Satellite Observers Workbench. NOT yet complete, just published for forum posters to \"cherry pick\" pieces of code as requiered as an example.
Diff: sgp4sdp4/solar.c
- Revision:
- 0:0a841b89d614
diff -r 000000000000 -r 0a841b89d614 sgp4sdp4/solar.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/sgp4sdp4/solar.c Mon Oct 11 10:34:55 2010 +0000 @@ -0,0 +1,69 @@ +/* + * Unit Solar + * Author: Dr TS Kelso + * Original Version: 1990 Jul 29 + * Current Revision: 1999 Nov 27 + * Version: 1.30 + * Copyright: 1990-1999, All Rights Reserved + * + * Ported to C by: Neoklis Kyriazis April 1 2001 + */ + +#include "sgp4sdp4.h" + +/* Calculates solar position vector */ +void +Calculate_Solar_Position(double _time, vector_t *solar_vector) +{ + double mjd,year,T,M,L,e,C,O,Lsa,nu,R,eps; + + mjd = _time - 2415020.0; + year = 1900 + mjd/365.25; + T = (mjd + Delta_ET(year)/secday)/36525.0; + M = Radians(Modulus(358.47583 + Modulus(35999.04975*T,360.0) + - (0.000150 + 0.0000033*T)*Sqr(T),360.0)); + L = Radians(Modulus(279.69668 + Modulus(36000.76892*T,360.0) + + 0.0003025*Sqr(T),360.0)); + e = 0.01675104 - (0.0000418 + 0.000000126*T)*T; + C = Radians((1.919460 - (0.004789 + 0.000014*T)*T)*sin(M) + + (0.020094 - 0.000100*T)*sin(2*M) + 0.000293*sin(3*M)); + O = Radians(Modulus(259.18 - 1934.142*T,360.0)); + Lsa = Modulus(L + C - Radians(0.00569 - 0.00479*sin(O)),twopi); + nu = Modulus(M + C,twopi); + R = 1.0000002*(1 - Sqr(e))/(1 + e*cos(nu)); + eps = Radians(23.452294 - (0.0130125 + (0.00000164 - + 0.000000503*T)*T)*T + 0.00256*cos(O)); + R = SGPAU*R; + solar_vector->x = R*cos(Lsa); + solar_vector->y = R*sin(Lsa)*cos(eps); + solar_vector->z = R*sin(Lsa)*sin(eps); + solar_vector->w = R; +} /*Procedure Calculate_Solar_Position*/ + +/*------------------------------------------------------------------*/ + +/* Calculates stellite's eclipse status and depth */ +int +Sat_Eclipsed(vector_t *pos, vector_t *sol, double *depth) +{ + double sd_sun, sd_earth, delta; + vector_t Rho, earth; + + /* Determine partial eclipse */ + sd_earth = ArcSin(xkmper/pos->w); + Vec_Sub(sol,pos,&Rho); + sd_sun = ArcSin(__sr__/Rho.w); + Scalar_Multiply(-1,pos,&earth); + delta = Angle(sol,&earth); + *depth = sd_earth - sd_sun - delta; + if( sd_earth < sd_sun ) + return( 0 ); + else + if( *depth >= 0 ) + return( 1 ); + else + return( 0 ); + +} /*Function Sat_Eclipsed*/ + +/*------------------------------------------------------------------*/