/// <summary>
/// Standard constructor.
/// </summary>
/// <param name="tle">Two-line element orbital parameters.</param>
public Orbit(TwoLineElement tle)
{
TwoLineElement = tle;
Epoch = TwoLineElement.EpochJulian;
m_Inclination = GetRad(TwoLineElement.Field.Inclination);
m_Eccentricity = TwoLineElement.GetField(TwoLineElement.Field.Eccentricity);
m_RAAN = GetRad(TwoLineElement.Field.Raan);
m_ArgPerigee = GetRad(TwoLineElement.Field.ArgPerigee);
m_BStar = TwoLineElement.GetField(TwoLineElement.Field.BStarDrag);
m_Drag = TwoLineElement.GetField(TwoLineElement.Field.MeanMotionDt);
m_MeanAnomaly = GetRad(TwoLineElement.Field.MeanAnomaly);
m_TleMeanMotion = TwoLineElement.GetField(TwoLineElement.Field.MeanMotion);
// Recover the original mean motion and semimajor axis from the
// input elements.
double mm = TleMeanMotion;
double rpmin = mm * OrbitConsts.TwoPi / OrbitConsts.MinPerDay; // rads per second
double a1 = Math.Pow(OrbitConsts.Xke / rpmin, 2.0 / 3.0);
double e = Eccentricity;
double i = Inclination;
double temp = (1.5 * OrbitConsts.Ck2 * (3.0 * GeoMath.Sqr(Math.Cos(i)) - 1.0) /
Math.Pow(1.0 - e * e, 1.5));
double delta1 = temp / (a1 * a1);
double a0 = a1 *
(1.0 - delta1 *
((1.0 / 3.0) + delta1 *
(1.0 + 134.0 / 81.0 * delta1)));
double delta0 = temp / (a0 * a0);
m_rmMeanMotionRec = rpmin / (1.0 + delta0);
m_aeAxisSemiMajorRec = a0 / (1.0 - delta0);
m_aeAxisSemiMinorRec = m_aeAxisSemiMajorRec * Math.Sqrt(1.0 - (e * e));
m_kmPerigeeRec = OrbitConsts.RadiusOfEquator * (m_aeAxisSemiMajorRec * (1.0 - e) - OrbitConsts.Ae);
m_kmApogeeRec = OrbitConsts.RadiusOfEquator * (m_aeAxisSemiMajorRec * (1.0 + e) - OrbitConsts.Ae);
//针对周期的不同，选择不同的模型。
if (Period.TotalMinutes >= 225.0)
{
// SDP4 - period >= 225 minutes.
NoradModel = new NoradSDP4(this);
}
else
{
// SGP4 - period < 225 minutes
NoradModel = new NoradSGP4(this);
}
}
protected double GetDeg(TwoLineElement.Field fld)
{
return TwoLineElement.GetField(fld, AngleUnit.Degree);
}
protected double GetRad(TwoLineElement.Field fld)
{
return TwoLineElement.GetField(fld, AngleUnit.Radian);
}