ADCS.environment.magnetic_field module

Selectable geomagnetic field model.

Every field evaluation in the package goes through field_gc(), which dispatches on a model name so that the implementation can be chosen per orbit – the magnetic counterpart of zonal_J for gravity:

"igrf_numba" (default)

The in-tree numba kernel, ADCS.environment.igrf.igrf_gc().

"igrf_ppigrf"

The ppigrf package, which was the field model up to 0.1.8. Kept so that older results can be reproduced exactly. It is an optional dependency (pip install "Generalized_ADCS[ppigrf]") and is imported only when selected.

Both evaluate IGRF-14 from the same coefficients and agree to ~1e-12 relative; they differ only in speed. A further model (e.g. WMM) is a new entry in MAGNETIC_MODELS plus a branch in field_gc().

ADCS.environment.magnetic_field.field_gc(magnetic_model, r, theta, phi, date)[source]

Geomagnetic field in geocentric spherical components, from a chosen model.

Parameters:

  • magnetic_model (str) – One of MAGNETIC_MODELS.

  • r (float or numpy.ndarray) – Geocentric radius [km].

  • theta (float or numpy.ndarray) – Geocentric colatitude [deg].

  • phi (float or numpy.ndarray) – Geocentric longitude [deg], positive east.

  • date (datetime.datetime or sequence) – One date, or one date per sample (paired elementwise).

Returns:

(Br, Btheta, Bphi) in nT, each with the broadcast shape of the coordinates.

Return type:

tuple

Raises:

  • ValueError – If magnetic_model is unknown.

  • ImportError – If "igrf_ppigrf" is requested and ppigrf is not installed.

Example:

>>> from datetime import datetime
>>> br, bt, bp = field_gc("igrf_numba", 6771.2, 45.0, 10.0, datetime(2024, 3, 1))
ADCS.environment.magnetic_field.DEFAULT_MAGNETIC_MODEL = 'igrf_numba'

Model used when none is requested.

ADCS.environment.magnetic_field.MAGNETIC_MODELS = ('igrf_numba', 'igrf_ppigrf')

Names accepted by magnetic_model arguments throughout the package.