I always thought that someone would invent a cheap, simple, reliable, and passive tracking system. No need for sensors or intelligent electronics.
You have a simple motor that slowly tilts the array from facing East to facing West as power is being generated. The motor does not start until the panel is generating a certain amount of power. The motor runs at a fixed rate with a screw that takes about 7 hours to move the panel.
Once power stops (when the sun sets) weights on the opposite side slowly tilt the panel back to the starting position so it is ready for the next day.
Good idea but has one major drawback: Shadows cast on single panels mid sequence would offset the angle. But majbe it is still worth it.
Like a big, very simple clock basically.