We can assume that the sensors are on, and as I said, he's talking almost to himself. You could put a radar display on the screen or something if you want to make that clear, which would probably be easier than changing the scene outside.
Alternatively, you can interpret the line "That looks pretty good" to refer to the crater, in which he maybe hopes to find somewhere to hide, and "Yeah, that'll do nicely" to refer to the cave when he sees it.