Module: magneticFieldWMM

Executive Summary

Evaluate a magnetic field model about Earth for a range of spacecraft locations using the World Magnetic Model (WMM).

For more information on this module see this For more information on this module see this PDF Description.

The module is a sub-class of the Module: magneticFieldBase base class. See that class for the nominal messages used and general instructions.

User Guide

The Module: magneticFieldWMM model is created using:

from Basilisk.utilities.supportDataTools.dataFetcher import get_path, DataFile
from Basilisk.simulation import magneticFieldWMM

magModule = magneticFieldWMM.MagneticFieldWMM()
magModule.ModelTag = "WMM"

# Configuration of WMM coefficient file
wmm_file = get_path(DataFile.MagneticFieldData.WMM)
magModule.configureWMMFile(str(wmm_file))

scSim.AddModelToTask(dynTaskName, magModule)

---

class MagneticFieldWMM : public MagneticFieldBase

#include <magneticFieldWMM.h>

magnetic field WMM class

Public Functions

MagneticFieldWMM()

The constructor method initializes the dipole parameters to zero, resuling in a zero magnetic field result by default.

~MagneticFieldWMM()

Clean up any memory allocations.

void configureWMMFile(const std::string &file)

Method to configure the Magnetic Field model with the data file path

Parameters:

file – WMM source data path

Public Members

double epochDateFractionalYear

Specified epoch date as a fractional year.

BSKLogger bskLogger

&#8212; BSK Logging

std::string wmmDataFullPath

Full path to the WMM file selected by the user.

Private Functions

void evaluateMagneticFieldModel(MagneticFieldMsgPayload *msg, double currentTime)

This method is evaluates the centered dipole magnetic field model.

Parameters:

• msg – magnetic field message structure

• currentTime – current time (s)

void initializeWmm()

void cleanupEarthMagFieldModel()

Performs memory cleanup necessary for magnetic field models

void computeWmmField(double decimalYear, MAGtype_CoordSpherical coord, double B_M[3])

void customReset(uint64_t CurrentClock)

Custom Reset() method. This loads the WMM coefficient file and gets the model setup.

void customSetEpochFromVariable()

Custom customSetEpochFromVariable() method. This allows specifying epochDateFractionYear directly from Python. If an epoch message is set then this variable is not used.

void decimalYear2Gregorian(double fractionalYear, struct tm *gregorian)

Convert a fraction year double value into a time structure with gregorian date/time information

double gregorian2DecimalYear(double currentTime)

Convert a time structure with gregorian date/time information into a fraction year value.

Returns:

double

Private Members

MAGtype_MagneticModel *magneticModel

MAGtype_MagneticModel *timedMagneticModel

MAGtype_Ellipsoid ellip

MAGtype_Geoid geoid

MAGtype_Date userDate

MAGtype_LegendreFunction *LegendreFunction

MAGtype_SphericalHarmonicVariables *SphVariables