Exemple #1
0
        static void Main(string[] args)
        {
            // string line0 = "ISS (ZARYA)    ";
            string line1 = "1 25544U 98067A   20206.38292522 -.00000985  00000-0 -95291-5 0  9998";
            string line2 = "2 25544  51.6430 164.3636 0001088 140.8410 323.1994 15.49511774237787";

            Sat_Io io     = new Sat_Io();
            Satrec satrec = io.twoline2satrec(line1, line2);

            Sgp4 sgp4 = new Sgp4();
            PositionAndVelocity positionAndVelocity = sgp4.sgp4(satrec, 0);



            // Set the Observer at 122.03 West by 36.96 North, in RADIANS
            Geodetic  observerGd = new Geodetic();
            Transform tf         = new Transform();

            observerGd.longitude = tf.degreesToRadians(-122.0308);
            observerGd.latitude  = tf.degreesToRadians(36.9613422);
            observerGd.height    = 0.370;


            Console.WriteLine(positionAndVelocity.position_ECI.x);
            Console.WriteLine(positionAndVelocity.position_ECI.y);
            Console.WriteLine(positionAndVelocity.position_ECI.z);



            Console.WriteLine("Look i didnt crash");
        }
Exemple #2
0
        public void CheckInitialisation()
        {
            string line1 = "1 25544U 98067A   20206.38292522 -.00000985  00000-0 -95291-5 0  9998";
            string line2 = "2 25544  51.6430 164.3636 0001088 140.8410 323.1994 15.49511774237787";

            Sat.Sat_Io io     = new Sat.Sat_Io();
            Sat.Satrec satrec = io.twoline2satrec(line1, line2);

            Sat.Sgp4 sgp4 = new Sat.Sgp4();
            Sat.PositionAndVelocity positionAndVelocity = sgp4.sgp4(satrec, 0);

            Assert.Equal(485.6716711104389, positionAndVelocity.position_ECI.x);  // Value from Sat.js
            Assert.Equal(-4381.651985814846, positionAndVelocity.position_ECI.y); // Value from Sat.js
            Assert.Equal(5162.784591395867, positionAndVelocity.position_ECI.z);  // Value from Sat.js
        }
Exemple #3
0
/*-----------------------------------------------------------------------------
 *
 *                             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 */
        }