclination

par1:

semi major axis if type_output is 'e' or 'i' ; eccentricity if type_output is 'a' [m] (1xN)

par2:

inclination if type_output is 'a' or 'e' ; eccentricity if type_output is 'i' [rad] (1xN)

er:

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

mu:

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

j2:

(optional) second zonal harmonic (default is %CL_j2)

om_sun :

(optional) mean apparent revolution speed of the Sun around the Earth (default is %CL_omSun) (1 x 1)

output:

semi major axis if type_output is 'a' ; eccentricity if type_output is 'e' ; inclination if type_output is 'i' [m rad] (1xN)

Authors

CNES - DCT/SB

Examples

// Compute inclination for sunsynchronism
sma = 7078.e3;
ecc = 0.01;
inc = CL_op_ssoJ2 ('i', sma, ecc)

// Compute eccentricity for sunsynchronism
sma = 7078.e3;
inc = CL_deg2rad(98.15);
ecc = CL_op_ssoJ2 ('e', sma, inc)

// Compute semi major axis for sunsynchronism
ecc = 0.01;
inc = CL_deg2rad(97);
sma = CL_op_ssoJ2 ('a', ecc, inc)