Using relative_angular_position Observable & Box-Wing Model in TUDAT

[luigigisolfi]

Question

User:
Hi all, I am trying to use the relative_angular_position observable, but I do not understand how to define the link ends dictionary, as I understand there should be 2 transmitters (presumably, the 2 spacecraft) based on the angular_position documentation (https://py.api.tudat.space/en/latest/observation.html#tudatpy.numerical_simulation.estimation_setup.observation.angular_position). Perhaps this is a 'work in progress' in the "Estimation Development" (https://github.com/orgs/tudat-team/projects/14/views/1) or am I missing something?
Finally, one suggestion. I am trying to replicate the a box-wing model used for the Galileo satellites, whereby the first plate models the solar arrays pointed toward the Sun, the second plate represents the antenna dish constantly pointed toward the Earth. Currently, there is no way to reproduce this, as the 'plated' model only takes 1 body-fixed reference frame (https://py.api.tudat.space/en/latest/radiation_pressure.html#tudatpy.numerical_simulation.environment_setup.radiation_pressure.panelled). I think this may potentially be a nice addition for future work. I see that "detailed radiation pressure models" is already included as a Planned development (https://docs.tudat.space/en/latest/_src_about/contribute_to_tudat.html) and I was wondering where I could find information on any (potential) latest developments. Otherwise, I would look into this myself. Thank you!

[luigigisolfi]

Answer

Tudat-team:

Hi, it looks like the API docs here: https://py.api.tudat.space/en/latest/observation.html#tudatpy.numerical_simulation.estimation_setup.observation.relative_angular_position are wrong. The relative angular position requires a transmitter, a transmitter2 and a receiver. The transmitter2 has not yet been exposed to Python though (let me know if you run into issues exposing it).

The new radiation pressure models are completed in the C++ code, but are not validated and exposed to Python. The new code does indeed allow pointing of panels. For more information on the capabilities, see my project plan (https://github.com/DominikStiller/tudelft-hpb-project/blob/main/planning/build/main.pdf) and code (https://github.com/DominikStiller/tudat/tree/feature/radiation_pressure_modeling). Also, feel free to message me or ask further questions 🙂

[luigigisolfi]

User:
Thank you! I am on my way to exposing the relative angular position observable. The clock models will take some time, as the implementation must be quite complex, let's catch up later when you have more time 🙂

And Fantastic! I will take a closer look at your code