Satellite clock offset

Good afternoon. Sorry for my bad english. Thank you very much for such a great tool as orekit, and a special thank you for python wrapper. I have a question. I’m trying to estimate the pv of the satellite using slr. Everything is being clarified, but I also need to estimate the satellite clock offset together with pv. I do this using Sattelite = ObservableSatellite(0).getClockOffsetDriver(). setSelected(True) before adding measurements to estimator. However, this parameter is not displayed in the covariance matrix or in getMeasurmentsParametersDrivers (False).getDrivers(). But it has a 0 value, although the selected flag is equal to True.
Maybe I’m doing something wrong.

Hi @Suslov46

Welcome to the Orekit forum.

This a strange behavior. What you’ve done looks good. Are you using a batch least squares or a Kalman Filter to estimate the PV and the clock offset?
Can you provide an executable code or a sample of code in order to see if the error is elsewhere?

Best regards,

thank you very much for wasting your time on my problem. I use a batch least squares
orekit_forum.7z (53.2 KB)

Thank you for the example. I will take the time to see if I found an error.

1 Like


I tried to solve your problem, but I realized something: I am a big newbie in Python … :sweat_smile:
I can’t execute the code because of my lack of Python skills.

Looking at your code, I don’t see any error. It seems that you initialize well the clock offset. Maybe you can try using debug mode and see if something wrong happens.

I’m sorry I can’t help you more.

Thank you for your time with my problem. if I can solve it I will write

I found a solution. it’s all about the twoway modifier for measurement. if it is true then satellite clock offset is not estimating, making it false everything works fine. but the problem with specifying the clock offset for inter-satellite measurements remains. if I can solve it I will write

Good day. I may have found a little bug. InterSatelliteRange lacks several lines that set partial derivatives with respect to parameters, which are present in classes of other measurements types. Because of this, estimator does not estimating the clockoffset remote satellite. I use the develop version from orekit gitlab.


You’re right. Could you open an issue on the Orekit issue tracker ?
Contributions welcome :slightly_smiling_face: