//! Convert to ECI
/*!
* \param double SidrealTime
* \return point3D ECI-Position vector of the Coordinate
*/
public Structs.point3D toECI(double siderealTime)
{
double srt = siderealTime;
double lat_rad = Constants.toRadians * latetude;
Structs.point3D eciPos = new Structs.point3D();
double c = 1.0 / Math.Sqrt(1.0 + f * (f - 2.0) *
(Math.Sin(lat_rad) * Math.Sin(lat_rad)));
double s = (1.0 - f) * (1.0 - f) * c;
eciPos.x = a_Wgs72 * c * Math.Cos(lat_rad) * Math.Cos(srt);
eciPos.y = a_Wgs72 * c * Math.Cos(lat_rad) * Math.Sin(srt);
eciPos.z = a_Wgs72 * s * Math.Sin(lat_rad);
return(eciPos);
}
//! Calculate ContactWindows for satellite and groundstations
/*!
* \param Station to calcuate if satellite is in View
* \param TimeDate start time
* \param List<Sgp4Data> satellite position vector
* \param string name of the satellite
* \param double tick in witch time is increased by each step
* \return List<contactWindow>
*/
public void calcContactWindows()
{
One_Sgp4.EpochTime starttime = new One_Sgp4.EpochTime(_time);
bool visible = false;
ContactWindow window = null;
double minElevation = _station.getMinElevation();
for (int i = 0; i < _satPosData.Count(); i++)
{
double lsr = starttime.getLocalSiderealTime(_station.getLongitude());
Structs.point3D groundLocation = _station.getEci(lsr);
Structs.point3D v = new Structs.point3D();
v.x = _satPosData[i].getX() - groundLocation.x;
v.y = _satPosData[i].getY() - groundLocation.y;
v.z = _satPosData[i].getZ() - groundLocation.z;
double r_lat = _station.getLatitude() * Constants.toRadians;
double sin_lat = Math.Sin(r_lat);
double cos_lat = Math.Cos(r_lat);
double sin_srt = Math.Sin(lsr);
double cos_srt = Math.Cos(lsr);
double rs = sin_lat * cos_srt * v.x
+ sin_lat * sin_srt * v.y
- cos_lat * v.z;
double re = -sin_srt * v.x
+ cos_srt * v.y;
double rz = cos_lat * cos_srt * v.x
+ cos_lat * sin_srt * v.y + sin_lat * v.z;
double range = Math.Sqrt(rs * rs + re * re + rz * rz);
double elevation = Math.Asin(rz / range);
double azimuth = Math.Atan(-re / rs);
if (rs > 0.0)
{
azimuth += Constants.pi;
}
if (azimuth < 0.0)
{
azimuth += Constants.twoPi;
}
if (elevation >= minElevation)
{
if (visible == false)
{
window = new ContactWindow(_satName, _station.getName());
window.setStartTime(starttime);
}
TrackingData testTrack = new TrackingData(azimuth,
elevation, range, starttime.ToString());
window.addTrackingData(testTrack);
visible = true;
}
else
{
if (visible == true)
{
window.setStopTime(starttime);
results.Add(window);
}
visible = false;
}
azimuth = azimuth * Constants.toDegrees;
starttime.addTick(_tick);
}
}
