Multi-satellite Kalman estimation

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I’ve been looking more closely at the Kalman filter implementation thanks to @Serrof’s recent question: Failing EKF without orbit estimation. I haven’t previously looked at estimation with multiple satellites, so I’m a bit curious about the behaviour.

In KalmanEstimatorTest test testIssue850, there are two propagator builders added to the estimator, with all their orbital parameters and propagation parameters. The estimated parameter is the “central attraction coefficient”, which is a common parameter. That seems fine!

If I add solar radiation pressure to both propagators, then, because the parameter drivers have the same name, they end up being common parameters for both propagators. That seems counterintuitive. But I expect that’s not really an issue because the intention of this functionality is for when you know the spacecraft very precisely and are interested in estimating the common parameters (like Earth orientation). Does that sound right?

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Hi @markrutten,

Yes, that’s expected but I’m not sure it’s really clear from the doc.
Parameter drivers are gathered in a big list that takes care of observation/update of these parameters.
In that list, the distinction between two parameters is made by their names.
So if you want to estimate the two SRP coefficients separately you have to set a custom name for at least one of them.

Cheers,
Maxime

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Thanks for the explanation, @MaximeJ. That’s really helpful!

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