@Heucuva
I translated the chapter for myself in Brazilian Portuguese and the Kanji is "Sonar" in fact.
Besides, the LN Vol 4 citation says:
"That evening, I was on the late-night watch with Nana.
Since there weren’t any animals or monsters around that would harm us, I
decided to do an experiment I’d been meaning to try for a while. Just to be sure,
I asked Nana to use her Foundation Magic spell
Sonar to keep an eye on our
surroundings."
@herpderp357
In the WN, Satou hunt some Spider-Bears to feed this children and clean a field crop for them.