Open steven-murray opened 2 years ago
Tagging in @jaguirre , @bhazelton , @AaronParsons and @jpober as people I think would be interested.
Another factor throw into the mix is brought up by this recent paper: https://ui.adsabs.harvard.edu/abs/2021ApJ...923...33B/abstract. They have a publicly available code for calculating the local horizon topography. I haven't looked at it, but if it's good code, it could be an interesting study to implement in our simulators.
Tagging @miguelfmorales who is also interested in this.
I personally don't know how to accurately model sources near the horizon, and the physics is really fascinating but confusing. I have no idea which effects are leading vs. next-to-leading order, but a few of them:
This is just all to say it is tricky.
Another factor throw into the mix is brought up by this recent paper: https://ui.adsabs.harvard.edu/abs/2021ApJ...923...33B/abstract. They have a publicly available code for calculating the local horizon topography. I haven't looked at it, but if it's good code, it could be an interesting study to implement in our simulators.
There are no unit tests at all in the repo. Also, as far as I can tell, the code only accounts for a spherical (or possibly ellipsoidal) earth, not local topography. But maybe my quick read of the code is incorrect. Not a ton of documentation.
I'm not surprised to hear the code is bad, but I'd be surprised if it really doesn't account for local topography (since they claim it does exactly that in the paper).
yeah, I'm confused about that. I probably missed something reading the code but it certainly doesn't make clear in the documentation where that information comes from.
It does read in elevation data from a file (on this line), but they don't share the file in the repository. The data are accessed with SRTM through the elevation
package (https://pypi.org/project/elevation/)
This looks like a potentially good tool for modeling the shape of the horizon (to Steven's point 2)! We'll still need to think about how to include the horizon cutoff in the RIME integral, though.
I'm writing up this issue to discuss how we should deal with the horizon in simulation.
There are a lot of factors to consider here, and I'm just going to mention a few of them, and hopefully we generate some discussion that leads to implementation. Factors include:
In terms of 4 and 5, I wrote up some basic ideas in the attached document. vissim-horizon.pdf