The HMM based multiple frequency line tracking algorithms of work well under very low SNR
except for a high complexity of computation and for generally unnegligible quantization error.In this paper a new choice of measurement vector and the corresponding computation of measurement probability are presented to reduce the quantization error.And to reduce the computation burden
the idea of the EM algorithm is applied to the multiple frequency line case and the EM-HMM tracking algorithm is naturally developed.Finally
two methods for initializing the EM-HMM algorithm are presented.Simulations show that all these are effective.