1. If you are going to fight this, try a Trial by Declaration first. It is the easiest way to have the violation thrown out. First off, if he was that far distant, he probably is an inadequate witness. Second, if he cited you as an automobile, and not a bicycle, you can have it thrown out on that technicality. Finally, cops don't get overtime to write declarations like they do attending court. He's unlikely to complete his declaration, in which case you'd get off if you wrote "Not Guilty" in crayon on construction paper.
2. It is a valid technicality that he did not cite you as a bicycle. FIght it based on this in court.