Abstract:The all-phase FFT (apFFT) has the advantage of phase consistency, which makes the phase estimation unaffected by frequency estimation performance. While the phase estimation performance of apFFT may be degraded by frequency offset because of spectrum leakage and fence effect. In refer to the problem, this paper proposed an improved apFFT method based on frequency compensation. Firstly, the frequency was accurately estimated to compensate the signal, and then calculate the apFFT of the compensated signal, and finally the phase was estimated. The Monte Carlo simulation results showed that the phase estimation performance of the novel method was almost immune to the frequency offset, and also was coincide with the theoretical analysis. Moreover, its performance which was restrained by Two-parameter Cramer Lower Band (CRLB2), was about 1.158 2 times CRLB2 under the Monte Carlo situation. The anti-noise capacity and phase estimation performance of the proposed method were significantly better than that of the traditional apFFT method and other two compared algorithms. Moreover, the raw data of TW-1 satellite was utilized to verify the proposed method, obtaining an accuracy of about 4 mrad of phase estimation, and an accuracy of about 50 ps of interferometry delay estimation.
