Non psuedo-inertial frame

Orekit usage
1

Hello,
first of all thank you for letting use this great tool.

I’ve been trying to use it, unfortunately I faced this issue: "non pseudo-inertial frame “CIO/2010-based ITRF simple EOP” once I added a NadirPointing. I understand the error message but I don’t know how to find a conventions that is as precise as this one.

see following code:

Frame earthFrame = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
BodyShape earth = new OneAxisEllipsoid(
                  WGS84_EARTH_EQUATORIAL_RADIUS,
                  WGS84_EARTH_FLATTENING,
                  earthFrame
          );
AttitudeProvider pointing = new NadirPointing(earthFrame, earth);

When I’m using the earthFrame for different purposes or if I modify the earthframe to be Frame earthFrame = FramesFactory.getEME2000(); it works.
The thing is, I’m using earth in other objects (TopocentricFrame, GeodeticPoint) without an issue.

My question is then how can I create such pointing?
I tried to find some documentation but I couldn’t find any that explains this issue.

2

Hi @jerome,

The NadirPointing requires the shape of the body and the frame in which the Orbital velocities are defined (which is usually the frame the propagator uses). For the body shape, it’s suggested to use ITRF as its body frame. So please modify the code as follows if your propagator uses EME2000 as the inertial frame to define position and velocities,

Frame earthFrame = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
BodyShape earth = new OneAxisEllipsoid(
                  WGS84_EARTH_EQUATORIAL_RADIUS,
                  WGS84_EARTH_FLATTENING,
                  earthFrame
          );
AttitudeProvider pointing = new NadirPointing(FramesFactory.getEME2000(), earth);
3

thank you, that works