<p>I have ephemeris data for state vectors of a satellite in a J2000.0 coordinate system. This data is already filtered and cleaned.</p>

<p>The data sample rate ranges between 1 second and 60 seconds, and I want to resample the data down to &lt;10 milliseconds with a constant, regular time step.</p>

<p>I have already managed to interpolate using methods from <a href="https://docs.scipy.org/doc/scipy/reference/interpolate.html" rel="nofollow noreferrer">scipy.interpolate</a> with cubic interpolation; <a href="https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html#scipy.interpolate.interp1d" rel="nofollow noreferrer">interp1d</a> and <a href="https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.griddata.html#scipy.interpolate.griddata" rel="nofollow noreferrer">griddata</a>. </p>

<p>This leads me to the question of how to choose between various methods to resample/interpolate ephemeris state vectors. Certainly the interpolation of tabular ephemerides is something that astronomers and orbital dynamicists need to do and so there must exist some guidelines or best practices or recognized-better or -worse ways to so this. </p>

<p><strong>Question:</strong> How to choose between methods to resample/interpolate ephemeris state vectors? Are there methods recognized as superior for orbital data?</p>

CC BY-SA 4.0
2019-05-02T14:21:59.410Z
I'm voting to close this question as off-topic because this is a software coding question and unrelated to the source of the data
Carl Witthoft
CC BY-SA 4.0
2019-05-02T14:29:12.017Z
This is not related to software coding at all, I'm look for a method or models to improve the sampling, independent from the implementation. I gave scipy as an example.
Matty
CC BY-SA 4.0
2019-05-02T15:09:05.800Z
There are a huge variety of ways to interpolate data, so I consider this too broad.
StephenG - Help Ukraine
CC BY-SA 4.0
2019-05-04T00:40:05.303Z
This is a great question, and it is on-topic both here and in [Space Exploration SE](https://space.stackexchange.com/) as well. The close-voters don't recognize how common it is for astronomers to interpolate ephemerides, or that you've already done the interpolation a few ways. Rather than *help you refine the wording of the question*, they chose to close it (I wouldn't have chosen that route). I've adjusted the wording to make your question more specific and amenable to the Stack Exchange format.
uhoh
CC BY-SA 4.0
2019-05-04T00:43:50.967Z
I don't know if there are more people who can answer here or in Space SE, so I am not sure if it's better to vote to re-open here, or wait to see if a moderator decides to migrate there. In the mean time, I'm curious what happens if you compare the results for the two methods how close they agree with each other. Also if you can describe how you are using the resampled data and how you would decide which results were better, that will be a big help. Do you just need least error on position, or best smoothness (lowest excursions in higher order derivatives, e.g. acceleration and above)?
uhoh
CC BY-SA 4.0
2019-05-06T13:34:25.790Z
Thank you for editing it, my native language is not english, so I had some problems with phrasing it. Right now I compare the python-resampled results with STK resampled results, and get an error of <30m, however I can't use STK programmatically for this because we only have one license to use, which is used by many people.
Matty
<orbital-mechanics><artificial-satellite><ephemeris>
How to choose between methods to resample/interpolate ephemeris state vectors? Are there recognized techniques for orbital data?
Matty
# How to choose between methods to resample/interpolate ephemeris state vectors? Are there recognized techniques for orbital data?

(Asked by: username_0 on 2019-05-02)

I have ephemeris data for state vectors of a satellite in a J2000.0 coordinate system. This data is already filtered and cleaned.

The data sample rate ranges between 1 second and 60 seconds, and I want to resample the data down to <10 milliseconds with a constant, regular time step.

I have already managed to interpolate using methods from [scipy.interpolate](https://docs.scipy.org/doc/scipy/reference/interpolate.html) with cubic interpolation; [interp1d](https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html#scipy.interpolate.interp1d) and [griddata](https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.griddata.html#scipy.interpolate.griddata).

This leads me to the question of how to choose between various methods to resample/interpolate ephemeris state vectors. Certainly the interpolation of tabular ephemerides is something that astronomers and orbital dynamicists need to do and so there must exist some guidelines or best practices or recognized-better or -worse ways to so this.

**Question:** How to choose between methods to resample/interpolate ephemeris state vectors? Are there methods recognized as superior for orbital data?

**Tags:** orbital-mechanics, artificial-satellite, ephemeris

> **Comments:**
> **username_1**: I'm voting to close this question as off-topic because this is a software coding question and unrelated to the source of the data  
> **username_0**: This is not related to software coding at all, I'm look for a method or models to improve the sampling, independent from the implementation. I gave scipy as an example.  
> **username_2**: There are a huge variety of ways to interpolate data, so I consider this too broad.  
> **username_3**: This is a great question, and it is on-topic both here and in [Space Exploration SE](https://space.stackexchange.com/) as well. The close-voters don't recognize how common it is for astronomers to interpolate ephemerides, or that you've already done the interpolation a few ways. Rather than *help you refine the wording of the question*, they chose to close it (I wouldn't have chosen that route). I've adjusted the wording to make your question more specific and amenable to the Stack Exchange format.  
> **username_3**: I don't know if there are more people who can answer here or in Space SE, so I am not sure if it's better to vote to re-open here, or wait to see if a moderator decides to migrate there. In the mean time, I'm curious what happens if you compare the results for the two methods how close they agree with each other. Also if you can describe how you are using the resampled data and how you would decide which results were better, that will be a big help. Do you just need least error on position, or best smoothness (lowest excursions in higher order derivatives, e.g. acceleration and above)?  
> **username_0**: Thank you for editing it, my native language is not english, so I had some problems with phrasing it. Right now I compare the python-resampled results with STK resampled results, and get an error of <30m, however I can't use STK programmatically for this because we only have one license to use, which is used by many people.  

---

## 0 answers

