Patent ID: 7535403

Claim:
A method to make a high resolution spectral analysis of a received range sampled periodic radiofrequency signal, said method determining the natural frequencies of the received signals, for each distance cell, from an autoregressive identification model, said method comprising the following steps: a filtering step applying to the received signal a trellis autoregressive filtering algorithm comprising M calculation stages, said step calculating, from N signal samples of said received signal, a set of M reflection coefficients μ n characteristic of the received signal, the trellis filtering algorithm being combined with a calculated coefficient regularization operation so as to render the expression of the reflection coefficients dependent on a regularization coefficient Γ; the trellis filtering algorithm being applied for different selected values of Γ during the filtering step, so as to obtain several sets of coefficients μ n , each corresponding to one of the selected values of Γ; a step for determining an optimum set of reflection coefficients, from the sets of coefficients determined in the filtering step; a step for determining the effective order P of the identification model of the filter, from the optimum set of M coefficients μ n by analysing the coefficients μ n through a contrast function G(μ n ); a step for determining the natural frequencies of the identification model, these natural frequencies being the roots of a polynomial A(z −1 ) characterizing the transfer function of the filter produced by the filtering algorithm, said natural frequencies being considered as the spectral components of the received signal.