Abstract:

Many parameter estimation algorithms have been proposed for frequency modulation (FM) slope of linear frequency modulation (LFM) signals, in which, however, there are some issues such as high complexity, bad realtime and a small adaptive range of the signal to noise ratio (SNR). An improved algorithm based on fractal box dimension is proposed, which uses boxcounting dimension to estimate the FM slope of LFM signals through calculating the relationship curves of FM slope and boxcounting dimension. The influence of the amplitude and phase of the signal to the boxcounting dimension is discussed and the estimation errors under different SNRs is calculated, and the curves relationship of the pulse width, FM bandwidth and boxcounting dimension is drawn to compare with the traditional parameter estimation algorithm based on matching Fourier transform. Simulation results show that, after establishing the corresponding relation database, the estimation errors are comparatively small under the larger variation scope of SNR, and the algorithm is simple. It owns good application value for realtime estimation.