Given any GPS coordinates, couldn't one simply calculate the location of the sun in the sky to point directly toward it?
Here is how they do it. https://gml.noaa.gov/grad/solcalc/calcdetails.html
Isn't this exactly the problem that can be better solved using real power data instead of values expected from theory ?
The trickiest part might be getting an accurate time on whatever cheap controller your using.
Of course, a $15 receiver might not have the best sensitivity, so reception might actually be a practical concern. On the other hand, you only need 4 satellites for a coarse fix, and you could seemingly tolerate a many minute cold fix time.
Just need your location and the time (quarter/season, month, day, hour, minute) and you'll know where the sun is in relation to the location given.
Besides, the panel can't move, only rotate and tilt. Have you actually read the article? (With rotate and tilt only, pointing directly at the sun should maximize the power output from a single panel even with shade from other objects. You can get a very small amount of movement from the fact that the point of rotation is outside of the plane of the panel. But that's not mentioned at all, is it?)
In any case, if you solve a problem with machine learning that already has a non-machine learning solution, you will get this kind of comment. If on top of that you don't compare the existing solution and yours and show that yours significantly improves performance, it just looks like doing ML for the kicks.