Doppler frequency deviation correction method and system

A Doppler frequency offset and frequency point technology, applied in the field of Doppler frequency offset correction method and system, can solve the problems of target detection performance degradation, processing gain loss, etc., to avoid detection performance degradation, avoid processing gain loss, Effect of improving bearing estimation accuracy

Inactive Publication Date: 2014-05-21
INST OF ACOUSTICS CHINESE ACAD OF SCI
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Problems solved by technology

[0006] The purpose of the present invention is to overcome the Doppler frequency offset caused by the relative motion between the hydrophone receiving array and the target when the actual sonar carrier adopts the motion mode of a uniform straight line to synthesize the aperture, and then the target detection performance is caused when the aperture is synthesized. decrease and deal with the loss caused by the gain, so as to provide a method and system for compensating the Doppler frequency offset

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  • Doppler frequency deviation correction method and system
  • Doppler frequency deviation correction method and system

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Embodiment Construction

[0033] The present invention will be further described now in conjunction with accompanying drawing.

[0034] Before describing the method of the present invention in detail, some concepts involved in the present invention are firstly described uniformly for ease of understanding.

[0035] Time orientation history graph: The time orientation history graph is formed by performing short-time Fourier transform on continuous sampling data. The sampling sequence of the original signal is divided into frames (for example, divided into 100 frames, 2000 points in each frame), and the frames overlap each other by 50%, and then the beamforming processing is performed on each frame signal to obtain the corresponding target position of each frame. The temporal union of each frame yields a time orientation history map. The azimuth of the target can be read out by using a time azimuth history map, and the azimuth record is subjected to subsequent fitting processing and threshold discrimina...

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Abstract

The invention relates to a Doppler frequency deviation correction method. The method comprises performing characteristic analysis on target radiation noise; building a receiving model and establishing a rectangular coordinate system for a towed line array; presetting the frequency point compensation total; performing Fast Fourier Transformation (FFT) and frequency domain beam forming on signals at certain initial moment and after the towed line array moves for certain time, and accumulating output results of frequency domain beam forming at the current frequency point; calculating a space moving compensation and a time delay compensation to obtain the total phase correction compensation, and obtaining the virtual array expansion output result according to the previous compensation result and the total phase correction compensation; obtaining a time azimuth course diagram, detecting the target signals through the time azimuth course diagram, determining if current frequency point compensation times reach the frequency point compensation total, changing the amplitude of the current frequency point if the compensation times do not reach the frequency point compensation total, and performing sampling again till the current frequency point compensation times reach the frequency point compensation total.

Description

technical field [0001] The invention relates to the field of underwater acoustic signal processing, in particular to a Doppler frequency offset correction method and system. Background technique [0002] With the development of low-noise ships and acoustic stealth technology, the underwater radiation noise and target intensity of ships and other aircraft have further decreased, and it is more difficult for traditional passive sonar to detect targets. It has been severely challenged by its emergence and rapid development. [0003] With the development of science and technology, the research of dragged line array sonar based on passive synthetic aperture technology has become a research hotspot in the field of underwater acoustic signal processing. The towed line array sonar is widely used in the measurement of underwater target characteristics because it can stay away from the self-noise of the ship, is not limited by the aperture, and can be towed in depth to make use of hy...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S7/539
CPCG01S7/52004
Inventor 赵闪陈新华孙长瑜
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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