/*-----------------------------------------------------------------------------
*
* procedure sgp4init
*
* this procedure initializes variables for sgp4.
*
* author : david vallado 719-573-2600 28 jun 2005
* author : david vallado 719-573-2600 28 jun 2005
*
* inputs :
* opsmode - mode of operation afspc or improved 'a', 'i'
* satn - satellite number
* bstar - sgp4 type drag coefficient kg/m2er
* ecco - eccentricity
* epoch - epoch time in days from jan 0, 1950. 0 hr
* argpo - argument of perigee (output if ds)
* inclo - inclination
* mo - mean anomaly (output if ds)
* no - mean motion
* nodeo - right ascension of ascending node
*
* outputs :
* rec - common values for subsequent calls
* return code - non-zero on error.
* 1 - mean elements, ecc >= 1.0 or ecc < -0.001 or a < 0.95 er
* 2 - mean motion less than 0.0
* 3 - pert elements, ecc < 0.0 or ecc > 1.0
* 4 - semi-latus rectum < 0.0
* 5 - epoch elements are sub-orbital
* 6 - satellite has decayed
*
* locals :
* cnodm , snodm , cosim , sinim , cosomm , sinomm
* cc1sq , cc2 , cc3
* coef , coef1
* cosio4 -
* day -
* dndt -
* em - eccentricity
* emsq - eccentricity squared
* eeta -
* etasq -
* gam -
* argpm - argument of perigee
* nodem -
* inclm - inclination
* mm - mean anomaly
* nm - mean motion
* perige - perigee
* pinvsq -
* psisq -
* qzms24 -
* rtemsq -
* s1, s2, s3, s4, s5, s6, s7 -
* sfour -
* ss1, ss2, ss3, ss4, ss5, ss6, ss7 -
* sz1, sz2, sz3
* sz11, sz12, sz13, sz21, sz22, sz23, sz31, sz32, sz33 -
* tc -
* temp -
* temp1, temp2, temp3 -
* tsi -
* xpidot -
* xhdot1 -
* z1, z2, z3 -
* z11, z12, z13, z21, z22, z23, z31, z32, z33 -
*
* coupling :
* getgravconst-
* initl -
* dscom -
* dpper -
* dsinit -
* sgp4 -
*
* references :
* hoots, roehrich, norad spacetrack report #3 1980
* hoots, norad spacetrack report #6 1986
* hoots, schumacher and glover 2004
* vallado, crawford, hujsak, kelso 2006
* ----------------------------------------------------------------------------*/
public void sgp4init(Satrec satrec, Sgp4initOptions options)
{
Globals globals = new Globals();
double pi = globals.pi;
double earthRadius = globals.earthRadius;
double j2 = globals.j2;
double j4 = globals.j4;
double j3oj2 = globals.j3oj2;
double x2o3 = globals.x2o3;
char opsmode = options.opsmode;
string satn = options.satn;
double epoch = options.epoch;
double xbstar = options.xbstar;
double xecco = options.xecco;
double xargpo = options.xargpo;
double xinclo = options.xinclo;
double xmo = options.xmo;
double xno = options.xno;
double xnodeo = options.xnodeo;
double cosim;
double sinim;
double cc1sq;
double cc2;
double cc3;
double coef;
double coef1;
double cosio4;
double em;
double emsq;
double eeta;
double etasq;
double argpm;
double nodem;
double inclm;
double mm;
double nm;
double perige;
double pinvsq;
double psisq;
double qzms24;
double s1;
double s2;
double s3;
double s4;
double s5;
double sfour;
double ss1;
double ss2;
double ss3;
double ss4;
double ss5;
double sz1;
double sz3;
double sz11;
double sz13;
double sz21;
double sz23;
double sz31;
double sz33;
double tc;
double temp;
double temp1;
double temp2;
double temp3;
double tsi;
double xpidot;
double xhdot1;
double z1;
double z3;
double z11;
double z13;
double z21;
double z23;
double z31;
double z33;
/* ------------------------ initialization --------------------- */
// sgp4fix divisor for divide by zero check on inclination
// the old check used 1.0 + Math.cos(pi-1.0e-9), but then compared it to
// 1.5 e-12, so the threshold was changed to 1.5e-12 for consistency
double temp4 = 1.5e-12;
// ----------- set all near earth variables to zero ------------
satrec.isimp = 0; satrec.method = 'n'; satrec.aycof = 0.0;
satrec.con41 = 0.0; satrec.cc1 = 0.0; satrec.cc4 = 0.0;
satrec.cc5 = 0.0; satrec.d2 = 0.0; satrec.d3 = 0.0;
satrec.d4 = 0.0; satrec.delmo = 0.0; satrec.eta = 0.0;
satrec.argpdot = 0.0; satrec.omgcof = 0.0; satrec.sinmao = 0.0;
satrec.t = 0.0; satrec.t2cof = 0.0; satrec.t3cof = 0.0;
satrec.t4cof = 0.0; satrec.t5cof = 0.0; satrec.x1mth2 = 0.0;
satrec.x7thm1 = 0.0; satrec.mdot = 0.0; satrec.nodedot = 0.0;
satrec.xlcof = 0.0; satrec.xmcof = 0.0; satrec.nodecf = 0.0;
// ----------- set all deep space variables to zero ------------
satrec.irez = 0; satrec.d2201 = 0.0; satrec.d2211 = 0.0;
satrec.d3210 = 0.0; satrec.d3222 = 0.0; satrec.d4410 = 0.0;
satrec.d4422 = 0.0; satrec.d5220 = 0.0; satrec.d5232 = 0.0;
satrec.d5421 = 0.0; satrec.d5433 = 0.0; satrec.dedt = 0.0;
satrec.del1 = 0.0; satrec.del2 = 0.0; satrec.del3 = 0.0;
satrec.didt = 0.0; satrec.dmdt = 0.0; satrec.dnodt = 0.0;
satrec.domdt = 0.0; satrec.e3 = 0.0; satrec.ee2 = 0.0;
satrec.peo = 0.0; satrec.pgho = 0.0; satrec.pho = 0.0;
satrec.pinco = 0.0; satrec.plo = 0.0; satrec.se2 = 0.0;
satrec.se3 = 0.0; satrec.sgh2 = 0.0; satrec.sgh3 = 0.0;
satrec.sgh4 = 0.0; satrec.sh2 = 0.0; satrec.sh3 = 0.0;
satrec.si2 = 0.0; satrec.si3 = 0.0; satrec.sl2 = 0.0;
satrec.sl3 = 0.0; satrec.sl4 = 0.0; satrec.gsto = 0.0;
satrec.xfact = 0.0; satrec.xgh2 = 0.0; satrec.xgh3 = 0.0;
satrec.xgh4 = 0.0; satrec.xh2 = 0.0; satrec.xh3 = 0.0;
satrec.xi2 = 0.0; satrec.xi3 = 0.0; satrec.xl2 = 0.0;
satrec.xl3 = 0.0; satrec.xl4 = 0.0; satrec.xlamo = 0.0;
satrec.zmol = 0.0; satrec.zmos = 0.0; satrec.atime = 0.0;
satrec.xli = 0.0; satrec.xni = 0.0;
// sgp4fix - note the following variables are also passed directly via satrec.
// it is possible to streamline the sgp4init call by deleting the "x"
// variables, but the user would need to set the satrec.* values first. we
// include the additional assignments in case twoline2rv is not used.
satrec.bstar = xbstar;
satrec.ecco = xecco;
satrec.argpo = xargpo;
satrec.inclo = xinclo;
satrec.mo = xmo;
satrec.no = xno;
satrec.nodeo = xnodeo;
// sgp4fix add opsmode
satrec.operationmode = opsmode;
// ------------------------ earth constants -----------------------
// sgp4fix identify constants and allow alternate values
double ss = (78.0 / earthRadius) + 1.0;
// sgp4fix use multiply for speed instead of pow
double qzms2ttemp = (120.0 - 78.0) / earthRadius;
double qzms2t = qzms2ttemp * qzms2ttemp * qzms2ttemp * qzms2ttemp;
satrec.init = 'y';
satrec.t = 0.0;
InitlOptions initlOptions = new InitlOptions();
initlOptions.satn = satn;
initlOptions.ecco = satrec.ecco;
initlOptions.epoch = epoch;
initlOptions.inlco = satrec.inclo;
initlOptions.no = satrec.no;
initlOptions.method = satrec.method;
initlOptions.opsmode = satrec.operationmode;
Initl initl = new Initl();
InitlResult initlResult = new InitlResult();
initlResult = initl.initl(initlOptions); //TODO: Finish impl
double ao = initlResult.ao;
double con42 = initlResult.con42;
double cosio = initlResult.cosio;
double cosio2 = initlResult.cosio2;
double eccsq = initlResult.eccsq;
double omeosq = initlResult.omeosq;
double posq = initlResult.posq;
double rp = initlResult.rp;
double rteosq = initlResult.rteosq;
double sinio = initlResult.sinio;
satrec.no = initlResult.no;
satrec.con41 = initlResult.con41;
satrec.gsto = initlResult.gsto;
satrec.error = 0;
// sgp4fix remove this check as it is unnecessary
// the mrt check in sgp4 handles decaying satellite cases even if the starting
// condition is below the surface of te earth
// if (rp < 1.0)
// {
// printf("// *** satn%d epoch elts sub-orbital ***\n", satn);
// satrec.error = 5;
// }
if (omeosq >= 0.0 || satrec.no >= 0.0)
{
satrec.isimp = 0;
if (rp < (220.0 / earthRadius + 1.0))
{
satrec.isimp = 1;
}
sfour = ss;
qzms24 = qzms2t;
perige = (rp - 1.0) * earthRadius;
// - for perigees below 156 km, s and qoms2t are altered -
if (perige < 156.0)
{
sfour = perige - 78.0;
if (perige < 98.0)
{
sfour = 20.0;
}
// sgp4fix use multiply for speed instead of pow
double qzms24temp = (120.0 - sfour) / earthRadius;
qzms24 = qzms24temp * qzms24temp * qzms24temp * qzms24temp;
sfour = (sfour / earthRadius) + 1.0;
}
pinvsq = 1.0 / posq;
tsi = 1.0 / (ao - sfour);
satrec.eta = ao * satrec.ecco * tsi;
etasq = satrec.eta * satrec.eta;
eeta = satrec.ecco * satrec.eta;
psisq = Math.Abs(1.0 - etasq);
coef = qzms24 * Math.Pow(tsi, 4.0);
coef1 = coef / (Math.Pow(psisq, 3.5));
cc2 = coef1 * satrec.no * ((ao * (1.0 + (1.5 * etasq) + (eeta * (4.0 + etasq))))
+ (((0.375 * j2 * tsi) / psisq) * satrec.con41
* (8.0 + (3.0 * etasq * (8.0 + etasq)))));
satrec.cc1 = satrec.bstar * cc2;
cc3 = 0.0;
if (satrec.ecco > 1.0e-4)
{
cc3 = (-2.0 * coef * tsi * j3oj2 * satrec.no * sinio) / satrec.ecco;
}
satrec.x1mth2 = 1.0 - cosio2;
satrec.cc4 = 2.0 * satrec.no * coef1 * ao * omeosq * (
((satrec.eta * (2.0 + (0.5 * etasq)))
+ (satrec.ecco * (0.5 + (2.0 * etasq))))
- (((j2 * tsi) / (ao * psisq))
* ((-3.0 * satrec.con41 * ((1.0 - (2.0 * eeta)) + (etasq * (1.5 - (0.5 * eeta)))))
+ (0.75 * satrec.x1mth2
* ((2.0 * etasq) - (eeta * (1.0 + etasq)))
* Math.Cos(2.0 * satrec.argpo))))
);
satrec.cc5 = 2.0 * coef1 * ao * omeosq * (1.0 + (2.75 * (etasq + eeta)) + (eeta * etasq));
cosio4 = cosio2 * cosio2;
temp1 = 1.5 * j2 * pinvsq * satrec.no;
temp2 = 0.5 * temp1 * j2 * pinvsq;
temp3 = -0.46875 * j4 * pinvsq * pinvsq * satrec.no;
satrec.mdot = satrec.no + (0.5 * temp1 * rteosq * satrec.con41)
+ (0.0625 * temp2 * rteosq * ((13.0 - (78.0 * cosio2)) + (137.0 * cosio4)));
satrec.argpdot = (-0.5 * temp1 * con42)
+ (0.0625 * temp2 * ((7.0 - (114.0 * cosio2)) + (395.0 * cosio4)))
+ (temp3 * ((3.0 - (36.0 * cosio2)) + (49.0 * cosio4)));
xhdot1 = -temp1 * cosio;
satrec.nodedot = xhdot1 + (((0.5 * temp2 * (4.0 - (19.0 * cosio2)))
+ (2.0 * temp3 * (3.0 - (7.0 * cosio2)))) * cosio);
xpidot = satrec.argpdot + satrec.nodedot;
satrec.omgcof = satrec.bstar * cc3 * Math.Cos(satrec.argpo);
satrec.xmcof = 0.0;
if (satrec.ecco > 1.0e-4)
{
satrec.xmcof = (-x2o3 * coef * satrec.bstar) / eeta;
}
satrec.nodecf = 3.5 * omeosq * xhdot1 * satrec.cc1;
satrec.t2cof = 1.5 * satrec.cc1;
// sgp4fix for divide by zero with xinco = 180 deg
if (Math.Abs(cosio + 1.0) > 1.5e-12)
{
satrec.xlcof = (-0.25 * j3oj2 * sinio * (3.0 + (5.0 * cosio))) / (1.0 + cosio);
}
else
{
satrec.xlcof = (-0.25 * j3oj2 * sinio * (3.0 + (5.0 * cosio))) / temp4;
}
satrec.aycof = -0.5 * j3oj2 * sinio;
// sgp4fix use multiply for speed instead of pow
double delmotemp = 1.0 + (satrec.eta * Math.Cos(satrec.mo));
satrec.delmo = delmotemp * delmotemp * delmotemp;
satrec.sinmao = Math.Sin(satrec.mo);
satrec.x7thm1 = (7.0 * cosio2) - 1.0;
// --------------- deep space initialization -------------
if ((2 * pi) / satrec.no >= 225.0)
{
satrec.method = 'd';
satrec.isimp = 1;
tc = 0.0;
inclm = satrec.inclo;
DscomOptions dscomOptions = new DscomOptions();
dscomOptions.epoch = epoch;
dscomOptions.ep = satrec.ecco;
dscomOptions.argpp = satrec.argpo;
dscomOptions.tc = tc;
dscomOptions.inclp = satrec.inclo;
dscomOptions.nodep = satrec.nodeo;
dscomOptions.np = satrec.no;
dscomOptions.e3 = satrec.e3;
dscomOptions.ee2 = satrec.ee2;
dscomOptions.peo = satrec.peo;
dscomOptions.pgho = satrec.pgho;
dscomOptions.pho = satrec.pho;
dscomOptions.pinco = satrec.pinco;
dscomOptions.plo = satrec.plo;
dscomOptions.se2 = satrec.se2;
dscomOptions.se3 = satrec.se3;
dscomOptions.sgh2 = satrec.sgh2;
dscomOptions.sgh3 = satrec.sgh3;
dscomOptions.sgh4 = satrec.sgh4;
dscomOptions.sh2 = satrec.sh2;
dscomOptions.sh3 = satrec.sh3;
dscomOptions.si2 = satrec.si2;
dscomOptions.si3 = satrec.si3;
dscomOptions.sl2 = satrec.sl2;
dscomOptions.sl3 = satrec.sl3;
dscomOptions.sl4 = satrec.sl4;
dscomOptions.xgh2 = satrec.xgh2;
dscomOptions.xgh3 = satrec.xgh3;
dscomOptions.xgh4 = satrec.xgh4;
dscomOptions.xh2 = satrec.xh2;
dscomOptions.xh3 = satrec.xh3;
dscomOptions.xi2 = satrec.xi2;
dscomOptions.xi3 = satrec.xi3;
dscomOptions.xl2 = satrec.xl2;
dscomOptions.xl3 = satrec.xl3;
dscomOptions.xl4 = satrec.xl4;
dscomOptions.zmol = satrec.zmol;
dscomOptions.zmos = satrec.zmos;
Dscom dscom = new Dscom();
DscomResult dscomResult = new DscomResult();
dscomResult = dscom.dscom(dscomOptions);
satrec.e3 = dscomResult.e3;
satrec.ee2 = dscomResult.ee2;
satrec.peo = dscomResult.peo;
satrec.pgho = dscomResult.pgho;
satrec.pho = dscomResult.pho;
satrec.pinco = dscomResult.pinco;
satrec.plo = dscomResult.plo;
satrec.se2 = dscomResult.se2;
satrec.se3 = dscomResult.se3;
satrec.sgh2 = dscomResult.sgh2;
satrec.sgh3 = dscomResult.sgh3;
satrec.sgh4 = dscomResult.sgh4;
satrec.sh2 = dscomResult.sh2;
satrec.sh3 = dscomResult.sh3;
satrec.si2 = dscomResult.si2;
satrec.si3 = dscomResult.si3;
satrec.sl2 = dscomResult.sl2;
satrec.sl3 = dscomResult.sl3;
satrec.sl4 = dscomResult.sl4;
sinim = dscomResult.sinim;
cosim = dscomResult.cosim;
em = dscomResult.em;
emsq = dscomResult.emsq;
s1 = dscomResult.s1;
s2 = dscomResult.s2;
s3 = dscomResult.s3;
s4 = dscomResult.s4;
s5 = dscomResult.s5;
ss1 = dscomResult.ss1;
ss2 = dscomResult.ss2;
ss3 = dscomResult.ss3;
ss4 = dscomResult.ss4;
ss5 = dscomResult.ss5;
sz1 = dscomResult.sz1;
sz3 = dscomResult.sz3;
sz11 = dscomResult.sz11;
sz13 = dscomResult.sz13;
sz21 = dscomResult.sz21;
sz23 = dscomResult.sz23;
sz31 = dscomResult.sz31;
sz33 = dscomResult.sz33;
satrec.xgh2 = dscomResult.xgh2;
satrec.xgh3 = dscomResult.xgh3;
satrec.xgh4 = dscomResult.xgh4;
satrec.xh2 = dscomResult.xh2;
satrec.xh3 = dscomResult.xh3;
satrec.xi2 = dscomResult.xi2;
satrec.xi3 = dscomResult.xi3;
satrec.xl2 = dscomResult.xl2;
satrec.xl3 = dscomResult.xl3;
satrec.xl4 = dscomResult.xl4;
satrec.zmol = dscomResult.zmol;
satrec.zmos = dscomResult.zmos;
nm = dscomResult.nm;
z1 = dscomResult.z1;
z3 = dscomResult.z3;
z11 = dscomResult.z11;
z13 = dscomResult.z13;
z21 = dscomResult.z21;
z23 = dscomResult.z23;
z31 = dscomResult.z31;
z33 = dscomResult.z33;
DpperOptions dpperOptions = new DpperOptions();
dpperOptions.inclo = inclm;
dpperOptions.init = satrec.init;
dpperOptions.ep = satrec.ecco;
dpperOptions.inclp = satrec.inclo;
dpperOptions.nodep = satrec.nodeo;
dpperOptions.argpp = satrec.argpo;
dpperOptions.mp = satrec.mo;
dpperOptions.opsmode = satrec.operationmode;
Dpper dpper = new Dpper();
DpperResult dpperResult = new DpperResult();
dpperResult = dpper.dpper(satrec, dpperOptions);
satrec.ecco = dpperResult.ep;
satrec.inclo = dpperResult.inclp;
satrec.nodeo = dpperResult.nodep;
satrec.argpo = dpperResult.argpp;
satrec.mo = dpperResult.mp;
argpm = 0.0;
nodem = 0.0;
mm = 0.0;
DsinitOptions dsinitOptions = new DsinitOptions();
dsinitOptions.cosim = cosim;
dsinitOptions.emsq = emsq;
dsinitOptions.argpo = satrec.argpo;
dsinitOptions.s1 = s1;
dsinitOptions.s2 = s2;
dsinitOptions.s3 = s3;
dsinitOptions.s4 = s4;
dsinitOptions.s5 = s5;
dsinitOptions.sinim = sinim;
dsinitOptions.ss1 = ss1;
dsinitOptions.ss2 = ss2;
dsinitOptions.ss3 = ss3;
dsinitOptions.ss4 = ss4;
dsinitOptions.ss5 = ss5;
dsinitOptions.sz1 = sz1;
dsinitOptions.sz3 = sz3;
dsinitOptions.sz11 = sz11;
dsinitOptions.sz13 = sz13;
dsinitOptions.sz21 = sz21;
dsinitOptions.sz23 = sz23;
dsinitOptions.sz31 = sz31;
dsinitOptions.sz33 = sz33;
dsinitOptions.t = satrec.t;
dsinitOptions.tc = tc;
dsinitOptions.gsto = satrec.gsto;
dsinitOptions.mo = satrec.mo;
dsinitOptions.mdot = satrec.mdot;
dsinitOptions.no = satrec.no;
dsinitOptions.nodeo = satrec.nodeo;
dsinitOptions.nodedot = satrec.nodedot;
dsinitOptions.xpidot = xpidot;
dsinitOptions.z1 = z1;
dsinitOptions.z3 = z3;
dsinitOptions.z11 = z11;
dsinitOptions.z13 = z13;
dsinitOptions.z21 = z21;
dsinitOptions.z23 = z23;
dsinitOptions.z31 = z31;
dsinitOptions.z33 = z33;
dsinitOptions.ecco = satrec.ecco;
dsinitOptions.eccsq = eccsq;
dsinitOptions.em = em;
dsinitOptions.argpm = argpm;
dsinitOptions.inclm = inclm;
dsinitOptions.mm = mm;
dsinitOptions.nm = nm;
dsinitOptions.nodem = nodem;
dsinitOptions.irez = satrec.irez;
dsinitOptions.atime = satrec.atime;
dsinitOptions.d2201 = satrec.d2201;
dsinitOptions.d2211 = satrec.d2211;
dsinitOptions.d3210 = satrec.d3210;
dsinitOptions.d3222 = satrec.d3222;
dsinitOptions.d4410 = satrec.d4410;
dsinitOptions.d4422 = satrec.d4422;
dsinitOptions.d5220 = satrec.d5220;
dsinitOptions.d5232 = satrec.d5232;
dsinitOptions.d5421 = satrec.d5421;
dsinitOptions.d5433 = satrec.d5433;
dsinitOptions.dedt = satrec.dedt;
dsinitOptions.didt = satrec.didt;
dsinitOptions.dmdt = satrec.dmdt;
dsinitOptions.dnodt = satrec.dnodt;
dsinitOptions.domdt = satrec.domdt;
dsinitOptions.del1 = satrec.del1;
dsinitOptions.del2 = satrec.del2;
dsinitOptions.del3 = satrec.del3;
dsinitOptions.xfact = satrec.xfact;
dsinitOptions.xlamo = satrec.xlamo;
dsinitOptions.xli = satrec.xli;
dsinitOptions.xni = satrec.xni;
Dsinit dsinit = new Dsinit();
DsinitResult dsinitResult = new DsinitResult();
dsinitResult = dsinit.dsinit(dsinitOptions);
satrec.irez = dsinitResult.irez;
satrec.atime = dsinitResult.atime;
satrec.d2201 = dsinitResult.d2201;
satrec.d2211 = dsinitResult.d2211;
satrec.d3210 = dsinitResult.d3210;
satrec.d3222 = dsinitResult.d3222;
satrec.d4410 = dsinitResult.d4410;
satrec.d4422 = dsinitResult.d4422;
satrec.d5220 = dsinitResult.d5220;
satrec.d5232 = dsinitResult.d5232;
satrec.d5421 = dsinitResult.d5421;
satrec.d5433 = dsinitResult.d5433;
satrec.dedt = dsinitResult.dedt;
satrec.didt = dsinitResult.didt;
satrec.dmdt = dsinitResult.dmdt;
satrec.dnodt = dsinitResult.dnodt;
satrec.domdt = dsinitResult.domdt;
satrec.del1 = dsinitResult.del1;
satrec.del2 = dsinitResult.del2;
satrec.del3 = dsinitResult.del3;
satrec.xfact = dsinitResult.xfact;
satrec.xlamo = dsinitResult.xlamo;
satrec.xli = dsinitResult.xli;
satrec.xni = dsinitResult.xni;
}
// ----------- set variables if not deep space -----------
if (satrec.isimp != 1)
{
cc1sq = satrec.cc1 * satrec.cc1;
satrec.d2 = 4.0 * ao * tsi * cc1sq;
temp = (satrec.d2 * tsi * satrec.cc1) / 3.0;
satrec.d3 = ((17.0 * ao) + sfour) * temp;
satrec.d4 = 0.5 * temp * ao * tsi * ((221.0 * ao) + (31.0 * sfour)) * satrec.cc1;
satrec.t3cof = satrec.d2 + (2.0 * cc1sq);
satrec.t4cof = 0.25 * ((3.0 * satrec.d3)
+ (satrec.cc1 * ((12.0 * satrec.d2) + (10.0 * cc1sq))));
satrec.t5cof = 0.2 * (
(3.0 * satrec.d4)
+ (12.0 * satrec.cc1 * satrec.d3)
+ (6.0 * satrec.d2 * satrec.d2)
+ (15.0 * cc1sq * ((2.0 * satrec.d2) + cc1sq))
);
}
/* finally propogate to zero epoch to initialize all others. */
// sgp4fix take out check to let satellites process until they are actually below earth surface
// if(satrec.error == 0)
}
Sgp4 sgp4 = new Sgp4();
sgp4.sgp4(satrec, 0);
satrec.init = 'n';
/* eslint-enable no-param-reassign */
}
/*-----------------------------------------------------------------------------
*
* procedure dscom
*
* this procedure provides deep space common items used by both the secular
* and periodics subroutines. input is provided as shown. this routine
* used to be called dpper, but the functions inside weren't well organized.
*
* author : david vallado 719-573-2600 28 jun 2005
*
* inputs :
* epoch -
* ep - eccentricity
* argpp - argument of perigee
* tc -
* inclp - inclination
* nodep - right ascension of ascending node
* np - mean motion
*
* outputs :
* sinim , cosim , sinomm , cosomm , snodm , cnodm
* day -
* e3 -
* ee2 -
* em - eccentricity
* emsq - eccentricity squared
* gam -
* peo -
* pgho -
* pho -
* pinco -
* plo -
* rtemsq -
* se2, se3 -
* sgh2, sgh3, sgh4 -
* sh2, sh3, si2, si3, sl2, sl3, sl4 -
* s1, s2, s3, s4, s5, s6, s7 -
* ss1, ss2, ss3, ss4, ss5, ss6, ss7, sz1, sz2, sz3 -
* sz11, sz12, sz13, sz21, sz22, sz23, sz31, sz32, sz33 -
* xgh2, xgh3, xgh4, xh2, xh3, xi2, xi3, xl2, xl3, xl4 -
* nm - mean motion
* z1, z2, z3, z11, z12, z13, z21, z22, z23, z31, z32, z33 -
* zmol -
* zmos -
*
* locals :
* a1, a2, a3, a4, a5, a6, a7, a8, a9, a10 -
* betasq -
* cc -
* ctem, stem -
* x1, x2, x3, x4, x5, x6, x7, x8 -
* xnodce -
* xnoi -
* zcosg , zsing , zcosgl , zsingl , zcosh , zsinh , zcoshl , zsinhl ,
* zcosi , zsini , zcosil , zsinil ,
* zx -
* zy -
*
* coupling :
* none.
*
* references :
* hoots, roehrich, norad spacetrack report #3 1980
* hoots, norad spacetrack report #6 1986
* hoots, schumacher and glover 2004
* vallado, crawford, hujsak, kelso 2006
* ----------------------------------------------------------------------------*/
public DscomResult dscom(DscomOptions dscomOptions)
{
Globals globals = new Globals();
double twoPi = globals.twoPi;
double epoch = dscomOptions.epoch;
double ep = dscomOptions.ep;
double argpp = dscomOptions.argpp;
double tc = dscomOptions.tc;
double inclp = dscomOptions.inclp;
double nodep = dscomOptions.nodep;
double np = dscomOptions.np;
double a1 = 0.0;
double a2 = 0.0;
double a3 = 0.0;
double a4 = 0.0;
double a5 = 0.0;
double a6 = 0.0;
double a7 = 0.0;
double a8 = 0.0;
double a9 = 0.0;
double a10 = 0.0;
double cc = 0.0;
double x1 = 0.0;
double x2 = 0.0;
double x3 = 0.0;
double x4 = 0.0;
double x5 = 0.0;
double x6 = 0.0;
double x7 = 0.0;
double x8 = 0.0;
double zcosg = 0.0;
double zsing = 0.0;
double zcosh = 0.0;
double zsinh = 0.0;
double zcosi = 0.0;
double zsini = 0.0;
double ss1 = 0.0;
double ss2 = 0.0;
double ss3 = 0.0;
double ss4 = 0.0;
double ss5 = 0.0;
double ss6 = 0.0;
double ss7 = 0.0;
double sz1 = 0.0;
double sz2 = 0.0;
double sz3 = 0.0;
double sz11 = 0.0;
double sz12 = 0.0;
double sz13 = 0.0;
double sz21 = 0.0;
double sz22 = 0.0;
double sz23 = 0.0;
double sz31 = 0.0;
double sz32 = 0.0;
double sz33 = 0.0;
double s1 = 0.0;
double s2 = 0.0;
double s3 = 0.0;
double s4 = 0.0;
double s5 = 0.0;
double s6 = 0.0;
double s7 = 0.0;
double z1 = 0.0;
double z2 = 0.0;
double z3 = 0.0;
double z11 = 0.0;
double z12 = 0.0;
double z13 = 0.0;
double z21 = 0.0;
double z22 = 0.0;
double z23 = 0.0;
double z31 = 0.0;
double z32 = 0.0;
double z33 = 0.0;
// -------------------------- ants -------------------------
double zes = 0.01675;
double zel = 0.05490;
double c1ss = 2.9864797e-6;
double c1l = 4.7968065e-7;
double zsinis = 0.39785416;
double zcosis = 0.91744867;
double zcosgs = 0.1945905;
double zsings = -0.98088458;
// --------------------- local variables ------------------------
double nm = np;
double em = ep;
double snodm = Math.Sin(nodep);
double cnodm = Math.Cos(nodep);
double sinomm = Math.Sin(argpp);
double cosomm = Math.Cos(argpp);
double sinim = Math.Sin(inclp);
double cosim = Math.Cos(inclp);
double emsq = em * em;
double betasq = 1.0 - emsq;
double rtemsq = Math.Sqrt(betasq);
// ----------------- initialize lunar solar terms ---------------
double peo = 0.0;
double pinco = 0.0;
double plo = 0.0;
double pgho = 0.0;
double pho = 0.0;
double day = epoch + 18261.5 + (tc / 1440.0);
double xnodce = (4.5236020 - (9.2422029e-4 * day)) % twoPi;
double stem = Math.Sin(xnodce);
double ctem = Math.Cos(xnodce);
double zcosil = 0.91375164 - (0.03568096 * ctem);
double zsinil = Math.Sqrt(1.0 - (zcosil * zcosil));
double zsinhl = (0.089683511 * stem) / zsinil;
double zcoshl = Math.Sqrt(1.0 - (zsinhl * zsinhl));
double gam = 5.8351514 + (0.0019443680 * day);
double zx = (0.39785416 * stem) / zsinil;
double zy = (zcoshl * ctem) + (0.91744867 * zsinhl * stem);
zx = Math.Atan2(zx, zy);
zx += gam - xnodce;
double zcosgl = Math.Cos(zx);
double zsingl = Math.Sin(zx);
// ------------------------- do solar terms ---------------------
zcosg = zcosgs;
zsing = zsings;
zcosi = zcosis;
zsini = zsinis;
zcosh = cnodm;
zsinh = snodm;
cc = c1ss;
double xnoi = 1.0 / nm;
double lsflg = 0;
while (lsflg < 2)
{
lsflg += 1;
a1 = (zcosg * zcosh) + (zsing * zcosi * zsinh);
a3 = (-zsing * zcosh) + (zcosg * zcosi * zsinh);
a7 = (-zcosg * zsinh) + (zsing * zcosi * zcosh);
a8 = zsing * zsini;
a9 = (zsing * zsinh) + (zcosg * zcosi * zcosh);
a10 = zcosg * zsini;
a2 = (cosim * a7) + (sinim * a8);
a4 = (cosim * a9) + (sinim * a10);
a5 = (-sinim * a7) + (cosim * a8);
a6 = (-sinim * a9) + (cosim * a10);
x1 = (a1 * cosomm) + (a2 * sinomm);
x2 = (a3 * cosomm) + (a4 * sinomm);
x3 = (-a1 * sinomm) + (a2 * cosomm);
x4 = (-a3 * sinomm) + (a4 * cosomm);
x5 = a5 * sinomm;
x6 = a6 * sinomm;
x7 = a5 * cosomm;
x8 = a6 * cosomm;
z31 = (12.0 * x1 * x1) - (3.0 * x3 * x3);
z32 = (24.0 * x1 * x2) - (6.0 * x3 * x4);
z33 = (12.0 * x2 * x2) - (3.0 * x4 * x4);
z1 = (3.0 * ((a1 * a1) + (a2 * a2))) + (z31 * emsq);
z2 = (6.0 * ((a1 * a3) + (a2 * a4))) + (z32 * emsq);
z3 = (3.0 * ((a3 * a3) + (a4 * a4))) + (z33 * emsq);
z11 = (-6.0 * a1 * a5)
+ (emsq * ((-24.0 * x1 * x7) - (6.0 * x3 * x5)));
z12 = (-6.0 * ((a1 * a6) + (a3 * a5)))
+ (emsq * ((-24.0 * ((x2 * x7) + (x1 * x8))) + (-6.0 * ((x3 * x6) + (x4 * x5)))));
z13 = (-6.0 * a3 * a6)
+ (emsq * ((-24.0 * x2 * x8) - (6.0 * x4 * x6)));
z21 = (6.0 * a2 * a5)
+ (emsq * ((24.0 * x1 * x5) - (6.0 * x3 * x7)));
z22 = (6.0 * ((a4 * a5) + (a2 * a6)))
+ (emsq * ((24.0 * ((x2 * x5) + (x1 * x6))) - (6.0 * ((x4 * x7) + (x3 * x8)))));
z23 = (6.0 * a4 * a6)
+ (emsq * ((24.0 * x2 * x6) - (6.0 * x4 * x8)));
z1 = z1 + z1 + (betasq * z31);
z2 = z2 + z2 + (betasq * z32);
z3 = z3 + z3 + (betasq * z33);
s3 = cc * xnoi;
s2 = (-0.5 * s3) / rtemsq;
s4 = s3 * rtemsq;
s1 = -15.0 * em * s4;
s5 = (x1 * x3) + (x2 * x4);
s6 = (x2 * x3) + (x1 * x4);
s7 = (x2 * x4) - (x1 * x3);
// ----------------------- do lunar terms -------------------
if (lsflg == 1)
{
ss1 = s1;
ss2 = s2;
ss3 = s3;
ss4 = s4;
ss5 = s5;
ss6 = s6;
ss7 = s7;
sz1 = z1;
sz2 = z2;
sz3 = z3;
sz11 = z11;
sz12 = z12;
sz13 = z13;
sz21 = z21;
sz22 = z22;
sz23 = z23;
sz31 = z31;
sz32 = z32;
sz33 = z33;
zcosg = zcosgl;
zsing = zsingl;
zcosi = zcosil;
zsini = zsinil;
zcosh = (zcoshl * cnodm) + (zsinhl * snodm);
zsinh = (snodm * zcoshl) - (cnodm * zsinhl);
cc = c1l;
}
}
double zmol = (4.7199672 + ((0.22997150 * day) - gam)) % twoPi;
double zmos = (6.2565837 + (0.017201977 * day)) % twoPi;
// ------------------------ do solar terms ----------------------
double se2 = 2.0 * ss1 * ss6;
double se3 = 2.0 * ss1 * ss7;
double si2 = 2.0 * ss2 * sz12;
double si3 = 2.0 * ss2 * (sz13 - sz11);
double sl2 = -2.0 * ss3 * sz2;
double sl3 = -2.0 * ss3 * (sz3 - sz1);
double sl4 = -2.0 * ss3 * (-21.0 - (9.0 * emsq)) * zes;
double sgh2 = 2.0 * ss4 * sz32;
double sgh3 = 2.0 * ss4 * (sz33 - sz31);
double sgh4 = -18.0 * ss4 * zes;
double sh2 = -2.0 * ss2 * sz22;
double sh3 = -2.0 * ss2 * (sz23 - sz21);
// ------------------------ do lunar terms ----------------------
double ee2 = 2.0 * s1 * s6;
double e3 = 2.0 * s1 * s7;
double xi2 = 2.0 * s2 * z12;
double xi3 = 2.0 * s2 * (z13 - z11);
double xl2 = -2.0 * s3 * z2;
double xl3 = -2.0 * s3 * (z3 - z1);
double xl4 = -2.0 * s3 * (-21.0 - (9.0 * emsq)) * zel;
double xgh2 = 2.0 * s4 * z32;
double xgh3 = 2.0 * s4 * (z33 - z31);
double xgh4 = -18.0 * s4 * zel;
double xh2 = -2.0 * s2 * z22;
double xh3 = -2.0 * s2 * (z23 - z21);
DscomResult dscomResult = new DscomResult();
dscomResult.snodm = snodm;
dscomResult.cnodm = cnodm;
dscomResult.sinim = sinim;
dscomResult.cosim = cosim;
dscomResult.sinomn = sinomm;
dscomResult.cosomm = cosomm;
dscomResult.day = day;
dscomResult.e3 = e3;
dscomResult.ee2 = ee2;
dscomResult.em = em;
dscomResult.emsq = emsq;
dscomResult.gam = gam;
dscomResult.peo = peo;
dscomResult.pgho = pgho;
dscomResult.pho = pho;
dscomResult.pinco = pinco;
dscomResult.plo = plo;
dscomResult.rtemsq = rtemsq;
dscomResult.se2 = se2;
dscomResult.se3 = se3;
dscomResult.sgh2 = sgh2;
dscomResult.sgh3 = sgh3;
dscomResult.sgh4 = sgh4;
dscomResult.sh2 = sh2;
dscomResult.sh3 = sh3;
dscomResult.si2 = si2;
dscomResult.si2 = si3;
dscomResult.sl2 = sl2;
dscomResult.sl3 = sl3;
dscomResult.sl4 = sl4;
dscomResult.s1 = s1;
dscomResult.s2 = s2;
dscomResult.s3 = s3;
dscomResult.s4 = s4;
dscomResult.s5 = s5;
dscomResult.s6 = s6;
dscomResult.s7 = s7;
dscomResult.ss1 = ss1;
dscomResult.ss2 = ss2;
dscomResult.ss3 = ss3;
dscomResult.ss4 = ss4;
dscomResult.ss5 = ss5;
dscomResult.ss6 = ss6;
dscomResult.ss7 = ss7;
dscomResult.sz1 = sz1;
dscomResult.sz2 = sz2;
dscomResult.sz3 = sz3;
dscomResult.sz11 = sz11;
dscomResult.sz12 = sz12;
dscomResult.sz13 = sz13;
dscomResult.sz21 = sz21;
dscomResult.sz22 = sz22;
dscomResult.sz23 = sz23;
dscomResult.sz31 = sz31;
dscomResult.sz32 = sz32;
dscomResult.sz33 = sz33;
dscomResult.xgh2 = xgh2;
dscomResult.xgh3 = xgh3;
dscomResult.xgh4 = xgh4;
dscomResult.xh2 = xh2;
dscomResult.xh3 = xh3;
dscomResult.xi2 = xi2;
dscomResult.xi3 = xi3;
dscomResult.xl2 = xl2;
dscomResult.xl3 = xl3;
dscomResult.xl4 = xl4;
dscomResult.nm = nm;
dscomResult.z1 = z1;
dscomResult.z2 = z2;
dscomResult.z3 = z3;
dscomResult.z11 = z11;
dscomResult.z12 = z12;
dscomResult.z13 = z13;
dscomResult.z21 = z21;
dscomResult.z21 = z22;
dscomResult.z23 = z23;
dscomResult.z31 = z31;
dscomResult.z32 = z32;
dscomResult.z33 = z33;
dscomResult.zmol = zmol;
dscomResult.zmos = zmos;
return(dscomResult);
}