Wave beam space domain meter wave radar height measurement method based on compressed sensing

Abstract

The invention discloses a wave beam space domain meter wave radar height measurement method based on compressed sensing and relates to low elevation height measurement under the condition that a signal to noise ratio is low and snapshots are less. A realization process is characterized in that a target signal is extracted from a radar echo and rough measurement of the elevation is performed so that the space domain theta where a target signal elevation is located is obtained; the space domain theta is divided into P parts, wave beam formation is performed in the space domain theta so as to obtain a wave beam transformation matrix B and prewhitening is performed on the wave beam transformation matrix B so as to obtain a whitening wave beam transformation matrix T; receiving data is projected to the whitening wave beam transformation matrix so as to obtain a wave beam domain measurement signal z and an observation matrix phi carries out compression sampling on the z so as to obtain an observation signal y; iterative operation of the whitening wave beam transformation matrix T and the observation signal y is used to obtain a target signal estimation value; a target angle is extracted from the target signal estimation value so as to obtain the target height. By using the method of the invention, sampling points of the target signal and operands are reduced; sidelobes of a signal power spectrum and a space spectrum are effectively reduced; height measurement precision under the low signal to noise ratio is increased; the method can be used in target positioning.

Description

technical field [0001] The invention belongs to the technical field of radar signal processing, in particular to compressed sensing and meter-wave radar altimetry methods, which can be used for high-resolution direction-of-arrival (DOA) estimation and positioning of targets. Background technique [0002] Meter wave radar altimetry method is an important research direction in array signal processing, and has been widely used and researched in the fields of radar, communication, sonar and navigation. Domestic and foreign radar circles generally believe that meter wave radar has anti-stealth capabilities. However, meter wave radar is limited by factors such as long wavelength, limited antenna size and height, which makes the antenna beam width wide and angular resolution low. More importantly, the so-called "multipath" problem due to ground and sea reflection makes it difficult It is difficult to measure height in a multipath environment, so the height measurement problem of m...

AI Technical Summary

Problems solved by technology

However, meter wave radar is limited by factors such as long wavelength, limited antenna size and height, which makes the antenna beam width wide and angular resolution low. More importantly, the so-called "multipath" problem due to ground and sea reflection makes it difficult It is difficult to measure height in a multipath environment, so the height measurement problem of meter wave radar has always been a problem that has not been well solved in the radar industry

But when the signal sources are completely coherent, the rank of the data covariance matrix received by the array will be 1, which will cause the dimension of the signal subspace to be smaller than the number of signal sources, that is, the existence of coherent sources makes the signal subspace and the noise subspace interpenetrate , so that the steering vector of some coherent sources is not completely orthogonal to the noise subspace, which makes the performance of many classical eigensubspace algorithms degrade, or even completely fail

[0009] The maximum likelihood algorithm has a simple idea and superior performance, and has good performance under high SNR and low SNR conditions, but the likelihood function solution is a nonlinear multidimensional optimization problem that requires multidimensional grid search , the amount of calculation increases exponentially with the increase of the number of targets, and the implementation process is more complicated

[0010] Among the above methods, method 1 has poor accuracy; method 2 is prone to ambiguity in height measurement; method 3 is only suitable for flat positions, and its accuracy is poor, which cannot meet actual needs; method 4 has a large amount of computation and requires a large number of samples. The performance is degraded or even invalid, and this method is based on the condition of satisfying the space domain Nyquist sampling theorem, that is, the distance between the array elements must be less than or equal to the half-wavelength of the incident signal, otherwise grating lobes will be generated, which will lead to angle measurement ambiguity

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