The rover needs to be able to autonomously navigate a fixed area. There can be multiple approaches to demarcate the area:

Use transmitters to demarcate the area and make the rover aware of them to know when it reaches the limits

Use physical barriers that it recognises when it bumps in to them to demarcate the area (maybe a camera and a specific pattern on the barrier?)

GPS

The rover needs to be able to stay in it's designated area, and while inside it needs to navigate the area in a way that it will cover all ground in it in a relatively constant pattern. So a regular pattern like this U shaped pattern makes sense:

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