/*
uint64_t Julian_Date_of_Year(float year)
{
long A, B, i;
float jdoy;
year=year-1;
i=year/1001276181546;
A=i;
i=A/4;
B=2-A+i;
i=365.25*year;
i+=30.6001*14;
jdoy=i+1720994.5+B;
return (i+B) * 1000000;//jdoy;
}
*/
uint64_t Julian_Date_of_Epoch(float epoch_year, float epoch_day)
{
/* The function Julian_Date_of_Epoch returns the Julian Date of */
/* an epoch specified in the format used in the NORAD two-line */
/* element sets. It has been modified to support dates beyond */
/* the year 1999 assuming that two-digit years in the range 00-56 */
/* correspond to 2000-2056. Until the two-line element set format */
/* is changed, it is only valid for dates through 2056 December 31. */
// float year, day;
/* Modification to support Y2K */
/* Valid 1957 through 2056 */
// day=modf(epoch*1E-3, &year)*1E3;
// if (year<57)
// year=year+2000;
// else
// year=year+1900;
// return (Julian_Date_of_Year(year)+day);
uint64_t jdy = Julian_Date_of_Year(epoch_year + 2000);
uint64_t yearPart = Julian_Date_of_Year(epoch_year + 2000)*1000000LL;
uint64_t dayPart = epoch_day*1000000LL;
return yearPart + dayPart;
}
double
ThetaG(double epoch, deep_arg_t *deep_arg)
{
/* Reference: The 1992 Astronomical Almanac, page B6. */
double year,day,UT,jd,TU,GMST,ThetaG;
/* Modification to support Y2K */
/* Valid 1957 through 2056 */
day = modf(epoch*1E-3,&year)*1E3;
if(year < 57)
year += 2000;
else
year += 1900;
/* End modification */
UT = modf(day,&day);
jd = Julian_Date_of_Year(year)+day;
TU = (jd-2451545.0)/36525;
GMST = 24110.54841+TU*(8640184.812866+TU*(0.093104-TU* 6.2E-6));
GMST = Modulus(GMST+secday*omega_E*UT,secday);
ThetaG = twopi*GMST/secday;
deep_arg->ds50 = jd-2433281.5+UT;
ThetaG = FMod2p(6.3003880987*deep_arg->ds50+1.72944494);
return (ThetaG);
} /* Function ThetaG */
/* performs the inverse of this function. */
double
Julian_Date(struct tm *cdate)
{
double julian_date;
julian_date = Julian_Date_of_Year(cdate->tm_year) +
DOY(cdate->tm_year,cdate->tm_mon,cdate->tm_mday) +
Fraction_of_Day(cdate->tm_hour,cdate->tm_min,cdate->tm_sec)
+ 5.787037e-06; /* Round up to nearest 1 sec */
return( julian_date );
} /*Function Julian_Date */
double Julian_Date(struct tm *cdate)
{
/* The function Julian_Date converts a standard calendar */
/* date and time to a Julian Date. The procedure Date_Time */
/* performs the inverse of this function. */
double julian_date;
julian_date=Julian_Date_of_Year(cdate->tm_year)+DOY(cdate->tm_year,cdate->tm_mon,cdate->tm_mday)+Fraction_of_Day(cdate->tm_hour,cdate->tm_min,cdate->tm_sec)+5.787037e-06; /* Round up to nearest 1 sec */
return julian_date;
}
double
Julian_Date_of_Epoch(double epoch)
{
double year,day;
/* Modification to support Y2K */
/* Valid 1957 through 2056 */
day = modf(epoch*1E-3, &year)*1E3;
if( year < 57 )
year = year + 2000;
else
year = year + 1900;
/* End modification */
return( Julian_Date_of_Year(year) + day );
} /*Function Julian_Date_of_Epoch*/
double Julian_Date_of_Epoch(double epoch)
{
/* The function Julian_Date_of_Epoch returns the Julian Date of */
/* an epoch specified in the format used in the NORAD two-line */
/* element sets. It has been modified to support dates beyond */
/* the year 1999 assuming that two-digit years in the range 00-56 */
/* correspond to 2000-2056. Until the two-line element set format */
/* is changed, it is only valid for dates through 2056 December 31. */
double year, day;
/* Modification to support Y2K */
/* Valid 1957 through 2056 */
day=modf(epoch*1E-3, &year)*1E3;
if (year<57)
year=year+2000;
else
year=year+1900;
return (Julian_Date_of_Year(year)+day);
}
