Abstract:This paper studies on time-varying frequency acquisition algorithms, taking Linear Frequency Modulation(LFM) signal as signal model. Firstly, this paper focuses on Delayed Autocorrelation Algorithm, which is one of the traditional time-varying frequency acquisition algorithms. Then, a pilot-aided Design For Testability(DFT) time-varying frequency acquisition algorithm is proposed, according to the problem that Delayed Autocorrelation Algorithm cannot realize the parameter estimation at low Signal to Noise Ratio(SNR). At last, the simulation results show that both the proposed algorithm and the Delayed Autocorrelation Algorithm are based on two Fast Fourier Transform(FFT) operations to estimate the frequency offset and the rate of frequency offset for LFM signal, and the proposed algorithm has a lower SNR threshold.