Abstract: This paper proposes a new carrier synchronization loop, which is applicable to the tracking environment with low signal-to-noise ratio (SNR) and large rate-of-change of Doppler frequency. Both maximum likelihood estimation (MLE) and Kalman filter are utilized to construct the loop. MLE could estimate carrier parameters accurately when SNR is low, and the Kalman filter would track parameter changes stably. Further, the dichotomous search of periodogram peak is adopted to improve the accuracy of estimation with low computation complexity. Simulation results show that the structure proposed has excellent tracking characteristics.