Samsung galaxy not keeping internet

RedBern

Hi, as title says, husbands galaxy is losing internet so gps won't work. We ve been through the wireless and network, wifi networks and we find the home hub, but it's really slow, and that's no good when he s outside trying to use map! Can anyone help please? In the top right of screen there's the connection bars and next to that is a dot with an arc of lines above it, but He thinks it should say wi or something else??
Thanks