Target azimuth estimation method based on low-frequency circular ring array

Abstract

The invention discloses a target azimuth estimation method based on a low-frequency circular ring array, and belongs to the field of underwater acoustic signal detection. A hydrophone receives an underwater acoustic signal of 20Hz-5kHz; and an ADC converts an analog signal into a digital signal, performs spectral analysis, beamforming and azimuth estimation on the AD signal to obtain a signal target direction, receives an instruction of a serial port and outputs a beamforming result. Meanwhile, original data collected by the AD are stored in a large-capacity SD card through DDR. According to the method, the weight vector is stored in advance, so that the complexity of software is reduced, the operation period of the software is shortened, and the detection efficiency and real-time performance are improved; aiming at a coherent signal offset phenomenon, a method of injecting man-made noise, namely a generally diagonal loading technology, is adopted; by adopting a diagonal loading weighting coefficient, the beam forming robustness can be greatly improved under the condition of ensuring the high gain of the MVM method.

Description

technical field [0001] The invention relates to the technical field of underwater acoustic signal detection, in particular to a target orientation estimation method based on a low-frequency circular array. Background technique [0002] The hydrophone array samples signals at different points in space. By comprehensively preprocessing the received signals in different ways, the signals arriving at the array in the desired direction can pass through as undistorted as possible, while at the same time, the signals in other directions The incident energy is suppressed. [0003] The beamformer is the same as the filter in the time-domain processing, which plays a role in filtering the incoming and outgoing information, and its output should have better and more ideal characteristics than the input. The performance of the array beam is mainly measured by the beam width and side lobe height, which is restricted by multiple parameters in the array. [0004] In the conventional beam...

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Problems solved by technology

[0006] The traditional underwater sound processing software for submersible marks mainly has the following disadvantages: (1) The signal processing ability is greatly affected by the environmental signal-to-noise ratio. (2) When calculating the weight vector in the beam stroke, there are many cyclic operations, the operation time is long, and the real-time performance is poor, and more complex beamforming algorithms cannot be used; (3) The performance of azimuth estimation in the presence of coherent interference is poor, Lack of anti-coherent interference capability, severe performance degradation in the presence of multipath propagation, poor robustness and directivity; (4) Multi-beam beamforming requires a lot of calculations, cannot achieve pre-forming more beams, and the azimuth angle difference between beams If the value is large, the azimuth estimation error is large, and the direction finding azimuth estimation of the target at a long distance is inaccurate

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