Hello everyone. I’m learning the orbit estimation tutorial on numerical methods. I learned that attitudeMode can be set in the YAML file, and I understand that this is just setting the coordinate system, I don’t see where there is code to set the true attitude of the satellite. Is it understandable that the influence of attitude on orbit estimation results can be ignored.
Or can it be understood that the actual attitude is aligned with the set coordinate system?
thank you!
Who can help me?
No, the attitude mode is taken into account by the propagator that is run by the orbit determination engine.
The attitude is used by the propagator for several tasks:
- it is used when computing the force models that correspond to surface forces like Solar Radiation Pressure and atmospheric drag
- it is used when computing the force models that correspond to maneuvers with thrusters defined with respect to spacecraft frame
- it is used by events detectors that depend on pointing vectors like fields of view
- it is used by measurements models that depend on antenna phase centers offsets
Everything is handled transparently for users: they just have to register the AttitudProvider corresponding to the required attitude. There is a special handling for maneuvers, as it is sometimes simpler to override the attitude just during the maneuver. For this to work, one just set a regular attitude mode and the overriding mode is just used to compute the thrust direction without really changing the full satellite orientation (of course, if one wants to both have the thrust direction as well as the solar array panels properly models so SRP is more accurate, then one needs to model the full attitude reorientation from normal mode to thrust mode, but this is more complex to set up).
When the AttitudeProvider has been set up, the propagator takes care to apply it whenever it needs a SpacecraftState, i.e when it evaluates a force model, when it evaluates an event detector, when it evaluates a measurement, or when it just provides this SpacecraftState as a propagation result to the caller.
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Thank you, I read your reply over and over again. I can understand some of it. However, what I don’t understand is that I see in many examples that the pose settings are set with VVLH, LVLH and other coordinate systems, and I don’t see the actual attitude settings. Why is that?
These are items from the LOFType enumerate that are used in the LofOffset attitude provider.
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Dropping by this conversation to recommand you @newWL to look at the following link. You’ll find a detailed list of all the possible attitude provider available as of Orekit 11.3 (including LofOffset mentioned by luc).
Cheers,
Vincent
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Okay, I’ll study again.Thanks!
Ok thanks. Let me study the information you provided.