Add Position & Velocity Outputs

[suvan-kumar]

Goals:

• Add option to modify coordinate system used for collect_orbit_track geometry
• Add option to output velocity in addition to position (geometry) for collect_orbit_track

Approach:

• Create str,Enum class to specify three coordinate system options:
  • WGS84 (lat/lon/altitude)
  • ECEF (Earth Centered Earth Fixed Cartesian) (x,y,z)
  • ECI (Earth Centered Inertial Cartesian) (x,y,z)
• Create str,Enum class to specify output options:
  • POSITION
  • POSITION_VELOCITY
• Add arguments to collect_orbit_track function with default values to match current behavior (WGS84 and POSITION)
• Implement functionality to output ECEF coordinates (use Skyfield library to transform)
• Implement functionality to output ECI coordinates (use Skyfield library to transform)
• Implement functionality to output POSITION_VELOCITY (use Skyfield library to expose velocity) using a new velocity key value in the dictionary. Note that velocity coordinates should be ECEF for WGS84 or ECEF options and ECI for ECI options.