Optimal correlation based frequency estimator with maximal estimation range

The estimation range and estimation accuracy are contradictory in conventional correlation based frequency estimators due to phase ambiguity. A novel frequency estimator is proposed to unwrap the correlation phase sequence through a differential-modulus-accumulation process. By utilizing the whole unwrapped phase sequence, the proposed estimator is able to achieve maximal estimation range with CRB approaching estimation accuracy and low SNR threshold simultaneously. Both analysis and simulation demonstrate the effectiveness of the proposed frequency estimator.