Creating a Satellite's Perifocal Frame in STK

A common reference frame to express a satellite's position or orbital maneuvers is the satellite's perifocal frame. The perifocal frame of a satellite is defined using the orbital motion around the central body. The X-Y plane coincides with the satellite's plane of motion, where the X axis points from the central body to periapsis and the Y axis points from the central body along the semilatus rectum in the direction of orbital motion. The Z vector points along the orbit's angular momentum vector.

You can create a perifocal frame for a satellite in STK, using Analysis Workbench, by following the steps  below:

1. Propagate a satellite.
2. Open the Vector Geometry tab in Analysis Workbench.
3. In the Filter by drop-down, select All Objects and select Earth (or another relevant central body).
4. Click Create new Axes.
5. Change the Type to Aligned and Constrained.
6. Name the axes "SatelliteName Perifocal Frame".
7. Verify that the Parent is set to CentralBody/Earth.
8. Change the Aligned Vector to the satellite's Periapsis vector.
9. Set X = 1, Y = 0, and Z = 0.
10. Change the Constrained Vector to either Orbit_AngMomentum or Orbit_Normal (unit vector of the orbital angular momentum).
11. Set X = 0, Y = 0, and Z = 1.
12. Click OK.

You now have the satellite's perifocal frame!