Add trajectory calculation

Version of internal and external geomagnetic field models.
Date of simulation.
Hour must be whole number in range 0 - 23.
Latitude must be number in range -90.0 - 90.0.
Longitude must be number in range 0 - 360.
Zenith must be number in range 0.0 - 90.0, 0.0 points upright.
Azimuth must be number in range 0.0 - 360.0, 0.0 points to south.
Radius in units of Earth radii Re, from 1.00 to 10.00 Re, 1.00 Re = 6371.2 km 1.00 Re is Earth surface
Rigidity must be a number with a value at least 0.01 GV and at most 999GV.