Hills2Goals:

--------------------------------------------------------------------------
   Reconstructs the geometric goals from the relative position and velocity in 
   Hills frame. The reference orbital elements are also required.

   Since version 7.
--------------------------------------------------------------------------
   Form:
   goals = Hills2Goals( el0, xH );
              -or-
   goals = Hills2Goals( n, theta, xH );
--------------------------------------------------------------------------

   ------
   Inputs
   ------
   el0             (1,6)     Reference orbital elements (Alfriend format) [a,theta,i,q1,q2,W]
   xH              (6,:)     Hills frame position and velocity  [km;km;km; km/s;km/s;km/s]
                                [x;y;z;Vx;Vy;Vz]

   -------
   Outputs
   -------
   goals            (.)      Geometric goals data structure with following fields:
     - y0          (1,:)        along-track offset                             [km]
     - aE          (1,:)        semi-major axis of relative ellipse            [km]
     - beta0       (1,:)        angle on ellipse at perigee                   [rad]
     - zInc        (1,:)        cross-track amplitude due to inclination diff  [km]
     - zLan        (1,:)        cross-track amplitude due to right ascen diff  [km]

--------------------------------------------------------------------------

Children:

FormationFlying: Coord/EllipsePhase
FormationFlying: DataStructures/Geometry_Structure
SC: BasicOrbit/OrbRate