1. A method for correlating first target data having at least one dimension generated by an electromagnetic sensor with second target data having at least one corresponding dimension generated by an optical sensor, comprising the steps of: generating a Figure of merit in each corresponding dimension related to the accuracy of a match between the first and second target data in the corresponding dimension; and combining the Figures of merit generated from the corresponding dimensions to output a measure of correlation between the first target data and second target data indicative of the likelihood that the target detected by the electromagnetic sensor and the target detected by the optical sensor are the same target.