I would say YES. Any attempt by someone to use your property should be met with immediate pushback, otherwise they may claim the property for themselves. Remember, the OP is paying taxes on the property and paid for it when he bought the house. Illegal use of someone's property is akin to stealing in my book.
I agree with Zigner, that the survey cost would not be reimbursed by a court, since it is necessary for the OP to get one to even know if the property is indeed his.
Another alternative would be to rent the property to the neighbor. That would stop the clock on adverse possession and compensate you for the encroachment. You could put some time limit on the rental, or condition it on ending when the equipment needs replacement, etc.