FieldDeepSDP4.java
- /* Copyright 2002-2025 CS GROUP
- * Licensed to CS GROUP (CS) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * CS licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.orekit.propagation.analytical.tle;
- import org.hipparchus.CalculusFieldElement;
- import org.hipparchus.util.FastMath;
- import org.hipparchus.util.FieldSinCos;
- import org.hipparchus.util.MathArrays;
- import org.hipparchus.util.MathUtils;
- import org.hipparchus.util.SinCos;
- import org.orekit.annotation.DefaultDataContext;
- import org.orekit.attitudes.AttitudeProvider;
- import org.orekit.data.DataContext;
- import org.orekit.frames.Frame;
- import org.orekit.time.DateTimeComponents;
- import org.orekit.utils.Constants;
- /** This class contains the methods that compute deep space perturbation terms.
- * <p>
- * The user should not bother in this class since it is handled internaly by the
- * {@link TLEPropagator}.
- * </p>
- * <p>This implementation is largely inspired from the paper and source code <a
- * href="https://www.celestrak.com/publications/AIAA/2006-6753/">Revisiting Spacetrack
- * Report #3</a> and is fully compliant with its results and tests cases.</p>
- * @author Felix R. Hoots, Ronald L. Roehrich, December 1980 (original fortran)
- * @author David A. Vallado, Paul Crawford, Richard Hujsak, T.S. Kelso (C++ translation and improvements)
- * @author Fabien Maussion (java translation)
- * @author Thomas Paulet (field translation)
- * @since 11.0
- * @param <T> type of the field elements
- */
- public class FieldDeepSDP4<T extends CalculusFieldElement<T>> extends FieldSDP4<T> {
- // CHECKSTYLE: stop JavadocVariable check
- /** Integration step (seconds). */
- private static final double SECULAR_INTEGRATION_STEP = 720.0;
- /** Intermediate values. */
- private double thgr;
- private T xnq;
- private T omegaq;
- private double zcosil;
- private double zsinil;
- private double zsinhl;
- private double zcoshl;
- private double zmol;
- private double zcosgl;
- private double zsingl;
- private double zmos;
- private T savtsn;
- private T ee2;
- private T e3;
- private T xi2;
- private T xi3;
- private T xl2;
- private T xl3;
- private T xl4;
- private T xgh2;
- private T xgh3;
- private T xgh4;
- private T xh2;
- private T xh3;
- private T d2201;
- private T d2211;
- private T d3210;
- private T d3222;
- private T d4410;
- private T d4422;
- private T d5220;
- private T d5232;
- private T d5421;
- private T d5433;
- private T xlamo;
- private T sse;
- private T ssi;
- private T ssl;
- private T ssh;
- private T ssg;
- private T se2;
- private T si2;
- private T sl2;
- private T sgh2;
- private T sh2;
- private T se3;
- private T si3;
- private T sl3;
- private T sgh3;
- private T sh3;
- private T sl4;
- private T sgh4;
- private T del1;
- private T del2;
- private T del3;
- private T xfact;
- private T xli;
- private T xni;
- private T atime;
- private T pe;
- private T pinc;
- private T pl;
- private T pgh;
- private T ph;
- private T[] derivs;
- // CHECKSTYLE: resume JavadocVariable check
- /** Flag for resonant orbits. */
- private boolean resonant;
- /** Flag for synchronous orbits. */
- private boolean synchronous;
- /** Flag for compliance with Dundee modifications. */
- private boolean isDundeeCompliant = true;
- /** Constructor for a unique initial TLE.
- *
- * <p>This constructor uses the {@link DataContext#getDefault() default data context}.
- *
- * @param initialTLE the TLE to propagate.
- * @param attitudeProvider provider for attitude computation
- * @param mass spacecraft mass (kg)
- * @param parameters SGP4 and SDP4 model parameters
- * @see #FieldDeepSDP4(FieldTLE, AttitudeProvider, CalculusFieldElement, Frame, CalculusFieldElement[])
- */
- @DefaultDataContext
- public FieldDeepSDP4(final FieldTLE<T> initialTLE, final AttitudeProvider attitudeProvider,
- final T mass, final T[] parameters) {
- this(initialTLE, attitudeProvider, mass,
- DataContext.getDefault().getFrames().getTEME(), parameters);
- }
- /** Constructor for a unique initial TLE.
- * @param initialTLE the TLE to propagate.
- * @param attitudeProvider provider for attitude computation
- * @param mass spacecraft mass (kg)
- * @param teme the TEME frame to use for propagation.
- * @param parameters SGP4 and SDP4 model parameters
- */
- public FieldDeepSDP4(final FieldTLE<T> initialTLE,
- final AttitudeProvider attitudeProvider,
- final T mass,
- final Frame teme,
- final T[] parameters) {
- super(initialTLE, attitudeProvider, mass, teme, parameters);
- }
- /** Computes luni - solar terms from initial coordinates and epoch.
- */
- protected void luniSolarTermsComputation() {
- final T zero = tle.getPerigeeArgument().getField().getZero();
- final T pi = zero.getPi();
- final FieldSinCos<T> scg = FastMath.sinCos(tle.getPerigeeArgument());
- final T sing = scg.sin();
- final T cosg = scg.cos();
- final FieldSinCos<T> scq = FastMath.sinCos(tle.getRaan());
- final T sinq = scq.sin();
- final T cosq = scq.cos();
- final T aqnv = a0dp.reciprocal();
- // Compute julian days since 1900
- final double daysSince1900 = (tle.getDate()
- .getComponents(utc)
- .offsetFrom(DateTimeComponents.JULIAN_EPOCH)) /
- Constants.JULIAN_DAY - 2415020;
- double cc = TLEConstants.C1SS;
- double ze = TLEConstants.ZES;
- double zn = TLEConstants.ZNS;
- T zsinh = sinq;
- T zcosh = cosq;
- thgr = thetaG(tle.getDate());
- xnq = xn0dp;
- omegaq = tle.getPerigeeArgument();
- final double xnodce = 4.5236020 - 9.2422029e-4 * daysSince1900;
- final SinCos scTem = FastMath.sinCos(xnodce);
- final double stem = scTem.sin();
- final double ctem = scTem.cos();
- final double c_minus_gam = 0.228027132 * daysSince1900 - 1.1151842;
- final double gam = 5.8351514 + 0.0019443680 * daysSince1900;
- zcosil = 0.91375164 - 0.03568096 * ctem;
- zsinil = FastMath.sqrt(1.0 - zcosil * zcosil);
- zsinhl = 0.089683511 * stem / zsinil;
- zcoshl = FastMath.sqrt(1.0 - zsinhl * zsinhl);
- zmol = MathUtils.normalizeAngle(c_minus_gam, pi.getReal());
- double zx = 0.39785416 * stem / zsinil;
- final double zy = zcoshl * ctem + 0.91744867 * zsinhl * stem;
- zx = FastMath.atan2( zx, zy) + gam - xnodce;
- final SinCos scZx = FastMath.sinCos(zx);
- zcosgl = scZx.cos();
- zsingl = scZx.sin();
- zmos = MathUtils.normalizeAngle(6.2565837 + 0.017201977 * daysSince1900, pi.getReal());
- // Do solar terms
- savtsn = zero.newInstance(1e20);
- T zcosi = zero.newInstance(0.91744867);
- T zsini = zero.newInstance(0.39785416);
- T zsing = zero.newInstance(-0.98088458);
- T zcosg = zero.newInstance(0.1945905);
- T se = zero;
- T sgh = zero;
- T sh = zero;
- T si = zero;
- T sl = zero;
- // There was previously some convoluted logic here, but it boils
- // down to this: we compute the solar terms, then the lunar terms.
- // On a second pass, we recompute the solar terms, taking advantage
- // of the improved data that resulted from computing lunar terms.
- for (int iteration = 0; iteration < 2; ++iteration) {
- final T a1 = zcosh.multiply(zcosg).add(zsinh.multiply(zsing).multiply(zcosi));
- final T a3 = zcosh.multiply(zsing.negate()).add(zsinh.multiply(zcosg).multiply(zcosi));
- final T a7 = zsinh.negate().multiply(zcosg).add(zcosh.multiply(zcosi).multiply(zsing));
- final T a8 = zsing.multiply(zsini);
- final T a9 = zsinh.multiply(zsing).add(zcosh.multiply(zcosi).multiply(zcosg));
- final T a10 = zcosg.multiply(zsini);
- final T a2 = cosi0.multiply(a7).add(sini0.multiply(a8));
- final T a4 = cosi0.multiply(a9).add(sini0.multiply(a10));
- final T a5 = sini0.negate().multiply(a7).add(cosi0.multiply(a8));
- final T a6 = sini0.negate().multiply(a9).add(cosi0.multiply(a10));
- final T x1 = a1.multiply(cosg).add(a2.multiply(sing));
- final T x2 = a3.multiply(cosg).add(a4.multiply(sing));
- final T x3 = a1.negate().multiply(sing).add(a2.multiply(cosg));
- final T x4 = a3.negate().multiply(sing).add(a4.multiply(cosg));
- final T x5 = a5.multiply(sing);
- final T x6 = a6.multiply(sing);
- final T x7 = a5.multiply(cosg);
- final T x8 = a6.multiply(cosg);
- final T z31 = x1.square().multiply(12).subtract(x3.square().multiply(3));
- final T z32 = x1.multiply(x2).multiply(24).subtract(x3.multiply(x4).multiply(6));
- final T z33 = x2.square().multiply(12).subtract(x4.square().multiply(3));
- final T z11 = a1.multiply(-6).multiply(a5).add(e0sq.multiply(x1.multiply(x7).multiply(-24).add(x3.multiply(x5).multiply(-6))));
- final T z12 = a1.multiply(a6).add(a3.multiply(a5)).multiply(-6).add(
- e0sq.multiply(x2.multiply(x7).add(x1.multiply(x8)).multiply(-24).add(
- x3.multiply(x6).add(x4.multiply(x5)).multiply(-6))));
- final T z13 = a3.multiply(a6).multiply(-6).add(e0sq.multiply(
- x2.multiply(x8).multiply(-24).subtract(x4.multiply(x6).multiply(6))));
- final T z21 = a2.multiply(a5).multiply(6).add(e0sq.multiply(
- x1.multiply(x5).multiply(24).subtract(x3.multiply(x7).multiply(6))));
- final T z22 = a4.multiply(a5).add(a2.multiply(a6)).multiply(6).add(
- e0sq.multiply(x2.multiply(x5).add(x1.multiply(x6)).multiply(24).subtract(
- x4.multiply(x7).add(x3.multiply(x8)).multiply(6))));
- final T z23 = a4.multiply(a6).multiply(6).add(e0sq.multiply(x2.multiply(x6).multiply(24).subtract(x4.multiply(x8).multiply(6))));
- final T s3 = xnq.reciprocal().multiply(cc);
- final T s2 = beta0.reciprocal().multiply(s3.multiply(-0.5));
- final T s4 = s3.multiply(beta0);
- final T s1 = tle.getE().multiply(s4).multiply(-15);
- final T s5 = x1.multiply(x3).add(x2.multiply(x4));
- final T s6 = x2.multiply(x3).add(x1.multiply(x4));
- final T s7 = x2.multiply(x4).subtract(x1.multiply(x3));
- T z1 = a1.square().add(a2.square()).multiply(3).add(z31.multiply(e0sq));
- T z2 = a1.multiply(a3).add(a2.multiply(a4)).multiply(6).add(z32.multiply(e0sq));
- T z3 = a3.square().add(a4.square()).multiply(3).add(z33.multiply(e0sq));
- z1 = z1.add(z1).add(beta02.multiply(z31));
- z2 = z2.add(z2).add(beta02.multiply(z32));
- z3 = z3.add(z3).add(beta02.multiply(z33));
- se = s1.multiply(zn).multiply(s5);
- si = s2.multiply(zn).multiply(z11.add(z13));
- sl = s3.multiply(-zn).multiply(z1.add(z3).subtract(14).subtract(e0sq.multiply(6)));
- sgh = s4.multiply(zn).multiply(z31.add(z33).subtract(6));
- if (tle.getI().getReal() < pi.divide(60.0).getReal()) {
- // inclination smaller than 3 degrees
- sh = zero;
- } else {
- sh = s2.multiply(-zn).multiply(z21.add(z23));
- }
- ee2 = s1.multiply(s6).multiply(2);
- e3 = s1.multiply(s7).multiply(2);
- xi2 = s2.multiply(z12).multiply(2);
- xi3 = s2.multiply(z13.subtract(z11)).multiply(2);
- xl2 = s3.multiply(z2).multiply(-2);
- xl3 = s3.multiply(z3.subtract(z1)).multiply(-2);
- xl4 = s3.multiply(e0sq.multiply(-9).add(-21)).multiply(ze).multiply(-2);
- xgh2 = s4.multiply(z32).multiply(2);
- xgh3 = s4.multiply(z33.subtract(z31)).multiply(2);
- xgh4 = s4.multiply(ze).multiply(-18);
- xh2 = s2.multiply(z22).multiply(-2);
- xh3 = s2.multiply(z23.subtract(z21)).multiply(-2);
- if (iteration == 0) { // we compute lunar terms only on the first pass:
- sse = se;
- ssi = si;
- ssl = sl;
- ssh = (tle.getI().getReal() < pi.divide(60.0).getReal()) ? zero : sh.divide(sini0);
- ssg = sgh.subtract(cosi0.multiply(ssh));
- se2 = ee2;
- si2 = xi2;
- sl2 = xl2;
- sgh2 = xgh2;
- sh2 = xh2;
- se3 = e3;
- si3 = xi3;
- sl3 = xl3;
- sgh3 = xgh3;
- sh3 = xh3;
- sl4 = xl4;
- sgh4 = xgh4;
- zcosg = zero.newInstance(zcosgl);
- zsing = zero.newInstance(zsingl);
- zcosi = zero.newInstance(zcosil);
- zsini = zero.newInstance(zsinil);
- zcosh = cosq.multiply(zcoshl).add(sinq.multiply(zsinhl));
- zsinh = sinq.multiply(zcoshl).subtract(cosq.multiply(zsinhl));
- zn = TLEConstants.ZNL;
- cc = TLEConstants.C1L;
- ze = TLEConstants.ZEL;
- }
- } // end of solar - lunar - solar terms computation
- sse = sse.add(se);
- ssi = ssi.add(si);
- ssl = ssl.add(sl);
- ssg = ssg.add(sgh).subtract((tle.getI().getReal() < pi.divide(60.0).getReal()) ? zero : (cosi0.divide(sini0).multiply(sh)));
- ssh = ssh.add((tle.getI().getReal() < pi.divide(60.0).getReal()) ? zero : sh.divide(sini0));
- // Start the resonant-synchronous tests and initialization
- T bfact = zero;
- // if mean motion is 1.893053 to 2.117652 revs/day, and eccentricity >= 0.5,
- // start of the 12-hour orbit, e > 0.5 section
- if (xnq.getReal() >= 0.00826 && xnq.getReal() <= 0.00924 && tle.getE().getReal() >= 0.5) {
- final T g201 = tle.getE().subtract(0.64).negate().multiply(0.440).add(-0.306);
- final T eoc = tle.getE().multiply(e0sq);
- final T sini2 = sini0.multiply(sini0);
- final T f220 = cosi0.multiply(2).add(theta2).add(1).multiply(0.75);
- final T f221 = sini2.multiply(1.5);
- final T f321 = sini0.multiply(1.875).multiply(cosi0.multiply(2).negate().subtract(theta2.multiply(3)).add(1));
- final T f322 = sini0.multiply(-1.875).multiply(cosi0.multiply(2).subtract(theta2.multiply(3)).add(1));
- final T f441 = sini2.multiply(f220).multiply(35);
- final T f442 = sini2.multiply(sini2).multiply(39.3750);
- final T f522 = sini0.multiply(9.84375).multiply(sini2.multiply(cosi0.multiply(-2).add(theta2.multiply(-5)).add(1.0)).add(
- cosi0.multiply(4.0).add(theta2.multiply(6.0)).add(-2).multiply(0.33333333)));
- final T f523 = sini0.multiply(sini2.multiply(cosi0.multiply(-4).add(theta2.multiply(10)).add(-2)).multiply(4.92187512).add(
- cosi0.multiply(2).subtract(theta2.multiply(3)).add(1).multiply(6.56250012)));
- final T f542 = sini0.multiply(29.53125).multiply(cosi0.multiply(-8).add(2).add(
- theta2.multiply(cosi0.multiply(8).add(theta2.multiply(10)).add(-12))));
- final T f543 = sini0.multiply(29.53125).multiply(cosi0.multiply(-8).add(-2).add(
- theta2.multiply(cosi0.multiply(8).subtract(theta2.multiply(10)).add(12))));
- final T g211;
- final T g310;
- final T g322;
- final T g410;
- final T g422;
- final T g520;
- resonant = true; // it is resonant...
- synchronous = false; // but it's not synchronous
- // Geopotential resonance initialization for 12 hour orbits :
- if (tle.getE().getReal() <= 0.65) {
- g211 = tle.getE().multiply( -13.247).add( e0sq.multiply( 16.290)).add( 3.616);
- g310 = tle.getE().multiply( 117.390).add( e0sq.multiply( -228.419)).add( eoc.multiply( 156.591)).add( -19.302);
- g322 = tle.getE().multiply(109.7927).add( e0sq.multiply(-214.6334)).add( eoc.multiply(146.5816)).add( -18.9068);
- g410 = tle.getE().multiply( 242.694).add( e0sq.multiply( -471.094)).add( eoc.multiply( 313.953)).add( -41.122);
- g422 = tle.getE().multiply( 841.880).add( e0sq.multiply(-1629.014)).add( eoc.multiply(1083.435)).add( -146.407);
- g520 = tle.getE().multiply(3017.977).add( e0sq.multiply(-5740.032)).add( eoc.multiply(3708.276)).add( -532.114);
- } else {
- g211 = tle.getE().multiply( 331.819).add( e0sq.multiply( -508.738)).add( eoc.multiply( 266.724)).add( -72.099);
- g310 = tle.getE().multiply(1582.851).add( e0sq.multiply(-2415.925)).add( eoc.multiply(1246.113)).add( -346.844);
- g322 = tle.getE().multiply(1554.908).add( e0sq.multiply(-2366.899)).add( eoc.multiply(1215.972)).add( -342.585);
- g410 = tle.getE().multiply(4758.686).add( e0sq.multiply(-7193.992)).add( eoc.multiply(3651.957)).add(-1052.797);
- g422 = tle.getE().multiply(16178.11).add( e0sq.multiply(-24462.77)).add( eoc.multiply(12422.52)).add( -3581.69);
- if (tle.getE().getReal() <= 0.715) {
- g520 = tle.getE().multiply(-4664.75).add( e0sq.multiply( 3763.64)).add( 1464.74);
- } else {
- g520 = tle.getE().multiply(29936.92).add( e0sq.multiply(-54087.36)).add( eoc.multiply(31324.56)).add( -5149.66);
- }
- }
- final T g533;
- final T g521;
- final T g532;
- if (tle.getE().getReal() < 0.7) {
- g533 = tle.getE().multiply( 4988.61).add( e0sq.multiply( -9064.77)).add( eoc.multiply( 5542.21)).add( -919.2277);
- g521 = tle.getE().multiply(4568.6173).add( e0sq.multiply(-8491.4146)).add( eoc.multiply( 5337.524)).add( -822.71072);
- g532 = tle.getE().multiply( 4690.25).add( e0sq.multiply( -8624.77)).add( eoc.multiply( 5341.4)).add( -853.666);
- } else {
- g533 = tle.getE().multiply(161616.52).add( e0sq.multiply( -229838.2)).add( eoc.multiply(109377.94)).add( -37995.78);
- g521 = tle.getE().multiply(218913.95).add( e0sq.multiply(-309468.16)).add( eoc.multiply(146349.42)).add( -51752.104);
- g532 = tle.getE().multiply(170470.89).add( e0sq.multiply(-242699.48)).add( eoc.multiply(115605.82)).add( -40023.88);
- }
- T temp1 = xnq.multiply(xnq).multiply(aqnv).multiply(aqnv).multiply(3);
- T temp = temp1.multiply(TLEConstants.ROOT22);
- d2201 = temp.multiply(f220).multiply(g201);
- d2211 = temp.multiply(f221).multiply(g211);
- temp1 = temp1.multiply(aqnv);
- temp = temp1.multiply(TLEConstants.ROOT32);
- d3210 = temp.multiply(f321).multiply(g310);
- d3222 = temp.multiply(f322).multiply(g322);
- temp1 = temp1.multiply(aqnv);
- temp = temp1.multiply(2 * TLEConstants.ROOT44);
- d4410 = temp.multiply(f441).multiply(g410);
- d4422 = temp.multiply(f442).multiply(g422);
- temp1 = temp1.multiply(aqnv);
- temp = temp1.multiply(TLEConstants.ROOT52);
- d5220 = temp.multiply(f522).multiply(g520);
- d5232 = temp.multiply(f523).multiply(g532);
- temp = temp1.multiply(2 * TLEConstants.ROOT54);
- d5421 = temp.multiply(f542).multiply(g521);
- d5433 = temp.multiply(f543).multiply(g533);
- xlamo = tle.getMeanAnomaly().add(tle.getRaan()).add(tle.getRaan()).subtract(thgr + thgr);
- bfact = xmdot.add(xnodot).add(xnodot).subtract(TLEConstants.THDT + TLEConstants.THDT);
- bfact = bfact.add(ssl).add(ssh).add(ssh);
- } else if (xnq.getReal() < 0.0052359877 && xnq.getReal() > 0.0034906585) {
- // if mean motion is .8 to 1.2 revs/day : (geosynch)
- final T cosio_plus_1 = cosi0.add(1.0);
- final T g200 = e0sq.multiply(e0sq.multiply(0.8125).add(-2.5)).add(1);
- final T g300 = e0sq.multiply(e0sq.multiply(6.60937).add(-6)).add(1);
- final T f311 = sini0.multiply(0.9375).multiply(sini0.multiply(cosi0.multiply(3).add(1))).subtract(cosio_plus_1.multiply(0.75));
- final T g310 = e0sq.multiply(2).add(1);
- final T f220 = cosio_plus_1.multiply(cosio_plus_1).multiply(0.75);
- final T f330 = f220.multiply(cosio_plus_1).multiply(2.5);
- resonant = true;
- synchronous = true;
- // Synchronous resonance terms initialization
- del1 = xnq.multiply(xnq).multiply(aqnv).multiply(aqnv).multiply(3);
- del2 = del1.multiply(f220).multiply(g200).multiply(2 * TLEConstants.Q22);
- del3 = del1.multiply(f330).multiply(g300).multiply(aqnv).multiply(3 * TLEConstants.Q33);
- del1 = del1.multiply(f311).multiply(g310).multiply(TLEConstants.Q31).multiply(aqnv);
- xlamo = tle.getMeanAnomaly().add(tle.getRaan()).add(tle.getPerigeeArgument()).subtract(thgr);
- bfact = xmdot.add(omgdot).add(xnodot).subtract(TLEConstants.THDT);
- bfact = bfact.add(ssl).add(ssg).add(ssh);
- } else {
- // it's neither a high-e 12-hours orbit nor a geosynchronous:
- resonant = false;
- synchronous = false;
- }
- if (resonant) {
- xfact = bfact.subtract(xnq);
- // Initialize integrator
- xli = xlamo;
- xni = xnq;
- atime = zero;
- }
- derivs = MathArrays.buildArray(xnq.getField(), 2);
- }
- /** Computes secular terms from current coordinates and epoch.
- * @param t offset from initial epoch (minutes)
- */
- protected void deepSecularEffects(final T t) {
- xll = xll.add(ssl.multiply(t));
- omgadf = omgadf.add(ssg.multiply(t));
- xnode = xnode.add(ssh.multiply(t));
- em = tle.getE().add(sse.multiply(t));
- xinc = tle.getI().add(ssi.multiply(t));
- if (resonant) {
- // If we're closer to t = 0 than to the currently-stored data
- // from the previous call to this function, then we're
- // better off "restarting", going back to the initial data.
- // The Dundee code rigs things up to _always_ take 720-minute
- // steps from epoch to end time, except for the final step.
- // Easiest way to arrange similar behavior in this code is
- // just to always do a restart, if we're in Dundee-compliant
- // mode.
- if (FastMath.abs(t).getReal() < FastMath.abs(t.subtract(atime)).getReal() || isDundeeCompliant) {
- // Epoch restart
- atime = t.getField().getZero();
- xni = xnq;
- xli = xlamo;
- }
- boolean lastIntegrationStep = false;
- // if |step|>|step max| then do one step at step max
- while (!lastIntegrationStep) {
- double delt = t.subtract(atime).getReal();
- if (delt > SECULAR_INTEGRATION_STEP) {
- delt = SECULAR_INTEGRATION_STEP;
- } else if (delt < -SECULAR_INTEGRATION_STEP) {
- delt = -SECULAR_INTEGRATION_STEP;
- } else {
- lastIntegrationStep = true;
- }
- computeSecularDerivs();
- final T xldot = xni.add(xfact);
- T xlpow = t.getField().getOne();
- xli = xli.add(xldot.multiply(delt));
- xni = xni.add(derivs[0].multiply(delt));
- double delt_factor = delt;
- xlpow = xlpow.multiply(xldot);
- derivs[1] = derivs[1].multiply(xlpow);
- delt_factor *= delt / 2;
- xli = xli.add(derivs[0].multiply(delt_factor));
- xni = xni.add(derivs[1].multiply(delt_factor));
- atime = atime.add(delt);
- }
- xn = xni;
- final T temp = xnode.negate().add(thgr).add(t.multiply(TLEConstants.THDT));
- xll = xli.add(temp).add(synchronous ? omgadf.negate() : temp);
- }
- }
- /** Computes periodic terms from current coordinates and epoch.
- * @param t offset from initial epoch (min)
- */
- protected void deepPeriodicEffects(final T t) {
- // If the time didn't change by more than 30 minutes,
- // there's no good reason to recompute the perturbations;
- // they don't change enough over so short a time span.
- // However, the Dundee code _always_ recomputes, so if
- // we're attempting to replicate its results, we've gotta
- // recompute everything, too.
- if (FastMath.abs(savtsn.subtract(t).getReal()) >= 30.0 || isDundeeCompliant) {
- savtsn = t;
- // Update solar perturbations for time T
- T zm = t.multiply(TLEConstants.ZNS).add(zmos);
- T zf = zm.add(FastMath.sin(zm).multiply(2 * TLEConstants.ZES));
- FieldSinCos<T> sczf = FastMath.sinCos(zf);
- T sinzf = sczf.sin();
- T f2 = sinzf.multiply(sinzf).multiply(0.5).subtract(0.25);
- T f3 = sinzf.multiply(sczf.cos()).multiply(-0.5);
- final T ses = se2.multiply(f2).add(se3.multiply(f3));
- final T sis = si2.multiply(f2).add(si3.multiply(f3));
- final T sls = sl2.multiply(f2).add(sl3.multiply(f3)).add(sl4.multiply(sinzf));
- final T sghs = sgh2.multiply(f2).add(sgh3.multiply(f3)).add(sgh4.multiply(sinzf));
- final T shs = sh2.multiply(f2).add(sh3.multiply(f3));
- // Update lunar perturbations for time T
- zm = t.multiply(TLEConstants.ZNL).add(zmol);
- zf = zm.add(FastMath.sin(zm).multiply(2 * TLEConstants.ZEL));
- sczf = FastMath.sinCos(zf);
- sinzf = sczf.sin();
- f2 = sinzf.multiply(sinzf).multiply(0.5).subtract(0.25);
- f3 = sinzf.multiply(sczf.cos()).multiply(-0.5);
- final T sel = ee2.multiply(f2).add(e3.multiply(f3));
- final T sil = xi2.multiply(f2).add(xi3.multiply(f3));
- final T sll = xl2.multiply(f2).add(xl3.multiply(f3)).add(xl4.multiply(sinzf));
- final T sghl = xgh2.multiply(f2).add(xgh3.multiply(f3)).add(xgh4.multiply(sinzf));
- final T sh1 = xh2.multiply(f2).add(xh3.multiply(f3));
- // Sum the solar and lunar contributions
- pe = ses.add(sel);
- pinc = sis.add(sil);
- pl = sls.add(sll);
- pgh = sghs.add(sghl);
- ph = shs.add(sh1);
- }
- xinc = xinc.add(pinc);
- final FieldSinCos<T> scis = FastMath.sinCos(xinc);
- final T sinis = scis.sin();
- final T cosis = scis.cos();
- /* Add solar/lunar perturbation correction to eccentricity: */
- em = em.add(pe);
- xll = xll.add(pl);
- omgadf = omgadf.add(pgh);
- xinc = MathUtils.normalizeAngle(xinc, t.getField().getZero());
- if (FastMath.abs(xinc).getReal() >= 0.2) {
- // Apply periodics directly
- final T temp_val = ph.divide(sinis);
- omgadf = omgadf.subtract(cosis.multiply(temp_val));
- xnode = xnode.add(temp_val);
- } else {
- // Apply periodics with Lyddane modification
- final FieldSinCos<T> scok = FastMath.sinCos(xnode);
- final T sinok = scok.sin();
- final T cosok = scok.cos();
- final T alfdp = ph.multiply(cosok).add((pinc.multiply(cosis).add(sinis)).multiply(sinok));
- final T betdp = ph.negate().multiply(sinok).add((pinc.multiply(cosis).add(sinis)).multiply(cosok));
- final T delta_xnode = MathUtils.normalizeAngle(FastMath.atan2(alfdp, betdp).subtract(xnode), t.getField().getZero());
- final T dls = xnode.negate().multiply(sinis).multiply(pinc);
- omgadf = omgadf.add(dls.subtract(cosis.multiply(delta_xnode)));
- xnode = xnode.add(delta_xnode);
- }
- }
- /** Computes internal secular derivs. */
- private void computeSecularDerivs() {
- final FieldSinCos<T> sc_li = FastMath.sinCos(xli);
- final T sin_li = sc_li.sin();
- final T cos_li = sc_li.cos();
- final T sin_2li = sin_li.multiply(cos_li).multiply(2.);
- final T cos_2li = cos_li.multiply(cos_li).multiply(2.).subtract(1.);
- // Dot terms calculated :
- if (synchronous) {
- final T sin_3li = sin_2li.multiply(cos_li).add(cos_2li.multiply(sin_li));
- final T cos_3li = cos_2li.multiply(cos_li).subtract(sin_2li.multiply(sin_li));
- final T term1a = del1.multiply(sin_li .multiply(TLEConstants.C_FASX2) .subtract(cos_li .multiply(TLEConstants.S_FASX2 )));
- final T term2a = del2.multiply(sin_2li.multiply(TLEConstants.C_2FASX4).subtract(cos_2li.multiply(TLEConstants.S_2FASX4)));
- final T term3a = del3.multiply(sin_3li.multiply(TLEConstants.C_3FASX6).subtract(cos_3li.multiply(TLEConstants.S_3FASX6)));
- final T term1b = del1.multiply(cos_li .multiply(TLEConstants.C_FASX2) .add(sin_li .multiply(TLEConstants.S_FASX2 )));
- final T term2b = del2.multiply(cos_2li.multiply(TLEConstants.C_2FASX4) .add(sin_2li.multiply(TLEConstants.S_2FASX4))).multiply(2.0);
- final T term3b = del3.multiply(cos_3li.multiply(TLEConstants.C_3FASX6) .add(sin_3li.multiply(TLEConstants.S_3FASX6))).multiply(3.0);
- derivs[0] = term1a.add(term2a).add(term3a);
- derivs[1] = term1b.add(term2b).add(term3b);
- } else {
- // orbit is a 12-hour resonant one
- final T xomi = omegaq.add(omgdot.multiply(atime));
- final FieldSinCos<T> sc_omi = FastMath.sinCos(xomi);
- final T sin_omi = sc_omi.sin();
- final T cos_omi = sc_omi.cos();
- final T sin_li_m_omi = sin_li.multiply(cos_omi).subtract(sin_omi.multiply(cos_li));
- final T sin_li_p_omi = sin_li.multiply(cos_omi).add( sin_omi.multiply(cos_li));
- final T cos_li_m_omi = cos_li.multiply(cos_omi).add( sin_omi.multiply(sin_li));
- final T cos_li_p_omi = cos_li.multiply(cos_omi).subtract(sin_omi.multiply(sin_li));
- final T sin_2omi = sin_omi.multiply(cos_omi).multiply(2.0);
- final T cos_2omi = cos_omi.multiply(cos_omi).multiply(2.0).subtract(1.0);
- final T sin_2li_m_omi = sin_2li.multiply(cos_omi ).subtract(sin_omi .multiply(cos_2li));
- final T sin_2li_p_omi = sin_2li.multiply(cos_omi ).add( sin_omi .multiply(cos_2li));
- final T cos_2li_m_omi = cos_2li.multiply(cos_omi ).add( sin_omi .multiply(sin_2li));
- final T cos_2li_p_omi = cos_2li.multiply(cos_omi ).subtract(sin_omi .multiply(sin_2li));
- final T sin_2li_p_2omi = sin_2li.multiply(cos_2omi).add( sin_2omi.multiply(cos_2li));
- final T cos_2li_p_2omi = cos_2li.multiply(cos_2omi).subtract(sin_2omi.multiply(sin_2li));
- final T sin_2omi_p_li = sin_li .multiply(cos_2omi).add( sin_2omi.multiply(cos_li ));
- final T cos_2omi_p_li = cos_li .multiply(cos_2omi).subtract(sin_2omi.multiply(sin_li ));
- final T term1a = d2201.multiply(sin_2omi_p_li .multiply(TLEConstants.C_G22).subtract(cos_2omi_p_li .multiply(TLEConstants.S_G22))) .add(
- d2211.multiply(sin_li .multiply(TLEConstants.C_G22).subtract(cos_li .multiply(TLEConstants.S_G22)))).add(
- d3210.multiply(sin_li_p_omi .multiply(TLEConstants.C_G32).subtract(cos_li_p_omi .multiply(TLEConstants.S_G32)))).add(
- d3222.multiply(sin_li_m_omi .multiply(TLEConstants.C_G32).subtract(cos_li_m_omi .multiply(TLEConstants.S_G32)))).add(
- d5220.multiply(sin_li_p_omi .multiply(TLEConstants.C_G52).subtract(cos_li_p_omi .multiply(TLEConstants.S_G52)))).add(
- d5232.multiply(sin_li_m_omi .multiply(TLEConstants.C_G52).subtract(cos_li_m_omi .multiply(TLEConstants.S_G52))));
- final T term2a = d4410.multiply(sin_2li_p_2omi.multiply(TLEConstants.C_G44).subtract(cos_2li_p_2omi.multiply(TLEConstants.S_G44))) .add(
- d4422.multiply(sin_2li .multiply(TLEConstants.C_G44).subtract(cos_2li .multiply(TLEConstants.S_G44)))).add(
- d5421.multiply(sin_2li_p_omi .multiply(TLEConstants.C_G54).subtract(cos_2li_p_omi .multiply(TLEConstants.S_G54)))).add(
- d5433.multiply(sin_2li_m_omi .multiply(TLEConstants.C_G54).subtract(cos_2li_m_omi .multiply(TLEConstants.S_G54))));
- final T term1b = d2201.multiply(cos_2omi_p_li .multiply(TLEConstants.C_G22) .add(sin_2omi_p_li .multiply(TLEConstants.S_G22))) .add(
- d2211.multiply(cos_li .multiply(TLEConstants.C_G22) .add(sin_li .multiply(TLEConstants.S_G22)))).add(
- d3210.multiply(cos_li_p_omi .multiply(TLEConstants.C_G32) .add(sin_li_p_omi .multiply(TLEConstants.S_G32)))).add(
- d3222.multiply(cos_li_m_omi .multiply(TLEConstants.C_G32) .add(sin_li_m_omi .multiply(TLEConstants.S_G32)))).add(
- d5220.multiply(cos_li_p_omi .multiply(TLEConstants.C_G52) .add(sin_li_p_omi .multiply(TLEConstants.S_G52)))).add(
- d5232.multiply(cos_li_m_omi .multiply(TLEConstants.C_G52) .add(sin_li_m_omi .multiply(TLEConstants.S_G52))));
- final T term2b = d4410.multiply(cos_2li_p_2omi.multiply(TLEConstants.C_G44) .add(sin_2li_p_2omi.multiply(TLEConstants.S_G44))) .add(
- d4422.multiply(cos_2li .multiply(TLEConstants.C_G44) .add(sin_2li .multiply(TLEConstants.S_G44)))).add(
- d5421.multiply(cos_2li_p_omi .multiply(TLEConstants.C_G54) .add(sin_2li_p_omi .multiply(TLEConstants.S_G54)))).add(
- d5433.multiply(cos_2li_m_omi .multiply(TLEConstants.C_G54) .add(sin_2li_m_omi .multiply(TLEConstants.S_G54)))).multiply(2.0);
- derivs[0] = term1a.add(term2a);
- derivs[1] = term1b.add(term2b);
- }
- }
- }