My sister had a barker, She did it for nothing in the day at silly noises, She also barked in the night aswell..Every time she barked she got a pint of water and threw it in her face and said simply *QUIET* then she walked away.
She did this everytime her dog barked and she stopped it, It was brilliant .

Yet pebbles in a bottle worked on my bull terrier who used to bark her face of when i opened the door to let her out last thing at night to do her buisness, that stopped her doing that

btw if you are going to try the water tactic then the water amount depends on the size of your dog, my sisters was a bull terrier so a pint was enough for her, No doubt if u have a smaller dog then a smaller amount of water is needed .

good luck