CL_stela_extrap

Description

• Propagates a mean orbital state using STELA.

  The results are described by res:

  - "m": Mean orbital elements (6xN)

  - "tm": Transition matrix for the mean orbital elements (6x6xN)

  - "i": Information data about the propagation, including an XML description of the inputs for the STELA tool

• Notes:

  - The dates offsets relative to the initial date (that is: cjd-cjd0) must be proportional to the integration time step.

  - The integration time step is typically chosen equal to 1 day.

  - The input orbital elements are internally converted to the adequate type and frame before the call to STELA. The results are then converted back to the specified type and frame.

  - The time scale offsets (ut1_tref and tt_tref) should be constant values (size = 1x1).

• See the STELA page for more details.

Parameters

type_oe:

(string) Type of orbital elements: "kep", "cir", "cireq", "equin", "pv".

cjd0:

Initial date (CJD, time scale: TREF) (1x1)

mean_oe0:

Initial mean orbital elements (6x1)

cjd:

Final dates (CJD, time scale: TREF) (1xN)

params:

(structure) Propagation model parameters.

res:

(string) Wanted results: "m", "tm", "i" (1xP).

frame:

(string, optional) Input/output frame. Default is "ECI"

ut1_tref:

(optional) UT1-TREF [seconds]. Default is %CL_UT1_TREF (1x1)

tt_tref:

(optional) TT-TREF [seconds]. Default is %CL_TT_TREF (1x1)

result1, result2, ...:

Mean orbital elements, transition matrix, or information data (see above)

Authors

• CNES - DCT/SB/MS

Examples

// Initial date (cjd, time scale: TREF) cjd0 = 20000; // Keplerian mean orbital elements (frame: ECI) mean_kep0 = [7.e6; 1.e-3; 98*(%pi/180); %pi/2; 0; 0]; // Final dates cjd = cjd0 + (0:60); // STELA model parameters (default values) params = CL_stela_params(); // Propagation [mean_kep, info] = CL_stela_extrap("kep", cjd0, mean_kep0, cjd, params, ["m", "i"]); // Plot inclination (deg) scf(); plot(cjd, mean_kep(3,:) * (180/%pi));