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Updated SolarPosition

feature/19
Daniel Warner 2011-12-14 11:11:42 +00:00
parent b39bef0611
commit 5f1583a6fc
3 changed files with 36 additions and 27 deletions
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1
Makefile
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@ -16,6 +16,7 @@ SOURCES=Eci.cpp \
Observer.cpp \ Observer.cpp \
OrbitalElements.cpp \ OrbitalElements.cpp \
SGP4.cpp \ SGP4.cpp \
SolarPosition.cpp \
Timespan.cpp \ Timespan.cpp \
Tle.cpp Tle.cpp
OBJECTS=$(SOURCES:.cpp=.o) OBJECTS=$(SOURCES:.cpp=.o)

48
SolarPosition.cpp
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@ -4,30 +4,29 @@
#include <cmath> #include <cmath>
SolarPosition::SolarPosition(void) { Eci SolarPosition::FindPosition(const Julian& j)
} {
SolarPosition::~SolarPosition(void) {
}
void SolarPosition::FindPosition(const Julian& j, Eci& eci) {
const double mjd = j.FromJan1_12h_1900(); const double mjd = j.FromJan1_12h_1900();
const double year = 1900 + mjd / 365.25; const double year = 1900 + mjd / 365.25;
const double T = (mjd + Delta_ET(year) / kSECONDS_PER_DAY) / 36525.0; const double T = (mjd + Delta_ET(year) / kSECONDS_PER_DAY) / 36525.0;
const double M = DegreesToRadians(Modulus(358.47583 + Modulus(35999.04975 * T, 360.0) const double M = DegreesToRadians(Modulus(358.47583
- (0.000150 + 0.0000033 * T) * T * T, 360.0)); + Modulus(35999.04975 * T, 360.0)
const double L = DegreesToRadians(Modulus(279.69668 + Modulus(36000.76892 * T, 360.0) - (0.000150 + 0.0000033 * T) * T * T, 360.0));
+ 0.0003025 * T*T, 360.0)); const double L = DegreesToRadians(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 e = 0.01675104 - (0.0000418 + 0.000000126 * T) * T;
const double C = DegreesToRadians((1.919460 - (0.004789 + 0.000014 * T) * T) * sin(M) const double C = DegreesToRadians((1.919460
+ (0.020094 - 0.000100 * T) * sin(2 * M) + 0.000293 * sin(3 * M)); - (0.004789 + 0.000014 * T) * T) * sin(M)
+ (0.020094 - 0.000100 * T) * sin(2 * M)
+ 0.000293 * sin(3 * M));
const double O = DegreesToRadians(Modulus(259.18 - 1934.142 * T, 360.0)); const double O = DegreesToRadians(Modulus(259.18 - 1934.142 * T, 360.0));
const double Lsa = Modulus(L + C - DegreesToRadians(0.00569 - 0.00479 * sin(O)), kTWOPI); const double Lsa = Modulus(L + C
- DegreesToRadians(0.00569 - 0.00479 * sin(O)), kTWOPI);
const double nu = Modulus(M + C, kTWOPI); const double nu = Modulus(M + C, kTWOPI);
double R = 1.0000002 * (1 - e * e) / (1 + e * cos(nu)); double R = 1.0000002 * (1 - e * e) / (1 + e * cos(nu));
const double eps = DegreesToRadians(23.452294 - (0.0130125 + (0.00000164 - const double eps = DegreesToRadians(23.452294 - (0.0130125
0.000000503 * T) * T) * T + 0.00256 * cos(O)); + (0.00000164 - 0.000000503 * T) * T) * T + 0.00256 * cos(O));
R = R * kAU; R = R * kAU;
Vector solar_position = Vector(R * cos(Lsa), Vector solar_position = Vector(R * cos(Lsa),
@ -35,18 +34,21 @@ void SolarPosition::FindPosition(const Julian& j, Eci& eci) {
R * sin(Lsa) * sin(eps), R * sin(Lsa) * sin(eps),
R); R);
eci = Eci(j, solar_position); return Eci(j, solar_position);
} }
double SolarPosition::Modulus(double arg1, double arg2) const { double SolarPosition::Modulus(double arg1, double arg2) const
{
double result = arg1 - arg2 * floor(arg1 / arg2); double result = arg1 - arg2 * floor(arg1 / arg2);
if (result < 0.0) if (result < 0.0)
{
result += arg2; result += arg2;
}
return result; return result;
} }
double SolarPosition::Delta_ET(double year) const { double SolarPosition::Delta_ET(double year) const
{
return 26.465 + 0.747622 * (year - 1950) + 1.886913 * sin(kTWOPI * (year - 1975) / 33); return 26.465 + 0.747622 * (year - 1950) + 1.886913
* sin(kTWOPI * (year - 1975) / 33);
} }

14
SolarPosition.h
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@ -4,12 +4,18 @@
#include "Julian.h" #include "Julian.h"
#include "Eci.h" #include "Eci.h"
class SolarPosition { class SolarPosition
{
public: public:
SolarPosition(void); SolarPosition()
virtual ~SolarPosition(void); {
}
void FindPosition(const Julian& j, Eci& eci); virtual ~SolarPosition()
{
}
Eci FindPosition(const Julian& j);
private: private:
double Modulus(double arg1, double arg2) const; double Modulus(double arg1, double arg2) const;