The hereO GPS Watch uses wifi scanning technology to pinpoint its location when indoors. Accuracy will depend on how many wifi networks are present in the vicinity of the watch (if any). Furthermore, if indoor mapping is available, you will not only see the location on a map, but also a detailed layout of the structure in which your child is located.
To attain a location indoors, the device seeks out wifi access points nearby and uses triangulation to pinpoint the watch’s precise location. In some locations the wifi signals are weak or haven't been mapped yet and you might experience issues tracking the watch indoors. If the watch is unable to connect to wifi, it will connect to GPS as soon as it's outdoors and you will be able to continue tracking it.