AdditionalData are removed by AbstractGradientConverter

Orekit development
1

Hi everyone,

I have come across an issue when trying to add a ForceModel which uses an additionalData of SpacecraftState to compute its acceleration.

More precisely, it works fine in a propagation but not in an orbit determination (with a BatchLSEstimator), because here in AbstractStateTransitionMatrixGenerator(line 270) the SpacecraftSate dsState provided to compute partial derivatives has no additionalData.

final Gradient[] ratesPartials = computeRatesPartialsAndUpdateFactor(forceModel, dsState, parameters, factor);

After investigation, it seems that NumericalGradientConverter does not keep the additionalData when creating dsStatefrom the parameter stateof the method AbstractStateTransitionMatrixGenerator.computePartials(final SpacecraftState state), which has the additionalData needed to compute the acceleration.

Is this a know issue ?

Best regards,
Lio

2

Hi @Lio,

Welcome to the forum!
And sorry for the delay.

I don’t think so, but I may be wrong.
By the time these converters were developed, I don’t think anyone envisioned implementing a ForceModel that uses additionalData.
So this would qualify for a bug or an enhancement of the actual behavior of the code.
Would you care to open the issue on the forge ?

Best regards,
Maxime

3

Hi !

Thanks for the reply. I have juste created the issue in Gitlab: Making sure you're not a bot!

Best regards,

Lio

4

Hi Lio,

this will be fixed in the next patch.
You’ll just have to make sure your ForceModel returns false in dependsOnlyOnPosition.

Cheers,
Romain.

5

Hi Romain,

Thank you very much !

Best regards,

Lio