Rapid suppression method of interference of linear frequency-modulated radar based on FRFT

Abstract

The invention discloses a rapid suppression method of interference of linear frequency-modulated radar based on FRFT, wherein the main idea comprises the following steps. A radar echo signal is obtained, and an interference signal is extracted from the radar echo signal,while the delay processed interference signal shown in the description is calculated. FFT of shown in the description is conducted for obtaining the fast fourier transformed signal, and W FRFT order values are obtained after a rough estimate of frequency-modulated slopes of the interference signal and a rough estimate of required orders of the interference signal in FRFT are calculated in order. A two-dimension plane is correspondingly obtained according to the W FRFT order values, a three-dimension searching graph of the interference signal is further obtained, and a precise order p<0> of the three-dimension searching graph of the interference signal is determined, then the interference signal is in suppression process after the radar echo signal with p0-order FRFT is obtained by calculation, a radar echo signal Chi'p<0>(u) with the suppression of the interference signal is obtained. The radar echo signal with inverse FRFT is obtained after an inverse FRFT of Chi'p<0>(u).

Description

technical field [0001] The invention belongs to the technical field of radar signal processing, and in particular relates to a fast suppression method for chirp radar interference based on FRFT, that is, a fast suppression method for chirp radar interference based on Fractional Fourier Transform (FRFT), which is applicable to linear frequency modulation radar interference in the frequency domain. Radar jamming suppression of FM signals. Background technique [0002] Radar is the most important equipment in the target information acquisition, command and control, precision guidance and fire strike combat system in the informationized battlefield and weapon system. Destroying the normal operation of the radar will not only destroy the important information source of the combat system, but also seriously affect the The combat effectiveness of the combat system as a whole. [0003] Radar countermeasures is an electronic countermeasure technology that detects, interferes, and de...

AI Technical Summary

Problems solved by technology

[0004] With the development of electronic warfare, radar communication is faced with various forms of interference, such as amplitude modulation interference, frequency modulation interference, amplitude-frequency modulation composite interference and deceptive interference, the difference between linear frequency modulation (LFM) interference signal and useful signal and noise There is a strong time-frequency coupling, and the classic filtering method is difficult to effectively separate the signal and interference; with the deepening of video analysis methods and application research, many LFM interference suppression algorithms based on time-frequency analysis have emerged

At present, there are three interference suppression methods for linear frequency modulation (LFM) interference signals, mainly the interference reconstruction method based on Wigner-Ville distribution (WVD), the ordinary time-domain cancellation method based on phase and amplitude estimation, and the FRFT-based Domain cancellation suppression method, the three suppression methods all rely on Wigner-Ville distribution (WVD) calculation, WVD is a bilinear transformation, the calculation amount is large, and the sampling rate is high, which is not conducive to engineering implementation; in addition, based on phase and The ordinary time-domain cancellation method of amplitude estimation has high requirements on the interference-to-noise ratio and is suitable for strong interference; the FRFT-based frequency-domain cancellation suppression method uses the fractional Fourier transform FRFT of the chirp signal The nature of interference suppression has a good effect, but this method uses variable step size search in the process of parameter estimation, which requires a large amount of calculation

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