From fac2fc4971b3dfbea6d9bdc2724ce255597e73dc Mon Sep 17 00:00:00 2001
From: Marius Eggert <eggertm@irs.uni-stuttgart.de>
Date: Thu, 8 Dec 2022 09:52:42 +0100
Subject: [PATCH] - fixed IGRF-13 model - fixed GST calculation - fixed
conversion ECI - ToDo: remove debug output, check normalization
---
mission/controller/acs/Igrf13Model.cpp | 128 ++++++++++++++++++-------
mission/controller/acs/Igrf13Model.h | 28 +++++-
2 files changed, 119 insertions(+), 37 deletions(-)
diff --git a/mission/controller/acs/Igrf13Model.cpp b/mission/controller/acs/Igrf13Model.cpp
index fcd95b68..ec1b3e08 100644
--- a/mission/controller/acs/Igrf13Model.cpp
+++ b/mission/controller/acs/Igrf13Model.cpp
@@ -1,22 +1,19 @@
-/*
- * Igrf13Model.cpp
- *
- * Created on: 10 Mar 2022
- * Author: Robin Marquardt
- */
-
#include "Igrf13Model.h"
-#include <fsfw/globalfunctions/constants.h>
-#include <fsfw/globalfunctions/math/MatrixOperations.h>
-#include <fsfw/globalfunctions/math/QuaternionOperations.h>
-#include <fsfw/globalfunctions/math/VectorOperations.h>
-#include <math.h>
+#include <fsfw/src/fsfw/globalfunctions/constants.h>
+#include <fsfw/src/fsfw/globalfunctions/math/MatrixOperations.h>
+#include <fsfw/src/fsfw/globalfunctions/math/QuaternionOperations.h>
+#include <fsfw/src/fsfw/globalfunctions/math/VectorOperations.h>
#include <stdint.h>
#include <string.h>
+#include <time.h>
+
+#include <cmath>
#include "util/MathOperations.h"
+using namespace Math;
+
Igrf13Model::Igrf13Model() {}
Igrf13Model::~Igrf13Model() {}
@@ -25,7 +22,7 @@ void Igrf13Model::magFieldComp(const double longitude, const double gcLatitude,
double* magFieldModelInertial) {
double phi = longitude, theta = gcLatitude; // geocentric
/* Here is the co-latitude needed*/
- theta -= 90 * Math::PI / 180;
+ theta -= 90 * PI / 180;
theta *= (-1);
double rE = 6371200.0; // radius earth [m]
@@ -43,7 +40,7 @@ void Igrf13Model::magFieldComp(const double longitude, const double gcLatitude,
/* Calculation of Legendre Polynoms (normalised) */
if (n == m) {
P2 = sin(theta) * P11;
- dP2 = sin(theta) * dP11 - cos(theta) * P11;
+ dP2 = sin(theta) * dP11 + cos(theta) * P11;
P11 = P2;
P10 = P11;
P20 = 0;
@@ -70,11 +67,11 @@ void Igrf13Model::magFieldComp(const double longitude, const double gcLatitude,
magFieldModel[0] +=
pow(rE / (altitude + rE), (n + 2)) * (n + 1) *
((updatedG[m][n - 1] * cos(m * phi) + updatedH[m][n - 1] * sin(m * phi)) * P2);
- /* gradient of scalar potential towards phi */
+ /* gradient of scalar potential towards theta */
magFieldModel[1] +=
pow(rE / (altitude + rE), (n + 2)) *
((updatedG[m][n - 1] * cos(m * phi) + updatedH[m][n - 1] * sin(m * phi)) * dP2);
- /* gradient of scalar potential towards theta */
+ /* gradient of scalar potential towards phi */
magFieldModel[2] +=
pow(rE / (altitude + rE), (n + 2)) *
((-updatedG[m][n - 1] * sin(m * phi) + updatedH[m][n - 1] * cos(m * phi)) * P2 * m);
@@ -85,31 +82,51 @@ void Igrf13Model::magFieldComp(const double longitude, const double gcLatitude,
magFieldModel[1] *= -1;
magFieldModel[2] *= (-1 / sin(theta));
- /* Next step: transform into inertial KOS (IJK)*/
+ // std::cout << " X=" << -magFieldModel[1] << " Y=" << magFieldModel[2]
+ // << " Z=" << -magFieldModel[0] << std::endl;
+
+ /* Next step: transform into inertial RF (IJK)*/
// Julean Centuries
- double JD2000Floor = 0;
+ // double JD2000Floor = 0;
+ // double JD2000 = MathOperations<double>::convertUnixToJD2000(timeOfMagMeasurement);
+ // JD2000Floor = floor(JD2000);
+ // double JC2000 = JD2000Floor / 36525.;
+
double JD2000 = MathOperations<double>::convertUnixToJD2000(timeOfMagMeasurement);
- JD2000Floor = floor(JD2000);
- double JC2000 = JD2000Floor / 36525;
+ double UT1 = JD2000 / 36525.;
- double gst = 100.4606184 + 36000.77005361 * JC2000 + 0.00038793 * pow(JC2000, 2) -
- 0.000000026 * pow(JC2000, 3); // greenwich sidereal time
- gst *= PI / 180; // convert to radians
- double sec =
- (JD2000 - JD2000Floor) * 86400; // Seconds on this day (Universal time) // FROM GPS ?
- double omega0 = 0.00007292115; // mean angular velocity earth [rad/s]
- gst += omega0 * sec;
+ double gst =
+ 280.46061837 + 360.98564736629 * JD2000 + 0.0003875 * pow(UT1, 2) - 2.6e-8 * pow(UT1, 3);
+ gst = std::fmod(gst, 360.);
+ gst *= PI / 180.;
+ // std::cout << " GMST=" << gst * 180. / Math::PI << std::endl;
+ // double gst = 100.4606184 + 36000.77005361 * JC2000 + 0.00038793 * pow(JC2000, 2) -
+ // 0.000000026 * pow(JC2000, 3); // greenwich sidereal time
+ // gst *= PI / 180; // convert to radians
+ // double sec =
+ // (JD2000 - JD2000Floor) * 86400; // Seconds on this day (Universal time) // FROM GPS ?
+ // double omega0 = 0.00007292115; // mean angular velocity earth [rad/s]
+ // gst += omega0 * sec;
+ // std::cout << " GMST=" << gst * 180. / Math::PI << std::endl;
double lst = gst + longitude; // local sidereal time [rad]
+ // std::cout << " LMST=" << lst * 180. / Math::PI << std::endl;
- magFieldModelInertial[0] = magFieldModel[0] * cos(theta) +
- magFieldModel[1] * sin(theta) * cos(lst) - magFieldModel[1] * sin(lst);
- magFieldModelInertial[1] = magFieldModel[0] * cos(theta) +
- magFieldModel[1] * sin(theta) * sin(lst) + magFieldModel[1] * cos(lst);
- magFieldModelInertial[2] = magFieldModel[0] * sin(theta) + magFieldModel[1] * cos(lst);
+ magFieldModelInertial[0] =
+ (magFieldModel[0] * cos(gcLatitude) + magFieldModel[1] * sin(gcLatitude)) * cos(lst) -
+ magFieldModel[2] * sin(lst);
+ magFieldModelInertial[1] =
+ (magFieldModel[0] * cos(gcLatitude) + magFieldModel[1] * sin(gcLatitude)) * sin(lst) +
+ magFieldModel[2] * cos(lst);
+ magFieldModelInertial[2] =
+ magFieldModel[0] * sin(gcLatitude) - magFieldModel[1] * cos(gcLatitude);
double normVecMagFieldInert[3] = {0, 0, 0};
VectorOperations<double>::normalize(magFieldModelInertial, normVecMagFieldInert, 3);
+
+ magFieldModel[0] = 0;
+ magFieldModel[1] = 0;
+ magFieldModel[2] = 0;
}
void Igrf13Model::updateCoeffGH(timeval timeOfMagMeasurement) {
@@ -123,3 +140,50 @@ void Igrf13Model::updateCoeffGH(timeval timeOfMagMeasurement) {
}
}
}
+
+void Igrf13Model::schmidtNormalization() {
+ double kronDelta = 0;
+ schmidtFactors[0][0] = 1;
+ // for (int n = 1; n <= igrfOrder; n++) {
+ // if (n == 1) {
+ // schmidtFactors[0][n - 1] = 1;
+ // } else {
+ // schmidtFactors[0][n - 1] = schmidtFactors[0][n - 2] * (2 * n - 1) / n;
+ // }
+ //
+ // for (int m = 1; m <= igrfOrder; m++) {
+ // if (m == 1) {
+ // kronDelta = 1;
+ // } else {
+ // kronDelta = 0;
+ // }
+ // schmidtFactors[m][n - 1] =
+ // schmidtFactors[m - 1][n - 1] * sqrt((n - m + 1) * (kronDelta + 1) / (n + m));
+ // }
+ // }
+
+ for (int n = 1; n <= igrfOrder; n++) {
+ for (int m = 0; m <= n; m++) {
+ if (m > 1) {
+ schmidtFactors[m][n - 1] = schmidtFactors[m - 1][n - 1] * pow((n - m + 1) / (n + m), .5);
+ } else if (m > 0) {
+ schmidtFactors[m][n - 1] =
+ schmidtFactors[m - 1][n - 1] * pow(2 * (n - m + 1) / (n + m), .5);
+ } else if (n == 1) {
+ schmidtFactors[m][n - 1] = 1;
+ } else {
+ schmidtFactors[m][n - 1] = schmidtFactors[0][n - 2] * (2 * n - 1) / (n);
+ }
+ }
+ }
+
+ for (int i = 0; i <= igrfOrder; i++) {
+ for (int j = 0; j <= (igrfOrder - 1); j++) {
+ coeffG[i][j] = schmidtFactors[i][j] * coeffG[i][j];
+ coeffH[i][j] = schmidtFactors[i][j] * coeffH[i][j];
+
+ svG[i][j] = schmidtFactors[i][j] * svG[i][j];
+ svH[i][j] = schmidtFactors[i][j] * svH[i][j];
+ }
+ }
+}
diff --git a/mission/controller/acs/Igrf13Model.h b/mission/controller/acs/Igrf13Model.h
index aa7e8b73..7abe97cc 100644
--- a/mission/controller/acs/Igrf13Model.h
+++ b/mission/controller/acs/Igrf13Model.h
@@ -43,14 +43,15 @@ class Igrf13Model /*:public HasParametersIF*/ {
* - timeOfMagMeasurement: time of actual measurement [s]
*
* Outputs:
- * - magFieldModelInertial: Magnetic Field Vector in IJK KOS [nT]*/
+ * - magFieldModelInertial: Magnetic Field Vector in IJK RF [nT]*/
// Coefficient wary over year, could be updated sometimes.
void updateCoeffGH(timeval timeOfMagMeasurement); // Secular variation (SV)
double magFieldModel[3];
+ void schmidtNormalization();
private:
- const double coeffG[14][13] = {
+ double coeffG[14][13] = {
{-29404.8, -2499.6, 1363.2, 903.0, -234.3, 66.0, 80.6, 23.7, 5.0, -1.9, 3.0, -2.0, 0.1},
{-1450.9, 2982.0, -2381.2, 809.5, 363.2, 65.5, -76.7, 9.7, 8.4, -6.2, -1.4, -0.1, -0.9},
{0.0, 1677.0, 1236.2, 86.3, 187.8, 72.9, -8.2, -17.6, 2.9, -0.1, -2.5, 0.5, 0.5},
@@ -66,7 +67,7 @@ class Igrf13Model /*:public HasParametersIF*/ {
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -0.3, -0.5},
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -0.4}}; // [m][n] in nT
- const double coeffH[14][13] = {
+ double coeffH[14][13] = {
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0},
{4652.5, -2991.6, -82.1, 281.9, 47.7, -19.1, -51.5, 8.4, -23.4, 3.4, 0.0, -1.2, -0.9},
{0.0, -734.6, 241.9, -158.4, 208.3, 25.1, -16.9, -15.3, 11.0, -0.2, 2.5, 0.5, 0.6},
@@ -82,7 +83,7 @@ class Igrf13Model /*:public HasParametersIF*/ {
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.5, -0.4},
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -0.6}}; // [m][n] in nT
- const double svG[14][13] = {
+ double svG[14][13] = {
{5.7, -11.0, 2.2, -1.2, -0.3, -0.5, -0.1, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
{7.4, -7.0, -5.9, -1.6, 0.5, -0.3, -0.2, 0.1, 0.0, 0.0, 0.0, 0.0, 0.0},
{0.0, -2.1, 3.1, -5.9, -0.6, 0.4, 0.0, -0.1, 0.0, 0.0, 0.0, 0.0, 0.0},
@@ -98,7 +99,7 @@ class Igrf13Model /*:public HasParametersIF*/ {
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}}; // [m][n] in nT
- const double svH[14][13] = {
+ double svH[14][13] = {
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
{-25.9, -30.2, 6.0, -0.1, 0.0, 0.0, 0.6, -0.2, 0.0, 0.0, 0.0, 0.0, 0.0},
{0.0, -22.4, -1.1, 6.5, 2.5, -1.6, 0.6, 0.6, 0.0, 0.0, 0.0, 0.0, 0.0},
@@ -113,6 +114,23 @@ class Igrf13Model /*:public HasParametersIF*/ {
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}}; // [m][n] in nT
+
+ double schmidtFactors[14][13] = {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}};
+ ;
+ bool schmidtNorm = false;
double updatedG[14][13];
double updatedH[14][13];