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Flight/Libraries: Updated to coding conventions

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find ./flight/Libraries/ \! \( -name '*~' -a -prune \) -type f    | xargs -I{} bash -c 'echo {}; dos2unix {}; gnuindent -npro -kr -i8 -ts8 -sob -ss -ncs -cp1 -il0 {};'

git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1706 ebee16cc-31ac-478f-84a7-5cbb03baadba
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peabody124 2010-09-21 19:29:35 +00:00 committed by peabody124
parent df0ed37d29
commit 833e8428d2
7 changed files with 2016 additions and 1850 deletions
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412
flight/Libraries/CoordinateConversions.c
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@ -1,187 +1,225 @@
/**
******************************************************************************
*
* @file CoordinateConversions.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief General conversions with different coordinate systems.
* - all angles in deg
* - distances in meters
* - altitude above WGS-84 elipsoid
*
* @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
*/
#include <math.h>
#include <stdint.h>
#include "CoordinateConversions.h"
#define RAD2DEG (180.0/M_PI)
#define DEG2RAD (M_PI/180.0)
// ****** convert Lat,Lon,Alt to ECEF ************
void LLA2ECEF(double LLA[3], double ECEF[3]){
const double a = 6378137.0; // Equatorial Radius
const double e = 8.1819190842622e-2; // Eccentricity
double sinLat, sinLon, cosLat, cosLon;
double N;
sinLat=sin(DEG2RAD*LLA[0]);
sinLon=sin(DEG2RAD*LLA[1]);
cosLat=cos(DEG2RAD*LLA[0]);
cosLon=cos(DEG2RAD*LLA[1]);
N = a / sqrt(1.0 - e*e*sinLat*sinLat); //prime vertical radius of curvature
ECEF[0] = (N+LLA[2])*cosLat*cosLon;
ECEF[1] = (N+LLA[2])*cosLat*sinLon;
ECEF[2] = ((1-e*e)*N + LLA[2]) * sinLat;
}
// ****** convert ECEF to Lat,Lon,Alt (ITERATIVE!) *********
uint16_t ECEF2LLA(double ECEF[3], double LLA[3])
{
const double a = 6378137.0; // Equatorial Radius
const double e = 8.1819190842622e-2; // Eccentricity
double x=ECEF[0], y=ECEF[1], z=ECEF[2];
double Lat, N, NplusH, delta, esLat;
uint16_t iter;
#define MAX_ITER 100
LLA[1] = RAD2DEG*atan2(y,x);
N = a;
NplusH = N;
delta = 1;
Lat = 1;
iter=0;
while (((delta > 1.0e-14)||(delta < -1.0e-14)) && (iter < MAX_ITER))
{
delta = Lat - atan(z / (sqrt(x*x + y*y)*(1-(N*e*e/NplusH))));
Lat = Lat-delta;
esLat = e*sin(Lat);
N = a / sqrt(1 - esLat*esLat);
NplusH = sqrt(x*x + y*y)/cos(Lat);
iter += 1;
}
LLA[0] = RAD2DEG*Lat;
LLA[2] = NplusH - N;
return (iter < MAX_ITER);
}
// ****** find ECEF to NED rotation matrix ********
void RneFromLLA(double LLA[3], float Rne[3][3]){
float sinLat, sinLon, cosLat, cosLon;
sinLat=(float)sin(DEG2RAD*LLA[0]);
sinLon=(float)sin(DEG2RAD*LLA[1]);
cosLat=(float)cos(DEG2RAD*LLA[0]);
cosLon=(float)cos(DEG2RAD*LLA[1]);
Rne[0][0] = -sinLat*cosLon; Rne[0][1] = -sinLat*sinLon; Rne[0][2] = cosLat;
Rne[1][0] = -sinLon; Rne[1][1] = cosLon; Rne[1][2] = 0;
Rne[2][0] = -cosLat*cosLon; Rne[2][1] = -cosLat*sinLon; Rne[2][2] = -sinLat;
}
// ****** find roll, pitch, yaw from quaternion ********
void Quaternion2RPY(float q[4], float rpy[3]){
float R13, R11, R12, R23, R33;
float q0s=q[0]*q[0];
float q1s=q[1]*q[1];
float q2s=q[2]*q[2];
float q3s=q[3]*q[3];
R13 = 2*(q[1]*q[3]-q[0]*q[2]);
R11 = q0s+q1s-q2s-q3s;
R12 = 2*(q[1]*q[2]+q[0]*q[3]);
R23 = 2*(q[2]*q[3]+q[0]*q[1]);
R33 = q0s-q1s-q2s+q3s;
rpy[1]=RAD2DEG*asinf(-R13); // pitch always between -pi/2 to pi/2
rpy[2]=RAD2DEG*atan2f(R12,R11);
rpy[0]=RAD2DEG*atan2f(R23,R33);
}
// ****** find quaternion from roll, pitch, yaw ********
void RPY2Quaternion(float rpy[3], float q[4]){
float phi, theta, psi;
float cphi, sphi, ctheta, stheta, cpsi, spsi;
phi=DEG2RAD*rpy[0]/2; theta=DEG2RAD*rpy[1]/2; psi=DEG2RAD*rpy[2]/2;
cphi=cosf(phi); sphi=sinf(phi);
ctheta=cosf(theta); stheta=sinf(theta);
cpsi=cosf(psi); spsi=sinf(psi);
q[0] = cphi*ctheta*cpsi + sphi*stheta*spsi;
q[1] = sphi*ctheta*cpsi - cphi*stheta*spsi;
q[2] = cphi*stheta*cpsi + sphi*ctheta*spsi;
q[3] = cphi*ctheta*spsi - sphi*stheta*cpsi;
if (q[0] < 0){ // q0 always positive for uniqueness
q[0]=-q[0];
q[1]=-q[1];
q[2]=-q[2];
q[3]=-q[3];
}
}
//** Find Rbe, that rotates a vector from earth fixed to body frame, from quaternion **
void Quaternion2R(float q[4], float Rbe[3][3]){
float q0s=q[0]*q[0], q1s=q[1]*q[1], q2s=q[2]*q[2], q3s=q[3]*q[3];
Rbe[0][0]=q0s+q1s-q2s-q3s;
Rbe[0][1]=2*(q[1]*q[2]+q[0]*q[3]);
Rbe[0][2]=2*(q[1]*q[3]-q[0]*q[2]);
Rbe[1][0]=2*(q[1]*q[2]-q[0]*q[3]);
Rbe[1][1]=q0s-q1s+q2s-q3s;
Rbe[1][2]=2*(q[2]*q[3]+q[0]*q[1]);
Rbe[2][0]=2*(q[1]*q[3]+q[0]*q[2]);
Rbe[2][1]=2*(q[2]*q[3]-q[0]*q[1]);
Rbe[2][2]=q0s-q1s-q2s+q3s;
}
// ****** Express LLA in a local NED Base Frame ********
void LLA2Base(double LLA[3], double BaseECEF[3], float Rne[3][3], float NED[3]){
double ECEF[3];
float diff[3];
LLA2ECEF(LLA,ECEF);
diff[0]=(float)(ECEF[0]-BaseECEF[0]);
diff[1]=(float)(ECEF[1]-BaseECEF[1]);
diff[2]=(float)(ECEF[2]-BaseECEF[2]);
NED[0]= Rne[0][0]*diff[0]+Rne[0][1]*diff[1]+Rne[0][2]*diff[2];
NED[1]= Rne[1][0]*diff[0]+Rne[1][1]*diff[1]+Rne[1][2]*diff[2];
NED[2]= Rne[2][0]*diff[0]+Rne[2][1]*diff[1]+Rne[2][2]*diff[2];
}
// ****** Express ECEF in a local NED Base Frame ********
void ECEF2Base(double ECEF[3], double BaseECEF[3], float Rne[3][3], float NED[3]){
float diff[3];
diff[0]=(float)(ECEF[0]-BaseECEF[0]);
diff[1]=(float)(ECEF[1]-BaseECEF[1]);
diff[2]=(float)(ECEF[2]-BaseECEF[2]);
NED[0]= Rne[0][0]*diff[0]+Rne[0][1]*diff[1]+Rne[0][2]*diff[2];
NED[1]= Rne[1][0]*diff[0]+Rne[1][1]*diff[1]+Rne[1][2]*diff[2];
NED[2]= Rne[2][0]*diff[0]+Rne[2][1]*diff[1]+Rne[2][2]*diff[2];
}
/**
******************************************************************************
*
* @file CoordinateConversions.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief General conversions with different coordinate systems.
* - all angles in deg
* - distances in meters
* - altitude above WGS-84 elipsoid
*
* @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
*/
#include <math.h>
#include <stdint.h>
#include "CoordinateConversions.h"
#define RAD2DEG (180.0/M_PI)
#define DEG2RAD (M_PI/180.0)
// ****** convert Lat,Lon,Alt to ECEF ************
void LLA2ECEF(double LLA[3], double ECEF[3])
{
const double a = 6378137.0; // Equatorial Radius
const double e = 8.1819190842622e-2; // Eccentricity
double sinLat, sinLon, cosLat, cosLon;
double N;
sinLat = sin(DEG2RAD * LLA[0]);
sinLon = sin(DEG2RAD * LLA[1]);
cosLat = cos(DEG2RAD * LLA[0]);
cosLon = cos(DEG2RAD * LLA[1]);
N = a / sqrt(1.0 - e * e * sinLat * sinLat); //prime vertical radius of curvature
ECEF[0] = (N + LLA[2]) * cosLat * cosLon;
ECEF[1] = (N + LLA[2]) * cosLat * sinLon;
ECEF[2] = ((1 - e * e) * N + LLA[2]) * sinLat;
}
// ****** convert ECEF to Lat,Lon,Alt (ITERATIVE!) *********
uint16_t ECEF2LLA(double ECEF[3], double LLA[3])
{
const double a = 6378137.0; // Equatorial Radius
const double e = 8.1819190842622e-2; // Eccentricity
double x = ECEF[0], y = ECEF[1], z = ECEF[2];
double Lat, N, NplusH, delta, esLat;
uint16_t iter;
#define MAX_ITER 100
LLA[1] = RAD2DEG * atan2(y, x);
N = a;
NplusH = N;
delta = 1;
Lat = 1;
iter = 0;
while (((delta > 1.0e-14) || (delta < -1.0e-14))
&& (iter < MAX_ITER)) {
delta =
Lat -
atan(z /
(sqrt(x * x + y * y) *
(1 - (N * e * e / NplusH))));
Lat = Lat - delta;
esLat = e * sin(Lat);
N = a / sqrt(1 - esLat * esLat);
NplusH = sqrt(x * x + y * y) / cos(Lat);
iter += 1;
}
LLA[0] = RAD2DEG * Lat;
LLA[2] = NplusH - N;
return (iter < MAX_ITER);
}
// ****** find ECEF to NED rotation matrix ********
void RneFromLLA(double LLA[3], float Rne[3][3])
{
float sinLat, sinLon, cosLat, cosLon;
sinLat = (float)sin(DEG2RAD * LLA[0]);
sinLon = (float)sin(DEG2RAD * LLA[1]);
cosLat = (float)cos(DEG2RAD * LLA[0]);
cosLon = (float)cos(DEG2RAD * LLA[1]);
Rne[0][0] = -sinLat * cosLon;
Rne[0][1] = -sinLat * sinLon;
Rne[0][2] = cosLat;
Rne[1][0] = -sinLon;
Rne[1][1] = cosLon;
Rne[1][2] = 0;
Rne[2][0] = -cosLat * cosLon;
Rne[2][1] = -cosLat * sinLon;
Rne[2][2] = -sinLat;
}
// ****** find roll, pitch, yaw from quaternion ********
void Quaternion2RPY(float q[4], float rpy[3])
{
float R13, R11, R12, R23, R33;
float q0s = q[0] * q[0];
float q1s = q[1] * q[1];
float q2s = q[2] * q[2];
float q3s = q[3] * q[3];
R13 = 2 * (q[1] * q[3] - q[0] * q[2]);
R11 = q0s + q1s - q2s - q3s;
R12 = 2 * (q[1] * q[2] + q[0] * q[3]);
R23 = 2 * (q[2] * q[3] + q[0] * q[1]);
R33 = q0s - q1s - q2s + q3s;
rpy[1] = RAD2DEG * asinf(-R13); // pitch always between -pi/2 to pi/2
rpy[2] = RAD2DEG * atan2f(R12, R11);
rpy[0] = RAD2DEG * atan2f(R23, R33);
}
// ****** find quaternion from roll, pitch, yaw ********
void RPY2Quaternion(float rpy[3], float q[4])
{
float phi, theta, psi;
float cphi, sphi, ctheta, stheta, cpsi, spsi;
phi = DEG2RAD * rpy[0] / 2;
theta = DEG2RAD * rpy[1] / 2;
psi = DEG2RAD * rpy[2] / 2;
cphi = cosf(phi);
sphi = sinf(phi);
ctheta = cosf(theta);
stheta = sinf(theta);
cpsi = cosf(psi);
spsi = sinf(psi);
q[0] = cphi * ctheta * cpsi + sphi * stheta * spsi;
q[1] = sphi * ctheta * cpsi - cphi * stheta * spsi;
q[2] = cphi * stheta * cpsi + sphi * ctheta * spsi;
q[3] = cphi * ctheta * spsi - sphi * stheta * cpsi;
if (q[0] < 0) { // q0 always positive for uniqueness
q[0] = -q[0];
q[1] = -q[1];
q[2] = -q[2];
q[3] = -q[3];
}
}
//** Find Rbe, that rotates a vector from earth fixed to body frame, from quaternion **
void Quaternion2R(float q[4], float Rbe[3][3])
{
float q0s = q[0] * q[0], q1s = q[1] * q[1], q2s =
q[2] * q[2], q3s = q[3] * q[3];
Rbe[0][0] = q0s + q1s - q2s - q3s;
Rbe[0][1] = 2 * (q[1] * q[2] + q[0] * q[3]);
Rbe[0][2] = 2 * (q[1] * q[3] - q[0] * q[2]);
Rbe[1][0] = 2 * (q[1] * q[2] - q[0] * q[3]);
Rbe[1][1] = q0s - q1s + q2s - q3s;
Rbe[1][2] = 2 * (q[2] * q[3] + q[0] * q[1]);
Rbe[2][0] = 2 * (q[1] * q[3] + q[0] * q[2]);
Rbe[2][1] = 2 * (q[2] * q[3] - q[0] * q[1]);
Rbe[2][2] = q0s - q1s - q2s + q3s;
}
// ****** Express LLA in a local NED Base Frame ********
void LLA2Base(double LLA[3], double BaseECEF[3], float Rne[3][3],
float NED[3])
{
double ECEF[3];
float diff[3];
LLA2ECEF(LLA, ECEF);
diff[0] = (float)(ECEF[0] - BaseECEF[0]);
diff[1] = (float)(ECEF[1] - BaseECEF[1]);
diff[2] = (float)(ECEF[2] - BaseECEF[2]);
NED[0] =
Rne[0][0] * diff[0] + Rne[0][1] * diff[1] +
Rne[0][2] * diff[2];
NED[1] =
Rne[1][0] * diff[0] + Rne[1][1] * diff[1] +
Rne[1][2] * diff[2];
NED[2] =
Rne[2][0] * diff[0] + Rne[2][1] * diff[1] +
Rne[2][2] * diff[2];
}
// ****** Express ECEF in a local NED Base Frame ********
void ECEF2Base(double ECEF[3], double BaseECEF[3], float Rne[3][3],
float NED[3])
{
float diff[3];
diff[0] = (float)(ECEF[0] - BaseECEF[0]);
diff[1] = (float)(ECEF[1] - BaseECEF[1]);
diff[2] = (float)(ECEF[2] - BaseECEF[2]);
NED[0] =
Rne[0][0] * diff[0] + Rne[0][1] * diff[1] +
Rne[0][2] * diff[2];
NED[1] =
Rne[1][0] * diff[0] + Rne[1][1] * diff[1] +
Rne[1][2] * diff[2];
NED[2] =
Rne[2][0] * diff[0] + Rne[2][1] * diff[1] +
Rne[2][2] * diff[2];
}

2222
flight/Libraries/WorldMagModel.c
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@ -1,1055 +1,1167 @@
/**
******************************************************************************
*
* @file WorldMagModel.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Source file for the World Magnetic Model
* This is a port of code available from the US NOAA.
* The hard coded coefficients should be valid until 2015.
* Major changes include:
* - No geoid model (altitude must be geodetic WGS-84)
* - Floating point calculation (not double precision)
* - Hard coded coefficients for model
* - Elimination of user interface
* - Elimination of dynamic memory allocation
*
* @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
*/
// I don't want this dependency, but currently using pvPortMalloc
#include "openpilot.h"
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <stdint.h>
#include "WorldMagModel.h"
#include "WMMInternal.h"
static WMMtype_Ellipsoid * Ellip;
static WMMtype_MagneticModel * MagneticModel;
/**************************************************************************************
* Example use - very simple - only two exposed functions
*
* WMM_Initialize(); // Set default values and constants
*
* WMM_GetMagVector(float Lat, float Lon, float Alt, uint16_t Month, uint16_t Day, uint16_t Year, float B[3]);
* e.g. Iceland in may of 2012 = WMM_GetMagVector(65.0, -20.0, 0.0, 5, 5, 2012, B);
* Alt is above the WGS-84 Ellipsoid
* B is the NED (XYZ) magnetic vector in nTesla
**************************************************************************************/
int WMM_Initialize()
// Sets default values for WMM subroutines.
// UPDATES : Ellip and MagneticModel
{
// Sets WGS-84 parameters
Ellip->a = 6378.137; // semi-major axis of the ellipsoid in km
Ellip->b = 6356.7523142; // semi-minor axis of the ellipsoid in km
Ellip->fla = 1/298.257223563; // flattening
Ellip->eps = sqrt(1- (Ellip->b*Ellip->b)/(Ellip->a*Ellip->a )); // first eccentricity
Ellip->epssq = (Ellip->eps*Ellip->eps); // first eccentricity squared
Ellip->re = 6371.2; // Earth's radius in km
// Sets Magnetic Model parameters
MagneticModel->nMax = WMM_MAX_MODEL_DEGREES;
MagneticModel->nMaxSecVar = WMM_MAX_SECULAR_VARIATION_MODEL_DEGREES;
MagneticModel->SecularVariationUsed = 0;
// Really, Really needs to be read from a file - out of date in 2015 at latest
MagneticModel->EditionDate = 5.7863328170559505e-307;
MagneticModel->epoch = 2010.0;
sprintf(MagneticModel->ModelName, "WMM-2010");
WMM_Set_Coeff_Array();
return 0;
}
void WMM_GetMagVector(float Lat, float Lon, float AltEllipsoid, uint16_t Month, uint16_t Day, uint16_t Year, float B[3])
{
char Error_Message[255];
Ellip = (WMMtype_Ellipsoid *) pvPortMalloc(sizeof(WMMtype_Ellipsoid));
MagneticModel = (WMMtype_MagneticModel *) pvPortMalloc(sizeof(WMMtype_MagneticModel));
WMMtype_CoordSpherical * CoordSpherical = (WMMtype_CoordSpherical *) pvPortMalloc(sizeof(CoordSpherical));
WMMtype_CoordGeodetic * CoordGeodetic = (WMMtype_CoordGeodetic *) pvPortMalloc(sizeof(CoordGeodetic));
WMMtype_Date * Date = (WMMtype_Date *) pvPortMalloc(sizeof(WMMtype_Date));
WMMtype_GeoMagneticElements * GeoMagneticElements = (WMMtype_GeoMagneticElements *) pvPortMalloc(sizeof(GeoMagneticElements));
WMM_Initialize();
CoordGeodetic->lambda = Lon;
CoordGeodetic->phi = Lat;
CoordGeodetic->HeightAboveEllipsoid = AltEllipsoid;
WMM_GeodeticToSpherical(CoordGeodetic, CoordSpherical); /*Convert from geodeitic to Spherical Equations: 17-18, WMM Technical report*/
Date->Month=Month;
Date->Day=Day;
Date->Year=Year;
WMM_DateToYear (Date, Error_Message);
WMM_TimelyModifyMagneticModel(Date);
WMM_Geomag(CoordSpherical, CoordGeodetic, GeoMagneticElements); /* Computes the geoMagnetic field elements and their time change*/
B[0]=GeoMagneticElements->X;
B[1]=GeoMagneticElements->Y;
B[2]=GeoMagneticElements->Z;
vPortFree(Ellip);
vPortFree(MagneticModel);
vPortFree(CoordSpherical);
vPortFree(CoordGeodetic);
vPortFree(Date);
vPortFree(GeoMagneticElements);
}
uint16_t WMM_Geomag( WMMtype_CoordSpherical * CoordSpherical, WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_GeoMagneticElements *GeoMagneticElements)
/*
The main subroutine that calls a sequence of WMM sub-functions to calculate the magnetic field elements for a single point.
The function expects the model coefficients and point coordinates as input and returns the magnetic field elements and
their rate of change. Though, this subroutine can be called successively to calculate a time series, profile or grid
of magnetic field, these are better achieved by the subroutine WMM_Grid.
INPUT: Ellip
CoordSpherical
CoordGeodetic
TimedMagneticModel
OUTPUT : GeoMagneticElements
CALLS: WMM_ComputeSphericalHarmonicVariables( Ellip, CoordSpherical, TimedMagneticModel->nMax, &SphVariables); (Compute Spherical Harmonic variables )
WMM_AssociatedLegendreFunction(CoordSpherical, TimedMagneticModel->nMax, LegendreFunction); Compute ALF
WMM_Summation(LegendreFunction, TimedMagneticModel, SphVariables, CoordSpherical, &MagneticResultsSph); Accumulate the spherical harmonic coefficients
WMM_SecVarSummation(LegendreFunction, TimedMagneticModel, SphVariables, CoordSpherical, &MagneticResultsSphVar); Sum the Secular Variation Coefficients
WMM_RotateMagneticVector(CoordSpherical, CoordGeodetic, MagneticResultsSph, &MagneticResultsGeo); Map the computed Magnetic fields to Geodeitic coordinates
WMM_RotateMagneticVector(CoordSpherical, CoordGeodetic, MagneticResultsSphVar, &MagneticResultsGeoVar); Map the secular variation field components to Geodetic coordinates
WMM_CalculateGeoMagneticElements(&MagneticResultsGeo, GeoMagneticElements); Calculate the Geomagnetic elements
WMM_CalculateSecularVariation(MagneticResultsGeoVar, GeoMagneticElements); Calculate the secular variation of each of the Geomagnetic elements
*/
{
WMMtype_LegendreFunction LegendreFunction;
WMMtype_SphericalHarmonicVariables SphVariables;
WMMtype_MagneticResults MagneticResultsSph, MagneticResultsGeo, MagneticResultsSphVar, MagneticResultsGeoVar;
WMM_ComputeSphericalHarmonicVariables( CoordSpherical, MagneticModel->nMax, &SphVariables); /* Compute Spherical Harmonic variables */
WMM_AssociatedLegendreFunction( CoordSpherical, MagneticModel->nMax, &LegendreFunction); /* Compute ALF */
WMM_Summation(&LegendreFunction, &SphVariables, CoordSpherical, &MagneticResultsSph); /* Accumulate the spherical harmonic coefficients*/
WMM_SecVarSummation(&LegendreFunction, &SphVariables, CoordSpherical, &MagneticResultsSphVar); /*Sum the Secular Variation Coefficients */
WMM_RotateMagneticVector(CoordSpherical, CoordGeodetic, &MagneticResultsSph, &MagneticResultsGeo); /* Map the computed Magnetic fields to Geodeitic coordinates */
WMM_RotateMagneticVector(CoordSpherical, CoordGeodetic, &MagneticResultsSphVar, &MagneticResultsGeoVar); /* Map the secular variation field components to Geodetic coordinates*/
WMM_CalculateGeoMagneticElements(&MagneticResultsGeo, GeoMagneticElements); /* Calculate the Geomagnetic elements, Equation 18 , WMM Technical report */
WMM_CalculateSecularVariation(&MagneticResultsGeoVar, GeoMagneticElements); /*Calculate the secular variation of each of the Geomagnetic elements*/
return TRUE;
}
uint16_t WMM_ComputeSphericalHarmonicVariables(WMMtype_CoordSpherical *CoordSpherical, uint16_t nMax, WMMtype_SphericalHarmonicVariables *SphVariables)
/* Computes Spherical variables
Variables computed are (a/r)^(n+2), cos_m(lamda) and sin_m(lambda) for spherical harmonic
summations. (Equations 10-12 in the WMM Technical Report)
INPUT Ellip data structure with the following elements
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
CoordSpherical A data structure with the following elements
float lambda; ( longitude)
float phig; ( geocentric latitude )
float r; ( distance from the center of the ellipsoid)
nMax integer ( Maxumum degree of spherical harmonic secular model)\
OUTPUT SphVariables Pointer to the data structure with the following elements
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 (mspherical coord. longitude)
float sin_mlambda[WMM_MAX_MODEL_DEGREES+1]; sp(m) - sine of (mspherical coord. longitude)
CALLS : none
*/
{
float cos_lambda, sin_lambda;
uint16_t m, n;
cos_lambda = cos(DEG2RAD(CoordSpherical->lambda));
sin_lambda = sin(DEG2RAD(CoordSpherical->lambda));
/* for n = 0 ... model_order, compute (Radius of Earth / Spherica radius r)^(n+2)
for n 1..nMax-1 (this is much faster than calling pow MAX_N+1 times). */
SphVariables->RelativeRadiusPower[0] = (Ellip->re / CoordSpherical->r) * (Ellip->re / CoordSpherical->r);
for (n = 1; n <= nMax; n++)
{
SphVariables->RelativeRadiusPower[n] = SphVariables->RelativeRadiusPower[n-1] * (Ellip->re / CoordSpherical->r);
}
/*
Compute cos(m*lambda), sin(m*lambda) for m = 0 ... nMax
cos(a + b) = cos(a)*cos(b) - sin(a)*sin(b)
sin(a + b) = cos(a)*sin(b) + sin(a)*cos(b)
*/
SphVariables->cos_mlambda[0] = 1.0;
SphVariables->sin_mlambda[0] = 0.0;
SphVariables->cos_mlambda[1] = cos_lambda;
SphVariables->sin_mlambda[1] = sin_lambda;
for (m = 2; m <= nMax; m++)
{
SphVariables->cos_mlambda[m] = SphVariables->cos_mlambda[m-1]*cos_lambda - SphVariables->sin_mlambda[m-1]*sin_lambda;
SphVariables->sin_mlambda[m] = SphVariables->cos_mlambda[m-1]*sin_lambda + SphVariables->sin_mlambda[m-1]*cos_lambda;
}
return TRUE;
} /*WMM_ComputeSphericalHarmonicVariables*/
uint16_t WMM_AssociatedLegendreFunction(WMMtype_CoordSpherical * CoordSpherical, uint16_t nMax, WMMtype_LegendreFunction *LegendreFunction)
/* Computes all of the Schmidt-semi normalized associated Legendre
functions up to degree nMax. If nMax <= 16, function WMM_PcupLow is used.
Otherwise WMM_PcupHigh is called.
INPUT CoordSpherical A data structure with the following elements
float lambda; ( longitude)
float phig; ( geocentric latitude )
float r; ( distance from the center of the ellipsoid)
nMax integer ( Maxumum degree of spherical harmonic secular model)
LegendreFunction Pointer to data structure with the following elements
float *Pcup; ( pointer to store Legendre Function )
float *dPcup; ( pointer to store Derivative of Lagendre function )
OUTPUT LegendreFunction Calculated Legendre variables in the data structure
*/
{
float sin_phi;
uint16_t FLAG = 1;
sin_phi = sin ( DEG2RAD ( CoordSpherical->phig ) ); /* sin (geocentric latitude) */
if (nMax <= 16 || (1 - fabs(sin_phi)) < 1.0e-10 ) /* If nMax is less tha 16 or at the poles */
FLAG = WMM_PcupLow(LegendreFunction->Pcup,LegendreFunction->dPcup,sin_phi, nMax);
else FLAG = WMM_PcupHigh(LegendreFunction->Pcup,LegendreFunction->dPcup,sin_phi, nMax);
if (FLAG == 0) /* Error while computing Legendre variables*/
return FALSE;
return TRUE;
} /*WMM_AssociatedLegendreFunction */
uint16_t WMM_Summation(WMMtype_LegendreFunction *LegendreFunction, WMMtype_SphericalHarmonicVariables * SphVariables, WMMtype_CoordSpherical * CoordSpherical, WMMtype_MagneticResults *MagneticResults)
{
/* Computes Geomagnetic Field Elements X, Y and Z in Spherical coordinate system using
spherical harmonic summation.
The vector Magnetic field is given by -grad V, where V is Geomagnetic scalar potential
The gradient in spherical coordinates is given by:
dV ^ 1 dV ^ 1 dV ^
grad V = -- r + - -- t + -------- -- p
dr r dt r sin(t) dp
INPUT : LegendreFunction
MagneticModel
SphVariables
CoordSpherical
OUTPUT : MagneticResults
CALLS : WMM_SummationSpecial
Manoj Nair, June, 2009 Manoj.C.Nair@Noaa.Gov
*/
uint16_t m, n, index;
float cos_phi;
MagneticResults->Bz = 0.0;
MagneticResults->By = 0.0;
MagneticResults->Bx = 0.0;
for (n = 1; n <= MagneticModel->nMax; n++)
{
for (m=0;m<=n;m++)
{
index = (n * (n + 1) / 2 + m);
/* nMax (n+2) n m m m
Bz = -SUM (a/r) (n+1) SUM [g cos(m p) + h sin(m p)] P (sin(phi))
n=1 m=0 n n n */
/* Equation 12 in the WMM Technical report. Derivative with respect to radius.*/
MagneticResults->Bz -= SphVariables->RelativeRadiusPower[n] *
( MagneticModel->Main_Field_Coeff_G[index]*SphVariables->cos_mlambda[m] +
MagneticModel->Main_Field_Coeff_H[index]*SphVariables->sin_mlambda[m] )
* (float) (n+1) * LegendreFunction-> Pcup[index];
/* 1 nMax (n+2) n m m m
By = SUM (a/r) (m) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Equation 11 in the WMM Technical report. Derivative with respect to longitude, divided by radius. */
MagneticResults->By += SphVariables->RelativeRadiusPower[n] *
( MagneticModel->Main_Field_Coeff_G[index]*SphVariables->sin_mlambda[m] -
MagneticModel->Main_Field_Coeff_H[index]*SphVariables->cos_mlambda[m] )
* (float) (m) * LegendreFunction-> Pcup[index];
/* nMax (n+2) n m m m
Bx = - SUM (a/r) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Equation 10 in the WMM Technical report. Derivative with respect to latitude, divided by radius. */
MagneticResults->Bx -= SphVariables->RelativeRadiusPower[n] *
( MagneticModel->Main_Field_Coeff_G[index]*SphVariables->cos_mlambda[m] +
MagneticModel->Main_Field_Coeff_H[index]*SphVariables->sin_mlambda[m] )
* LegendreFunction-> dPcup[index];
}
}
cos_phi = cos ( DEG2RAD ( CoordSpherical->phig ) );
if ( fabs(cos_phi) > 1.0e-10 )
{
MagneticResults->By = MagneticResults->By / cos_phi ;
}
else
/* Special calculation for component - By - at Geographic poles.
* If the user wants to avoid using this function, please make sure that
* the latitude is not exactly +/-90. An option is to make use the function
* WMM_CheckGeographicPoles.
*/
{
WMM_SummationSpecial(SphVariables, CoordSpherical, MagneticResults);
}
return TRUE;
}/*WMM_Summation */
uint16_t WMM_SecVarSummation(WMMtype_LegendreFunction *LegendreFunction, WMMtype_SphericalHarmonicVariables * SphVariables, WMMtype_CoordSpherical * CoordSpherical, WMMtype_MagneticResults *MagneticResults)
{
/*This Function sums the secular variation coefficients to get the secular variation of the Magnetic vector.
INPUT : LegendreFunction
MagneticModel
SphVariables
CoordSpherical
OUTPUT : MagneticResults
CALLS : WMM_SecVarSummationSpecial
*/
uint16_t m, n, index;
float cos_phi;
MagneticModel->SecularVariationUsed = TRUE;
MagneticResults->Bz = 0.0;
MagneticResults->By = 0.0;
MagneticResults->Bx = 0.0;
for (n = 1; n <= MagneticModel->nMaxSecVar; n++)
{
for (m=0;m<=n;m++)
{
index = (n * (n + 1) / 2 + m);
/* nMax (n+2) n m m m
Bz = -SUM (a/r) (n+1) SUM [g cos(m p) + h sin(m p)] P (sin(phi))
n=1 m=0 n n n */
/* Derivative with respect to radius.*/
MagneticResults->Bz -= SphVariables->RelativeRadiusPower[n] *
( MagneticModel->Secular_Var_Coeff_G[index]*SphVariables->cos_mlambda[m] +
MagneticModel->Secular_Var_Coeff_H[index]*SphVariables->sin_mlambda[m] )
* (float) (n+1) * LegendreFunction-> Pcup[index];
/* 1 nMax (n+2) n m m m
By = SUM (a/r) (m) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Derivative with respect to longitude, divided by radius. */
MagneticResults->By += SphVariables->RelativeRadiusPower[n] *
( MagneticModel->Secular_Var_Coeff_G[index]*SphVariables->sin_mlambda[m] -
MagneticModel->Secular_Var_Coeff_H[index]*SphVariables->cos_mlambda[m] )
* (float) (m) * LegendreFunction-> Pcup[index];
/* nMax (n+2) n m m m
Bx = - SUM (a/r) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Derivative with respect to latitude, divided by radius. */
MagneticResults->Bx -= SphVariables->RelativeRadiusPower[n] *
( MagneticModel->Secular_Var_Coeff_G[index]*SphVariables->cos_mlambda[m] +
MagneticModel->Secular_Var_Coeff_H[index]*SphVariables->sin_mlambda[m] )
* LegendreFunction-> dPcup[index];
}
}
cos_phi = cos ( DEG2RAD ( CoordSpherical->phig ) );
if ( fabs(cos_phi) > 1.0e-10 )
{
MagneticResults->By = MagneticResults->By / cos_phi ;
}
else
/* Special calculation for component By at Geographic poles */
{
WMM_SecVarSummationSpecial(SphVariables, CoordSpherical, MagneticResults);
}
return TRUE;
} /*WMM_SecVarSummation*/
uint16_t WMM_RotateMagneticVector(WMMtype_CoordSpherical * CoordSpherical, WMMtype_CoordGeodetic * CoordGeodetic, WMMtype_MagneticResults * MagneticResultsSph, WMMtype_MagneticResults *MagneticResultsGeo)
/* Rotate the Magnetic Vectors to Geodetic Coordinates
Manoj Nair, June, 2009 Manoj.C.Nair@Noaa.Gov
Equation 16, WMM Technical report
INPUT : CoordSpherical : Data structure WMMtype_CoordSpherical with the following elements
float lambda; ( longitude)
float phig; ( geocentric latitude )
float r; ( distance from the center of the ellipsoid)
CoordGeodetic : Data structure WMMtype_CoordGeodetic with the following elements
float lambda; (longitude)
float phi; ( geodetic latitude)
float HeightAboveEllipsoid; (height above the ellipsoid (HaE) )
float HeightAboveGeoid;(height above the Geoid )
MagneticResultsSph : Data structure WMMtype_MagneticResults with the following elements
float Bx; North
float By; East
float Bz; Down
OUTPUT: MagneticResultsGeo Pointer to the data structure WMMtype_MagneticResults, with the following elements
float Bx; North
float By; East
float Bz; Down
CALLS : none
*/
{
float Psi;
/* Difference between the spherical and Geodetic latitudes */
Psi = ( M_PI/180 ) * ( CoordSpherical->phig - CoordGeodetic->phi );
/* Rotate spherical field components to the Geodeitic system */
MagneticResultsGeo->Bz = MagneticResultsSph->Bx * sin(Psi) + MagneticResultsSph->Bz * cos(Psi);
MagneticResultsGeo->Bx = MagneticResultsSph->Bx * cos(Psi) - MagneticResultsSph->Bz * sin(Psi);
MagneticResultsGeo->By = MagneticResultsSph->By;
return TRUE;
} /*WMM_RotateMagneticVector*/
uint16_t WMM_CalculateGeoMagneticElements(WMMtype_MagneticResults *MagneticResultsGeo, WMMtype_GeoMagneticElements *GeoMagneticElements)
/* Calculate all the Geomagnetic elements from X,Y and Z components
INPUT MagneticResultsGeo Pointer to data structure with the following elements
float Bx; ( North )
float By; ( East )
float Bz; ( Down )
OUTPUT GeoMagneticElements Pointer to data structure with the following elements
float Decl; (Angle between the magnetic field vector and true north, positive east)
float Incl; Angle between the magnetic field vector and the horizontal plane, positive down
float F; Magnetic Field Strength
float H; Horizontal Magnetic Field Strength
float X; Northern component of the magnetic field vector
float Y; Eastern component of the magnetic field vector
float Z; Downward component of the magnetic field vector
CALLS : none
*/
{
GeoMagneticElements->X = MagneticResultsGeo->Bx;
GeoMagneticElements->Y = MagneticResultsGeo->By;
GeoMagneticElements->Z = MagneticResultsGeo->Bz;
GeoMagneticElements->H = sqrt (MagneticResultsGeo->Bx* MagneticResultsGeo->Bx + MagneticResultsGeo->By * MagneticResultsGeo->By);
GeoMagneticElements->F = sqrt (GeoMagneticElements->H*GeoMagneticElements->H + MagneticResultsGeo->Bz * MagneticResultsGeo->Bz);
GeoMagneticElements->Decl = RAD2DEG(atan2 (GeoMagneticElements->Y , GeoMagneticElements->X));
GeoMagneticElements->Incl = RAD2DEG(atan2 (GeoMagneticElements->Z , GeoMagneticElements->H));
return TRUE;
} /*WMM_CalculateGeoMagneticElements */
uint16_t WMM_CalculateSecularVariation(WMMtype_MagneticResults * MagneticVariation, WMMtype_GeoMagneticElements *MagneticElements)
/*This takes the Magnetic Variation in x, y, and z and uses it to calculate the secular variation of each of the Geomagnetic elements.
INPUT MagneticVariation Data structure with the following elements
float Bx; ( North )
float By; ( East )
float Bz; ( Down )
OUTPUT MagneticElements Pointer to the data structure with the following elements updated
float Decldot; Yearly Rate of change in declination
float Incldot; Yearly Rate of change in inclination
float Fdot; Yearly rate of change in Magnetic field strength
float Hdot; Yearly rate of change in horizontal field strength
float Xdot; Yearly rate of change in the northern component
float Ydot; Yearly rate of change in the eastern component
float Zdot; Yearly rate of change in the downward component
float GVdot;Yearly rate of chnage in grid variation
CALLS : none
*/
{
MagneticElements->Xdot = MagneticVariation->Bx;
MagneticElements->Ydot = MagneticVariation->By;
MagneticElements->Zdot = MagneticVariation->Bz;
MagneticElements->Hdot = (MagneticElements->X * MagneticElements->Xdot + MagneticElements->Y * MagneticElements->Ydot) / MagneticElements->H; //See equation 19 in the WMM technical report
MagneticElements->Fdot = (MagneticElements->X * MagneticElements->Xdot + MagneticElements->Y * MagneticElements->Ydot + MagneticElements->Z * MagneticElements->Zdot) / MagneticElements->F;
MagneticElements->Decldot = 180.0 / M_PI * (MagneticElements->X * MagneticElements->Ydot - MagneticElements->Y * MagneticElements->Xdot) / (MagneticElements->H * MagneticElements->H);
MagneticElements->Incldot = 180.0 / M_PI * (MagneticElements->H * MagneticElements->Zdot - MagneticElements->Z * MagneticElements->Hdot) / (MagneticElements->F * MagneticElements->F);
MagneticElements->GVdot = MagneticElements->Decldot;
return TRUE;
} /*WMM_CalculateSecularVariation*/
uint16_t WMM_PcupHigh(float *Pcup, float *dPcup, float x, uint16_t nMax)
/* This function evaluates all of the Schmidt-semi normalized associated Legendre
functions up to degree nMax. The functions are initially scaled by
10^280 sin^m in order to minimize the effects of underflow at large m
near the poles (see Holmes and Featherstone 2002, J. Geodesy, 76, 279-299).
Note that this function performs the same operation as WMM_PcupLow.
However this function also can be used for high degree (large nMax) models.
Calling Parameters:
INPUT
nMax: Maximum spherical harmonic degree to compute.
x: cos(colatitude) or sin(latitude).
OUTPUT
Pcup: A vector of all associated Legendgre polynomials evaluated at
x up to nMax. The lenght must by greater or equal to (nMax+1)*(nMax+2)/2.
dPcup: Derivative of Pcup(x) with respect to latitude
CALLS : none
Notes:
Adopted from the FORTRAN code written by Mark Wieczorek September 25, 2005.
Manoj Nair, Nov, 2009 Manoj.C.Nair@Noaa.Gov
Change from the previous version
The prevous version computes the derivatives as
dP(n,m)(x)/dx, where x = sin(latitude) (or cos(colatitude) ).
However, the WMM Geomagnetic routines requires dP(n,m)(x)/dlatitude.
Hence the derivatives are multiplied by sin(latitude).
Removed the options for CS phase and normalizations.
Note: In geomagnetism, the derivatives of ALF are usually found with
respect to the colatitudes. Here the derivatives are found with respect
to the latitude. The difference is a sign reversal for the derivative of
the Associated Legendre Functions.
The derivates can't be computed for latitude = |90| degrees.
*/
{
float pm2, pm1, pmm, plm, rescalem, z, scalef;
float f1[NUMPCUP], f2[NUMPCUP], PreSqr[NUMPCUP];
uint16_t k, kstart, m, n;
if (fabs(x) == 1.0)
{
// printf("Error in PcupHigh: derivative cannot be calculated at poles\n");
return FALSE;
}
scalef = 1.0e-280;
for(n = 0 ; n <= 2*nMax+1 ; ++n )
{
PreSqr[n] = sqrt((float)(n));
}
k = 2;
for(n=2 ; n<=nMax ; n++)
{
k = k + 1;
f1[k] = (float)(2*n-1) /(float)(n);
f2[k] = (float)(n-1) /(float)(n);
for(m=1 ; m<=n-2 ; m++)
{
k = k+1;
f1[k] = (float)(2*n-1) / PreSqr[n+m] / PreSqr[n-m];
f2[k] = PreSqr[n-m-1] * PreSqr[n+m-1] / PreSqr[n+m] / PreSqr[n-m];
}
k = k + 2;
}
/*z = sin (geocentric latitude) */
z = sqrt((1.0-x)*(1.0+x));
pm2 = 1.0;
Pcup[0] = 1.0;
dPcup[0] = 0.0;
if (nMax == 0)
return FALSE;
pm1 = x;
Pcup[1] = pm1;
dPcup[1] = z;
k = 1;
for(n = 2; n <= nMax; n++ )
{
k = k+n;
plm = f1[k]*x*pm1-f2[k]*pm2;
Pcup[k] = plm;
dPcup[k] = (float)(n) * (pm1 - x * plm) / z;
pm2 = pm1;
pm1 = plm;
}
pmm = PreSqr[2]*scalef;
rescalem = 1.0/scalef;
kstart = 0;
for(m = 1; m <= nMax - 1; ++m)
{
rescalem = rescalem*z;
/* Calculate Pcup(m,m)*/
kstart = kstart+m+1;
pmm = pmm * PreSqr[2*m+1] / PreSqr[2*m];
Pcup[kstart] = pmm*rescalem / PreSqr[2*m+1];
dPcup[kstart] = -((float)(m) * x * Pcup[kstart] / z);
pm2 = pmm/PreSqr[2*m+1];
/* Calculate Pcup(m+1,m)*/
k = kstart+m+1 ;
pm1 = x * PreSqr[2*m+1] * pm2;
Pcup[k] = pm1*rescalem;
dPcup[k] = ((pm2*rescalem) * PreSqr[2*m+1] - x * (float)(m+1) * Pcup[k]) / z;
/* Calculate Pcup(n,m)*/
for(n = m+2; n <= nMax; ++n)
{
k = k+n;
plm = x*f1[k]*pm1-f2[k]*pm2;
Pcup[k] = plm*rescalem;
dPcup[k] = (PreSqr[n+m] * PreSqr[n-m] * (pm1 * rescalem) - (float)(n) * x * Pcup[k] ) / z;
pm2 = pm1;
pm1 = plm;
}
}
/* Calculate Pcup(nMax,nMax)*/
rescalem = rescalem*z;
kstart = kstart+m+1;
pmm = pmm / PreSqr[2*nMax];
Pcup[kstart] = pmm * rescalem;
dPcup[kstart] = -(float)(nMax) * x * Pcup[kstart] / z;
return TRUE ;
} /* WMM_PcupHigh */
uint16_t WMM_PcupLow( float *Pcup, float *dPcup, float x, uint16_t nMax)
/* This function evaluates all of the Schmidt-semi normalized associated Legendre
functions up to degree nMax.
Calling Parameters:
INPUT
nMax: Maximum spherical harmonic degree to compute.
x: cos(colatitude) or sin(latitude).
OUTPUT
Pcup: A vector of all associated Legendgre polynomials evaluated at
x up to nMax.
dPcup: Derivative of Pcup(x) with respect to latitude
Notes: Overflow may occur if nMax > 20 , especially for high-latitudes.
Use WMM_PcupHigh for large nMax.
Writted by Manoj Nair, June, 2009 . Manoj.C.Nair@Noaa.Gov.
Note: In geomagnetism, the derivatives of ALF are usually found with
respect to the colatitudes. Here the derivatives are found with respect
to the latitude. The difference is a sign reversal for the derivative of
the Associated Legendre Functions.
*/
{
uint16_t n, m, index, index1, index2;
float k, z, schmidtQuasiNorm[NUMPCUP];
Pcup[0] = 1.0;
dPcup[0] = 0.0;
/*sin (geocentric latitude) - sin_phi */
z = sqrt( ( 1.0 - x ) * ( 1.0 + x ) ) ;
/* First, Compute the Gauss-normalized associated Legendre functions*/
for (n = 1; n <= nMax; n++)
{
for (m=0;m<=n;m++)
{
index = (n * (n + 1) / 2 + m);
if (n == m)
{
index1 = ( n - 1 ) * n / 2 + m -1;
Pcup [index] = z * Pcup[index1];
dPcup[index] = z * dPcup[index1] + x * Pcup[index1];
}
else if (n == 1 && m == 0)
{
index1 = ( n - 1 ) * n / 2 + m;
Pcup[index] = x * Pcup[index1];
dPcup[index] = x * dPcup[index1] - z * Pcup[index1];
}
else if (n > 1 && n != m)
{
index1 = ( n - 2 ) * ( n - 1 ) / 2 + m;
index2 = ( n - 1) * n / 2 + m;
if (m > n - 2)
{
Pcup[index] = x * Pcup[index2];
dPcup[index] = x * dPcup[index2] - z * Pcup[index2];
}
else
{
k = (float)( ( ( n - 1 ) * ( n - 1 ) ) - ( m * m ) ) / ( float ) ( ( 2 * n - 1 ) * ( 2 * n - 3 ) );
Pcup[index] = x * Pcup[index2] - k * Pcup[index1];
dPcup[index] = x * dPcup[index2] - z * Pcup[index2] - k * dPcup[index1];
}
}
}
}
/*Compute the ration between the Gauss-normalized associated Legendre
functions and the Schmidt quasi-normalized version. This is equivalent to
sqrt((m==0?1:2)*(n-m)!/(n+m!))*(2n-1)!!/(n-m)! */
schmidtQuasiNorm[0] = 1.0;
for (n = 1; n <= nMax; n++)
{
index = (n * (n + 1) / 2);
index1 = (n - 1) * n / 2 ;
/* for m = 0 */
schmidtQuasiNorm[index] = schmidtQuasiNorm[index1] * (float) (2 * n - 1) / (float) n;
for ( m = 1; m <= n; m++)
{
index = (n * (n + 1) / 2 + m);
index1 = (n * (n + 1) / 2 + m - 1);
schmidtQuasiNorm[index] = schmidtQuasiNorm[index1] * sqrt( (float) ((n - m + 1) * (m == 1 ? 2 : 1)) / (float) (n + m));
}
}
/* Converts the Gauss-normalized associated Legendre
functions to the Schmidt quasi-normalized version using pre-computed
relation stored in the variable schmidtQuasiNorm */
for (n = 1; n <= nMax; n++)
{
for (m=0;m<=n;m++)
{
index = (n * (n + 1) / 2 + m);
Pcup[index] = Pcup[index] * schmidtQuasiNorm[index];
dPcup[index] = - dPcup[index] * schmidtQuasiNorm[index];
/* The sign is changed since the new WMM routines use derivative with respect to latitude
insted of co-latitude */
}
}
return TRUE;
} /*WMM_PcupLow */
uint16_t WMM_SummationSpecial(WMMtype_SphericalHarmonicVariables * SphVariables, WMMtype_CoordSpherical * CoordSpherical, WMMtype_MagneticResults *MagneticResults)
/* Special calculation for the component By at Geographic poles.
Manoj Nair, June, 2009 manoj.c.nair@noaa.gov
INPUT: MagneticModel
SphVariables
CoordSpherical
OUTPUT: MagneticResults
CALLS : none
See Section 1.4, "SINGULARITIES AT THE GEOGRAPHIC POLES", WMM Technical report
*/
{
uint16_t n, index;
float k, sin_phi, PcupS[NUMPCUPS], schmidtQuasiNorm1, schmidtQuasiNorm2, schmidtQuasiNorm3;
PcupS[0] = 1;
schmidtQuasiNorm1 = 1.0;
MagneticResults->By = 0.0;
sin_phi = sin ( DEG2RAD ( CoordSpherical->phig ) );
for (n = 1; n <= MagneticModel->nMax; n++)
{
/*Compute the ration between the Gauss-normalized associated Legendre
functions and the Schmidt quasi-normalized version. This is equivalent to
sqrt((m==0?1:2)*(n-m)!/(n+m!))*(2n-1)!!/(n-m)! */
index = (n * (n + 1) / 2 + 1);
schmidtQuasiNorm2 = schmidtQuasiNorm1 * (float) (2 * n - 1) / (float) n;
schmidtQuasiNorm3 = schmidtQuasiNorm2 * sqrt( (float) (n * 2) / (float) (n + 1));
schmidtQuasiNorm1 = schmidtQuasiNorm2;
if (n == 1)
{
PcupS[n] = PcupS[n-1];
}
else
{
k = (float)( ( (n - 1) * (n - 1) ) - 1) / ( float ) ( (2 * n - 1) * (2 * n - 3) );
PcupS[n] = sin_phi * PcupS[n-1] - k * PcupS[n-2];
}
/* 1 nMax (n+2) n m m m
By = SUM (a/r) (m) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Equation 11 in the WMM Technical report. Derivative with respect to longitude, divided by radius. */
MagneticResults->By += SphVariables->RelativeRadiusPower[n] *
( MagneticModel->Main_Field_Coeff_G[index]*SphVariables->sin_mlambda[1] -
MagneticModel->Main_Field_Coeff_H[index]*SphVariables->cos_mlambda[1] )
* PcupS[n] * schmidtQuasiNorm3;
}
return TRUE;
}/*WMM_SummationSpecial */
uint16_t WMM_SecVarSummationSpecial(WMMtype_SphericalHarmonicVariables * SphVariables, WMMtype_CoordSpherical * CoordSpherical, WMMtype_MagneticResults *MagneticResults)
{
/*Special calculation for the secular variation summation at the poles.
INPUT: MagneticModel
SphVariables
CoordSpherical
OUTPUT: MagneticResults
CALLS : none
*/
uint16_t n, index;
float k, sin_phi, PcupS[NUMPCUPS], schmidtQuasiNorm1, schmidtQuasiNorm2, schmidtQuasiNorm3;
PcupS[0] = 1;
schmidtQuasiNorm1 = 1.0;
MagneticResults->By = 0.0;
sin_phi = sin ( DEG2RAD ( CoordSpherical->phig ) );
for (n = 1; n <= MagneticModel->nMaxSecVar; n++)
{
index = (n * (n + 1) / 2 + 1);
schmidtQuasiNorm2 = schmidtQuasiNorm1 * (float) (2 * n - 1) / (float) n;
schmidtQuasiNorm3 = schmidtQuasiNorm2 * sqrt( (float) (n * 2) / (float) (n + 1));
schmidtQuasiNorm1 = schmidtQuasiNorm2;
if (n == 1)
{
PcupS[n] = PcupS[n-1];
}
else
{
k = (float)( ( (n - 1) * (n - 1) ) - 1) / ( float ) ( (2 * n - 1) * (2 * n - 3) );
PcupS[n] = sin_phi * PcupS[n-1] - k * PcupS[n-2];
}
/* 1 nMax (n+2) n m m m
By = SUM (a/r) (m) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Derivative with respect to longitude, divided by radius. */
MagneticResults->By += SphVariables->RelativeRadiusPower[n] *
( MagneticModel->Secular_Var_Coeff_G[index]*SphVariables->sin_mlambda[1] -
MagneticModel->Secular_Var_Coeff_H[index]*SphVariables->cos_mlambda[1] )
* PcupS[n] * schmidtQuasiNorm3;
}
return TRUE;
}/*SecVarSummationSpecial*/
void WMM_TimelyModifyMagneticModel(WMMtype_Date * UserDate)
// Time change the Model coefficients from the base year of the model using secular variation coefficients.
//
// Modified to work on the global data structure to reduce memory footprint
{
uint16_t n, m, index, a, b;
a = MagneticModel->nMaxSecVar;
b = (a * (a + 1) / 2 + a);
for (n = 1; n <= MagneticModel->nMax; n++)
{
for (m=0;m<=n;m++)
{
index = (n * (n + 1) / 2 + m);
if(index <= b)
{
MagneticModel->Main_Field_Coeff_H[index] += (UserDate->DecimalYear - MagneticModel->epoch) * MagneticModel->Secular_Var_Coeff_H[index];
MagneticModel->Main_Field_Coeff_G[index] += (UserDate->DecimalYear - MagneticModel->epoch) * MagneticModel->Secular_Var_Coeff_G[index];
}
}
}
} /* WMM_TimelyModifyMagneticModel */
uint16_t WMM_DateToYear (WMMtype_Date *CalendarDate, char *Error)
// Converts a given calendar date into a decimal year
{
uint16_t temp = 0; // Total number of days
uint16_t MonthDays[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
uint16_t ExtraDay = 0;
uint16_t i;
if((CalendarDate->Year%4 == 0 && CalendarDate->Year%100 != 0) || CalendarDate->Year%400 == 0)
ExtraDay=1;
MonthDays[2] += ExtraDay;
/******************Validation********************************/
if(CalendarDate->Month <= 0 || CalendarDate->Month > 12)
{
strcpy(Error, "\nError: The Month entered is invalid, valid months are '1 to 12'\n");
return 0;
}
if(CalendarDate->Day <= 0 || CalendarDate->Day > MonthDays[CalendarDate->Month])
{
// printf("\nThe number of days in month %d is %d\n", CalendarDate->Month, MonthDays[CalendarDate->Month]);
strcpy(Error, "\nError: The day entered is invalid\n");
return 0;
}
/****************Calculation of t***************************/
for(i = 1; i <= CalendarDate->Month; i++)
temp+=MonthDays[i-1];
temp+=CalendarDate->Day;
CalendarDate->DecimalYear = CalendarDate->Year + (temp-1)/(365.0 + ExtraDay);
return 1;
} /*WMM_DateToYear*/
void WMM_GeodeticToSpherical(WMMtype_CoordGeodetic *CoordGeodetic, WMMtype_CoordSpherical *CoordSpherical)
// Converts Geodetic coordinates to Spherical coordinates
// Convert geodetic coordinates, (defined by the WGS-84
// reference ellipsoid), to Earth Centered Earth Fixed Cartesian
// coordinates, and then to spherical coordinates.
{
float CosLat, SinLat, rc, xp, zp; // all local variables
CosLat = cos(DEG2RAD(CoordGeodetic->phi));
SinLat = sin(DEG2RAD(CoordGeodetic->phi));
// compute the local radius of curvature on the WGS-84 reference ellipsoid
rc = Ellip->a / sqrt(1.0 - Ellip->epssq * SinLat * SinLat);
// compute ECEF Cartesian coordinates of specified point (for longitude=0)
xp = (rc + CoordGeodetic->HeightAboveEllipsoid) * CosLat;
zp = (rc*(1.0 - Ellip->epssq) + CoordGeodetic->HeightAboveEllipsoid) * SinLat;
// compute spherical radius and angle lambda and phi of specified point
CoordSpherical->r = sqrt(xp * xp + zp * zp);
CoordSpherical->phig = RAD2DEG(asin(zp / CoordSpherical->r)); // geocentric latitude
CoordSpherical->lambda = CoordGeodetic->lambda; // longitude
}// WMM_GeodeticToSpherical
void WMM_Set_Coeff_Array()
{
// const should hopefully keep them in the flash region
static const float CoeffFile[91][6] =
{{0, 0, 0, 0, 0, 0},
{1, 0, -29496.6, 0.0, 11.6, 0.0},
{1, 1, -1586.3, 4944.4, 16.5, -25.9},
{2, 0, -2396.6, 0.0, -12.1, 0.0},
{2, 1, 3026.1, -2707.7, -4.4, -22.5},
{2, 2, 1668.6, -576.1, 1.9, -11.8},
{3, 0, 1340.1, 0.0, 0.4, 0.0},
{3, 1, -2326.2, -160.2, -4.1, 7.3},
{3, 2, 1231.9, 251.9, -2.9, -3.9},
{3, 3, 634.0, -536.6, -7.7, -2.6},
{4, 0, 912.6, 0.0, -1.8, 0.0},
{4, 1, 808.9, 286.4, 2.3, 1.1},
{4, 2, 166.7, -211.2, -8.7, 2.7},
{4, 3, -357.1, 164.3, 4.6, 3.9},
{4, 4, 89.4, -309.1, -2.1, -0.8},
{5, 0, -230.9, 0.0, -1.0, 0.0},
{5, 1, 357.2, 44.6, 0.6, 0.4},
{5, 2, 200.3, 188.9, -1.8, 1.8},
{5, 3, -141.1, -118.2, -1.0, 1.2},
{5, 4, -163.0, 0.0, 0.9, 4.0},
{5, 5, -7.8, 100.9, 1.0, -0.6},
{6, 0, 72.8, 0.0, -0.2, 0.0},
{6, 1, 68.6, -20.8, -0.2, -0.2},
{6, 2, 76.0, 44.1, -0.1, -2.1},
{6, 3, -141.4, 61.5, 2.0, -0.4},
{6, 4, -22.8, -66.3, -1.7, -0.6},
{6, 5, 13.2, 3.1, -0.3, 0.5},
{6, 6, -77.9, 55.0, 1.7, 0.9},
{7, 0, 80.5, 0.0, 0.1, 0.0},
{7, 1, -75.1, -57.9, -0.1, 0.7},
{7, 2, -4.7, -21.1, -0.6, 0.3},
{7, 3, 45.3, 6.5, 1.3, -0.1},
{7, 4, 13.9, 24.9, 0.4, -0.1},
{7, 5, 10.4, 7.0, 0.3, -0.8},
{7, 6, 1.7, -27.7, -0.7, -0.3},
{7, 7, 4.9, -3.3, 0.6, 0.3},
{8, 0, 24.4, 0.0, -0.1, 0.0},
{8, 1, 8.1, 11.0, 0.1, -0.1},
{8, 2, -14.5, -20.0, -0.6, 0.2},
{8, 3, -5.6, 11.9, 0.2, 0.4},
{8, 4, -19.3, -17.4, -0.2, 0.4},
{8, 5, 11.5, 16.7, 0.3, 0.1},
{8, 6, 10.9, 7.0, 0.3, -0.1},
{8, 7, -14.1, -10.8, -0.6, 0.4},
{8, 8, -3.7, 1.7, 0.2, 0.3},
{9, 0, 5.4, 0.0, 0.0, 0.0},
{9, 1, 9.4, -20.5, -0.1, 0.0},
{9, 2, 3.4, 11.5, 0.0, -0.2},
{9, 3, -5.2, 12.8, 0.3, 0.0},
{9, 4, 3.1, -7.2, -0.4, -0.1},
{9, 5, -12.4, -7.4, -0.3, 0.1},
{9, 6, -0.7, 8.0, 0.1, 0.0},
{9, 7, 8.4, 2.1, -0.1, -0.2},
{9, 8, -8.5, -6.1, -0.4, 0.3},
{9, 9, -10.1, 7.0, -0.2, 0.2},
{10, 0, -2.0, 0.0, 0.0, 0.0},
{10, 1, -6.3, 2.8, 0.0, 0.1},
{10, 2, 0.9, -0.1, -0.1, -0.1},
{10, 3, -1.1, 4.7, 0.2, 0.0},
{10, 4, -0.2, 4.4, 0.0, -0.1},
{10, 5, 2.5, -7.2, -0.1, -0.1},
{10, 6, -0.3, -1.0, -0.2, 0.0},
{10, 7, 2.2, -3.9, 0.0, -0.1},
{10, 8, 3.1, -2.0, -0.1, -0.2},
{10, 9, -1.0, -2.0, -0.2, 0.0},
{10, 10, -2.8, -8.3, -0.2, -0.1},
{11, 0, 3.0, 0.0, 0.0, 0.0},
{11, 1, -1.5, 0.2, 0.0, 0.0},
{11, 2, -2.1, 1.7, 0.0, 0.1},
{11, 3, 1.7, -0.6, 0.1, 0.0},
{11, 4, -0.5, -1.8, 0.0, 0.1},
{11, 5, 0.5, 0.9, 0.0, 0.0},
{11, 6, -0.8, -0.4, 0.0, 0.1},
{11, 7, 0.4, -2.5, 0.0, 0.0},
{11, 8, 1.8, -1.3, 0.0, -0.1},
{11, 9, 0.1, -2.1, 0.0, -0.1},
{11, 10, 0.7, -1.9, -0.1, 0.0},
{11, 11, 3.8, -1.8, 0.0, -0.1},
{12, 0, -2.2, 0.0, 0.0, 0.0},
{12, 1, -0.2, -0.9, 0.0, 0.0},
{12, 2, 0.3, 0.3, 0.1, 0.0},
{12, 3, 1.0, 2.1, 0.1, 0.0},
{12, 4, -0.6, -2.5, -0.1, 0.0},
{12, 5, 0.9, 0.5, 0.0, 0.0},
{12, 6, -0.1, 0.6, 0.0, 0.1},
{12, 7, 0.5, 0.0, 0.0, 0.0},
{12, 8, -0.4, 0.1, 0.0, 0.0},
{12, 9, -0.4, 0.3, 0.0, 0.0},
{12, 10, 0.2, -0.9, 0.0, 0.0},
{12, 11, -0.8, -0.2, -0.1, 0.0},
{12, 12, 0.0, 0.9, 0.1, 0.0}};
// TODO: If this works here, delete first two columns to save space
for(uint16_t i=0; i<NUMTERMS; i++){
MagneticModel->Main_Field_Coeff_G[i]=CoeffFile[i][2];
MagneticModel->Main_Field_Coeff_H[i]=CoeffFile[i][3];
MagneticModel->Secular_Var_Coeff_G[i]=CoeffFile[i][4];
MagneticModel->Secular_Var_Coeff_H[i]=CoeffFile[i][5];
}
}
/**
******************************************************************************
*
* @file WorldMagModel.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Source file for the World Magnetic Model
* This is a port of code available from the US NOAA.
* The hard coded coefficients should be valid until 2015.
* Major changes include:
* - No geoid model (altitude must be geodetic WGS-84)
* - Floating point calculation (not double precision)
* - Hard coded coefficients for model
* - Elimination of user interface
* - Elimination of dynamic memory allocation
*
* @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
*/
// I don't want this dependency, but currently using pvPortMalloc
#include "openpilot.h"
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <stdint.h>
#include "WorldMagModel.h"
#include "WMMInternal.h"
static WMMtype_Ellipsoid *Ellip;
static WMMtype_MagneticModel *MagneticModel;
/**************************************************************************************
* Example use - very simple - only two exposed functions
*
* WMM_Initialize(); // Set default values and constants
*
* WMM_GetMagVector(float Lat, float Lon, float Alt, uint16_t Month, uint16_t Day, uint16_t Year, float B[3]);
* e.g. Iceland in may of 2012 = WMM_GetMagVector(65.0, -20.0, 0.0, 5, 5, 2012, B);
* Alt is above the WGS-84 Ellipsoid
* B is the NED (XYZ) magnetic vector in nTesla
**************************************************************************************/
int WMM_Initialize()
// Sets default values for WMM subroutines.
// UPDATES : Ellip and MagneticModel
{
// Sets WGS-84 parameters
Ellip->a = 6378.137; // semi-major axis of the ellipsoid in km
Ellip->b = 6356.7523142; // semi-minor axis of the ellipsoid in km
Ellip->fla = 1 / 298.257223563; // flattening
Ellip->eps = sqrt(1 - (Ellip->b * Ellip->b) / (Ellip->a * Ellip->a)); // first eccentricity
Ellip->epssq = (Ellip->eps * Ellip->eps); // first eccentricity squared
Ellip->re = 6371.2; // Earth's radius in km
// Sets Magnetic Model parameters
MagneticModel->nMax = WMM_MAX_MODEL_DEGREES;
MagneticModel->nMaxSecVar =
WMM_MAX_SECULAR_VARIATION_MODEL_DEGREES;
MagneticModel->SecularVariationUsed = 0;
// Really, Really needs to be read from a file - out of date in 2015 at latest
MagneticModel->EditionDate = 5.7863328170559505e-307;
MagneticModel->epoch = 2010.0;
sprintf(MagneticModel->ModelName, "WMM-2010");
WMM_Set_Coeff_Array();
return 0;
}
void WMM_GetMagVector(float Lat, float Lon, float AltEllipsoid,
uint16_t Month, uint16_t Day, uint16_t Year,
float B[3])
{
char Error_Message[255];
Ellip =
(WMMtype_Ellipsoid *) pvPortMalloc(sizeof(WMMtype_Ellipsoid));
MagneticModel =
(WMMtype_MagneticModel *)
pvPortMalloc(sizeof(WMMtype_MagneticModel));
WMMtype_CoordSpherical *CoordSpherical =
(WMMtype_CoordSpherical *)
pvPortMalloc(sizeof(CoordSpherical));
WMMtype_CoordGeodetic *CoordGeodetic =
(WMMtype_CoordGeodetic *) pvPortMalloc(sizeof(CoordGeodetic));
WMMtype_Date *Date =
(WMMtype_Date *) pvPortMalloc(sizeof(WMMtype_Date));
WMMtype_GeoMagneticElements *GeoMagneticElements =
(WMMtype_GeoMagneticElements *)
pvPortMalloc(sizeof(GeoMagneticElements));
WMM_Initialize();
CoordGeodetic->lambda = Lon;
CoordGeodetic->phi = Lat;
CoordGeodetic->HeightAboveEllipsoid = AltEllipsoid;
WMM_GeodeticToSpherical(CoordGeodetic, CoordSpherical); /*Convert from geodeitic to Spherical Equations: 17-18, WMM Technical report */
Date->Month = Month;
Date->Day = Day;
Date->Year = Year;
WMM_DateToYear(Date, Error_Message);
WMM_TimelyModifyMagneticModel(Date);
WMM_Geomag(CoordSpherical, CoordGeodetic, GeoMagneticElements); /* Computes the geoMagnetic field elements and their time change */
B[0] = GeoMagneticElements->X;
B[1] = GeoMagneticElements->Y;
B[2] = GeoMagneticElements->Z;
vPortFree(Ellip);
vPortFree(MagneticModel);
vPortFree(CoordSpherical);
vPortFree(CoordGeodetic);
vPortFree(Date);
vPortFree(GeoMagneticElements);
}
uint16_t WMM_Geomag(WMMtype_CoordSpherical * CoordSpherical,
WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_GeoMagneticElements * GeoMagneticElements)
/*
The main subroutine that calls a sequence of WMM sub-functions to calculate the magnetic field elements for a single point.
The function expects the model coefficients and point coordinates as input and returns the magnetic field elements and
their rate of change. Though, this subroutine can be called successively to calculate a time series, profile or grid
of magnetic field, these are better achieved by the subroutine WMM_Grid.
INPUT: Ellip
CoordSpherical
CoordGeodetic
TimedMagneticModel
OUTPUT : GeoMagneticElements
CALLS: WMM_ComputeSphericalHarmonicVariables( Ellip, CoordSpherical, TimedMagneticModel->nMax, &SphVariables); (Compute Spherical Harmonic variables )
WMM_AssociatedLegendreFunction(CoordSpherical, TimedMagneticModel->nMax, LegendreFunction); Compute ALF
WMM_Summation(LegendreFunction, TimedMagneticModel, SphVariables, CoordSpherical, &MagneticResultsSph); Accumulate the spherical harmonic coefficients
WMM_SecVarSummation(LegendreFunction, TimedMagneticModel, SphVariables, CoordSpherical, &MagneticResultsSphVar); Sum the Secular Variation Coefficients
WMM_RotateMagneticVector(CoordSpherical, CoordGeodetic, MagneticResultsSph, &MagneticResultsGeo); Map the computed Magnetic fields to Geodeitic coordinates
WMM_RotateMagneticVector(CoordSpherical, CoordGeodetic, MagneticResultsSphVar, &MagneticResultsGeoVar); Map the secular variation field components to Geodetic coordinates
WMM_CalculateGeoMagneticElements(&MagneticResultsGeo, GeoMagneticElements); Calculate the Geomagnetic elements
WMM_CalculateSecularVariation(MagneticResultsGeoVar, GeoMagneticElements); Calculate the secular variation of each of the Geomagnetic elements
*/
{
WMMtype_LegendreFunction LegendreFunction;
WMMtype_SphericalHarmonicVariables SphVariables;
WMMtype_MagneticResults MagneticResultsSph, MagneticResultsGeo,
MagneticResultsSphVar, MagneticResultsGeoVar;
WMM_ComputeSphericalHarmonicVariables(CoordSpherical, MagneticModel->nMax, &SphVariables); /* Compute Spherical Harmonic variables */
WMM_AssociatedLegendreFunction(CoordSpherical, MagneticModel->nMax, &LegendreFunction); /* Compute ALF */
WMM_Summation(&LegendreFunction, &SphVariables, CoordSpherical, &MagneticResultsSph); /* Accumulate the spherical harmonic coefficients */
WMM_SecVarSummation(&LegendreFunction, &SphVariables, CoordSpherical, &MagneticResultsSphVar); /*Sum the Secular Variation Coefficients */
WMM_RotateMagneticVector(CoordSpherical, CoordGeodetic, &MagneticResultsSph, &MagneticResultsGeo); /* Map the computed Magnetic fields to Geodeitic coordinates */
WMM_RotateMagneticVector(CoordSpherical, CoordGeodetic, &MagneticResultsSphVar, &MagneticResultsGeoVar); /* Map the secular variation field components to Geodetic coordinates */
WMM_CalculateGeoMagneticElements(&MagneticResultsGeo, GeoMagneticElements); /* Calculate the Geomagnetic elements, Equation 18 , WMM Technical report */
WMM_CalculateSecularVariation(&MagneticResultsGeoVar, GeoMagneticElements); /*Calculate the secular variation of each of the Geomagnetic elements */
return TRUE;
}
uint16_t WMM_ComputeSphericalHarmonicVariables(WMMtype_CoordSpherical *
CoordSpherical,
uint16_t nMax,
WMMtype_SphericalHarmonicVariables
* SphVariables)
/* Computes Spherical variables
Variables computed are (a/r)^(n+2), cos_m(lamda) and sin_m(lambda) for spherical harmonic
summations. (Equations 10-12 in the WMM Technical Report)
INPUT Ellip data structure with the following elements
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
CoordSpherical A data structure with the following elements
float lambda; ( longitude)
float phig; ( geocentric latitude )
float r; ( distance from the center of the ellipsoid)
nMax integer ( Maxumum degree of spherical harmonic secular model)\
OUTPUT SphVariables Pointer to the data structure with the following elements
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 (mspherical coord. longitude)
float sin_mlambda[WMM_MAX_MODEL_DEGREES+1]; sp(m) - sine of (mspherical coord. longitude)
CALLS : none
*/
{
float cos_lambda, sin_lambda;
uint16_t m, n;
cos_lambda = cos(DEG2RAD(CoordSpherical->lambda));
sin_lambda = sin(DEG2RAD(CoordSpherical->lambda));
/* for n = 0 ... model_order, compute (Radius of Earth / Spherica radius r)^(n+2)
for n 1..nMax-1 (this is much faster than calling pow MAX_N+1 times). */
SphVariables->RelativeRadiusPower[0] =
(Ellip->re / CoordSpherical->r) * (Ellip->re /
CoordSpherical->r);
for (n = 1; n <= nMax; n++) {
SphVariables->RelativeRadiusPower[n] =
SphVariables->RelativeRadiusPower[n -
1] * (Ellip->re /
CoordSpherical->
r);
}
/*
Compute cos(m*lambda), sin(m*lambda) for m = 0 ... nMax
cos(a + b) = cos(a)*cos(b) - sin(a)*sin(b)
sin(a + b) = cos(a)*sin(b) + sin(a)*cos(b)
*/
SphVariables->cos_mlambda[0] = 1.0;
SphVariables->sin_mlambda[0] = 0.0;
SphVariables->cos_mlambda[1] = cos_lambda;
SphVariables->sin_mlambda[1] = sin_lambda;
for (m = 2; m <= nMax; m++) {
SphVariables->cos_mlambda[m] =
SphVariables->cos_mlambda[m - 1] * cos_lambda -
SphVariables->sin_mlambda[m - 1] * sin_lambda;
SphVariables->sin_mlambda[m] =
SphVariables->cos_mlambda[m - 1] * sin_lambda +
SphVariables->sin_mlambda[m - 1] * cos_lambda;
}
return TRUE;
} /*WMM_ComputeSphericalHarmonicVariables */
uint16_t WMM_AssociatedLegendreFunction(WMMtype_CoordSpherical *
CoordSpherical, uint16_t nMax,
WMMtype_LegendreFunction *
LegendreFunction)
/* Computes all of the Schmidt-semi normalized associated Legendre
functions up to degree nMax. If nMax <= 16, function WMM_PcupLow is used.
Otherwise WMM_PcupHigh is called.
INPUT CoordSpherical A data structure with the following elements
float lambda; ( longitude)
float phig; ( geocentric latitude )
float r; ( distance from the center of the ellipsoid)
nMax integer ( Maxumum degree of spherical harmonic secular model)
LegendreFunction Pointer to data structure with the following elements
float *Pcup; ( pointer to store Legendre Function )
float *dPcup; ( pointer to store Derivative of Lagendre function )
OUTPUT LegendreFunction Calculated Legendre variables in the data structure
*/
{
float sin_phi;
uint16_t FLAG = 1;
sin_phi = sin(DEG2RAD(CoordSpherical->phig)); /* sin (geocentric latitude) */
if (nMax <= 16 || (1 - fabs(sin_phi)) < 1.0e-10) /* If nMax is less tha 16 or at the poles */
FLAG =
WMM_PcupLow(LegendreFunction->Pcup,
LegendreFunction->dPcup, sin_phi, nMax);
else
FLAG =
WMM_PcupHigh(LegendreFunction->Pcup,
LegendreFunction->dPcup, sin_phi, nMax);
if (FLAG == 0) /* Error while computing Legendre variables */
return FALSE;
return TRUE;
} /*WMM_AssociatedLegendreFunction */
uint16_t WMM_Summation(WMMtype_LegendreFunction * LegendreFunction,
WMMtype_SphericalHarmonicVariables * SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults * MagneticResults)
{
/* Computes Geomagnetic Field Elements X, Y and Z in Spherical coordinate system using
spherical harmonic summation.
The vector Magnetic field is given by -grad V, where V is Geomagnetic scalar potential
The gradient in spherical coordinates is given by:
dV ^ 1 dV ^ 1 dV ^
grad V = -- r + - -- t + -------- -- p
dr r dt r sin(t) dp
INPUT : LegendreFunction
MagneticModel
SphVariables
CoordSpherical
OUTPUT : MagneticResults
CALLS : WMM_SummationSpecial
Manoj Nair, June, 2009 Manoj.C.Nair@Noaa.Gov
*/
uint16_t m, n, index;
float cos_phi;
MagneticResults->Bz = 0.0;
MagneticResults->By = 0.0;
MagneticResults->Bx = 0.0;
for (n = 1; n <= MagneticModel->nMax; n++) {
for (m = 0; m <= n; m++) {
index = (n * (n + 1) / 2 + m);
/* nMax (n+2) n m m m
Bz = -SUM (a/r) (n+1) SUM [g cos(m p) + h sin(m p)] P (sin(phi))
n=1 m=0 n n n */
/* Equation 12 in the WMM Technical report. Derivative with respect to radius.*/
MagneticResults->Bz -=
SphVariables->RelativeRadiusPower[n] *
(MagneticModel->Main_Field_Coeff_G[index] *
SphVariables->cos_mlambda[m] +
MagneticModel->Main_Field_Coeff_H[index] *
SphVariables->sin_mlambda[m])
* (float)(n +
1) * LegendreFunction->Pcup[index];
/* 1 nMax (n+2) n m m m
By = SUM (a/r) (m) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Equation 11 in the WMM Technical report. Derivative with respect to longitude, divided by radius. */
MagneticResults->By +=
SphVariables->RelativeRadiusPower[n] *
(MagneticModel->Main_Field_Coeff_G[index] *
SphVariables->sin_mlambda[m] -
MagneticModel->Main_Field_Coeff_H[index] *
SphVariables->cos_mlambda[m])
* (float)(m) * LegendreFunction->Pcup[index];
/* nMax (n+2) n m m m
Bx = - SUM (a/r) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Equation 10 in the WMM Technical report. Derivative with respect to latitude, divided by radius. */
MagneticResults->Bx -=
SphVariables->RelativeRadiusPower[n] *
(MagneticModel->Main_Field_Coeff_G[index] *
SphVariables->cos_mlambda[m] +
MagneticModel->Main_Field_Coeff_H[index] *
SphVariables->sin_mlambda[m])
* LegendreFunction->dPcup[index];
}
}
cos_phi = cos(DEG2RAD(CoordSpherical->phig));
if (fabs(cos_phi) > 1.0e-10) {
MagneticResults->By = MagneticResults->By / cos_phi;
} else
/* Special calculation for component - By - at Geographic poles.
* If the user wants to avoid using this function, please make sure that
* the latitude is not exactly +/-90. An option is to make use the function
* WMM_CheckGeographicPoles.
*/
{
WMM_SummationSpecial(SphVariables, CoordSpherical,
MagneticResults);
}
return TRUE;
} /*WMM_Summation */
uint16_t WMM_SecVarSummation(WMMtype_LegendreFunction * LegendreFunction,
WMMtype_SphericalHarmonicVariables *
SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults * MagneticResults)
{
/*This Function sums the secular variation coefficients to get the secular variation of the Magnetic vector.
INPUT : LegendreFunction
MagneticModel
SphVariables
CoordSpherical
OUTPUT : MagneticResults
CALLS : WMM_SecVarSummationSpecial
*/
uint16_t m, n, index;
float cos_phi;
MagneticModel->SecularVariationUsed = TRUE;
MagneticResults->Bz = 0.0;
MagneticResults->By = 0.0;
MagneticResults->Bx = 0.0;
for (n = 1; n <= MagneticModel->nMaxSecVar; n++) {
for (m = 0; m <= n; m++) {
index = (n * (n + 1) / 2 + m);
/* nMax (n+2) n m m m
Bz = -SUM (a/r) (n+1) SUM [g cos(m p) + h sin(m p)] P (sin(phi))
n=1 m=0 n n n */
/* Derivative with respect to radius.*/
MagneticResults->Bz -=
SphVariables->RelativeRadiusPower[n] *
(MagneticModel->Secular_Var_Coeff_G[index] *
SphVariables->cos_mlambda[m] +
MagneticModel->Secular_Var_Coeff_H[index] *
SphVariables->sin_mlambda[m])
* (float)(n +
1) * LegendreFunction->Pcup[index];
/* 1 nMax (n+2) n m m m
By = SUM (a/r) (m) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Derivative with respect to longitude, divided by radius. */
MagneticResults->By +=
SphVariables->RelativeRadiusPower[n] *
(MagneticModel->Secular_Var_Coeff_G[index] *
SphVariables->sin_mlambda[m] -
MagneticModel->Secular_Var_Coeff_H[index] *
SphVariables->cos_mlambda[m])
* (float)(m) * LegendreFunction->Pcup[index];
/* nMax (n+2) n m m m
Bx = - SUM (a/r) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Derivative with respect to latitude, divided by radius. */
MagneticResults->Bx -=
SphVariables->RelativeRadiusPower[n] *
(MagneticModel->Secular_Var_Coeff_G[index] *
SphVariables->cos_mlambda[m] +
MagneticModel->Secular_Var_Coeff_H[index] *
SphVariables->sin_mlambda[m])
* LegendreFunction->dPcup[index];
}
}
cos_phi = cos(DEG2RAD(CoordSpherical->phig));
if (fabs(cos_phi) > 1.0e-10) {
MagneticResults->By = MagneticResults->By / cos_phi;
} else
/* Special calculation for component By at Geographic poles */
{
WMM_SecVarSummationSpecial(SphVariables, CoordSpherical,
MagneticResults);
}
return TRUE;
} /*WMM_SecVarSummation */
uint16_t WMM_RotateMagneticVector(WMMtype_CoordSpherical * CoordSpherical,
WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_MagneticResults *
MagneticResultsSph,
WMMtype_MagneticResults *
MagneticResultsGeo)
/* Rotate the Magnetic Vectors to Geodetic Coordinates
Manoj Nair, June, 2009 Manoj.C.Nair@Noaa.Gov
Equation 16, WMM Technical report
INPUT : CoordSpherical : Data structure WMMtype_CoordSpherical with the following elements
float lambda; ( longitude)
float phig; ( geocentric latitude )
float r; ( distance from the center of the ellipsoid)
CoordGeodetic : Data structure WMMtype_CoordGeodetic with the following elements
float lambda; (longitude)
float phi; ( geodetic latitude)
float HeightAboveEllipsoid; (height above the ellipsoid (HaE) )
float HeightAboveGeoid;(height above the Geoid )
MagneticResultsSph : Data structure WMMtype_MagneticResults with the following elements
float Bx; North
float By; East
float Bz; Down
OUTPUT: MagneticResultsGeo Pointer to the data structure WMMtype_MagneticResults, with the following elements
float Bx; North
float By; East
float Bz; Down
CALLS : none
*/
{
float Psi;
/* Difference between the spherical and Geodetic latitudes */
Psi = (M_PI / 180) * (CoordSpherical->phig - CoordGeodetic->phi);
/* Rotate spherical field components to the Geodeitic system */
MagneticResultsGeo->Bz =
MagneticResultsSph->Bx * sin(Psi) +
MagneticResultsSph->Bz * cos(Psi);
MagneticResultsGeo->Bx =
MagneticResultsSph->Bx * cos(Psi) -
MagneticResultsSph->Bz * sin(Psi);
MagneticResultsGeo->By = MagneticResultsSph->By;
return TRUE;
} /*WMM_RotateMagneticVector */
uint16_t WMM_CalculateGeoMagneticElements(WMMtype_MagneticResults *
MagneticResultsGeo,
WMMtype_GeoMagneticElements *
GeoMagneticElements)
/* Calculate all the Geomagnetic elements from X,Y and Z components
INPUT MagneticResultsGeo Pointer to data structure with the following elements
float Bx; ( North )
float By; ( East )
float Bz; ( Down )
OUTPUT GeoMagneticElements Pointer to data structure with the following elements
float Decl; (Angle between the magnetic field vector and true north, positive east)
float Incl; Angle between the magnetic field vector and the horizontal plane, positive down
float F; Magnetic Field Strength
float H; Horizontal Magnetic Field Strength
float X; Northern component of the magnetic field vector
float Y; Eastern component of the magnetic field vector
float Z; Downward component of the magnetic field vector
CALLS : none
*/
{
GeoMagneticElements->X = MagneticResultsGeo->Bx;
GeoMagneticElements->Y = MagneticResultsGeo->By;
GeoMagneticElements->Z = MagneticResultsGeo->Bz;
GeoMagneticElements->H =
sqrt(MagneticResultsGeo->Bx * MagneticResultsGeo->Bx +
MagneticResultsGeo->By * MagneticResultsGeo->By);
GeoMagneticElements->F =
sqrt(GeoMagneticElements->H * GeoMagneticElements->H +
MagneticResultsGeo->Bz * MagneticResultsGeo->Bz);
GeoMagneticElements->Decl =
RAD2DEG(atan2(GeoMagneticElements->Y, GeoMagneticElements->X));
GeoMagneticElements->Incl =
RAD2DEG(atan2(GeoMagneticElements->Z, GeoMagneticElements->H));
return TRUE;
} /*WMM_CalculateGeoMagneticElements */
uint16_t WMM_CalculateSecularVariation(WMMtype_MagneticResults *
MagneticVariation,
WMMtype_GeoMagneticElements *
MagneticElements)
/*This takes the Magnetic Variation in x, y, and z and uses it to calculate the secular variation of each of the Geomagnetic elements.
INPUT MagneticVariation Data structure with the following elements
float Bx; ( North )
float By; ( East )
float Bz; ( Down )
OUTPUT MagneticElements Pointer to the data structure with the following elements updated
float Decldot; Yearly Rate of change in declination
float Incldot; Yearly Rate of change in inclination
float Fdot; Yearly rate of change in Magnetic field strength
float Hdot; Yearly rate of change in horizontal field strength
float Xdot; Yearly rate of change in the northern component
float Ydot; Yearly rate of change in the eastern component
float Zdot; Yearly rate of change in the downward component
float GVdot;Yearly rate of chnage in grid variation
CALLS : none
*/
{
MagneticElements->Xdot = MagneticVariation->Bx;
MagneticElements->Ydot = MagneticVariation->By;
MagneticElements->Zdot = MagneticVariation->Bz;
MagneticElements->Hdot = (MagneticElements->X * MagneticElements->Xdot + MagneticElements->Y * MagneticElements->Ydot) / MagneticElements->H; //See equation 19 in the WMM technical report
MagneticElements->Fdot =
(MagneticElements->X * MagneticElements->Xdot +
MagneticElements->Y * MagneticElements->Ydot +
MagneticElements->Z * MagneticElements->Zdot) /
MagneticElements->F;
MagneticElements->Decldot =
180.0 / M_PI * (MagneticElements->X * MagneticElements->Ydot -
MagneticElements->Y * MagneticElements->Xdot) /
(MagneticElements->H * MagneticElements->H);
MagneticElements->Incldot =
180.0 / M_PI * (MagneticElements->H * MagneticElements->Zdot -
MagneticElements->Z * MagneticElements->Hdot) /
(MagneticElements->F * MagneticElements->F);
MagneticElements->GVdot = MagneticElements->Decldot;
return TRUE;
} /*WMM_CalculateSecularVariation */
uint16_t WMM_PcupHigh(float *Pcup, float *dPcup, float x, uint16_t nMax)
/* This function evaluates all of the Schmidt-semi normalized associated Legendre
functions up to degree nMax. The functions are initially scaled by
10^280 sin^m in order to minimize the effects of underflow at large m
near the poles (see Holmes and Featherstone 2002, J. Geodesy, 76, 279-299).
Note that this function performs the same operation as WMM_PcupLow.
However this function also can be used for high degree (large nMax) models.
Calling Parameters:
INPUT
nMax: Maximum spherical harmonic degree to compute.
x: cos(colatitude) or sin(latitude).
OUTPUT
Pcup: A vector of all associated Legendgre polynomials evaluated at
x up to nMax. The lenght must by greater or equal to (nMax+1)*(nMax+2)/2.
dPcup: Derivative of Pcup(x) with respect to latitude
CALLS : none
Notes:
Adopted from the FORTRAN code written by Mark Wieczorek September 25, 2005.
Manoj Nair, Nov, 2009 Manoj.C.Nair@Noaa.Gov
Change from the previous version
The prevous version computes the derivatives as
dP(n,m)(x)/dx, where x = sin(latitude) (or cos(colatitude) ).
However, the WMM Geomagnetic routines requires dP(n,m)(x)/dlatitude.
Hence the derivatives are multiplied by sin(latitude).
Removed the options for CS phase and normalizations.
Note: In geomagnetism, the derivatives of ALF are usually found with
respect to the colatitudes. Here the derivatives are found with respect
to the latitude. The difference is a sign reversal for the derivative of
the Associated Legendre Functions.
The derivates can't be computed for latitude = |90| degrees.
*/
{
float pm2, pm1, pmm, plm, rescalem, z, scalef;
float f1[NUMPCUP], f2[NUMPCUP], PreSqr[NUMPCUP];
uint16_t k, kstart, m, n;
if (fabs(x) == 1.0) {
// printf("Error in PcupHigh: derivative cannot be calculated at poles\n");
return FALSE;
}
scalef = 1.0e-280;
for (n = 0; n <= 2 * nMax + 1; ++n) {
PreSqr[n] = sqrt((float)(n));
}
k = 2;
for (n = 2; n <= nMax; n++) {
k = k + 1;
f1[k] = (float)(2 * n - 1) / (float)(n);
f2[k] = (float)(n - 1) / (float)(n);
for (m = 1; m <= n - 2; m++) {
k = k + 1;
f1[k] =
(float)(2 * n - 1) / PreSqr[n + m] / PreSqr[n -
m];
f2[k] =
PreSqr[n - m - 1] * PreSqr[n + m -
1] / PreSqr[n +
m] /
PreSqr[n - m];
}
k = k + 2;
}
/*z = sin (geocentric latitude) */
z = sqrt((1.0 - x) * (1.0 + x));
pm2 = 1.0;
Pcup[0] = 1.0;
dPcup[0] = 0.0;
if (nMax == 0)
return FALSE;
pm1 = x;
Pcup[1] = pm1;
dPcup[1] = z;
k = 1;
for (n = 2; n <= nMax; n++) {
k = k + n;
plm = f1[k] * x * pm1 - f2[k] * pm2;
Pcup[k] = plm;
dPcup[k] = (float)(n) * (pm1 - x * plm) / z;
pm2 = pm1;
pm1 = plm;
}
pmm = PreSqr[2] * scalef;
rescalem = 1.0 / scalef;
kstart = 0;
for (m = 1; m <= nMax - 1; ++m) {
rescalem = rescalem * z;
/* Calculate Pcup(m,m) */
kstart = kstart + m + 1;
pmm = pmm * PreSqr[2 * m + 1] / PreSqr[2 * m];
Pcup[kstart] = pmm * rescalem / PreSqr[2 * m + 1];
dPcup[kstart] = -((float)(m) * x * Pcup[kstart] / z);
pm2 = pmm / PreSqr[2 * m + 1];
/* Calculate Pcup(m+1,m) */
k = kstart + m + 1;
pm1 = x * PreSqr[2 * m + 1] * pm2;
Pcup[k] = pm1 * rescalem;
dPcup[k] =
((pm2 * rescalem) * PreSqr[2 * m + 1] -
x * (float)(m + 1) * Pcup[k]) / z;
/* Calculate Pcup(n,m) */
for (n = m + 2; n <= nMax; ++n) {
k = k + n;
plm = x * f1[k] * pm1 - f2[k] * pm2;
Pcup[k] = plm * rescalem;
dPcup[k] =
(PreSqr[n + m] * PreSqr[n - m] *
(pm1 * rescalem) -
(float)(n) * x * Pcup[k]) / z;
pm2 = pm1;
pm1 = plm;
}
}
/* Calculate Pcup(nMax,nMax) */
rescalem = rescalem * z;
kstart = kstart + m + 1;
pmm = pmm / PreSqr[2 * nMax];
Pcup[kstart] = pmm * rescalem;
dPcup[kstart] = -(float)(nMax) * x * Pcup[kstart] / z;
return TRUE;
} /* WMM_PcupHigh */
uint16_t WMM_PcupLow(float *Pcup, float *dPcup, float x, uint16_t nMax)
/* This function evaluates all of the Schmidt-semi normalized associated Legendre
functions up to degree nMax.
Calling Parameters:
INPUT
nMax: Maximum spherical harmonic degree to compute.
x: cos(colatitude) or sin(latitude).
OUTPUT
Pcup: A vector of all associated Legendgre polynomials evaluated at
x up to nMax.
dPcup: Derivative of Pcup(x) with respect to latitude
Notes: Overflow may occur if nMax > 20 , especially for high-latitudes.
Use WMM_PcupHigh for large nMax.
Writted by Manoj Nair, June, 2009 . Manoj.C.Nair@Noaa.Gov.
Note: In geomagnetism, the derivatives of ALF are usually found with
respect to the colatitudes. Here the derivatives are found with respect
to the latitude. The difference is a sign reversal for the derivative of
the Associated Legendre Functions.
*/
{
uint16_t n, m, index, index1, index2;
float k, z, schmidtQuasiNorm[NUMPCUP];
Pcup[0] = 1.0;
dPcup[0] = 0.0;
/*sin (geocentric latitude) - sin_phi */
z = sqrt((1.0 - x) * (1.0 + x));
/* First, Compute the Gauss-normalized associated Legendre functions */
for (n = 1; n <= nMax; n++) {
for (m = 0; m <= n; m++) {
index = (n * (n + 1) / 2 + m);
if (n == m) {
index1 = (n - 1) * n / 2 + m - 1;
Pcup[index] = z * Pcup[index1];
dPcup[index] =
z * dPcup[index1] + x * Pcup[index1];
} else if (n == 1 && m == 0) {
index1 = (n - 1) * n / 2 + m;
Pcup[index] = x * Pcup[index1];
dPcup[index] =
x * dPcup[index1] - z * Pcup[index1];
} else if (n > 1 && n != m) {
index1 = (n - 2) * (n - 1) / 2 + m;
index2 = (n - 1) * n / 2 + m;
if (m > n - 2) {
Pcup[index] = x * Pcup[index2];
dPcup[index] =
x * dPcup[index2] -
z * Pcup[index2];
} else {
k = (float)(((n - 1) * (n - 1)) -
(m * m)) / (float)((2 *
n -
1)
*
(2 *
n -
3));
Pcup[index] =
x * Pcup[index2] -
k * Pcup[index1];
dPcup[index] =
x * dPcup[index2] -
z * Pcup[index2] -
k * dPcup[index1];
}
}
}
}
/*Compute the ration between the Gauss-normalized associated Legendre
functions and the Schmidt quasi-normalized version. This is equivalent to
sqrt((m==0?1:2)*(n-m)!/(n+m!))*(2n-1)!!/(n-m)! */
schmidtQuasiNorm[0] = 1.0;
for (n = 1; n <= nMax; n++) {
index = (n * (n + 1) / 2);
index1 = (n - 1) * n / 2;
/* for m = 0 */
schmidtQuasiNorm[index] =
schmidtQuasiNorm[index1] * (float)(2 * n -
1) / (float)n;
for (m = 1; m <= n; m++) {
index = (n * (n + 1) / 2 + m);
index1 = (n * (n + 1) / 2 + m - 1);
schmidtQuasiNorm[index] =
schmidtQuasiNorm[index1] *
sqrt((float)((n - m + 1) * (m == 1 ? 2 : 1)) /
(float)(n + m));
}
}
/* Converts the Gauss-normalized associated Legendre
functions to the Schmidt quasi-normalized version using pre-computed
relation stored in the variable schmidtQuasiNorm */
for (n = 1; n <= nMax; n++) {
for (m = 0; m <= n; m++) {
index = (n * (n + 1) / 2 + m);
Pcup[index] =
Pcup[index] * schmidtQuasiNorm[index];
dPcup[index] =
-dPcup[index] * schmidtQuasiNorm[index];
/* The sign is changed since the new WMM routines use derivative with respect to latitude
insted of co-latitude */
}
}
return TRUE;
} /*WMM_PcupLow */
uint16_t WMM_SummationSpecial(WMMtype_SphericalHarmonicVariables *
SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults * MagneticResults)
/* Special calculation for the component By at Geographic poles.
Manoj Nair, June, 2009 manoj.c.nair@noaa.gov
INPUT: MagneticModel
SphVariables
CoordSpherical
OUTPUT: MagneticResults
CALLS : none
See Section 1.4, "SINGULARITIES AT THE GEOGRAPHIC POLES", WMM Technical report
*/
{
uint16_t n, index;
float k, sin_phi, PcupS[NUMPCUPS], schmidtQuasiNorm1,
schmidtQuasiNorm2, schmidtQuasiNorm3;
PcupS[0] = 1;
schmidtQuasiNorm1 = 1.0;
MagneticResults->By = 0.0;
sin_phi = sin(DEG2RAD(CoordSpherical->phig));
for (n = 1; n <= MagneticModel->nMax; n++) {
/*Compute the ration between the Gauss-normalized associated Legendre
functions and the Schmidt quasi-normalized version. This is equivalent to
sqrt((m==0?1:2)*(n-m)!/(n+m!))*(2n-1)!!/(n-m)! */
index = (n * (n + 1) / 2 + 1);
schmidtQuasiNorm2 =
schmidtQuasiNorm1 * (float)(2 * n - 1) / (float)n;
schmidtQuasiNorm3 =
schmidtQuasiNorm2 * sqrt((float)(n * 2) /
(float)(n + 1));
schmidtQuasiNorm1 = schmidtQuasiNorm2;
if (n == 1) {
PcupS[n] = PcupS[n - 1];
} else {
k = (float)(((n - 1) * (n - 1)) -
1) / (float)((2 * n - 1) * (2 * n -
3));
PcupS[n] =
sin_phi * PcupS[n - 1] - k * PcupS[n - 2];
}
/* 1 nMax (n+2) n m m m
By = SUM (a/r) (m) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Equation 11 in the WMM Technical report. Derivative with respect to longitude, divided by radius. */
MagneticResults->By +=
SphVariables->RelativeRadiusPower[n] *
(MagneticModel->Main_Field_Coeff_G[index] *
SphVariables->sin_mlambda[1] -
MagneticModel->Main_Field_Coeff_H[index] *
SphVariables->cos_mlambda[1])
* PcupS[n] * schmidtQuasiNorm3;
}
return TRUE;
} /*WMM_SummationSpecial */
uint16_t WMM_SecVarSummationSpecial(WMMtype_SphericalHarmonicVariables *
SphVariables,
WMMtype_CoordSpherical *
CoordSpherical,
WMMtype_MagneticResults *
MagneticResults)
{
/*Special calculation for the secular variation summation at the poles.
INPUT: MagneticModel
SphVariables
CoordSpherical
OUTPUT: MagneticResults
CALLS : none
*/
uint16_t n, index;
float k, sin_phi, PcupS[NUMPCUPS], schmidtQuasiNorm1,
schmidtQuasiNorm2, schmidtQuasiNorm3;
PcupS[0] = 1;
schmidtQuasiNorm1 = 1.0;
MagneticResults->By = 0.0;
sin_phi = sin(DEG2RAD(CoordSpherical->phig));
for (n = 1; n <= MagneticModel->nMaxSecVar; n++) {
index = (n * (n + 1) / 2 + 1);
schmidtQuasiNorm2 =
schmidtQuasiNorm1 * (float)(2 * n - 1) / (float)n;
schmidtQuasiNorm3 =
schmidtQuasiNorm2 * sqrt((float)(n * 2) /
(float)(n + 1));
schmidtQuasiNorm1 = schmidtQuasiNorm2;
if (n == 1) {
PcupS[n] = PcupS[n - 1];
} else {
k = (float)(((n - 1) * (n - 1)) -
1) / (float)((2 * n - 1) * (2 * n -
3));
PcupS[n] =
sin_phi * PcupS[n - 1] - k * PcupS[n - 2];
}
/* 1 nMax (n+2) n m m m
By = SUM (a/r) (m) SUM [g cos(m p) + h sin(m p)] dP (sin(phi))
n=1 m=0 n n n */
/* Derivative with respect to longitude, divided by radius. */
MagneticResults->By +=
SphVariables->RelativeRadiusPower[n] *
(MagneticModel->Secular_Var_Coeff_G[index] *
SphVariables->sin_mlambda[1] -
MagneticModel->Secular_Var_Coeff_H[index] *
SphVariables->cos_mlambda[1])
* PcupS[n] * schmidtQuasiNorm3;
}
return TRUE;
} /*SecVarSummationSpecial */
void WMM_TimelyModifyMagneticModel(WMMtype_Date * UserDate)
// Time change the Model coefficients from the base year of the model using secular variation coefficients.
//
// Modified to work on the global data structure to reduce memory footprint
{
uint16_t n, m, index, a, b;
a = MagneticModel->nMaxSecVar;
b = (a * (a + 1) / 2 + a);
for (n = 1; n <= MagneticModel->nMax; n++) {
for (m = 0; m <= n; m++) {
index = (n * (n + 1) / 2 + m);
if (index <= b) {
MagneticModel->Main_Field_Coeff_H[index] +=
(UserDate->DecimalYear -
MagneticModel->epoch) *
MagneticModel->
Secular_Var_Coeff_H[index];
MagneticModel->Main_Field_Coeff_G[index] +=
(UserDate->DecimalYear -
MagneticModel->epoch) *
MagneticModel->
Secular_Var_Coeff_G[index];
}
}
}
} /* WMM_TimelyModifyMagneticModel */
uint16_t WMM_DateToYear(WMMtype_Date * CalendarDate, char *Error)
// Converts a given calendar date into a decimal year
{
uint16_t temp = 0; // Total number of days
uint16_t MonthDays[13] =
{ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
uint16_t ExtraDay = 0;
uint16_t i;
if ((CalendarDate->Year % 4 == 0 && CalendarDate->Year % 100 != 0)
|| CalendarDate->Year % 400 == 0)
ExtraDay = 1;
MonthDays[2] += ExtraDay;
/******************Validation********************************/
if (CalendarDate->Month <= 0 || CalendarDate->Month > 12) {
strcpy(Error,
"\nError: The Month entered is invalid, valid months are '1 to 12'\n");
return 0;
}
if (CalendarDate->Day <= 0
|| CalendarDate->Day > MonthDays[CalendarDate->Month]) {
// printf("\nThe number of days in month %d is %d\n", CalendarDate->Month, MonthDays[CalendarDate->Month]);
strcpy(Error, "\nError: The day entered is invalid\n");
return 0;
}
/****************Calculation of t***************************/
for (i = 1; i <= CalendarDate->Month; i++)
temp += MonthDays[i - 1];
temp += CalendarDate->Day;
CalendarDate->DecimalYear =
CalendarDate->Year + (temp - 1) / (365.0 + ExtraDay);
return 1;
} /*WMM_DateToYear */
void WMM_GeodeticToSpherical(WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_CoordSpherical * CoordSpherical)
// Converts Geodetic coordinates to Spherical coordinates
// Convert geodetic coordinates, (defined by the WGS-84
// reference ellipsoid), to Earth Centered Earth Fixed Cartesian
// coordinates, and then to spherical coordinates.
{
float CosLat, SinLat, rc, xp, zp; // all local variables
CosLat = cos(DEG2RAD(CoordGeodetic->phi));
SinLat = sin(DEG2RAD(CoordGeodetic->phi));
// compute the local radius of curvature on the WGS-84 reference ellipsoid
rc = Ellip->a / sqrt(1.0 - Ellip->epssq * SinLat * SinLat);
// compute ECEF Cartesian coordinates of specified point (for longitude=0)
xp = (rc + CoordGeodetic->HeightAboveEllipsoid) * CosLat;
zp = (rc * (1.0 - Ellip->epssq) +
CoordGeodetic->HeightAboveEllipsoid) * SinLat;
// compute spherical radius and angle lambda and phi of specified point
CoordSpherical->r = sqrt(xp * xp + zp * zp);
CoordSpherical->phig = RAD2DEG(asin(zp / CoordSpherical->r)); // geocentric latitude
CoordSpherical->lambda = CoordGeodetic->lambda; // longitude
} // WMM_GeodeticToSpherical
void WMM_Set_Coeff_Array()
{
// const should hopefully keep them in the flash region
static const float CoeffFile[91][6] = { {0, 0, 0, 0, 0, 0},
{1, 0, -29496.6, 0.0, 11.6, 0.0},
{1, 1, -1586.3, 4944.4, 16.5, -25.9},
{2, 0, -2396.6, 0.0, -12.1, 0.0},
{2, 1, 3026.1, -2707.7, -4.4, -22.5},
{2, 2, 1668.6, -576.1, 1.9, -11.8},
{3, 0, 1340.1, 0.0, 0.4, 0.0},
{3, 1, -2326.2, -160.2, -4.1, 7.3},
{3, 2, 1231.9, 251.9, -2.9, -3.9},
{3, 3, 634.0, -536.6, -7.7, -2.6},
{4, 0, 912.6, 0.0, -1.8, 0.0},
{4, 1, 808.9, 286.4, 2.3, 1.1},
{4, 2, 166.7, -211.2, -8.7, 2.7},
{4, 3, -357.1, 164.3, 4.6, 3.9},
{4, 4, 89.4, -309.1, -2.1, -0.8},
{5, 0, -230.9, 0.0, -1.0, 0.0},
{5, 1, 357.2, 44.6, 0.6, 0.4},
{5, 2, 200.3, 188.9, -1.8, 1.8},
{5, 3, -141.1, -118.2, -1.0, 1.2},
{5, 4, -163.0, 0.0, 0.9, 4.0},
{5, 5, -7.8, 100.9, 1.0, -0.6},
{6, 0, 72.8, 0.0, -0.2, 0.0},
{6, 1, 68.6, -20.8, -0.2, -0.2},
{6, 2, 76.0, 44.1, -0.1, -2.1},
{6, 3, -141.4, 61.5, 2.0, -0.4},
{6, 4, -22.8, -66.3, -1.7, -0.6},
{6, 5, 13.2, 3.1, -0.3, 0.5},
{6, 6, -77.9, 55.0, 1.7, 0.9},
{7, 0, 80.5, 0.0, 0.1, 0.0},
{7, 1, -75.1, -57.9, -0.1, 0.7},
{7, 2, -4.7, -21.1, -0.6, 0.3},
{7, 3, 45.3, 6.5, 1.3, -0.1},
{7, 4, 13.9, 24.9, 0.4, -0.1},
{7, 5, 10.4, 7.0, 0.3, -0.8},
{7, 6, 1.7, -27.7, -0.7, -0.3},
{7, 7, 4.9, -3.3, 0.6, 0.3},
{8, 0, 24.4, 0.0, -0.1, 0.0},
{8, 1, 8.1, 11.0, 0.1, -0.1},
{8, 2, -14.5, -20.0, -0.6, 0.2},
{8, 3, -5.6, 11.9, 0.2, 0.4},
{8, 4, -19.3, -17.4, -0.2, 0.4},
{8, 5, 11.5, 16.7, 0.3, 0.1},
{8, 6, 10.9, 7.0, 0.3, -0.1},
{8, 7, -14.1, -10.8, -0.6, 0.4},
{8, 8, -3.7, 1.7, 0.2, 0.3},
{9, 0, 5.4, 0.0, 0.0, 0.0},
{9, 1, 9.4, -20.5, -0.1, 0.0},
{9, 2, 3.4, 11.5, 0.0, -0.2},
{9, 3, -5.2, 12.8, 0.3, 0.0},
{9, 4, 3.1, -7.2, -0.4, -0.1},
{9, 5, -12.4, -7.4, -0.3, 0.1},
{9, 6, -0.7, 8.0, 0.1, 0.0},
{9, 7, 8.4, 2.1, -0.1, -0.2},
{9, 8, -8.5, -6.1, -0.4, 0.3},
{9, 9, -10.1, 7.0, -0.2, 0.2},
{10, 0, -2.0, 0.0, 0.0, 0.0},
{10, 1, -6.3, 2.8, 0.0, 0.1},
{10, 2, 0.9, -0.1, -0.1, -0.1},
{10, 3, -1.1, 4.7, 0.2, 0.0},
{10, 4, -0.2, 4.4, 0.0, -0.1},
{10, 5, 2.5, -7.2, -0.1, -0.1},
{10, 6, -0.3, -1.0, -0.2, 0.0},
{10, 7, 2.2, -3.9, 0.0, -0.1},
{10, 8, 3.1, -2.0, -0.1, -0.2},
{10, 9, -1.0, -2.0, -0.2, 0.0},
{10, 10, -2.8, -8.3, -0.2, -0.1},
{11, 0, 3.0, 0.0, 0.0, 0.0},
{11, 1, -1.5, 0.2, 0.0, 0.0},
{11, 2, -2.1, 1.7, 0.0, 0.1},
{11, 3, 1.7, -0.6, 0.1, 0.0},
{11, 4, -0.5, -1.8, 0.0, 0.1},
{11, 5, 0.5, 0.9, 0.0, 0.0},
{11, 6, -0.8, -0.4, 0.0, 0.1},
{11, 7, 0.4, -2.5, 0.0, 0.0},
{11, 8, 1.8, -1.3, 0.0, -0.1},
{11, 9, 0.1, -2.1, 0.0, -0.1},
{11, 10, 0.7, -1.9, -0.1, 0.0},
{11, 11, 3.8, -1.8, 0.0, -0.1},
{12, 0, -2.2, 0.0, 0.0, 0.0},
{12, 1, -0.2, -0.9, 0.0, 0.0},
{12, 2, 0.3, 0.3, 0.1, 0.0},
{12, 3, 1.0, 2.1, 0.1, 0.0},
{12, 4, -0.6, -2.5, -0.1, 0.0},
{12, 5, 0.9, 0.5, 0.0, 0.0},
{12, 6, -0.1, 0.6, 0.0, 0.1},
{12, 7, 0.5, 0.0, 0.0, 0.0},
{12, 8, -0.4, 0.1, 0.0, 0.0},
{12, 9, -0.4, 0.3, 0.0, 0.0},
{12, 10, 0.2, -0.9, 0.0, 0.0},
{12, 11, -0.8, -0.2, -0.1, 0.0},
{12, 12, 0.0, 0.9, 0.1, 0.0}
};
// TODO: If this works here, delete first two columns to save space
for (uint16_t i = 0; i < NUMTERMS; i++) {
MagneticModel->Main_Field_Coeff_G[i] = CoeffFile[i][2];
MagneticModel->Main_Field_Coeff_H[i] = CoeffFile[i][3];
MagneticModel->Secular_Var_Coeff_G[i] = CoeffFile[i][4];
MagneticModel->Secular_Var_Coeff_H[i] = CoeffFile[i][5];
}
}

482
flight/Libraries/buffer.c
View File

@ -1,244 +1,238 @@
/**
******************************************************************************
*
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup Flight_Libraries Miscellaneous library functions
* @brief Miscellaneous library functions shared between PIOS / OpenPilot / AHRS
* @{
*
* @file buffer.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Simplies buffering data
* @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
*/
//*****************************************************************************
//
// File Name : 'buffer.c'
// Title : Multipurpose byte buffer structure and methods
// Author : Pascal Stang - Copyright (C) 2001-2002
// Created : 9/23/2001
// Revised : 9/23/2001
// Version : 1.0
// Target MCU : any
// Editor Tabs : 4
//
// This code is distributed under the GNU Public License
// which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************
#include "buffer.h"
/**
* @brief Initialize a cBuffer structure
* @param[in] buffer Points to the buffer structure
* @param[in] start Allocated memory to store data
* @param[in] size Maximum size of buffer
* @return None
*/
void bufferInit(cBuffer* buffer, uint8_t *start, uint32_t size)
{
// set start pointer of the buffer
buffer->dataptr = start;
buffer->size = size;
// initialize index and length
buffer->dataindex = 0;
buffer->datalength = 0;
}
/**
* @brief Return remaining space in buffer
* @param[in] buffer Pointer to buffer structure
* @return Amount of space remaining on buffer
*/
uint32_t bufferRemainingSpace(cBuffer* buffer)
{
return buffer->size - buffer->datalength;
}
/**
* @brief Return amount of data
* @param[in] buffer Pointer to buffer structure
* @return Amount of data queued in buffer
*/
uint32_t bufferBufferedData(cBuffer* buffer)
{
return buffer->datalength;
}
/**
* @brief Pop one element from buffer
* @param[in] buffer Pointer to the buffer structure
* @return None
*/
uint8_t bufferGetFromFront(cBuffer* buffer)
{
unsigned char data = 0;
// check to see if there's data in the buffer
if(buffer->datalength)
{
// get the first character from buffer
data = buffer->dataptr[buffer->dataindex];
// move index down and decrement length
buffer->dataindex++;
if(buffer->dataindex >= buffer->size)
{
buffer->dataindex %= buffer->size;
}
buffer->datalength--;
}
// return
return data;
}
/**
* @brief Copy number of elements into another buffer
* @param[in] buffer Pointer to the buffer structure
* @param[in] dest Point to destimation, must be allocated enough space for size
* @param[in] size Number of elements to get
* @return
* @arg -1 for success
* @arg 0 error
*/
uint8_t bufferGetChunkFromFront(cBuffer* buffer, uint8_t * dest, uint32_t size)
{
if(size > buffer->datalength)
return -1;
for(uint32_t i = 0; i < size; i++)
{
dest[i] = bufferGetFromFront(buffer);
}
return 0;
}
/**
* @brief Shift index to trash data from front of buffer
* @param[in] buffer Pointer to buffer structure
* @param[in] numbytes Number of bytes to drop
* @return None
*/
void bufferDumpFromFront(cBuffer* buffer, uint32_t numbytes)
{
// dump numbytes from the front of the buffer
// are we dumping less than the entire buffer?
if(numbytes < buffer->datalength)
{
// move index down by numbytes and decrement length by numbytes
buffer->dataindex += numbytes;
if(buffer->dataindex >= buffer->size)
{
buffer->dataindex %= buffer->size;
}
buffer->datalength -= numbytes;
}
else
{
// flush the whole buffer
buffer->datalength = 0;
}
}
/**
* @brief Get element indexed from the front of buffer
* @param[in] buffer Point to the buffer structure
* @param[in] index Index into the buffer relative to front
* @return None
*/
uint8_t bufferGetAtIndex(cBuffer* buffer, uint32_t index)
{
// return character at index in buffer
return buffer->dataptr[(buffer->dataindex+index)%(buffer->size)];
}
/**
* @brief Queue a character to end of buffer
* @param[in] buffer Point to the buffer structure
* @param[in] data Byte to add
* @return
* @arg -1 for success
* @arg 0 error
*/
uint8_t bufferAddToEnd(cBuffer* buffer, uint8_t data)
{
// make sure the buffer has room
if(buffer->datalength < buffer->size)
{
// save data byte at end of buffer
buffer->dataptr[(buffer->dataindex + buffer->datalength) % buffer->size] = data;
// increment the length
buffer->datalength++;
// return success
return -1;
}
else return 0;
}
/**
* @brief Queue a block of character to end of buffer
* @param[in] buffer Point to the buffer structure
* @param[in] data Pointer to data to add
* @param[in] size Number of bytes to add
* @return
* @arg -1 for success
* @arg 0 error
*/
uint8_t bufferAddChunkToEnd(cBuffer* buffer, const uint8_t * data, uint32_t size)
{
// TODO: replace with memcpy and logic, for now keeping it simple
for(uint32_t i = 0; i < size; i++)
{
if(bufferAddToEnd(buffer,data[i]) == 0)
return 0;
}
return -1;
}
/**
* @brief Check to see if the buffer has room
* @param[in] buffer Point to the buffer structure
* @return
* @arg True there is room available in buffer
* @arg False buffer is full
*/
unsigned char bufferIsNotFull(cBuffer* buffer)
{
return (buffer->datalength < buffer->size);
}
/**
* @brief Trash all data in buffer
* @param[in] buffer Point to the buffer structure
*/
void bufferFlush(cBuffer* buffer)
{
// flush contents of the buffer
buffer->datalength = 0;
}
/**
* @}
* @}
*/
/**
******************************************************************************
*
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup Flight_Libraries Miscellaneous library functions
* @brief Miscellaneous library functions shared between PIOS / OpenPilot / AHRS
* @{
*
* @file buffer.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Simplies buffering data
* @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
*/
//*****************************************************************************
//
// File Name : 'buffer.c'
// Title : Multipurpose byte buffer structure and methods
// Author : Pascal Stang - Copyright (C) 2001-2002
// Created : 9/23/2001
// Revised : 9/23/2001
// Version : 1.0
// Target MCU : any
// Editor Tabs : 4
//
// This code is distributed under the GNU Public License
// which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************
#include "buffer.h"
/**
* @brief Initialize a cBuffer structure
* @param[in] buffer Points to the buffer structure
* @param[in] start Allocated memory to store data
* @param[in] size Maximum size of buffer
* @return None
*/
void bufferInit(cBuffer * buffer, uint8_t * start, uint32_t size)
{
// set start pointer of the buffer
buffer->dataptr = start;
buffer->size = size;
// initialize index and length
buffer->dataindex = 0;
buffer->datalength = 0;
}
/**
* @brief Return remaining space in buffer
* @param[in] buffer Pointer to buffer structure
* @return Amount of space remaining on buffer
*/
uint32_t bufferRemainingSpace(cBuffer * buffer)
{
return buffer->size - buffer->datalength;
}
/**
* @brief Return amount of data
* @param[in] buffer Pointer to buffer structure
* @return Amount of data queued in buffer
*/
uint32_t bufferBufferedData(cBuffer * buffer)
{
return buffer->datalength;
}
/**
* @brief Pop one element from buffer
* @param[in] buffer Pointer to the buffer structure
* @return None
*/
uint8_t bufferGetFromFront(cBuffer * buffer)
{
unsigned char data = 0;
// check to see if there's data in the buffer
if (buffer->datalength) {
// get the first character from buffer
data = buffer->dataptr[buffer->dataindex];
// move index down and decrement length
buffer->dataindex++;
if (buffer->dataindex >= buffer->size) {
buffer->dataindex %= buffer->size;
}
buffer->datalength--;
}
// return
return data;
}
/**
* @brief Copy number of elements into another buffer
* @param[in] buffer Pointer to the buffer structure
* @param[in] dest Point to destimation, must be allocated enough space for size
* @param[in] size Number of elements to get
* @return
* @arg -1 for success
* @arg 0 error
*/
uint8_t bufferGetChunkFromFront(cBuffer * buffer, uint8_t * dest,
uint32_t size)
{
if (size > buffer->datalength)
return -1;
for (uint32_t i = 0; i < size; i++) {
dest[i] = bufferGetFromFront(buffer);
}
return 0;
}
/**
* @brief Shift index to trash data from front of buffer
* @param[in] buffer Pointer to buffer structure
* @param[in] numbytes Number of bytes to drop
* @return None
*/
void bufferDumpFromFront(cBuffer * buffer, uint32_t numbytes)
{
// dump numbytes from the front of the buffer
// are we dumping less than the entire buffer?
if (numbytes < buffer->datalength) {
// move index down by numbytes and decrement length by numbytes
buffer->dataindex += numbytes;
if (buffer->dataindex >= buffer->size) {
buffer->dataindex %= buffer->size;
}
buffer->datalength -= numbytes;
} else {
// flush the whole buffer
buffer->datalength = 0;
}
}
/**
* @brief Get element indexed from the front of buffer
* @param[in] buffer Point to the buffer structure
* @param[in] index Index into the buffer relative to front
* @return None
*/
uint8_t bufferGetAtIndex(cBuffer * buffer, uint32_t index)
{
// return character at index in buffer
return buffer->dataptr[(buffer->dataindex + index) %
(buffer->size)];
}
/**
* @brief Queue a character to end of buffer
* @param[in] buffer Point to the buffer structure
* @param[in] data Byte to add
* @return
* @arg -1 for success
* @arg 0 error
*/
uint8_t bufferAddToEnd(cBuffer * buffer, uint8_t data)
{
// make sure the buffer has room
if (buffer->datalength < buffer->size) {
// save data byte at end of buffer
buffer->dataptr[(buffer->dataindex + buffer->datalength) %
buffer->size] = data;
// increment the length
buffer->datalength++;
// return success
return -1;
} else
return 0;
}
/**
* @brief Queue a block of character to end of buffer
* @param[in] buffer Point to the buffer structure
* @param[in] data Pointer to data to add
* @param[in] size Number of bytes to add
* @return
* @arg -1 for success
* @arg 0 error
*/
uint8_t bufferAddChunkToEnd(cBuffer * buffer, const uint8_t * data,
uint32_t size)
{
// TODO: replace with memcpy and logic, for now keeping it simple
for (uint32_t i = 0; i < size; i++) {
if (bufferAddToEnd(buffer, data[i]) == 0)
return 0;
}
return -1;
}
/**
* @brief Check to see if the buffer has room
* @param[in] buffer Point to the buffer structure
* @return
* @arg True there is room available in buffer
* @arg False buffer is full
*/
unsigned char bufferIsNotFull(cBuffer * buffer)
{
return (buffer->datalength < buffer->size);
}
/**
* @brief Trash all data in buffer
* @param[in] buffer Point to the buffer structure
*/
void bufferFlush(cBuffer * buffer)
{
// flush contents of the buffer
buffer->datalength = 0;
}
/**
* @}
* @}
*/

114
flight/Libraries/inc/CoordinateConversions.h
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@ -1,56 +1,58 @@
/**
******************************************************************************
*
* @file CoordinateConverions.h
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Header for Coordinate conversions library in CoordinateConversions.c
* - all angles in deg
* - distances in meters
* - altitude above WGS-84 elipsoid
*
* @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 COORDINATECONVERSIONS_H_
#define COORDINATECONVERSIONS_H_
// ****** convert Lat,Lon,Alt to ECEF ************
void LLA2ECEF(double LLA[3], double ECEF[3]);
// ****** convert ECEF to Lat,Lon,Alt (ITERATIVE!) *********
uint16_t ECEF2LLA(double ECEF[3], double LLA[3]);
void RneFromLLA(double LLA[3], float Rne[3][3]);
// ****** find roll, pitch, yaw from quaternion ********
void Quaternion2RPY(float q[4], float rpy[3]);
// ****** find quaternion from roll, pitch, yaw ********
void RPY2Quaternion(float rpy[3], float q[4]);
//** Find Rbe, that rotates a vector from earth fixed to body frame, from quaternion **
void Quaternion2R(float q[4], float Rbe[3][3]);
// ****** Express LLA in a local NED Base Frame ********
void LLA2Base(double LLA[3], double BaseECEF[3], float Rne[3][3], float NED[3]);
// ****** Express ECEF in a local NED Base Frame ********
void ECEF2Base(double ECEF[3], double BaseECEF[3], float Rne[3][3], float NED[3]);
#endif // COORDINATECONVERSIONS_H_
/**
******************************************************************************
*
* @file CoordinateConverions.h
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Header for Coordinate conversions library in CoordinateConversions.c
* - all angles in deg
* - distances in meters
* - altitude above WGS-84 elipsoid
*
* @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 COORDINATECONVERSIONS_H_
#define COORDINATECONVERSIONS_H_
// ****** convert Lat,Lon,Alt to ECEF ************
void LLA2ECEF(double LLA[3], double ECEF[3]);
// ****** convert ECEF to Lat,Lon,Alt (ITERATIVE!) *********
uint16_t ECEF2LLA(double ECEF[3], double LLA[3]);
void RneFromLLA(double LLA[3], float Rne[3][3]);
// ****** find roll, pitch, yaw from quaternion ********
void Quaternion2RPY(float q[4], float rpy[3]);
// ****** find quaternion from roll, pitch, yaw ********
void RPY2Quaternion(float rpy[3], float q[4]);
//** Find Rbe, that rotates a vector from earth fixed to body frame, from quaternion **
void Quaternion2R(float q[4], float Rbe[3][3]);
// ****** Express LLA in a local NED Base Frame ********
void LLA2Base(double LLA[3], double BaseECEF[3], float Rne[3][3],
float NED[3]);
// ****** Express ECEF in a local NED Base Frame ********
void ECEF2Base(double ECEF[3], double BaseECEF[3], float Rne[3][3],
float NED[3]);
#endif // COORDINATECONVERSIONS_H_

353
flight/Libraries/inc/WMMInternal.h
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@ -1,168 +1,185 @@
/**
******************************************************************************
*
* @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_
// 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
#define RAD2DEG(rad) ((rad)*(180.0L/M_PI))
#define DEG2RAD(deg) ((deg)*(M_PI/180.0L))
// 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();
void WMM_GeodeticToSpherical(WMMtype_CoordGeodetic * CoordGeodetic, WMMtype_CoordSpherical *CoordSpherical);
uint16_t WMM_DateToYear (WMMtype_Date *CalendarDate, char *Error);
void WMM_TimelyModifyMagneticModel(WMMtype_Date * UserDate);
uint16_t WMM_Geomag(WMMtype_CoordSpherical * CoordSpherical,
WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_GeoMagneticElements *GeoMagneticElements);
uint16_t WMM_AssociatedLegendreFunction( WMMtype_CoordSpherical * CoordSpherical, uint16_t nMax, WMMtype_LegendreFunction *LegendreFunction);
uint16_t WMM_CalculateGeoMagneticElements(WMMtype_MagneticResults *MagneticResultsGeo, WMMtype_GeoMagneticElements *GeoMagneticElements);
uint16_t WMM_CalculateSecularVariation(WMMtype_MagneticResults *MagneticVariation, WMMtype_GeoMagneticElements *MagneticElements);
uint16_t WMM_ComputeSphericalHarmonicVariables( WMMtype_CoordSpherical *CoordSpherical,
uint16_t nMax,
WMMtype_SphericalHarmonicVariables * SphVariables);
uint16_t WMM_PcupLow( float *Pcup, float *dPcup, float x, uint16_t nMax);
uint16_t WMM_PcupHigh( float *Pcup, float *dPcup, float x, uint16_t nMax);
uint16_t WMM_RotateMagneticVector(WMMtype_CoordSpherical * ,
WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_MagneticResults * MagneticResultsSph,
WMMtype_MagneticResults *MagneticResultsGeo);
uint16_t WMM_SecVarSummation(WMMtype_LegendreFunction *LegendreFunction,
WMMtype_SphericalHarmonicVariables * SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults *MagneticResults);
uint16_t WMM_SecVarSummationSpecial(WMMtype_SphericalHarmonicVariables * SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults *MagneticResults);
uint16_t WMM_Summation( WMMtype_LegendreFunction *LegendreFunction,
WMMtype_SphericalHarmonicVariables * SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults *MagneticResults);
uint16_t WMM_SummationSpecial(WMMtype_SphericalHarmonicVariables * SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults *MagneticResults);
#endif /* WMMINTERNAL_H_ */
/**
******************************************************************************
*
* @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_
// 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
#define RAD2DEG(rad) ((rad)*(180.0L/M_PI))
#define DEG2RAD(deg) ((deg)*(M_PI/180.0L))
// 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();
void WMM_GeodeticToSpherical(WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_CoordSpherical * CoordSpherical);
uint16_t WMM_DateToYear(WMMtype_Date * CalendarDate, char *Error);
void WMM_TimelyModifyMagneticModel(WMMtype_Date * UserDate);
uint16_t WMM_Geomag(WMMtype_CoordSpherical * CoordSpherical,
WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_GeoMagneticElements * GeoMagneticElements);
uint16_t WMM_AssociatedLegendreFunction(WMMtype_CoordSpherical *
CoordSpherical, uint16_t nMax,
WMMtype_LegendreFunction *
LegendreFunction);
uint16_t WMM_CalculateGeoMagneticElements(WMMtype_MagneticResults *
MagneticResultsGeo,
WMMtype_GeoMagneticElements *
GeoMagneticElements);
uint16_t WMM_CalculateSecularVariation(WMMtype_MagneticResults *
MagneticVariation,
WMMtype_GeoMagneticElements *
MagneticElements);
uint16_t WMM_ComputeSphericalHarmonicVariables(WMMtype_CoordSpherical *
CoordSpherical,
uint16_t nMax,
WMMtype_SphericalHarmonicVariables
* SphVariables);
uint16_t WMM_PcupLow(float *Pcup, float *dPcup, float x, uint16_t nMax);
uint16_t WMM_PcupHigh(float *Pcup, float *dPcup, float x, uint16_t nMax);
uint16_t WMM_RotateMagneticVector(WMMtype_CoordSpherical *,
WMMtype_CoordGeodetic * CoordGeodetic,
WMMtype_MagneticResults *
MagneticResultsSph,
WMMtype_MagneticResults *
MagneticResultsGeo);
uint16_t WMM_SecVarSummation(WMMtype_LegendreFunction * LegendreFunction,
WMMtype_SphericalHarmonicVariables *
SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults * MagneticResults);
uint16_t WMM_SecVarSummationSpecial(WMMtype_SphericalHarmonicVariables *
SphVariables,
WMMtype_CoordSpherical *
CoordSpherical,
WMMtype_MagneticResults *
MagneticResults);
uint16_t WMM_Summation(WMMtype_LegendreFunction * LegendreFunction,
WMMtype_SphericalHarmonicVariables * SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults * MagneticResults);
uint16_t WMM_SummationSpecial(WMMtype_SphericalHarmonicVariables *
SphVariables,
WMMtype_CoordSpherical * CoordSpherical,
WMMtype_MagneticResults * MagneticResults);
#endif /* WMMINTERNAL_H_ */

70
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@ -1,34 +1,36 @@
/**
******************************************************************************
*
* @file WorldMagModel.h
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Include file of the WorldMagModel exposed 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 WORLDMAGMODEL_H_
#define WORLDMAGMODEL_H_
// Exposed Function Prototypes
int WMM_Initialize();
void WMM_GetMagVector(float Lat, float Lon, float AltEllipsoid, uint16_t Month, uint16_t Day, uint16_t Year, float B[3]);
#endif /* WORLDMAGMODEL_H_ */
/**
******************************************************************************
*
* @file WorldMagModel.h
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Include file of the WorldMagModel exposed 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 WORLDMAGMODEL_H_
#define WORLDMAGMODEL_H_
// Exposed Function Prototypes
int WMM_Initialize();
void WMM_GetMagVector(float Lat, float Lon, float AltEllipsoid,
uint16_t Month, uint16_t Day, uint16_t Year,
float B[3]);
#endif /* WORLDMAGMODEL_H_ */

213
flight/Libraries/inc/buffer.h
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@ -1,106 +1,107 @@
/**
******************************************************************************
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup GSPModule GPS Module
* @brief Process GPS information
* @{
*
* @file buffer.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief see below
* As with all modules only the initialize function is exposed all other
* interactions with the module take place through the event queue and
* objects.
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
//*****************************************************************************
//
// File Name : 'buffer.h'
// Title : Multipurpose byte buffer structure and methods
// Author : Pascal Stang - Copyright (C) 2001-2002
// Created : 9/23/2001
// Revised : 11/16/2002
// Version : 1.1
// Target MCU : any
// Editor Tabs : 4
//
/// \code #include "buffer.h" \endcode
/// \par Overview
/// This byte-buffer structure provides an easy and efficient way to store
/// and process a stream of bytes.  You can create as many buffers as you
/// like (within memory limits), and then use this common set of functions to
/// access each buffer.  The buffers are designed for FIFO operation (first
/// in, first out).  This means that the first byte you put in the buffer
/// will be the first one you get when you read out the buffer.  Supported
/// functions include buffer initialize, get byte from front of buffer, add
/// byte to end of buffer, check if buffer is full, and flush buffer.  The
/// buffer uses a circular design so no copying of data is ever necessary.
/// This buffer is not dynamically allocated, it has a user-defined fixed
/// maximum size.  This buffer is used in many places in the avrlib code.
//
// This code is distributed under the GNU Public License
// which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************
//@{
#ifndef BUFFER_H
#define BUFFER_H
#include "stdint.h"
// structure/typdefs
//! cBuffer structure
typedef struct struct_cBuffer
{
unsigned char *dataptr; ///< the physical memory address where the buffer is stored
unsigned short size; ///< the allocated size of the buffer
unsigned short datalength; ///< the length of the data currently in the buffer
unsigned short dataindex; ///< the index into the buffer where the data starts
} cBuffer;
// function prototypes
//! initialize a buffer to start at a given address and have given size
void bufferInit(cBuffer* buffer, uint8_t *start, uint32_t size);
//! check free space in buffer
uint32_t bufferRemainingSpace(cBuffer* buffer);
//! get the first byte from the front of the buffer
uint8_t bufferGetFromFront(cBuffer* buffer);
//! get the number of bytes buffered
uint32_t bufferBufferedData(cBuffer* buffer);
//! copy number of elements into another buffer
uint8_t bufferGetChunkFromFront(cBuffer* buffer, uint8_t * dest, uint32_t size);
//! dump (discard) the first numbytes from the front of the buffer
void bufferDumpFromFront(cBuffer* buffer, uint32_t numbytes);
//! get a byte at the specified index in the buffer (kind of like array access)
// ** note: this does not remove the byte that was read from the buffer
uint8_t bufferGetAtIndex(cBuffer* buffer, uint32_t index);
//! add a byte to the end of the buffer
uint8_t bufferAddToEnd(cBuffer* buffer, uint8_t data);
//! queue a block of character to end of buffer
uint8_t bufferAddChunkToEnd(cBuffer* buffer, const uint8_t * data, uint32_t size);
//! check if the buffer is full/not full (returns non-zero value if not full)
uint8_t bufferIsNotFull(cBuffer* buffer);
//! flush (clear) the contents of the buffer
void bufferFlush(cBuffer* buffer);
#endif
/**
* @}
*/
/**
******************************************************************************
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup GSPModule GPS Module
* @brief Process GPS information
* @{
*
* @file buffer.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief see below
* As with all modules only the initialize function is exposed all other
* interactions with the module take place through the event queue and
* objects.
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
//*****************************************************************************
//
// File Name : 'buffer.h'
// Title : Multipurpose byte buffer structure and methods
// Author : Pascal Stang - Copyright (C) 2001-2002
// Created : 9/23/2001
// Revised : 11/16/2002
// Version : 1.1
// Target MCU : any
// Editor Tabs : 4
//
/// \code #include "buffer.h" \endcode
/// \par Overview
/// This byte-buffer structure provides an easy and efficient way to store
/// and process a stream of bytes.  You can create as many buffers as you
/// like (within memory limits), and then use this common set of functions to
/// access each buffer.  The buffers are designed for FIFO operation (first
/// in, first out).  This means that the first byte you put in the buffer
/// will be the first one you get when you read out the buffer.  Supported
/// functions include buffer initialize, get byte from front of buffer, add
/// byte to end of buffer, check if buffer is full, and flush buffer.  The
/// buffer uses a circular design so no copying of data is ever necessary.
/// This buffer is not dynamically allocated, it has a user-defined fixed
/// maximum size.  This buffer is used in many places in the avrlib code.
//
// This code is distributed under the GNU Public License
// which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************
//@{
#ifndef BUFFER_H
#define BUFFER_H
#include "stdint.h"
// structure/typdefs
//! cBuffer structure
typedef struct struct_cBuffer {
unsigned char *dataptr; ///< the physical memory address where the buffer is stored
unsigned short size; ///< the allocated size of the buffer
unsigned short datalength; ///< the length of the data currently in the buffer
unsigned short dataindex; ///< the index into the buffer where the data starts
} cBuffer;
// function prototypes
//! initialize a buffer to start at a given address and have given size
void bufferInit(cBuffer * buffer, uint8_t * start, uint32_t size);
//! check free space in buffer
uint32_t bufferRemainingSpace(cBuffer * buffer);
//! get the first byte from the front of the buffer
uint8_t bufferGetFromFront(cBuffer * buffer);
//! get the number of bytes buffered
uint32_t bufferBufferedData(cBuffer * buffer);
//! copy number of elements into another buffer
uint8_t bufferGetChunkFromFront(cBuffer * buffer, uint8_t * dest,
uint32_t size);
//! dump (discard) the first numbytes from the front of the buffer
void bufferDumpFromFront(cBuffer * buffer, uint32_t numbytes);
//! get a byte at the specified index in the buffer (kind of like array access)
// ** note: this does not remove the byte that was read from the buffer
uint8_t bufferGetAtIndex(cBuffer * buffer, uint32_t index);
//! add a byte to the end of the buffer
uint8_t bufferAddToEnd(cBuffer * buffer, uint8_t data);
//! queue a block of character to end of buffer
uint8_t bufferAddChunkToEnd(cBuffer * buffer, const uint8_t * data,
uint32_t size);
//! check if the buffer is full/not full (returns non-zero value if not full)
uint8_t bufferIsNotFull(cBuffer * buffer);
//! flush (clear) the contents of the buffer
void bufferFlush(cBuffer * buffer);
#endif
/**
* @}
*/