/* -----------------------------------------------------------------------------
*
* procedure days2mdhms
*
* this procedure converts the day of the year, days, to the equivalent month
* day, hour, minute and second.
*
* algorithm : set up array for the number of days per month
* find leap year - use 1900 because 2000 is a leap year
* loop through a temp value while the value is < the days
* perform int conversions to the correct day and month
* convert remainder into h m s using type conversions
*
* author : david vallado 719-573-2600 1 mar 2001
*
* inputs description range / units
* year - year 1900 .. 2100
* days - julian day of the year 0.0 .. 366.0
*
* outputs :
* mon - month 1 .. 12
* day - day 1 .. 28,29,30,31
* hr - hour 0 .. 23
* min - minute 0 .. 59
* sec - second 0.0 .. 59.999
*
* locals :
* dayofyr - day of year
* temp - temporary extended values
* inttemp - temporary int value
* i - index
* lmonth[12] - int array containing the number of days per month
*
* coupling :
* none.
* --------------------------------------------------------------------------- */
public MdhmsResult days2mdhms(int year, float days)
{
MdhmsResult mdhmsResult = new MdhmsResult();
int feb = ((year % 4) == 0 ? 29 : 28); // Account for leap year
int[] lmonth = new int[] { 31, feb, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
double dayofyr = Math.Floor(days);
// ----------------- find month and day of month ----------------
int i = 1;
int inttemp = 0;
while ((dayofyr > (inttemp + lmonth[i - 1])) && i < 12)
{
inttemp += lmonth[i - 1];
i += 1;
}
int mon = i;
double day = dayofyr - inttemp;
// ----------------- find hours minutes and seconds -------------
double temp = (days - dayofyr) * 24.0;
double hr = Math.Floor(temp);
temp = (temp - hr) * 60.0;
double minute = Math.Floor(temp);
double sec = (temp - minute) * 60.0;
// Set params in object and return
mdhmsResult.mon = mon;
mdhmsResult.day = day;
mdhmsResult.hr = hr;
mdhmsResult.minute = minute;
mdhmsResult.sec = sec;
// return {
// mon,
// day,
// hr,
// minute,
// sec,
// };
return(mdhmsResult);
}
public Satrec twoline2satrec(string longstr1, string longstr2)
{
Globals globals = new Globals();
const char opsmode = 'i';
const double xpdotp = 1440.0 / (2.0 * Math.PI); // 229.1831180523293;
int year = 0;
Satrec satrec = new Satrec();
satrec.error = 0;
// satrec.satnum = longstr1.Substring(2, 7); // From satellite.js
satrec.satnum = longstr1.Substring(2, 5); // 5 length
// satrec.epochyr = parseInt(longstr1.substring(18, 20), 10);
satrec.epochyr = Int32.Parse(longstr1.Substring(18, 2));
// satrec.epochdays = parseFloat(longstr1.substring(20, 32));
satrec.epochdays = float.Parse(longstr1.Substring(20, 12));
// satrec.ndot = parseFloat(longstr1.substring(33, 43));
satrec.ndot = double.Parse(longstr1.Substring(33, 10));
// satrec.nddot = parseFloat(
// `.${parseInt(longstr1.substring(44, 50), 10)
// }E${longstr1.substring(50, 52)}`,
// );
// Get the exponetial from the TLE line
string nddot = "." + longstr1.Substring(44, 6).Trim() + "E" + longstr1.Substring(50, 2);
satrec.nddot = double.Parse(nddot);
// satrec.bstar = parseFloat(
// `${longstr1.substring(53, 54)
// }.${parseInt(longstr1.substring(54, 59), 10)
// }E${longstr1.substring(59, 61)}`,
// );
string bstar = longstr1.Substring(53, 1) + "." + longstr1.Substring(54, 5) + "E" + longstr1.Substring(59, 2);
satrec.bstar = double.Parse(bstar);
// satrec.inclo = parseFloat(longstr2.substring(8, 16));
satrec.inclo = double.Parse(longstr2.Substring(8, 8));
// satrec.nodeo = parseFloat(longstr2.substring(17, 25));
satrec.nodeo = double.Parse(longstr2.Substring(17, 8));
// satrec.ecco = parseFloat(`.${longstr2.substring(26, 33)}`);
string ecco = "." + longstr2.Substring(26, 7);
satrec.ecco = double.Parse(ecco);
// satrec.argpo = parseFloat(longstr2.substring(34, 42));
satrec.argpo = double.Parse(longstr2.Substring(34, 8));
// satrec.mo = parseFloat(longstr2.substring(43, 51));
satrec.mo = double.Parse(longstr2.Substring(43, 8));
// satrec.no = parseFloat(longstr2.substring(52, 63));
satrec.no = double.Parse(longstr2.Substring(52, 11));
// ---- find no, ndot, nddot ----
satrec.no /= xpdotp; // rad/min
// satrec.nddot= satrec.nddot * Math.pow(10.0, nexp);
// satrec.bstar= satrec.bstar * Math.pow(10.0, ibexp);
// ---- convert to sgp4 units ----
// satrec.a = ((satrec.no * tumin) ** (-2.0 / 3.0));
satrec.a = Math.Pow((satrec.no * globals.tumin), (-2.0 / 3.0));
satrec.ndot /= (xpdotp * 1440.0); // ? * minperday
satrec.nddot /= (xpdotp * 1440.0 * 1440);
// ---- find standard orbital elements ----
satrec.inclo *= globals.deg2rad;
satrec.nodeo *= globals.deg2rad;
satrec.argpo *= globals.deg2rad;
satrec.mo *= globals.deg2rad;
satrec.alta = (satrec.a * (1.0 + satrec.ecco)) - 1.0;
satrec.altp = (satrec.a * (1.0 - satrec.ecco)) - 1.0;
// ----------------------------------------------------------------
// find sgp4epoch time of element set
// remember that sgp4 uses units of days from 0 jan 1950 (sgp4epoch)
// and minutes from the epoch (time)
// ----------------------------------------------------------------
// ---------------- temp fix for years from 1957-2056 -------------------
// --------- correct fix will occur when year is 4-digit in tle ---------
if (satrec.epochyr < 57)
{
year = satrec.epochyr + 2000;
}
else
{
year = satrec.epochyr + 1900;
}
// const mdhmsResult = days2mdhms(year, satrec.epochdays);
Ext ext = new Ext();
MdhmsResult mdhmsResult = ext.days2mdhms(year, satrec.epochdays);
satrec.jdsatepoch = ext.jday(year, mdhmsResult.mon, mdhmsResult.day, mdhmsResult.hr, mdhmsResult.minute, mdhmsResult.sec);
// ---------------- initialize the orbit at sgp4epoch -------------------
// sgp4init(satrec, {
// opsmode,
// satn: satrec.satnum,
// epoch: satrec.jdsatepoch - 2433281.5,
// xbstar: satrec.bstar,
// xecco: satrec.ecco,
// xargpo: satrec.argpo,
// xinclo: satrec.inclo,
// xmo: satrec.mo,
// xno: satrec.no,
// xnodeo: satrec.nodeo,
// });
Sgp4initOptions sgp4initOptions = new Sgp4initOptions();
sgp4initOptions.opsmode = opsmode;
sgp4initOptions.satn = satrec.satnum;
sgp4initOptions.epoch = satrec.jdsatepoch - 2433281.5;
sgp4initOptions.xbstar = satrec.bstar;
sgp4initOptions.xecco = satrec.ecco;
sgp4initOptions.xargpo = satrec.argpo;
sgp4initOptions.xinclo = satrec.inclo;
sgp4initOptions.xmo = satrec.mo;
sgp4initOptions.xno = satrec.no;
sgp4initOptions.xnodeo = satrec.nodeo;
Sgp4init sgp4init = new Sgp4init();
sgp4init.sgp4init(satrec, sgp4initOptions);
return(satrec);
}