Is she is a chained up dog? If so, get her off the chain and work with her.
Why aren't you doing things with her, regardless of her not being an inside dog?
She barks out of boredom, frustration. How can she have any obedience if she is out and about to her own devices? Truthfully, committing yourself to your dog, may not be in her best interest if it is living life in a yard with no purpose. She deserves more than that.
Classes, and activities can be done with an outdoor dog, living outside isn't an excuse to not work with her.