/**
******************************************************************************
*
* @file WMMInternal.h
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Include file of the WorldMagModel internal functionality.
*
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef WMMINTERNAL_H_
#define WMMINTERNAL_H_
#include <pios_math.h>
// internal constants
#define TRUE ((uint16_t)1)
#define FALSE ((uint16_t)0)
#define WMM_MAX_MODEL_DEGREES 12
#define WMM_MAX_SECULAR_VARIATION_MODEL_DEGREES 12
#define NUMTERMS 91 // ((WMM_MAX_MODEL_DEGREES+1)*(WMM_MAX_MODEL_DEGREES+2)/2);
#define NUMPCUP 92 // NUMTERMS +1
#define NUMPCUPS 13 // WMM_MAX_MODEL_DEGREES +1
// internal structure definitions
typedef struct {
float EditionDate;
float epoch; // Base time of Geomagnetic model epoch (yrs)
char ModelName[20];
// float Main_Field_Coeff_G[NUMTERMS]; // C - Gauss coefficients of main geomagnetic model (nT)
// float Main_Field_Coeff_H[NUMTERMS]; // C - Gauss coefficients of main geomagnetic model (nT)
// float Secular_Var_Coeff_G[NUMTERMS]; // CD - Gauss coefficients of secular geomagnetic model (nT/yr)
// float Secular_Var_Coeff_H[NUMTERMS]; // CD - Gauss coefficients of secular geomagnetic model (nT/yr)
uint16_t nMax; // Maximum degree of spherical harmonic model
uint16_t nMaxSecVar; // Maxumum degree of spherical harmonic secular model
uint16_t SecularVariationUsed; // Whether or not the magnetic secular variation vector will be needed by program
} WMMtype_MagneticModel;
typedef struct {
float a; // semi-major axis of the ellipsoid
float b; // semi-minor axis of the ellipsoid
float fla; // flattening
float epssq; // first eccentricity squared
float eps; // first eccentricity
float re; // mean radius of ellipsoid
} WMMtype_Ellipsoid;
typedef struct {
float lambda; // longitude
float phi; // geodetic latitude
float HeightAboveEllipsoid; // height above the ellipsoid (HaE)
} WMMtype_CoordGeodetic;
typedef struct {
float lambda; // longitude
float phig; // geocentric latitude
float r; // distance from the center of the ellipsoid
} WMMtype_CoordSpherical;
typedef struct {
uint16_t Year;
uint16_t Month;
uint16_t Day;
float DecimalYear;
} WMMtype_Date;
typedef struct {
float Pcup[NUMPCUP]; // Legendre Function
float dPcup[NUMPCUP]; // Derivative of Lagendre fn
} WMMtype_LegendreFunction;
typedef struct {
float Bx; // North
float By; // East
float Bz; // Down
} WMMtype_MagneticResults;
typedef struct {
float RelativeRadiusPower[WMM_MAX_MODEL_DEGREES + 1]; // [earth_reference_radius_km / sph. radius ]^n
float cos_mlambda[WMM_MAX_MODEL_DEGREES + 1]; // cp(m) - cosine of (m*spherical coord. longitude
float sin_mlambda[WMM_MAX_MODEL_DEGREES + 1]; // sp(m) - sine of (m*spherical coord. longitude)
} WMMtype_SphericalHarmonicVariables;
typedef struct {
float Decl; /* 1. Angle between the magnetic field vector and true north, positive east */
float Incl; /*2. Angle between the magnetic field vector and the horizontal plane, positive down */
float F; /*3. Magnetic Field Strength */
float H; /*4. Horizontal Magnetic Field Strength */
float X; /*5. Northern component of the magnetic field vector */
float Y; /*6. Eastern component of the magnetic field vector */
float Z; /*7. Downward component of the magnetic field vector */
float GV; /*8. The Grid Variation */
float Decldot; /*9. Yearly Rate of change in declination */
float Incldot; /*10. Yearly Rate of change in inclination */
float Fdot; /*11. Yearly rate of change in Magnetic field strength */
float Hdot; /*12. Yearly rate of change in horizontal field strength */
float Xdot; /*13. Yearly rate of change in the northern component */
float Ydot; /*14. Yearly rate of change in the eastern component */
float Zdot; /*15. Yearly rate of change in the downward component */
float GVdot; /*16. Yearly rate of chnage in grid variation */
} WMMtype_GeoMagneticElements;
// Internal Function Prototypes
void WMM_Set_Coeff_Array();
int WMM_GeodeticToSpherical(WMMtype_CoordGeodetic *CoordGeodetic, WMMtype_CoordSpherical *CoordSpherical);
int WMM_DateToYear(uint16_t month, uint16_t day, uint16_t year);
int WMM_Geomag(WMMtype_CoordSpherical *CoordSpherical,
WMMtype_CoordGeodetic *CoordGeodetic, WMMtype_GeoMagneticElements *GeoMagneticElements);
int WMM_AssociatedLegendreFunction(WMMtype_CoordSpherical *CoordSpherical, uint16_t nMax, WMMtype_LegendreFunction *LegendreFunction);
int WMM_CalculateGeoMagneticElements(WMMtype_MagneticResults *MagneticResultsGeo, WMMtype_GeoMagneticElements *GeoMagneticElements);
int WMM_CalculateSecularVariation(WMMtype_MagneticResults *MagneticVariation, WMMtype_GeoMagneticElements *MagneticElements);
int WMM_ComputeSphericalHarmonicVariables(WMMtype_CoordSpherical *
CoordSpherical, uint16_t nMax, WMMtype_SphericalHarmonicVariables *SphVariables);
int WMM_PcupLow(float *Pcup, float *dPcup, float x, uint16_t nMax);
int WMM_PcupHigh(float *Pcup, float *dPcup, float x, uint16_t nMax);
int WMM_RotateMagneticVector(WMMtype_CoordSpherical *,
WMMtype_CoordGeodetic *CoordGeodetic,
WMMtype_MagneticResults *MagneticResultsSph, WMMtype_MagneticResults *MagneticResultsGeo);
int WMM_SecVarSummation(WMMtype_LegendreFunction *LegendreFunction,
WMMtype_SphericalHarmonicVariables *
SphVariables, WMMtype_CoordSpherical *CoordSpherical, WMMtype_MagneticResults *MagneticResults);
int WMM_SecVarSummationSpecial(WMMtype_SphericalHarmonicVariables *
SphVariables, WMMtype_CoordSpherical *CoordSpherical, WMMtype_MagneticResults *MagneticResults);
int WMM_Summation(WMMtype_LegendreFunction *LegendreFunction,
WMMtype_SphericalHarmonicVariables *SphVariables,
WMMtype_CoordSpherical *CoordSpherical, WMMtype_MagneticResults *MagneticResults);
int WMM_SummationSpecial(WMMtype_SphericalHarmonicVariables *
SphVariables, WMMtype_CoordSpherical *CoordSpherical, WMMtype_MagneticResults *MagneticResults);
float WMM_get_main_field_coeff_g(uint16_t index);
float WMM_get_main_field_coeff_h(uint16_t index);
float WMM_get_secular_var_coeff_g(uint16_t index);
float WMM_get_secular_var_coeff_h(uint16_t index);
#endif /* WMMINTERNAL_H_ */