Abstract:

Aiming at the parameter estimation problem of Cubic Frequency Modulated（CFM） signals, a parameter estimation method based on High order Ambiguity Function（HAF） and Coherently Integrated Trilinear Autocorrelation Function（CITAF） is proposed in this paper. First, the method demodulates CFM signals to Quadratic Frequency Modulated（QFM） signals via the HAF, and then the CITAF is applied to realize the parameter estimation of QFM signals. The CITAF can accomplish two-dimensional signal energy integration coherently both in time and lag-time domains, and its implementation can be accomplished through complex multiplication, Fourier transform, and addition operations. Therefore, the proposed method can improve the resolution and anti-noise ability of parameter estimation, and its computational cost is low. The effectiveness and performance superiority of the proposed method have been verified through experimental results.

Key words: cubic frequency modulated signals, parameter estimation, coherent integration, High order Ambiguity Function（HAF）, Coherently Integrated Trilinear Autocorrelation Function（CITAF）

摘要：

针对立方调频（Cubic Frequency Modulated，CFM）信号的参数估计问题，提出了一种基于高阶模糊函数（High order Ambiguity Function，HAF）和相参积累三阶自相关函数（Coherently Integrated Trilinear Autocorrelation Function，CITAF）的参数估计方法。利用HAF将立方相位信号降阶为二次调频（Quadratic Frequency Modulated，QFM）信号，再利用CITAF完成参数估计。由于CITAF能够在时域和时延域完成信号能量的二维相参积累，其实现过程利用复乘、傅里叶变换和加法操作即可完成，因此该方法能够提高参数估计的分辨率和抗噪声干扰能力，并保持较低的计算量。实验结果证实了该算法的有效性和性能上的优越性。

关键词: 立方调频信号, 参数估计, 相参积累, 高阶模糊函数, 相参积累三阶自相关函数