Separation of Multicomponent Chirp Signals Using Morphological Component Analysis and Fractional Fourier Transform

A chirp signal is a large-bandwidth signal which is widely used in engineering. In many applications, it is necessary to decompose a mixed chirp signal into its components. However, the traditional Fourier transform method cannot process a mixed chirp signal when its components intersect in the joint time–frequency domain. Combining the advantages of the morphological component analysis (MCA) with multicomponent signal processing and the fractional Fourier transform (FrFT) in chirp signal processing, this letter proposes the MCA-FrFT method to decompose a multicomponent chirp signal. First, the cost function is defined using the FrFT and optimized by the split augmented Lagrangian shrinkage algorithm (SALSA), and then, all the morphological components are obtained. The proposed method is verified by simulations, and simulation results show that the proposed method has good performance in separating the multicomponent chirp signals into components. Besides, the proposed method is evaluated experimentally in the sea target detection, and the experimental results confirm that the proposed method can not only extract the low observable targets from a heavy sea-clutter environment but also separate them from each other.