226 lines
4.4 KiB
C
226 lines
4.4 KiB
C
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <math.h>
|
|
#include "sgdp4h.h"
|
|
#include "satutl.h"
|
|
#include "cpgplot.h"
|
|
|
|
#define LIM 80
|
|
#define D2R M_PI/180.0
|
|
#define R2D 180.0/M_PI
|
|
#define XKMPER 6378.135 // Earth radius in km
|
|
#define XKMPAU 149597879.691 // AU in km
|
|
#define FLAT (1.0/298.257)
|
|
#define C 299792.458 // Speed of light in km/s
|
|
|
|
struct point {
|
|
xyz_t obspos,obsvel;
|
|
};
|
|
struct site {
|
|
int id;
|
|
double lng,lat;
|
|
float alt;
|
|
char observer[64];
|
|
};
|
|
|
|
// Return x modulo y [0,y)
|
|
double modulo(double x,double y)
|
|
{
|
|
x=fmod(x,y);
|
|
if (x<0.0) x+=y;
|
|
|
|
return x;
|
|
}
|
|
|
|
// Read a line of maximum length int lim from file FILE into string s
|
|
int fgetline(FILE *file,char *s,int lim)
|
|
{
|
|
int c,i=0;
|
|
|
|
while (--lim > 0 && (c=fgetc(file)) != EOF && c != '\n')
|
|
s[i++] = c;
|
|
// if (c == '\n')
|
|
// s[i++] = c;
|
|
s[i] = '\0';
|
|
return i;
|
|
}
|
|
|
|
// Greenwich Mean Sidereal Time
|
|
double gmst(double mjd)
|
|
{
|
|
double t,gmst;
|
|
|
|
t=(mjd-51544.5)/36525.0;
|
|
|
|
gmst=modulo(280.46061837+360.98564736629*(mjd-51544.5)+t*t*(0.000387933-t/38710000),360.0);
|
|
|
|
return gmst;
|
|
}
|
|
|
|
// Greenwich Mean Sidereal Time
|
|
double dgmst(double mjd)
|
|
{
|
|
double t,dgmst;
|
|
|
|
t=(mjd-51544.5)/36525.0;
|
|
|
|
dgmst=360.98564736629+t*(0.000387933-t/38710000);
|
|
|
|
return dgmst;
|
|
}
|
|
|
|
// Observer position
|
|
void obspos_xyz(double mjd,double lng,double lat,float alt,xyz_t *pos,xyz_t *vel)
|
|
{
|
|
double ff,gc,gs,theta,s,dtheta;
|
|
|
|
s=sin(lat*D2R);
|
|
ff=sqrt(1.0-FLAT*(2.0-FLAT)*s*s);
|
|
gc=1.0/ff+alt/XKMPER;
|
|
gs=(1.0-FLAT)*(1.0-FLAT)/ff+alt/XKMPER;
|
|
|
|
theta=gmst(mjd)+lng;
|
|
dtheta=dgmst(mjd)*D2R/86400;
|
|
|
|
pos->x=gc*cos(lat*D2R)*cos(theta*D2R)*XKMPER;
|
|
pos->y=gc*cos(lat*D2R)*sin(theta*D2R)*XKMPER;
|
|
pos->z=gs*sin(lat*D2R)*XKMPER;
|
|
vel->x=-gc*cos(lat*D2R)*sin(theta*D2R)*XKMPER*dtheta;
|
|
vel->y=gc*cos(lat*D2R)*cos(theta*D2R)*XKMPER*dtheta;
|
|
vel->z=0.0;
|
|
|
|
return;
|
|
}
|
|
|
|
// Get observing site
|
|
struct site get_site(int site_id)
|
|
{
|
|
int i=0;
|
|
char line[LIM];
|
|
FILE *file;
|
|
int id;
|
|
double lat,lng;
|
|
float alt;
|
|
char abbrev[3],observer[64];
|
|
struct site s;
|
|
char *env,filename[LIM];
|
|
|
|
env=getenv("ST_DATADIR");
|
|
sprintf(filename,"%s/data/sites.txt",env);
|
|
|
|
file=fopen(filename,"r");
|
|
if (file==NULL) {
|
|
printf("File with site information not found!\n");
|
|
return;
|
|
}
|
|
while (fgets(line,LIM,file)!=NULL) {
|
|
// Skip
|
|
if (strstr(line,"#")!=NULL)
|
|
continue;
|
|
|
|
// Strip newline
|
|
line[strlen(line)-1]='\0';
|
|
|
|
// Read data
|
|
sscanf(line,"%4d %2s %lf %lf %f",
|
|
&id,abbrev,&lat,&lng,&alt);
|
|
strcpy(observer,line+38);
|
|
|
|
// Change to km
|
|
alt/=1000.0;
|
|
|
|
// Copy site
|
|
if (id==site_id) {
|
|
s.lat=lat;
|
|
s.lng=lng;
|
|
s.alt=alt;
|
|
s.id=id;
|
|
strcpy(s.observer,observer);
|
|
}
|
|
|
|
}
|
|
fclose(file);
|
|
|
|
return s;
|
|
}
|
|
|
|
// Plot overlay
|
|
void overlay(double *mjd,int n,int site_id)
|
|
{
|
|
int i,imode,flag,satno,tflag;
|
|
struct point *p;
|
|
struct site s;
|
|
FILE *file,*infile;
|
|
orbit_t orb;
|
|
xyz_t satpos,satvel;
|
|
double dx,dy,dz,dvx,dvy,dvz,r,v,za;
|
|
double freq,freq0;
|
|
char line[LIM],text[8];
|
|
|
|
// Get site
|
|
s=get_site(site_id);
|
|
|
|
// Allocate
|
|
p=(struct point *) malloc(sizeof(struct point)*n);
|
|
|
|
// Get observer position
|
|
for (i=0;i<n;i++)
|
|
obspos_xyz(mjd[i],s.lng,s.lat,s.alt,&p[i].obspos,&p[i].obsvel);
|
|
|
|
infile=fopen("frequencies.txt","r");
|
|
while (fgetline(infile,line,LIM)>0) {
|
|
sscanf(line,"%d %lf",&satno,&freq0);
|
|
sprintf(text," %d",satno);
|
|
// Loop over TLEs
|
|
file=fopen("/home/bassa/code/c/satellite/sattools/tle/bulk.tle","r");
|
|
while (read_twoline(file,satno,&orb)==0) {
|
|
// Initialize
|
|
imode=init_sgdp4(&orb);
|
|
if (imode==SGDP4_ERROR)
|
|
printf("Error\n");
|
|
|
|
// Loop over points
|
|
for (i=0,flag=0,tflag=0;i<n;i++) {
|
|
// Get satellite position
|
|
satpos_xyz(mjd[i]+2400000.5,&satpos,&satvel);
|
|
|
|
dx=satpos.x-p[i].obspos.x;
|
|
dy=satpos.y-p[i].obspos.y;
|
|
dz=satpos.z-p[i].obspos.z;
|
|
dvx=satvel.x-p[i].obsvel.x;
|
|
dvy=satvel.y-p[i].obsvel.y;
|
|
dvz=satvel.z-p[i].obsvel.z;
|
|
r=sqrt(dx*dx+dy*dy+dz*dz);
|
|
v=(dvx*dx+dvy*dy+dvz*dz)/r;
|
|
za=acos((p[i].obspos.x*dx+p[i].obspos.y*dy+p[i].obspos.z*dz)/(r*XKMPER))*R2D;
|
|
|
|
freq=(1.0-v/C)*freq0;
|
|
|
|
if (flag==0) {
|
|
cpgmove((float) i,(float) freq);
|
|
flag=1;
|
|
} else {
|
|
cpgdraw((float) i,(float) freq);
|
|
}
|
|
|
|
if (za<90.0 && flag==0) {
|
|
flag=1;
|
|
} else if (za>90.0 && flag==1) {
|
|
if (tflag==0) {
|
|
tflag=1;
|
|
cpgtext((float) i,(float) freq,text);
|
|
}
|
|
flag=0;
|
|
}
|
|
}
|
|
}
|
|
fclose(file);
|
|
}
|
|
fclose(infile);
|
|
|
|
// Free
|
|
free(p);
|
|
|
|
return;
|
|
}
|