A Frequency-Independent Iterative DFT Interpolation Method for Robust Sinusoidal Frequency Estimation
摘要
Frequency estimation of complex exponential signals in low signal to noise ratio environments has attracted considerable attention in many fields. This paper proposes an asymptotically unbiased frequency estimation algorithm for accurate and robust extraction of sinusoidal frequency parameters under low SNR conditions. A frequency fitting model is constructed by using the magnitudes of the spectral peak and its adjacent interpolation points. By combining segmentation averaging with iterative refinement, the proposed method reduces the influence of fractional frequency offset and improves both estimation accuracy and noise robustness. Both theoretical analysis and experimental results demonstrate that the estimation variance of the proposed method can asymptotically approach the Cramer Rao lower bound, and the minimum ratio of the mean square error (MSE) to the Cramer Rao lower bound reaches 1.0073. Compared with existing interpolation based frequency estimation methods, the proposed method achieves higher estimation accuracy and stronger noise robustness while maintaining stable performance over different fractional frequency offset values, which makes it well suited for practical engineering applications.