Precession target micro-Doppler extracting method based on instant frequency modulation rate estimation

Abstract

The invention discloses a precession target micro-Doppler extracting method based on instant frequency modulation rate estimation. The precession target micro-Doppler extracting method based on instant frequency modulation rate estimation comprises the steps that (1) an equivalent scattering point model of a spatial precession conical target is established, echo signals of the conical target are received by a radar, echo sequences are obtained from the echo signals by using the equivalent scattering point model; (2) frequency modulation rates of the echo sequences are estimated with a relaxation demodulation line frequency modulation method; (3) the frequency modulation rates of the echo sequences are processed through a random sampling consistency algorithm, and P frequency modulation rate curves are obtained; (4) integral operation is carried out on the P frequency modulation rate curves respectively, and P instant micro-Doppler frequency estimation curves are obtained. According to the precession target micro-Doppler extracting method based on instant frequency modulation, high estimation accuracy can be obtained under the situation of the lower signal to noise ratio. The precession target micro-Doppler extracting method based on instant frequency modulation can be applied to analysis of the micro-Doppler frequency of the spatial precession conical target.

Description

Technical field [0001] The invention belongs to the field of radar technology, and relates to an instantaneous Doppler frequency estimation method, in particular to a micro-Doppler extraction method of a precession target based on instantaneous frequency modulation estimation, which is used to estimate the micro-Doppler of a spatial precession target frequency. Background technique [0002] When a target with a smooth surface is flying outside the atmosphere, in order to maintain the stability of the attitude, it needs to make a spin motion. When it is subjected to lateral interference, it will spin motion while making a cone motion around another directional axis in space. This form of movement is called precession. V.C. Chen of the US Naval Laboratory defined precession as a kind of micro-motion, and named the Doppler modulation in the radar echo generated by micro-motion as micro-Doppler modulation. Since the micro-motion of the target can reflect its structure, size, micro-...

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Problems solved by technology

For example, the micro-Doppler frequency extraction method of spatial cone targets based on multi-target tracking proposed by Shao Changyu et al. This method first applies the classic short-time Fourier transform to obtain the time-frequency distribution map of the echo, and then uses the multi-target tracking technology to track The time-frequency curve on the time-frequency distribution map can be used to extract the micro-Doppler frequency of each equivalent scattering center of the target. Contradictory problems, it is difficult to obtain a higher accuracy of instantaneous frequency estimation; another type of method for instantaneous frequency estimation is the parametric method, which differs from the non-parametric method in that it needs to use the prior information of the signal to establish a parametric model to describe signal, such as the instantaneous frequency estimation method based on the time-varying autoregressive model proposed by Han Xun et al., this method first uses the p-order time-varying autoregressive model to represent the echo signal of the target, obtains the time-varying parameters of the model, and then calculates The phase of the signal power spectral density poles is used to estimate the instantaneous frequency. Although this method can obtain high estimation accuracy in the case of high SNR, the estimation accuracy will decrease in the case of low SNR. In addition, there are model order number choice problem

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