dsinit function
Implementation
Map<String, dynamic> dsinit(Map<String, dynamic> options) {
final cosim = options['cosim'];
final argpo = options['argpo'];
final s1 = options['s1'];
final s2 = options['s2'];
final s3 = options['s3'];
final s4 = options['s4'];
final s5 = options['s5'];
final sinim = options['sinim'];
final ss1 = options['ss1'];
final ss2 = options['ss2'];
final ss3 = options['ss3'];
final ss4 = options['ss4'];
final ss5 = options['ss5'];
final sz1 = options['sz1'];
final sz3 = options['sz3'];
final sz11 = options['sz11'];
final sz13 = options['sz13'];
final sz21 = options['sz21'];
final sz23 = options['sz23'];
final sz31 = options['sz31'];
final sz33 = options['sz33'];
final t = options['t'];
final tc = options['tc'];
final gsto = options['gsto'];
final mo = options['mo'];
final mdot = options['mdot'];
final no = options['no'];
final nodeo = options['nodeo'];
final nodedot = options['nodedot'];
final xpidot = options['xpidot'];
final z1 = options['z1'];
final z3 = options['z3'];
final z11 = options['z11'];
final z13 = options['z13'];
final z21 = options['z21'];
final z23 = options['z23'];
final z31 = options['z31'];
final z33 = options['z33'];
final ecco = options['ecco'];
final eccsq = options['eccsq'];
var emsq = options['emsq'];
var em = options['em'];
var argpm = options['argpm'];
var inclm = options['inclm'];
var mm = options['mm'];
var nm = options['nm'];
var nodem = options['nodem'];
var irez = options['irez'];
var atime = options['atime'];
var d2201 = options['d2201'];
var d2211 = options['d2211'];
var d3210 = options['d3210'];
var d3222 = options['d3222'];
var d4410 = options['d4410'];
var d4422 = options['d4422'];
var d5220 = options['d5220'];
var d5232 = options['d5232'];
var d5421 = options['d5421'];
var d5433 = options['d5433'];
var dedt = options['dedt'];
var didt = options['didt'];
var dmdt = options['dmdt'];
var dnodt = options['dnodt'];
var domdt = options['domdt'];
var del1 = options['del1'];
var del2 = options['del2'];
var del3 = options['del3'];
var xfact = options['xfact'];
var xlamo = options['xlamo'];
var xli = options['xli'];
var xni = options['xni'];
var f220;
var f221;
var f311;
var f321;
var f322;
var f330;
var f441;
var f442;
var f522;
var f523;
var f542;
var f543;
var g200;
var g201;
var g211;
var g300;
var g310;
var g322;
var g410;
var g422;
var g520;
var g521;
var g532;
var g533;
var sini2;
var temp;
var temp1;
var xno2;
var ainv2;
var aonv;
var cosisq;
var eoc;
final q22 = 1.7891679e-6;
final q31 = 2.1460748e-6;
final q33 = 2.2123015e-7;
final root22 = 1.7891679e-6;
final root44 = 7.3636953e-9;
final root54 = 2.1765803e-9;
final rptim =
4.37526908801129966e-3; // equates to 7.29211514668855e-5 rad/sec
final root32 = 3.7393792e-7;
final root52 = 1.1428639e-7;
final znl = 1.5835218e-4;
final zns = 1.19459e-5;
// -------------------- deep space initialization ------------
irez = 0;
if ((nm < 0.0052359877) && (nm > 0.0034906585)) {
irez = 1;
}
if ((nm >= 8.26e-3) && (nm <= 9.24e-3) && (em >= 0.5)) {
irez = 2;
}
// ------------------------ do solar terms -------------------
final ses = ss1 * zns * ss5;
final sis = ss2 * zns * (sz11 + sz13);
final sls = -zns * ss3 * ((sz1 + sz3) - 14.0 - (6.0 * emsq));
final sghs = ss4 * zns * ((sz31 + sz33) - 6.0);
var shs = -zns * ss2 * (sz21 + sz23);
// sgp4fix for 180 deg incl
if (inclm < 5.2359877e-2 || inclm > pi - 5.2359877e-2) {
shs = 0.0;
}
if (sinim != 0.0) {
shs /= sinim;
}
final sgs = sghs - (cosim * shs);
// ------------------------- do lunar terms ------------------
dedt = ses + (s1 * znl * s5);
didt = sis + (s2 * znl * (z11 + z13));
dmdt = sls - (znl * s3 * ((z1 + z3) - 14.0 - (6.0 * emsq)));
final sghl = s4 * znl * ((z31 + z33) - 6.0);
var shll = -znl * s2 * (z21 + z23);
// sgp4fix for 180 deg incl
if ((inclm < 5.2359877e-2) || (inclm > (pi - 5.2359877e-2))) {
shll = 0.0;
}
domdt = sgs + sghl;
dnodt = shs;
if (sinim != 0.0) {
domdt -= (cosim / sinim) * shll;
dnodt += shll / sinim;
}
// ----------- calculate deep space resonance effects --------
final dndt = 0.0;
final theta = (gsto + (tc * rptim)) % twoPi;
em += dedt * t;
inclm += didt * t;
argpm += domdt * t;
nodem += dnodt * t;
mm += dmdt * t;
// sgp4fix for negative inclinations
// the following if statement should be commented out
// if (inclm < 0.0)
// {
// inclm = -inclm;
// argpm = argpm - pi;
// nodem = nodem + pi;
// }
// -------------- initialize the resonance terms -------------
if (irez != 0) {
aonv = Math.pow((nm / xke), x2o3);
// ---------- geopotential resonance for 12 hour orbits ------
if (irez == 2) {
cosisq = cosim * cosim;
final emo = em;
em = ecco;
final emsqo = emsq;
emsq = eccsq;
eoc = em * emsq;
g201 = -0.306 - ((em - 0.64) * 0.440);
if (em <= 0.65) {
g211 = (3.616 - (13.2470 * em)) + (16.2900 * emsq);
g310 = ((-19.302 + (117.3900 * em)) - (228.4190 * emsq)) +
(156.5910 * eoc);
g322 = ((-18.9068 + (109.7927 * em)) - (214.6334 * emsq)) +
(146.5816 * eoc);
g410 = ((-41.122 + (242.6940 * em)) - (471.0940 * emsq)) +
(313.9530 * eoc);
g422 = ((-146.407 + (841.8800 * em)) - (1629.014 * emsq)) +
(1083.4350 * eoc);
g520 = ((-532.114 + (3017.977 * em)) - (5740.032 * emsq)) +
(3708.2760 * eoc);
} else {
g211 =
((-72.099 + (331.819 * em)) - (508.738 * emsq)) + (266.724 * eoc);
g310 = ((-346.844 + (1582.851 * em)) - (2415.925 * emsq)) +
(1246.113 * eoc);
g322 = ((-342.585 + (1554.908 * em)) - (2366.899 * emsq)) +
(1215.972 * eoc);
g410 = ((-1052.797 + (4758.686 * em)) - (7193.992 * emsq)) +
(3651.957 * eoc);
g422 = ((-3581.690 + (16178.110 * em)) - (24462.770 * emsq)) +
(12422.520 * eoc);
if (em > 0.715) {
g520 = ((-5149.66 + (29936.92 * em)) - (54087.36 * emsq)) +
(31324.56 * eoc);
} else {
g520 = (1464.74 - (4664.75 * em)) + (3763.64 * emsq);
}
}
if (em < 0.7) {
g533 = ((-919.22770 + (4988.6100 * em)) - (9064.7700 * emsq)) +
(5542.21 * eoc);
g521 = ((-822.71072 + (4568.6173 * em)) - (8491.4146 * emsq)) +
(5337.524 * eoc);
g532 = ((-853.66600 + (4690.2500 * em)) - (8624.7700 * emsq)) +
(5341.4 * eoc);
} else {
g533 = ((-37995.780 + (161616.52 * em)) - (229838.20 * emsq)) +
(109377.94 * eoc);
g521 = ((-51752.104 + (218913.95 * em)) - (309468.16 * emsq)) +
(146349.42 * eoc);
g532 = ((-40023.880 + (170470.89 * em)) - (242699.48 * emsq)) +
(115605.82 * eoc);
}
sini2 = sinim * sinim;
f220 = 0.75 * (1.0 + (2.0 * cosim) + cosisq);
f221 = 1.5 * sini2;
f321 = 1.875 * sinim * (1.0 - (2.0 * cosim) - (3.0 * cosisq));
f322 = -1.875 * sinim * ((1.0 + (2.0 * cosim)) - (3.0 * cosisq));
f441 = 35.0 * sini2 * f220;
f442 = 39.3750 * sini2 * sini2;
f522 = 9.84375 *
sinim *
((sini2 * (1.0 - (2.0 * cosim) - (5.0 * cosisq))) +
(0.33333333 * (-2.0 + (4.0 * cosim) + (6.0 * cosisq))));
f523 = sinim *
((4.92187512 * sini2 * ((-2.0 - (4.0 * cosim)) + (10.0 * cosisq))) +
(6.56250012 * ((1.0 + (2.0 * cosim)) - (3.0 * cosisq))));
f542 = 29.53125 *
sinim *
((2.0 - (8.0 * cosim)) +
(cosisq * (-12.0 + (8.0 * cosim) + (10.0 * cosisq))));
f543 = 29.53125 *
sinim *
((-2.0 - (8.0 * cosim)) +
(cosisq * ((12.0 + (8.0 * cosim)) - (10.0 * cosisq))));
xno2 = nm * nm;
ainv2 = aonv * aonv;
temp1 = 3.0 * xno2 * ainv2;
temp = temp1 * root22;
d2201 = temp * f220 * g201;
d2211 = temp * f221 * g211;
temp1 *= aonv;
temp = temp1 * root32;
d3210 = temp * f321 * g310;
d3222 = temp * f322 * g322;
temp1 *= aonv;
temp = 2.0 * temp1 * root44;
d4410 = temp * f441 * g410;
d4422 = temp * f442 * g422;
temp1 *= aonv;
temp = temp1 * root52;
d5220 = temp * f522 * g520;
d5232 = temp * f523 * g532;
temp = 2.0 * temp1 * root54;
d5421 = temp * f542 * g521;
d5433 = temp * f543 * g533;
xlamo = ((mo + nodeo + nodeo) - (theta + theta)) % twoPi;
xfact = (mdot + dmdt + (2.0 * ((nodedot + dnodt) - rptim))) - no;
em = emo;
emsq = emsqo;
}
// ---------------- synchronous resonance terms --------------
if (irez == 1) {
g200 = 1.0 + (emsq * (-2.5 + (0.8125 * emsq)));
g310 = 1.0 + (2.0 * emsq);
g300 = 1.0 + (emsq * (-6.0 + (6.60937 * emsq)));
f220 = 0.75 * (1.0 + cosim) * (1.0 + cosim);
f311 = (0.9375 * sinim * sinim * (1.0 + (3.0 * cosim))) -
(0.75 * (1.0 + cosim));
f330 = 1.0 + cosim;
f330 *= 1.875 * f330 * f330;
del1 = 3.0 * nm * nm * aonv * aonv;
del2 = 2.0 * del1 * f220 * g200 * q22;
del3 = 3.0 * del1 * f330 * g300 * q33 * aonv;
del1 = del1 * f311 * g310 * q31 * aonv;
xlamo = ((mo + nodeo + argpo) - theta) % twoPi;
xfact = (mdot + xpidot + dmdt + domdt + dnodt) - (no + rptim);
}
// ------------ for sgp4, initialize the integrator ----------
xli = xlamo;
xni = no;
atime = 0.0;
nm = no + dndt;
}
return {
'em': em,
'argpm': argpm,
'inclm': inclm,
'mm': mm,
'nm': nm,
'nodem': nodem,
'irez': irez,
'atime': atime,
'd2201': d2201,
'd2211': d2211,
'd3210': d3210,
'd3222': d3222,
'd4410': d4410,
'd4422': d4422,
'd5220': d5220,
'd5232': d5232,
'd5421': d5421,
'd5433': d5433,
'dedt': dedt,
'didt': didt,
'dmdt': dmdt,
'dndt': dndt,
'dnodt': dnodt,
'domdt': domdt,
'del1': del1,
'del2': del2,
'del3': del3,
'xfact': xfact,
'xlamo': xlamo,
'xli': xli,
'xni': xni,
};
}
