Underwater target DOA estimation method based on active virtual time reversal method

Abstract

The invention provides an underwater target DOA (Directional of Arrival) estimation method based on an active virtual time reversal method. In a uniform linear array of a hydrophone, a detection acoustic source sends a signal, and a target receives the signal and reflects the signal. Each array element of the uniform linear array receives the signal and virtual time reversal is realized in a computer after filtering. After normalization processing, the time reversal signals are virtually transmitted to a channel as secondary transmission signals in the computer. Spatial smoothing is performedon secondary receiving signals and a covariance matrix of each sub-array is obtained respectively. A spatial spectral function of a Capon algorithm based on ADVTR (Active Detection on Virtual Time Reversal) is calculated and spectral peak searching is performed, and a spectral peak value is used as a DOA estimation value of the target. The invention reduces the energy attenuation of signals, improves the signal-to-noise ratio of the receiving signals, and can be directly extended to two or more targets.

Description

technical field [0001] The invention relates to the field of underwater acoustic multipath channel, active virtual time-reversal and array signal processing, in particular to an underwater target DOA estimation method. Background technique [0002] Target orientation (direction of arrival, DOA) estimation is an important content in target parameter estimation. Underwater target azimuth estimation is often based on the air target azimuth estimation method, combined with array signal processing theory. Whether in the air or underwater, an inevitable problem in signal transmission is the multipath effect of the channel. Conventional array signal processing DOA estimation methods are based on the direct arrival wave, ignoring multipath or trying to eliminate the influence of multipath, considering multipath as an unfavorable factor, and only considering the one-way distance between the target and the receiving array when estimating The propagation channel realizes the azimuth ...

AI Technical Summary

Problems solved by technology

However, the key problem of the PTR-based estimation method is the accuracy of channel estimation. Only when the estimated channel is relatively close to the ocean channel, PTR can complete the correct estimation of the target, which is difficult in practice; Compared with PTR, the estimation method based on ATR does not need the estimation process of the ocean channel, and its focusing process is completed adaptively in the real channel, but it needs two signal transmission processes, so that the signal propagation experiences two channel attenuation, to a certain extent Affects the distance at which the signal can be detected and estimated

The limitation of the ADVTR-based beamforming method is that it can only achieve target orientation in one direction, and this method is a model established from the perspective of signal detection, which cannot be directly extended to direction estimation for two or more targets

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