Added SolarPosition class

Eci.cpp

@@ -43,6 +43,11 @@ Eci::Eci(const Julian &date, const CoordGeodetic &geo)
     velocity_.SetW(velocity_.GetMagnitude());
 }
 
+Eci::Eci(const Julian &date, const Vector &position)
+: date_(date), position_(position) {
+
+}
+
 Eci::Eci(const Julian &date, const Vector &position, const Vector &velocity)
 : date_(date), position_(position), velocity_(velocity) {
 

Eci.h

@@ -11,6 +11,7 @@ public:
     Eci() {
     };
     Eci(const Julian &date, const CoordGeodetic &geo);
+    Eci(const Julian &date, const Vector &position);
     Eci(const Julian &date, const Vector &position, const Vector &velocity);
     virtual ~Eci(void);
 

Globals.h

@@ -26,6 +26,10 @@ public:
         return 1.00273790934;
     }
 
+    static const double AU() {
+        return 1.49597870691e8;
+    }
+
     static const double XKMPER() {
         return 6378.135;
     }

Rewrite.vcxproj

@@ -83,6 +83,7 @@
     <ClCompile Include="RunTest.cpp" />
     <ClCompile Include="SatelliteOrbit.cpp" />
     <ClCompile Include="SGP4.cpp" />
+    <ClCompile Include="SolarPosition.cpp" />
     <ClCompile Include="Timespan.cpp" />
     <ClCompile Include="Tle.cpp" />
     <ClCompile Include="Vector.cpp" />
@@ -97,6 +98,7 @@
     <ClInclude Include="SatelliteException.h" />
     <ClInclude Include="SatelliteOrbit.h" />
     <ClInclude Include="SGP4.h" />
+    <ClInclude Include="SolarPosition.h" />
     <ClInclude Include="Timespan.h" />
     <ClInclude Include="Tle.h" />
     <ClInclude Include="Vector.h" />

Rewrite.vcxproj.filters

@@ -51,6 +51,9 @@
     <ClCompile Include="RunTest.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="SolarPosition.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Julian.h">
@@ -89,5 +92,8 @@
     <ClInclude Include="CoordTopographic.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="SolarPosition.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>

SolarPosition.cpp

@@ -0,0 +1,52 @@
+#include "SolarPosition.h"
+
+#include "Globals.h"
+
+#include <cmath>
+
+SolarPosition::SolarPosition(void) {
+}
+
+SolarPosition::~SolarPosition(void) {
+}
+
+void SolarPosition::FindPosition(const Julian& j, Eci& eci) {
+
+    const double mjd = j.FromJan1_12h_1900();
+    const double year = 1900 + mjd / 365.25;
+    const double T = (mjd + Delta_ET(year) / Globals::SEC_PER_DAY()) / 36525.0;
+    const double M = Globals::Deg2Rad(Modulus(358.47583 + Modulus(35999.04975 * T, 360.0)
+            - (0.000150 + 0.0000033 * T) * T * T, 360.0));
+    const double L = Globals::Deg2Rad(Modulus(279.69668 + Modulus(36000.76892 * T, 360.0)
+            + 0.0003025 * T*T, 360.0));
+    const double e = 0.01675104 - (0.0000418 + 0.000000126 * T) * T;
+    const double C = Globals::Deg2Rad((1.919460 - (0.004789 + 0.000014 * T) * T) * sin(M)
+            + (0.020094 - 0.000100 * T) * sin(2 * M) + 0.000293 * sin(3 * M));
+    const double O = Globals::Deg2Rad(Modulus(259.18 - 1934.142 * T, 360.0));
+    const double Lsa = Modulus(L + C - Globals::Deg2Rad(0.00569 - 0.00479 * sin(O)), Globals::TWOPI());
+    const double nu = Modulus(M + C, Globals::TWOPI());
+    double R = 1.0000002 * (1 - e * e) / (1 + e * cos(nu));
+    const double eps = Globals::Deg2Rad(23.452294 - (0.0130125 + (0.00000164 -
+            0.000000503 * T) * T) * T + 0.00256 * cos(O));
+    R = R * Globals::AU();
+
+    Vector solar_position = Vector(R * cos(Lsa),
+            R * sin(Lsa) * cos(eps),
+            R * sin(Lsa) * sin(eps),
+            R);
+
+    eci = Eci(j, solar_position);
+}
+
+double SolarPosition::Modulus(double arg1, double arg2) const {
+
+    double result = arg1 - arg2 * floor(arg1 / arg2);
+    if (result < 0.0)
+        result += arg2;
+    return result;
+}
+
+double SolarPosition::Delta_ET(double year) const {
+
+    return 26.465 + 0.747622 * (year - 1950) + 1.886913 * sin(Globals::TWOPI() * (year - 1975) / 33);
+}

SolarPosition.h

@@ -0,0 +1,19 @@
+#ifndef SOLARPOSITION_H_
+#define SOLARPOSITION_H_
+
+#include "Julian.h"
+#include "Eci.h"
+
+class SolarPosition {
+public:
+    SolarPosition(void);
+    virtual ~SolarPosition(void);
+
+    void FindPosition(const Julian& j, Eci& eci);
+
+private:
+    double Modulus(double arg1, double arg2) const;
+    double Delta_ET(double year) const;
+};
+
+#endif