Telescope tracking data

[Alexander Dvorak 6943f9b61a46a]

I am trying to track satellites and debris using a telescope. I want to propagate TLEs in FreeFlyer and generate an ephemeris file to program my telescope with it. As far as I understand the methods so far, after setting up my groundstation and my spacecraft, I can use groundstation.Elevation(spacecraft) for example to get the elevation and report it to my ephemeris file. However, I am trying to increase my tracking precision. So I would like to account for the time it takes the light to travel from the spacecraft to my groundstation (telescope) and adapt the ephemeris data (epoch, Azimuth and Elevation) accordingly. I realize that TLE data itself is not that precise, but as part of a university-project I have to get as precise as possible.

So my question basically is: Is there a smart way to compensate for light-travel-time in the azimuth-elevation-epoch data? I need those values to be adapted, so that my telescope points towards the right azimuth+elevation at the right epoch so that it points at where the satellite was when he emitted the light.

Any help is appreciated. Best regards

[Nate McCoun 6613f484be0f7]

A good way to improve this in FreeFlyer is to avoid manually offsetting the epoch from raw GroundStation azimuth/elevation calls and instead use FreeFlyer’s observation/OD framework, where light-time correction is handled directly as part of the measurement modeling. In practice, that means modeling Azimuth/Elevation observations with light-time correction enabled, so the reported pointing corresponds to where the object was when the light left it, rather than where it is at the receive time.

That said, if your starting point is only a TLE, the main accuracy limit will still be the TLE/SGP4 solution itself. So if your project goal is “as precise as possible,” the better long-term path is orbit determination rather than trying to post-process TLE-based azimuth/elevation alone. In the SGP4/TLE workflow, the FreeFlyer SGP4StateEstimator is the right direction, because it lets you fit a better SGP4 state from observations or higher-quality reference data and then generate your telescope ephemeris from that improved solution.