public OrbitalElements ToOrbitalElements(Quantity mu)
{
var eccA = (velocity.SqrMagitude - (mu / position.Magnitude).Magnitude) * position;
var eccB = Quantity3.Dot(position, velocity) * velocity;
var eccVec = (eccA - eccB) / mu;
var oe = new OrbitalElements();
oe.Eccentricity = eccVec.Magnitude.DoubleValue;
var specMechEnergy = (velocity.SqrMagitude / 2) - (mu / position.Magnitude);
oe.SemiMajorAxis = -1 * (mu / (2 * specMechEnergy.Magnitude));
Quantity3 angularMomentum = Quantity3.Cross(position, velocity);
oe.Inclination = Math.Acos((angularMomentum.Y / angularMomentum.Magnitude).DoubleValue);
Quantity3 nodeVector = Quantity3.Cross(new Quantity3(SciNumber.One, SciNumber.Zero, SciNumber.Zero), angularMomentum);
oe.LongitudeOfAscendingNode = Math.Acos((nodeVector.X / nodeVector.Magnitude).DoubleValue);
oe.ArgumentOfPeriapsis = Math.Acos((Quantity3.Dot(nodeVector, eccVec) / (nodeVector.Magnitude * eccVec.Magnitude)).DoubleValue);
oe.TrueAnomoly = Math.Acos((Quantity3.Dot(eccVec, position) / (eccVec.Magnitude * position.Magnitude)).DoubleValue);
return(oe);
}
public virtual string getDefaultUnit(string unitPreference)
{
string selUnit = Unit1;
if (defaultQuantity == null || defaultQuantity == 0)
{
selUnit = Unit1;
if (Quantity2 != null && !Quantity2.Equals(BigDecimalMath.ZERO))
{
selUnit = Unit2;
}
if (Quantity3 != null && !Quantity3.Equals(BigDecimalMath.ZERO))
{
selUnit = Unit3;
}
if (QuantityF != null && !QuantityF.Equals(BigDecimalMath.ZERO))
{
selUnit = UnitF;
}
}
else if (defaultQuantity.Value == 1)
{
selUnit = Unit1;
}
else if (defaultQuantity.Value == 2)
{
selUnit = Unit2;
}
else if (defaultQuantity.Value == 3)
{
selUnit = Unit3;
}
else if (defaultQuantity.Value == 4)
{
selUnit = UnitF;
}
if (!selUnit.Equals(unitPreference))
{
if (Quantity1 != null && unitPreference.Equals(Unit1))
{
selUnit = Unit1;
}
if (Quantity2 != null && unitPreference.Equals(Unit2))
{
selUnit = Unit2;
}
if (Quantity3 != null && unitPreference.Equals(Unit3))
{
selUnit = Unit3;
}
if (QuantityF != null && unitPreference.Equals(UnitF))
{
selUnit = UnitF;
}
//System.out.println("AFTER COMPARING: "+selUnit+ " and "+ut);
}
return(selUnit);
}
public static Quantity3 Cross(Quantity3 a, Quantity3 b)
{
return(new Quantity3(new List <SciNumber>()
{
(a.Y * b.Z - a.Z * b.Y).TrueValue,
(a.Z * b.X - a.X * b.Z).TrueValue,
(a.X * b.Y - a.Y * b.X).TrueValue,
}, a.units + b.units));
}
private Quantity3 PositionAt(double timestep)
{
var e = orbitalElements.Eccentricity;
var M = MeanAnomoly(orbitalElements.TrueAnomoly, e);
var E = EccentricAnomoly(M, e);
var P = orbitalElements.SemiMajorAxis * (Math.Cos(E) - e);
var Q = orbitalElements.SemiMajorAxis * Math.Sin(E) * Math.Sqrt(1 - (e * e));
var perifocal = new Quantity3(P.TrueValue, Q.TrueValue, SciNumber.Zero, orbitalElements.SemiMajorAxis.units);
return(perifocal.Mul(orbitalElements.PerifocalToEquitorial()));
}
/// <param name="trueAnomoly">Provide a true anomoly to sample the orbit</param>
public MechanicalElements ToMechanicalElements(Quantity mu, double?trueAnomoly = null)
{
var ta = trueAnomoly ?? this.TrueAnomoly;
var rA = SemiMajorAxis / (1 + Eccentricity * Math.Cos(ta));
var perifocalR = new Quantity3(rA.TrueValue * Math.Cos(ta), rA.TrueValue * Math.Sin(ta), SciNumber.Zero, rA.units);
var vP = new SciNumber(-Math.Sin(ta));
var vQ = new SciNumber(Eccentricity + Math.Cos(ta));
var perifocalV = (mu / SemiMajorAxis).Sqrt <Quantity>() * new Quantity3(vP, vQ, SciNumber.Zero);
//TODO: use doubles instead
var pToE = PerifocalToEquitorial();
return(new MechanicalElements()
{
position = perifocalR.Mul(pToE),
velocity = perifocalV.Mul(pToE),
});
}
public Quantity4(Quantity3 xyz, SciNumber w) :
base(new List <SciNumber>() { xyz.X.TrueValue, xyz.Y.TrueValue, xyz.Z.TrueValue, w }, xyz.units)
{
}
public static Quantity Dot(Quantity3 a, Quantity3 b)
{
return((a.X * b.X) + (a.Y * b.Y) + (a.Z * b.Z));
}
