Husqvarna has a pretty excellent roomba-for-your-yard system. 100% autonomous. It's somewhat expensive, but if that's the only thing that's holding up a home purchase for you, it might be worth at least looking at. Alternatively, you can probably whip something up with some kind of frankenstein assembly of an electric wheelchair base, an electric lawnmower, a Raspberry Pi, and a camera.

https://www.husqvarna.com/us/products/robotic-lawn-mowers/