The possibility of a computation engine on the internet puts a ceiling on control costs.
Meaning, if an Arduino-type microcontroller can’t calculate solar position, keep a reliable clock, issue motor controls AND do additional features (like go into a locked position if winds >30 miles/hour, or run test sequences to identify module failures, etc), then a computer sitting on the internet could do some of that work instead. The local microcontroller could be responsible for internet connection and i/o to the motor controllers. Given an internet connection (a big if), you could query an external server for time and solar position, motor instructions, or for more complex add-on programs. These servers could be government run or privately hosted. They would follow a defined standard a la SMTP (STP = Solar Tracking Protocol anyone?).
Not necessary, but possible.