Abstract:

In modern electronic warfare, to solve the problems of high computation cost, poor anti-noise performance, and low estimation accuracy of no delay Linear Frequency Modulation (LFM) signal methods under a low Signal-to-Noise Ratio (SNR), an effective method for analysis of no delay LFM signals is proposed. By using Local Scale Fourier Transform (LSFT) and Fourier transform, the LFM signal is transformed into a two-dimensional domain named the Centroid Frequency-Chirp Rate (CFCR) domain. In the CFCR domain, the energy of the LFM signal is effectively accumulated to form a peak which is easy to detect. By locating the peak, the parameter estimation of the LFM signal is obtained. In order to improve the estimation accuracy and reduce the computational cost, a two-scale estimation strategy is adopted in this paper. The algorithm has low computational complexity and is easy to implement. The simulation results verify that the algorithm has a good anti-noise performance and estimation accuracy under a low SNR.

Key words: linear frequency modulation signal, parameter estimation, local scale Fourier transform, two-scale estimation strategy, signal analysis