Conversion between anomalies#

spacekernel.state.eca_from_mea(mea: double | ndarray[double], ecc: double | ndarray[double]) → double | ndarray[double]#

Compute the eccentric anomaly from the mean anomaly.

Parameters:
meafloat or ndarray of shape (N,)

Mean anomaly [radians].

eccfloat or ndarray of shape (N,)

Eccentricity.

Returns:
ecafloat or ndarray of shape (N,)

Eccentric anomaly [radians].

Notes

  • Accepts scalars or arrays.

  • Uses a Newton-Raphson iterative solution for Kepler’s equation.

  • Reference: Vallado, Algorithm 2, p. 65.

spacekernel.state.mea_from_eca(eca: double | ndarray[double], ecc: double | ndarray[double]) → double | ndarray[double]#

Compute the mean anomaly from the eccentric anomaly.

Parameters:
ecafloat or ndarray of shape (N,)

Eccentric anomaly [radians].

eccfloat or ndarray of shape (N,)

Eccentricity.

Returns:
meafloat or ndarray of shape (N,)

Mean anomaly [radians].

Notes

  • Accepts scalars or arrays.

  • Uses the analytical relation: MEA = ECA - e * sin(ECA).

spacekernel.state.tra_from_eca(eca: double | ndarray[double], ecc: double | ndarray[double]) → double | ndarray[double]#

Compute the true anomaly from the eccentric anomaly.

Parameters:
ecafloat or ndarray of shape (N,)

Eccentric anomaly [radians].

eccfloat or ndarray of shape (N,)

Eccentricity.

Returns:
trafloat or ndarray of shape (N,)

True anomaly [radians].

spacekernel.state.eca_from_tra(tra: double | ndarray[double], ecc: double | ndarray[double]) → double | ndarray[double]#

Compute the eccentric anomaly from the true anomaly.

Parameters:
trafloat or ndarray of shape (N,)

True anomaly [radians].

eccfloat or ndarray of shape (N,)

Eccentricity.

Returns:
ecafloat or ndarray of shape (N,)

Eccentric anomaly [radians].

spacekernel.state.tra_from_mea(mea: double | ndarray[double], ecc: double | ndarray[double]) → double | ndarray[double]#

Compute the true anomaly from the mean anomaly.

Parameters:
meafloat or ndarray of shape (N,)

Mean anomaly [radians].

eccfloat or ndarray of shape (N,)

Eccentricity.

Returns:
trafloat or ndarray of shape (N,)

True anomaly [radians].

Notes

  • Composite function: true anomaly is computed via eccentric anomaly.

spacekernel.state.mea_from_tra(tra: double | ndarray[double], ecc: double | ndarray[double]) → double | ndarray[double]#

Compute the mean anomaly from the true anomaly.

Parameters:
trafloat or ndarray of shape (N,)

True anomaly [radians].

eccfloat or ndarray of shape (N,)

Eccentricity.

Returns:
meafloat or ndarray of shape (N,)

Mean anomaly [radians].

Notes

  • Composite function: mean anomaly is computed via eccentric anomaly.