There's not really much you can do if they're feeding the dog, giving it some sort of shelter, and not outright mistreating it.
I suppose you could complain to the police if the barking is really bothering you, but who knows what would happen to the dog after that. Best case scenario, it would eventually end up in a better home.
Don't really understand why people would get a dog and then keep it outside.
"The gods who nurse this universe think little of mortals' cares. They sit in crowds on exclusive clouds and laugh at our love affairs. I might have had a real romance if they'd given me a chance. I loved him, but he didn't love me. I wanted him, but he didn't want me. Then the gods had a spree and indulged in another whim. Now he loves me, but I don't love him." - Cole Porter