I have a few thoughts about this.

Consider walking with a dog yourself. Once you do that, most dogs will never even see you. They will always focus on the dog you're with.

When walking my two dogs (both around 60 pounds), I have been charged and approached by lots of dogs including a few that have burst through gates. Mostly, these end in a sniff-off and/or an eventual retreat by the charging dog. The exceptions have always been very small dogs which more than once have run up and snapped at my dogs and then run-away. (One dark night, a very silent Yorky actually ran right past me -- at speed -- bit one of my dogs and kept on going right under the legs of my other dog before any of us knew what happened).

Some of the suggestions made above certainly work: Calmly and assertively telling the dog 'no' and sending it back to its yard has worked for me. I've also seen dogs (not mine) hit by the repellent that letter carriers use and it's pretty effective.