Near field focusing beam forming positioning method

A technology of near-field focusing and positioning method, which is applied in the directions of sound wave re-radiation, radio wave measurement system, and utilization of re-radiation, etc., which can solve the problems of limited and restricted near-field range

Inactive Publication Date: 2011-03-30
INST OF ACOUSTICS CHINESE ACAD OF SCI
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Problems solved by technology

[0004] In general, focused beamforming technology is effective for near-field targets, but it has only been used based on actual arrays in the past, and the near-field range is limited, that is, the distance that can accurately locate targets is limited by the actual array aperture; passive synthetic aperture technology, especially the Extended towed array technology effectively increases the array aperture, but it has not been combined with focused beamforming technology to achieve precise positioning of closer targets

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[0091] Simulation parameters: the number of elements of the actual sound pressure sensor linear array M = 40, the distance between array elements d = 1m, ML = 8 times of aperture expansion, the number of elements of the towed array after expansion MM = 200, the movement speed of the towed array v = 4m / s; signal sampling rate fs=20KHz. Three sinusoidal signals, the frequency, receiving signal-to-noise ratio, azimuth, and distance are: (133Hz, 0dB, 126°, 300m), (149Hz, 0dB, 150°, 500m), (157Hz, 0dB, 60°, 700m). Sound velocity c=1500m / s, snapshot length N=2000, processing frequency band 130Hz~160Hz. The angle scanning range is [0°, 180°], scanning every 1°, a total of 181 angles. The distance scanning range is [100m, 1000m], scanning every 10m, a total of 91 distances.

[0092] Such as image 3 As shown, the specific steps of a near-field focused beamforming positioning method proposed by the present invention are as follows:

[0093] Step 1: Correspondence image 3 In 301...

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Abstract

The invention relates to a near field focusing beam forming positioning method. In the method, the response of a signal received by each array element of a virtual array in a frequency domain, to be processed, within the frequency band range [fmin, fmax] is firstly obtained based on an expansion towing array passive synthesized aperture method, and then a target is accurately positioned by utilizing the near field focusing beam forming positioning method, wherein the frequency band range [fmin, fmax] is selected according to the actual requirement, and only the conditions that fmin is greater than 0, and fmax is not greater than one half of data sampling rate are satisfied. The invention effectively combines the expansion towing array passive synthesized aperture method and the near field focusing beam forming positioning method together and meanwhile acquires the benefits brought by the two methods. Moreover, the beam forming arithmetic is realized in the frequency domain; a broadband signal is decomposed into a plurality of frequency point signals, and each frequency point within the signal frequency band range is processed, and finally, results are accumulated; and the processing performances, such as robustness, resolution and the like, are more superior to those of direct processing in a time domain.

Description

technical field [0001] The invention relates to the field of sonar digital signal processing, in particular to a near-field focusing beam forming positioning method. Background technique [0002] For the detection and measurement of targets in the middle and far fields, the commonly used underwater passive positioning methods include the three-subarray positioning method, target motion analysis method, and matching field processing method. For the precise positioning of near-field targets, the focused beamforming positioning method is more suitable. Conventional beamforming technology is based on the assumption of far-field plane waves, which is equivalent to a spatial filter. According to the azimuth calculation, the delay compensation of the received sound wave is performed to obtain the spatial spectral density of the signal for azimuth measurement. However, for near-field targets, only the orientation is considered and the influence of the distance factor is ignored. Th...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S15/02G01S15/89G01S7/41
CPCG01S15/8904
Inventor 曾雄飞黄海宁孙贵青李峥
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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