Time reversal coherent angle estimation method for radar low-altitude target

Abstract

The invention discloses a time reversal coherent angle estimation method for a radar low-altitude target, and aims to solve the problem of low angle estimation accuracy of the radar target in a multipath environment. The method comprises the following implementation steps: acquiring radar echo data; performing energy normalization and time reversal on the echo data to obtain a time reversal signal; retransmitting the time reversal signal to obtain time reversal echo data; and further obtaining a covariance matrix, reconstructing a time reversal covariance matrix with the element mean value Toeplitz of the diagonal line of the covariance matrix, performing MUSIC spectrum estimation with the time reversal covariance matrix, and estimating a target angle according to the position of a spectral peak. According to the method, energy normalization and time reversal are performed on the echo data, and the time reversal signal is retransmitted and forms energy accumulation at a target, therebyimproving the signal-to-noise ratio of time reversal echo. Decoherence of the target is realized by the time reversal covariance matrix. Angle estimation of the target is realized by a MUSIC method,so that the estimation method has the advantages of higher angle measurement accuracy, higher probability in successful distinguishing of the target, relatively low cost and wider application range, and is applied to coherent angle estimation of the low-altitude radar target.

Description

technical field [0001] The invention belongs to the technical field of radar, and in particular relates to target angle estimation, in particular to a radar low-altitude target time inversion coherent angle estimation method, which can be used for angle measurement of low-altitude multipath environment targets. Background technique [0002] When the radar target is in a multipath environment and is affected by the multipath effect, the echo received by the radar includes the direct wave signal from the target and the multipath wave signal reflected from the reflecting surface. The direct wave signal and the multipath wave signal are very close in the distance domain and angle domain, and can be regarded as two coherent signals. Radar uses the echo signal to estimate the target angle. Affected by the multipath effect, the accuracy of the target angle estimation result will decrease, and even the real angle of the target cannot be accurately measured. [0003] In view of the ...

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Problems solved by technology

[0004] Affected by the multipath effect, in the case of low signal-to-noise ratio and low angle, the direct wave and the multipath wave are mutually coherent source signals. The MUSIC angle estimation method has low accuracy. In order to improve the accuracy, the multipath signal is suppressed by the method of space domain and time domain, which has problems such as high cost and small scope of application.

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