Yes, you will very likely have to go to court and prove this (e.g. with proof of your identify; evidence or proof that you own different cars than the one cited; etc.)--the court does not usually simply accept someone writing in and saying "oh, that wasn't me," for obvious reasons. And the burden of raising this affirmative defense--mistaken identity--is on you: don't count on the court or prosecutor doing your job for you, to prove that it's not you. Proving it's not you is your responsibility. You legally are allowed to do this on your own, but a lawyer--someone familiar with the rules and procedures--would absolutely help.