Hop timing estimation for noncoherent frequency-hopped M-FSK intercept receivers

The optimum hop timing estimator (based on likelihood-ratio (LR) theory) is derived for noncoherent slow and fast frequency-hopped M-FSK intercept receivers. Such receivers have no a priori knowledge of the hopping code and thus the solution to this estimation problem differs considerably from the more commonly considered case of the friendly receiver. The implementation and performance of the LR hop timing structures are presented and compared with that of other suboptimum schemes that have been discussed in the literature.