ecfToEci function

Map<String, dynamic> ecfToEci(
  1. Map<String, dynamic> ecf,
  2. dynamic gmst
)

Implementation

Map<String, dynamic> ecfToEci(Map<String, dynamic> ecf, gmst) {
  // ccar.colorado.edu/ASEN5070/handouts/coordsys.doc
  //
  // [X]     [C -S  0][X]
  // [Y]  =  [S  C  0][Y]
  // [Z]eci  [0  0  1][Z]ecf
  //
  final X = (ecf['x'] * Math.cos(gmst)) - (ecf['y'] * Math.sin(gmst));
  final Y = (ecf['x'] * (Math.sin(gmst))) + (ecf['y'] * Math.cos(gmst));
  final Z = ecf['z'];
  return { 'x': X, 'y': Y, 'z': Z };
}