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A Method of Frequency Modulation Fourier Transform for Radar Signal

A Fourier transform, radar signal technology, applied in radio wave measurement systems, instruments, etc., to reduce the amount of calculation and improve the feasibility

Active Publication Date: 2021-07-30
BEIJING UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But for the FM signal, it is a variable frequency signal. If you continue to use the Fourier transform to analyze its spectrum, there are limitations.

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  • A Method of Frequency Modulation Fourier Transform for Radar Signal
  • A Method of Frequency Modulation Fourier Transform for Radar Signal
  • A Method of Frequency Modulation Fourier Transform for Radar Signal

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Embodiment Construction

[0021] The present invention will be further described below in combination with the derivation process. The chirp signal is a commonly used radar signal, and the present invention mainly uses the chirp signal as an example to describe specific implementation modes.

[0022] Firstly, the definition of FM Fourier transform is given:

[0023]

[0024] Among them, l represents the modulation frequency, that is, the slope of the frequency linear transformation; j is an imaginary number; f is the initial frequency. F(l, f) represents the frequency modulation Fourier transform formula; t is a time variable.

[0025] The expression for the chirp signal is:

[0026]

[0027] f 0 is the initial frequency of the chirp signal whose parameter value is to be estimated, l 0 is the modulation frequency of the chirp signal whose parameter value is to be estimated.

[0028] For discretization of chirp signal, dt→Ts, Ts is the sampling period; t→nTs, n is the serial number of the fun...

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Abstract

The invention discloses a method for performing frequency-modulated Fourier transform on radar signals. Firstly, the continuous frequency-modulated Fourier transform is discretized to obtain the expression of discrete frequency-modulated Fourier transform, and then the exponential factor in the expression is expanded to perform discrete Fourier transform on a complex number. transformed form. Then, according to the linear nature of discrete Fourier transform, Fourier transform is obtained for the real part and imaginary part of the expanded complex number respectively. Here, in order to reduce the amount of calculation, fast Fourier transform is used instead of discrete Fourier transform. Then multiply the result of the original imaginary part by the fast Fourier transform by j, and add it to the result of the original real part after the fast Fourier transform. Finally, the arithmetic formula is sorted out, and the result of discrete frequency modulation Fourier transform in a complex form is obtained. The main purpose of this algorithm is to estimate the parameters of the signal and analyze the signal components.

Description

technical field [0001] The method relates to radar signal processing, mainly on the basis of discrete frequency modulation Fourier transform, and proposes an algorithm for realizing discrete frequency modulation Fourier transform by using fast Fourier transform. Background technique [0002] Chirp signal refers to the signal whose frequency changes linearly continuously during the duration, and is a commonly used radar signal. Due to its remarkable advantages, it is widely used. The linear frequency modulation signal has the advantages of low peak power, wide operating frequency range, high distance resolution, long working distance, and relatively simple signal processing. [0003] Fourier transform is a commonly used method for processing signals. It moves the signal from the time domain to the frequency domain. After Fourier transform, the frequency spectrum of the signal can be obtained, and then the frequency of the original signal and the amplitude corresponding to th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S7/35
Inventor 赛景波于安钰
Owner BEIJING UNIV OF TECH