Spherical Coordinate Type

The Spherical coordinate type enables you to define the path of an orbit using polar rather than rectangular coordinates. The first two elements depend on whether the coordinate system is fixed or inertial.

Spherical elements

Option	Description
Right Ascension (inertial)/ Longitude (fixed)	Right Ascension is defined as the angle from the X axis to the projection of the satellite position vector in the equatorial plane measured as positive in the direction of the Y axis.
Declination (inertial)/ Latitude (fixed)	Declination is defined as the angle between the satellite position vector and the inertial equatorial plane measured as positive toward the positive inertial Z axis.
Radius	This is the magnitude of the satellite position vector.
Flight Path Angle	This is either horizontal (Hor FPA) or vertical (Ver FPA) flight path angle. It is the angle between the velocity vector and the radius vector (vertical) or the complement of this angle (horizontal).
Azimuth	This is the angle in the satellite local horizontal plane between the projection of the velocity vector onto this plane and the local north direction measured as positive in the clockwise direction.
Velocity	This is the magnitude of the velocity vector.

Position and velocity for spherical coordinate elements