Radar signal modulation mode analysis method based on improved HHT and signal processing system

Abstract

The invention belongs to the positioning or presence detection technology field utilizing radio wave reflection or re-radiation and discloses a radar signal modulation mode analysis method based on the improved HHT and a signal processing system. The radar signal time-frequency analysis method integrated with wavelet packet decomposition, CEEMD and correlation spectrum filtering is utilized to obtain each eigenmode component, improved Hilbert transform is utilized to obtain Hilbert spectrum instantaneous frequency distribution of a radar signal, and time-frequency parameter extraction of the radar signal is carried out. The method is advantaged in that a frequency component of an original signal is accurately extracted through utilizing the wavelet packet decomposition method for de-noising in combination with envelope correlation spectrum screening, problems of false components and modal aliasing caused by the noise are suppressed, a problem of the inaccurate HHT analysis result due to modal aliasing and the false components is effectively overcome, time-frequency distribution that is more aggregated and adapts to a lower signal-to-noise ratio is obtained through improved Hilberttransform, and high accuracy is realized.

Description

technical field [0001] The invention belongs to the technical field of positioning or presence detection using radio wave reflection or re-radiation, and in particular relates to an improved HHT-based radar signal modulation method analysis method and a signal processing system. Background technique [0002] At present, the existing technologies commonly used in the industry are as follows: The traditional radar signal analysis and processing technology mainly focuses on the five parameters of angle of arrival (DOA), pulse width (PW), time of arrival (TOA), pulse amplitude (PA) and carrier frequency (RF). With the development of radars with new and complex systems, the traditional five main parameters can no longer meet the needs of detecting new radars, and it is urgent to extract some more precise and stable intrapulse features, so the concept of intrapulse analysis (Intrapulse Analysis) appeared. There are two purposes of radar intrapulse analysis: one is to identify the...

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Problems solved by technology

[0004] (1) There is a problem of spurious components in the Hilbert-Huang transform empirical mode decomposition

[0005] (2) The ensemble empirical mode decomposition method still produces some false components. When the false components exist, the empirical mode decomposition of the signal does not obey energy conservation, and the decomposition results cannot reflect the real frequency information of the signal.

[0006] (3) In the method of combining energy fluctuations and correlations to jointly screen false components, the thresholds of energy coefficients and correlation coefficients are mainly determined by experience, and the thresholds can only be determined by the experience of researchers, and the processing results are largely Relying on the experience value of researchers, the results may not be accurate, and it is not conducive to programming, which affects the actual promotion and application of the method

[0008] The signal sampling frequency is closely related to the error of empirical mode decomposition. When the sampling frequency is in the range of 2 to 10 times the signal frequency, the empirical mode decomposition will derive false components, which are difficult to eliminate, making the radar signal undergo HHT transformation The resulting time-frequency distribution cannot reflect the real time-frequency information of the signal, which is not good for signal analysis

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