public static void ToScanningAngle(LatitudeCalculations latitudeCalculations, double longitude, SatelliteDefinition definition, out double scanningX, out double scanningY)
{
var satelliteLongitude = definition.Longitude;
var satelliteHeight = definition.Height + RadiusEquator;
var sx = satelliteHeight - latitudeCalculations.RcCosLatitude * Cos(longitude - satelliteLongitude);
var sy = -latitudeCalculations.RcCosLatitude * Sin(longitude - satelliteLongitude);
var sy2 = sy * sy;
// Check if geodetic angle is visible from satellite
if (satelliteHeight * (satelliteHeight - sx) < sy2 + latitudeCalculations.RadiusRatioSz2)
{
scanningX = scanningY = double.NaN;
return;
}
// Calculate (x,y) scanning angle
scanningX = Asin(-sy / Sqrt(sx * sx + sy2 + latitudeCalculations.Sz2));
scanningY = Atan(latitudeCalculations.Sz / sx);
}
public static LatitudeCalculations LatitudeCalculations(double latitude)
{
var geocentricLatitude = Atan(RadiusPolarSquared / RadiusEquatorSquared * Tan(latitude));
var cosLatitude = Cos(geocentricLatitude);
var sinLatitude = Sin(geocentricLatitude);
var rc = RadiusPolar / Sqrt(1 - Eccentricity * Eccentricity * cosLatitude * cosLatitude);
var sz = rc * sinLatitude;
var calculations = new LatitudeCalculations
{
CosLatitude = cosLatitude,
Rc = rc,
Sz = sz,
Sz2 = sz * sz
};
calculations.RcCosLatitude = calculations.Rc * calculations.CosLatitude;
calculations.RadiusRatioSz2 = RadiusEquatorSquared / RadiusPolarSquared * calculations.Sz2;
return(calculations);
}
