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Costa-Dyakiw/src/jat/core/cm/ThreeBodyAPL.java
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/* JAT: Java Astrodynamics Toolkit | |
* | |
Copyright 2012 Tobias Berthold | |
Licensed 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 jat.core.cm; | |
import jat.coreNOSA.algorithm.integrators.Printable; | |
import jat.coreNOSA.cm.Constants; | |
import jat.coreNOSA.cm.TwoBody; | |
import jat.coreNOSA.math.MatrixVector.data.Matrix; | |
import jat.coreNOSA.math.MatrixVector.data.VectorN; | |
import java.util.ArrayList; | |
import org.apache.commons.math3.geometry.euclidean.threed.Vector3D; | |
import org.apache.commons.math3.ode.FirstOrderDifferentialEquations; | |
import org.apache.commons.math3.ode.sampling.StepHandler; | |
import org.apache.commons.math3.ode.sampling.StepInterpolator; | |
public class ThreeBodyAPL extends ThreeBody implements FirstOrderDifferentialEquations { | |
double initial_ta; | |
public ArrayList<Double> time = new ArrayList<Double>(); | |
public ArrayList<Double> xsol = new ArrayList<Double>(); | |
public ArrayList<Double> ysol = new ArrayList<Double>(); | |
public ArrayList<Double> zsol = new ArrayList<Double>(); | |
public ThreeBodyAPL(double mu, VectorN r, VectorN v) { | |
super(mu, r, v); | |
initial_ta = ta; | |
} | |
public ThreeBodyAPL(double a, double e, double i, double raan, double w, double ta) { | |
super(a, e, i, raan, w, ta); | |
} | |
@Override | |
public void computeDerivatives(double t, double[] y, double[] yDot) { | |
Vector3D r = new Vector3D(y[0], y[1], y[2]); | |
double rnorm = r.getNorm(); | |
double r3 = rnorm * rnorm * rnorm; | |
double k = -1. * this.mu / r3; | |
yDot[0] = y[3]; | |
yDot[1] = y[4]; | |
yDot[2] = y[5]; | |
yDot[3] = k * y[0]; | |
yDot[4] = k * y[1]; | |
yDot[5] = k * y[2]; | |
} | |
public StepHandler stepHandler = new StepHandler() { | |
public void init(double t0, double[] y0, double t) { | |
} | |
public void handleStep(StepInterpolator interpolator, boolean isLast) { | |
double t = interpolator.getCurrentTime(); | |
double[] y = interpolator.getInterpolatedState(); | |
// System.out.println(t + " " + y[0] + " " + y[1]+ " " + y[2]); | |
time.add(t); | |
xsol.add(y[0]); | |
ysol.add(y[1]); | |
zsol.add(y[2]); | |
} | |
}; | |
@Override | |
public int getDimension() { | |
return 6; | |
} | |
public VectorN position(double t) { | |
double[] temp = new double[6]; | |
// Determine step size | |
double n = this.meanMotion(); | |
// determine initial E and M | |
double sqrome2 = Math.sqrt(1.0 - this.e * this.e); | |
double cta = Math.cos(this.ta); | |
double sta = Math.sin(this.ta); | |
double sine0 = (sqrome2 * sta) / (1.0 + this.e * cta); | |
double cose0 = (this.e + cta) / (1.0 + this.e * cta); | |
double e0 = Math.atan2(sine0, cose0); | |
double ma = e0 - this.e * Math.sin(e0); | |
ma = ma + n * t; | |
double ea = solveKepler(ma, this.e); | |
double sinE = Math.sin(ea); | |
double cosE = Math.cos(ea); | |
double den = 1.0 - this.e * cosE; | |
double sinv = (sqrome2 * sinE) / den; | |
double cosv = (cosE - this.e) / den; | |
this.ta = Math.atan2(sinv, cosv); | |
if (this.ta < 0.0) { | |
this.ta = this.ta + 2.0 * Constants.pi; | |
} | |
temp = this.randv(); | |
this.rv = new VectorN(temp); | |
// Reset everything to before | |
this.ta = initial_ta; | |
VectorN out = new VectorN(3); | |
out.x[0] = temp[0]; | |
out.x[1] = temp[1]; | |
out.x[2] = temp[2]; | |
// out.print("sat pos at t"); | |
return out; | |
} | |
// propagates from whatever ta is starting from time t=0 relative to the | |
// starting point | |
public void propagate(double t0, double tf, Printable pr, boolean print_switch, double steps) { | |
double[] temp = new double[6]; | |
// double ta_save = this.ta; | |
this.steps = steps; | |
// Determine step size | |
double n = this.meanMotion(); | |
double period = this.period(); | |
double dt = period / steps; | |
if ((t0 + dt) > tf) // check to see if we're going past tf | |
{ | |
dt = tf - t0; | |
} | |
// determine initial E and M | |
double sqrome2 = Math.sqrt(1.0 - this.e * this.e); | |
double cta = Math.cos(this.ta); | |
double sta = Math.sin(this.ta); | |
double sine0 = (sqrome2 * sta) / (1.0 + this.e * cta); | |
double cose0 = (this.e + cta) / (1.0 + this.e * cta); | |
double e0 = Math.atan2(sine0, cose0); | |
double ma = e0 - this.e * Math.sin(e0); | |
// initialize t | |
double t = t0; | |
if (print_switch) { | |
temp = this.randv(); | |
pr.print(t, temp); | |
} | |
while (t < tf) { | |
ma = ma + n * dt; | |
double ea = solveKepler(ma, this.e); | |
double sinE = Math.sin(ea); | |
double cosE = Math.cos(ea); | |
double den = 1.0 - this.e * cosE; | |
double sinv = (sqrome2 * sinE) / den; | |
double cosv = (cosE - this.e) / den; | |
this.ta = Math.atan2(sinv, cosv); | |
if (this.ta < 0.0) { | |
this.ta = this.ta + 2.0 * Constants.pi; | |
} | |
t = t + dt; | |
temp = this.randv(); | |
this.rv = new VectorN(temp); | |
if (print_switch) { | |
pr.print(t, temp); | |
} | |
if ((t + dt) > tf) { | |
dt = tf - t; | |
} | |
} | |
// Reset everything to before | |
this.ta = initial_ta; | |
} | |
public double[] randv(double ta) { | |
double p = a * (1.0 - e * e); | |
double cta = Math.cos(ta); | |
double sta = Math.sin(ta); | |
double opecta = 1.0 + e * cta; | |
double sqmuop = Math.sqrt(this.mu / p); | |
VectorN xpqw = new VectorN(6); | |
xpqw.x[0] = p * cta / opecta; | |
xpqw.x[1] = p * sta / opecta; | |
xpqw.x[2] = 0.0; | |
xpqw.x[3] = -sqmuop * sta; | |
xpqw.x[4] = sqmuop * (e + cta); | |
xpqw.x[5] = 0.0; | |
Matrix cmat = PQW2ECI(); | |
VectorN rpqw = new VectorN(xpqw.x[0], xpqw.x[1], xpqw.x[2]); | |
VectorN vpqw = new VectorN(xpqw.x[3], xpqw.x[4], xpqw.x[5]); | |
VectorN rijk = cmat.times(rpqw); | |
VectorN vijk = cmat.times(vpqw); | |
double[] out = new double[6]; | |
for (int i = 0; i < 3; i++) { | |
out[i] = rijk.x[i]; | |
out[i + 3] = vijk.x[i]; | |
} | |
return out; | |
} | |
public double eccentricAnomaly(double ta) { | |
double cta = Math.cos(ta); | |
double e0 = Math.acos((e + cta) / (1.0 + e * cta)); | |
return e0; | |
} | |
public double meanAnomaly(double t) { | |
return 2. * Math.PI * t / period(); | |
} | |
public double t_from_ta() { | |
double M = meanAnomaly(); | |
double P = period(); | |
return P * M / 2. / Math.PI; | |
} | |
public double ta_from_t(double t) { | |
double M = meanAnomaly(t); | |
double ea = solveKepler(M, this.e); | |
double sinE = Math.sin(ea); | |
double cosE = Math.cos(ea); | |
double den = 1.0 - this.e * cosE; | |
double sqrome2 = Math.sqrt(1.0 - this.e * this.e); | |
double sinv = (sqrome2 * sinE) / den; | |
double cosv = (cosE - this.e) / den; | |
double ta = Math.atan2(sinv, cosv); | |
if (this.ta < 0.0) { | |
this.ta = this.ta + 2.0 * Constants.pi; | |
} | |
return ta; | |
} | |
} |