public static void calculateSatellitePosition(string catalogID, Site site)
{
// update TLE values
if (dataObject.getLatestN(satelliteList, numTLEs)) { writeConfigSatelliteFile(); }
Satellite theSat;
dataObject.satelliteList.TryGetValue(catalogID, out theSat);
TLE tle = new TLE(theSat.TLEs[0].name, theSat.TLEs[0].line1, theSat.TLEs[0].line2);
// Create an orbit object using the TLE object.
Orbit orbit = new Orbit(tle);
// Get the location of the satellite from the Orbit object. The
// earth-centered inertial information is placed into eciSDP4.
// Here we ask for the location of the satellite 90 minutes after
// the TLE epoch.
//EciTime eciSDP4 = orbitSDP4.GetPosition(90.0);
// get the position, as of NOW!!!
EciTime eciSDP4 = orbit.GetPosition((DateTime.UtcNow - orbit.EpochTime).TotalMinutes);
Console.Write("\n TSINCE X Y Z\n");
Console.Write("{0,12} {1,19:f8} {2,19:f8} {3,19:f8}\n",
DateTime.UtcNow.ToString(),
eciSDP4.Position.X,
eciSDP4.Position.Y,
eciSDP4.Position.Z);
Console.Write("\n XVEL YVEL ZVEL\n");
Console.Write("{0,38:f8} {1,20:f8} {2,20:f8}\n",
eciSDP4.Velocity.X,
eciSDP4.Velocity.Y,
eciSDP4.Velocity.Z);
// Now get the "look angle" from the site to the satellite.
// Note that the ECI object "eciSDP4" has a time associated
// with the coordinates it contains; this is the time at which
// the look angle is valid.
Topo topoLook = site.GetLookAngle(eciSDP4);
// Print out the results. Note that the Azimuth and Elevation are
// stored in the CoordTopo object as radians. Here we convert
// to degrees using Rad2Deg()
Console.Write("\n{0,15} - AZ: {1:f3} EL: {2:f3}\n", tle.Name, topoLook.AzimuthDeg, topoLook.ElevationDeg);
Console.WriteLine("-------------------------------------------------------------------------");
}
// //////////////////////////////////////////////////////////////////////////
//
// Routine to output position and velocity information of satellite
// in orbit described by TLE information.
//
static void PrintPosVel(TLE tle)
{
const int Step = 360;
Orbit orbit = new Orbit(tle);
List<Eci> coords = new List<Eci>();
// Calculate position, velocity
// mpe = "minutes past epoch"
for (int mpe = 0; mpe <= (Step * 4); mpe += Step)
{
// Get the position of the satellite at time "mpe".
// The coordinates are placed into the variable "eci".
Eci eci = orbit.GetPosition(mpe);
// Add the coordinate object to the list
coords.Add(eci);
}
// Print TLE data
Console.Write("{0}\n", tle.Name);
Console.Write("{0}\n", tle.Line1);
Console.Write("{0}\n", tle.Line2);
// Header
Console.Write("\n TSINCE X Y Z\n\n");
// Iterate over each of the ECI position objects pushed onto the
// coordinate list, above, printing the ECI position information
// as we go.
for (int i = 0; i < coords.Count; i++)
{
Eci e = coords[i] as Eci;
Console.Write("{0,8}.00 {1,16:f8} {2,16:f8} {3,16:f8}\n",
i * Step,
e.Position.X,
e.Position.Y,
e.Position.Z);
}
Console.Write("\n XVEL YVEL ZVEL\n\n");
// Iterate over each of the ECI position objects in the coordinate
// list again, but this time print the velocity information.
for (int i = 0; i < coords.Count; i++)
{
Eci e = coords[i] as Eci;
Console.Write("{0,24:f8} {1,16:f8} {2,16:f8}\n",
e.Velocity.X,
e.Velocity.Y,
e.Velocity.Z);
}
}
// ///////////////////////////////////////////////////////////////////
protected double GetRad(TLE.Field fld)
{
return Tle.GetField(fld, TLE.Unit.Radians);
}
// ///////////////////////////////////////////////////////////////////
protected double GetDeg(TLE.Field fld)
{
return Tle.GetField(fld, TLE.Unit.Degrees);
}
// //////////////////////////////////////////////////////////////////////////
public TLE(TLE tle)
: this(tle.Name, tle.Line1, tle.Line2)
{
}
/// <summary>
/// Standard constructor.
/// </summary>
/// <param name="tle">Two-line element orbital parameters.</param>
public Orbit(TLE tle)
{
Tle = tle;
Epoch = Tle.EpochJulian;
m_Inclination = GetRad(TLE.Field.Inclination);
m_Eccentricity = Tle.GetField(TLE.Field.Eccentricity);
m_RAAN = GetRad(TLE.Field.Raan);
m_ArgPerigee = GetRad(TLE.Field.ArgPerigee);
m_BStar = Tle.GetField(TLE.Field.BStarDrag);
m_Drag = Tle.GetField(TLE.Field.MeanMotionDt);
m_MeanAnomaly = GetRad(TLE.Field.MeanAnomaly);
m_TleMeanMotion = Tle.GetField(TLE.Field.MeanMotion);
// Recover the original mean motion and semimajor axis from the
// input elements.
double mm = TleMeanMotion;
double rpmin = mm * Globals.TwoPi / Globals.MinPerDay; // rads per minute
double a1 = Math.Pow(Globals.Xke / rpmin, 2.0 / 3.0);
double e = Eccentricity;
double i = Inclination;
double temp = (1.5 * Globals.Ck2 * (3.0 * Globals.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 = Globals.Xkmper * (m_aeAxisSemiMajorRec * (1.0 - e) - Globals.Ae);
m_kmApogeeRec = Globals.Xkmper * (m_aeAxisSemiMajorRec * (1.0 + e) - Globals.Ae);
if (Period.TotalMinutes >= 225.0)
{
// SDP4 - period >= 225 minutes.
NoradModel = new NoradSDP4(this);
}
else
{
// SGP4 - period < 225 minutes
NoradModel = new NoradSGP4(this);
}
}
