Parameter estimation method of qfm signal based on fourth-order asymmetric product kernel function

Abstract

The invention belongs to the technical field of radar signal detection and evaluation, and particularly relates to a QFM signal parameter evaluation method based on a four-order asymmetrical product type kernel function. The method includes the steps of firstly, calculating the initial signal energy, setting a circulation initial value and establishing a matrix used for storing all subsequent component parameter estimation values; secondly, multiplying the time delay function of the four-order asymmetrical product type kernel function with the conjugation time delay function of the four-order asymmetrical product type kernel function, and conducting phase matching and converting on phases of the four-order asymmetrical product type kernel function, wherein the estimation values of the second parameters of the signal components can be obtained in the positions of frequency domain peak values; thirdly, constructing a new four-order asymmetrical product type kernel function for signals with compensation conducted on the second parameter estimation values, and conducting fast Fourier transform to obtain a frequency-frequency change rate two-dimensional distribution diagram, wherein third parameter estimation values and third parameter estimation values of the signal components can be obtained from the positions of the peak values; fourthly, filtering the signal components, estimated in the steps, out of the signal; fifthly, resetting cyclic variables and a signal, and calculating the ratio of the total energy of the signal to the initial signal energy.

Description

technical field [0001] The invention belongs to the technical field of radar signal detection and estimation, in particular to a QFM signal parameter estimation method based on a fourth-order asymmetric product kernel function. Background technique [0002] FM signal is a signal whose instantaneous frequency changes with time, so it is a typical non-stationary signal. According to the linear relationship between frequency modulation frequency and time, frequency modulation signals can be divided into two types of signals: linear frequency modulation and nonlinear frequency modulation. The QFM (Quadratic frequency modulated) signal, which has a quadratic function relationship between instantaneous frequency and time, is a signal commonly found in nature and artificial applications. It is used in sonar, high-resolution radar, seismic signal analysis, remote sensing and telemetry, communication It has a wide range of applications in engineering and science fields. [0003] Th...

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Problems solved by technology

In order to avoid the 3-dimensional objective function and the corresponding 3-dimensional maximum search, the cubic phase function (Cubic Phase Function, CPF) is proposed and used, but it cannot handle multi-component QFM signals; PHMT (Product High-Order Matched- Phase Transform) and PGCPF (Product Generalized Cubic Phase Function) methods can be applied to parameter estimation of multi-component QFM signals, but these two methods can only estimate the highest-order parameters after high-order nonlinear transformation, and cannot estimate other parameters at the same time. It is necessary to continuously search and estimate parameters of different orders through iterative compensation, and the compensation accuracy affects the estimation effect

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