[nico_h]

Here is a negative two cents idea: Attach a dumb auger drive "robot" to the end of tether adjustable from the top, with an umbilical to solar panels, maybe a lidar or sonar to see the shape of the field, make it go in spiral back and forth Roomba style. Eventually you'll have run all over the grain multiple times. No need for fancy deep learning AI.

[nico_h]

If you don't have to make it as fast as possible in a pay per time used way, maybe the dumb solution can be cost effective.