Very sorry to hear that but lucky you only have the problem during late night hours. It seems that we hear our neighbor's dogs barking constantly...can't sleep, can't talk on the phone - can't even hear ourselves think. It is incomprehensible that barking nuisances are not enforceable and that surrounding residents have to go through so much protocol (Pasadena City District Attorney's Office) just to maintain peace and quiet for the neighborhood as a whole. We found it offensive that the Humane Society/Animal Control's response to our years of concern is, "Dogs bark --- that's just they do." That's not necessarily true. We have a dog and neighbors have commented, "Wow! Didn't even know you had a dog...its so quiet." Good luck to you...we can even get cooperation from other neighbors.
Please google "barking dogs" and you'll be pleased to see lots of resources on how to deal with the problem. You have more control than you think. If you haven't talked to the neighbors - and I hope you haven't, it doesn't work - take the anonymous approach by leaving a polite letter, then escalate from there. You might need to hire an attorney. But there are other options. Buy a very powerful flashlight and shine it into the neighbor's yard when the dog barks at night. Use technology - videotape the dog barking and post it on youtube. See if you can get the neighbor's cell phone number and email them a clip of their dog barking constantly. You'll need to tailor your approach based on the specifics of tthe situation. For example, after clearing it with my neighbor, I give dog treats to his dog when they are noisy - but they have to quiet down first. Maybe you can establish a rapport with the dog yourself - get them to like you, then they may gradually accept your authority. Bottom line, go onto the Internet and research the issue - take control!