source: ntrip/trunk/BNC/bnctides.cpp@ 2578

Last change on this file since 2578 was 2578, checked in by mervart, 14 years ago
File size: 5.4 KB
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1
2#include <cmath>
3#include <iostream>
4#include <iomanip>
5
6#include "bnctides.h"
7
8using namespace std;
9
10// Auxiliary Functions
11///////////////////////////////////////////////////////////////////////////
12namespace {
13
14 static const double RHO_DEG = 180.0 / M_PI;
15 static const double RHO_SEC = 3600.0 * RHO_DEG;
16 static const double MJD_J2000 = 51544.5;
17
18 double Frac (double x) { return x-floor(x); };
19 double Modulo (double x, double y) { return y*Frac(x/y); }
20
21 Matrix rotX(double Angle) {
22 const double C = cos(Angle);
23 const double S = sin(Angle);
24 Matrix UU(3,3);
25 UU[0][0] = 1.0; UU[0][1] = 0.0; UU[0][2] = 0.0;
26 UU[1][0] = 0.0; UU[1][1] = +C; UU[1][2] = +S;
27 UU[2][0] = 0.0; UU[2][1] = -S; UU[2][2] = +C;
28 return UU;
29 }
30
31 Matrix rotY(double Angle) {
32 const double C = cos(Angle);
33 const double S = sin(Angle);
34 Matrix UU(3,3);
35 UU[0][0] = +C; UU[0][1] = 0.0; UU[0][2] = -S;
36 UU[1][0] = 0.0; UU[1][1] = 1.0; UU[1][2] = 0.0;
37 UU[2][0] = +S; UU[2][1] = 0.0; UU[2][2] = +C;
38 return UU;
39 }
40
41 Matrix rotZ(double Angle) {
42 const double C = cos(Angle);
43 const double S = sin(Angle);
44 Matrix UU(3,3);
45 UU[0][0] = +C; UU[0][1] = +S; UU[0][2] = 0.0;
46 UU[1][0] = -S; UU[1][1] = +C; UU[1][2] = 0.0;
47 UU[2][0] = 0.0; UU[2][1] = 0.0; UU[2][2] = 1.0;
48 return UU;
49 }
50}
51
52// Greenwich Mean Sidereal Time
53///////////////////////////////////////////////////////////////////////////
54double GMST(double Mjd_UT1) {
55
56 const double Secs = 86400.0;
57
58 double Mjd_0 = floor(Mjd_UT1);
59 double UT1 = Secs*(Mjd_UT1-Mjd_0);
60 double T_0 = (Mjd_0 -MJD_J2000)/36525.0;
61 double T = (Mjd_UT1-MJD_J2000)/36525.0;
62
63 double gmst = 24110.54841 + 8640184.812866*T_0 + 1.002737909350795*UT1
64 + (0.093104-6.2e-6*T)*T*T;
65
66 return 2.0*M_PI*Frac(gmst/Secs);
67}
68
69// Nutation Matrix
70///////////////////////////////////////////////////////////////////////////
71Matrix NutMatrix(double Mjd_TT) {
72
73 const double T = (Mjd_TT-MJD_J2000)/36525.0;
74
75 double ls = 2.0*M_PI*Frac(0.993133+ 99.997306*T);
76 double D = 2.0*M_PI*Frac(0.827362+1236.853087*T);
77 double F = 2.0*M_PI*Frac(0.259089+1342.227826*T);
78 double N = 2.0*M_PI*Frac(0.347346- 5.372447*T);
79
80 double dpsi = ( -17.200*sin(N) - 1.319*sin(2*(F-D+N)) - 0.227*sin(2*(F+N))
81 + 0.206*sin(2*N) + 0.143*sin(ls) ) / RHO_SEC;
82 double deps = ( + 9.203*cos(N) + 0.574*cos(2*(F-D+N)) + 0.098*cos(2*(F+N))
83 - 0.090*cos(2*N) ) / RHO_SEC;
84
85 double eps = 0.4090928-2.2696E-4*T;
86
87 return rotX(-eps-deps)*rotZ(-dpsi)*rotX(+eps);
88}
89
90// Precession Matrix
91///////////////////////////////////////////////////////////////////////////
92Matrix PrecMatrix (double Mjd_1, double Mjd_2) {
93
94 const double T = (Mjd_1-MJD_J2000)/36525.0;
95 const double dT = (Mjd_2-Mjd_1)/36525.0;
96
97 double zeta = ( (2306.2181+(1.39656-0.000139*T)*T)+
98 ((0.30188-0.000344*T)+0.017998*dT)*dT )*dT/RHO_SEC;
99 double z = zeta + ( (0.79280+0.000411*T)+0.000205*dT)*dT*dT/RHO_SEC;
100 double theta = ( (2004.3109-(0.85330+0.000217*T)*T)-
101 ((0.42665+0.000217*T)+0.041833*dT)*dT )*dT/RHO_SEC;
102
103 return rotZ(-z) * rotY(theta) * rotZ(-zeta);
104}
105
106// Sun's position
107///////////////////////////////////////////////////////////////////////////
108ColumnVector Sun(double Mjd_TT) {
109
110 const double eps = 23.43929111/RHO_DEG;
111 const double T = (Mjd_TT-MJD_J2000)/36525.0;
112
113 double M = 2.0*M_PI * Frac ( 0.9931267 + 99.9973583*T);
114 double L = 2.0*M_PI * Frac ( 0.7859444 + M/2.0*M_PI +
115 (6892.0*sin(M)+72.0*sin(2.0*M)) / 1296.0e3);
116 double r = 149.619e9 - 2.499e9*cos(M) - 0.021e9*cos(2*M);
117
118 ColumnVector r_Sun(3);
119 r_Sun << r*cos(L) << r*sin(L) << 0.0; r_Sun = rotX(-eps) * r_Sun;
120
121 return rotZ(GMST(Mjd_TT))
122 * NutMatrix(Mjd_TT)
123 * PrecMatrix(MJD_J2000, Mjd_TT)
124 * r_Sun;
125}
126
127// Moon's position
128///////////////////////////////////////////////////////////////////////////
129ColumnVector Moon(double Mjd_TT) {
130
131 const double eps = 23.43929111/RHO_DEG;
132 const double T = (Mjd_TT-MJD_J2000)/36525.0;
133
134 double L_0 = Frac ( 0.606433 + 1336.851344*T );
135 double l = 2.0*M_PI*Frac ( 0.374897 + 1325.552410*T );
136 double lp = 2.0*M_PI*Frac ( 0.993133 + 99.997361*T );
137 double D = 2.0*M_PI*Frac ( 0.827361 + 1236.853086*T );
138 double F = 2.0*M_PI*Frac ( 0.259086 + 1342.227825*T );
139
140 double dL = +22640*sin(l) - 4586*sin(l-2*D) + 2370*sin(2*D) + 769*sin(2*l)
141 -668*sin(lp) - 412*sin(2*F) - 212*sin(2*l-2*D)- 206*sin(l+lp-2*D)
142 +192*sin(l+2*D) - 165*sin(lp-2*D) - 125*sin(D) - 110*sin(l+lp)
143 +148*sin(l-lp) - 55*sin(2*F-2*D);
144
145 double L = 2.0*M_PI * Frac( L_0 + dL/1296.0e3 );
146
147 double S = F + (dL+412*sin(2*F)+541*sin(lp)) / RHO_SEC;
148 double h = F-2*D;
149 double N = -526*sin(h) + 44*sin(l+h) - 31*sin(-l+h) - 23*sin(lp+h)
150 +11*sin(-lp+h) - 25*sin(-2*l+F) + 21*sin(-l+F);
151
152 double B = ( 18520.0*sin(S) + N ) / RHO_SEC;
153
154 double cosB = cos(B);
155
156 double R = 385000e3 - 20905e3*cos(l) - 3699e3*cos(2*D-l) - 2956e3*cos(2*D)
157 -570e3*cos(2*l) + 246e3*cos(2*l-2*D) - 205e3*cos(lp-2*D)
158 -171e3*cos(l+2*D) - 152e3*cos(l+lp-2*D);
159
160 ColumnVector r_Moon(3);
161 r_Moon << R*cos(L)*cosB << R*sin(L)*cosB << R*sin(B);
162 r_Moon = rotX(-eps) * r_Moon;
163
164 return rotZ(GMST(Mjd_TT))
165 * NutMatrix(Mjd_TT)
166 * PrecMatrix(MJD_J2000, Mjd_TT)
167 * r_Moon;
168}
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