Method and device for estimating parameters of chirp signal of underwater acoustic channel

Abstract

The invention belongs to the technical field of underwater acoustic communications, and particularly relates to a method and device for estimating parameters of a chirp signal of an underwater acoustic channel. The method includes the following steps: constructing an underwater acoustic channel signal model; receiving an N-component Chirp signal processed by the underwater acoustic channel model,performing order search by the fractional Fourier transform to obtain a modulation frequency of the N-component Chirp signal; performing frequency modulation compensation on the N-component Chirp signal, and estimating and outputting the initial frequency by the fast Fourier transform. The method rotates the FRFT domain starting frequency estimation to the FFT domain after the frequency modulationcomponent processing to obtain an initial frequency estimation value with a smaller mean signal error under a low SNR, and obtains multi-component Chirp signal parameter estimation in the backgroundof underwater acoustic multipath channel by modeling the underwater acoustic channel, thereby improving the initial frequency estimation performance, ensuring the signal reconstruction accuracy, improving the underwater acoustic communication quality, ensuring the stable communication, and having stable performance and high efficiency, which has strong practical application value and development prospects.

Description

technical field [0001] The invention belongs to the technical field of underwater acoustic communication, and in particular relates to a method and device for estimating a linear frequency modulation signal parameter in an underwater acoustic channel. Background technique [0002] As a mature non-stationary signal, Chirp or LFM is widely used in radar, sonar and underwater acoustic communication. Onset frequency and modulation frequency are the key parameters of Chirp signal, and the estimation of both has been extensively studied. [0003] In the context of traditional wireless channels, the parameter estimation methods for Chirp signals are mainly based on maximum likelihood (Maximum Likelihood, ML), short-term Fourier transform, wavelet transform, Wigner-Hough transform, Wigner-Ville distribution, fractional Fourier Fractional Fourier transform (FRFT) and other methods, among which the maximum likelihood estimation method has good estimation performance, but its computat...

AI Technical Summary

Problems solved by technology

The underwater acoustic channel is a complex channel with dual diffusion of time delay and frequency shift, and its multipath effect is very serious. The time delay in underwater acoustic communication can reach tens of milliseconds or even hundreds of milliseconds. The impact is small, but it will have a serious impact on the initial frequency, so that the classic parameter estimation algorithm cannot be directly applied to the underwater acoustic channel in the background of the wireless channel. In order to obtain accurate parameter estimation performance, it is urgent to find a method suitable for underwater acoustic Parameter Estimation Method for Chirp Signal under Channel

Images