Sliding window principle-based optical fiber segmented hydrophone system

A sliding window processing and optical fiber technology, which can be used in optical device exploration, alarms based on broken/disturbed straightened ropes/metal wires, anti-theft alarm mechanical activation, etc., can solve problems such as poor signal-to-noise ratio and insufficient precision

Inactive Publication Date: 2018-07-13
光子瑞利科技(北京)有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its limitation is that the signal-to-noise ratio is relatively poor and the accuracy is not enough

Method used

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  • Sliding window principle-based optical fiber segmented hydrophone system
  • Sliding window principle-based optical fiber segmented hydrophone system
  • Sliding window principle-based optical fiber segmented hydrophone system

Examples

Experimental program
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Embodiment Construction

[0019] Assuming that the clutter and noise of the received signal obey the Gaussian distribution, and its envelope is Rayleigh distribution, after passing through the square law detector, the reference unit samples x i (i=1,2,...,R) obey exponential distribution, where PDF and CDF are respectively

[0020]

[0021] μ represents the total clutter plus noise power level, λ is the ratio of the signal to the average power of clutter; H 0 is the assumption that there is no target, H 1 is the assumption that the target exists. In a uniform clutter background x i (i=1,2,...,R) are statistically independent and identically distributed.

[0022] The CFAR detector of ordered statistics is characterized by sorting the reference unit samples from small to large. In the case of a uniform background, the PDF of k ordered samples from R total samples is

[0023]

[0024] His CDF is

[0025]

[0026] where f(x) and F(x) represent the reference unit sample x in the uniform backgr...

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Abstract

The invention discloses a sliding window principle-based optical fiber segmented hydrophone system. The system mainly comprises an optical fiber, a laser, an erbium-doped fiber amplifier (EDFA), an APD, an ADC, a DSP, and an upper computer. The optical fiber is arranged in an underwater protective region. The laser is used for emitting light waves. The erbium-doped fiber amplifier (EDFA) is used for amplifying optical pulses. The APD is used for converting photoelectric signals. The ADC is used for converting electric signals into digital signals. The DSP is used for processing digital signals. The upper computer is used for further processing identification signals and displaying the alarm. Due to the fact that the underwater environment is complex and the detection distance is long, thesegmented detection is carried out on the change of the Ryleigh scattering waveform by adopting the sliding window principle. Therefore, the influence of the complex environment on system detection accuracy is eliminated to the maximum extent. The detection principle of the system is provided and carried out based on the processing of ordered samples in a reference sliding window. The processing flow is as follows: determining the length of an optimal sliding window according to an experiment, sorting samples through a front-edge sliding window and a rear-edge sliding window, figuring out an intermediate value as a reference sliding window value, adopting a difference value between a current point and the reference sliding window value as a vibration value, and determining the invasion type, the invasion position and other information through analyzing the vibration value.

Description

technical field [0001] The invention relates to an underwater monitoring hydrophone system used in some important sea areas, ports, etc. The main technologies and principles used include: optical fiber vibration, Rayleigh scattering, and the principle of orderly statistical sliding windows. It belongs to the technical fields of optical fiber sensor, photoelectric signal conversion, sliding window algorithm, water area security, and hydrophone system. Background technique [0002] At present, the more popular fiber optic hydrophone systems can be divided into: intensity fiber optic hydrophones, interference fiber optic hydrophones, and fiber optic grating hydrophones. [0003] The intensity-type fiber optic hydrophone is based on the principle of microbending loss, and is made according to the principle that the microbending loss of the fiber causes the transmission mode in the fiber to be lost in the form of a radiation mode, which in turn leads to a change in optical power....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V8/10G08B13/12
CPCG01V8/10G08B13/12
Inventor 柴军杰刘本刚李建彬刘浩宇魏嘉
Owner 光子瑞利科技(北京)有限公司
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