Double-margin phase modulation laser Doppler velocimetry system and method

A technology of Doppler speed measurement and phase modulation, which is applied in the field of Doppler speed measurement, can solve the problems that the Doppler frequency shift information cannot be fully utilized, and the Doppler frequency shift information cannot be simultaneously used to achieve wide measurement range and high measurement sensitivity. high effect

Inactive Publication Date: 2016-07-13
HARBIN NORMAL UNIVERSITY
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Problems solved by technology

[0005] The present invention aims to solve the problem that the existing phase-modulated laser Doppler speed measurement system cannot simultaneously utilize the Doppler frequency shift information in the phase of the beat frequency signal and cannot fully utilize the Doppler frequency shift information in all the echo signal light. In order to solve the problem of Le frequency shift information, a dual-edge phase modulation laser Doppler velocity measurement system and velocity measurement method are proposed

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  • Double-margin phase modulation laser Doppler velocimetry system and method
  • Double-margin phase modulation laser Doppler velocimetry system and method
  • Double-margin phase modulation laser Doppler velocimetry system and method

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specific Embodiment approach 1

[0035] Specific implementation mode 1. Combination figure 1 Describe this specific embodiment, double-edge phase modulation laser Doppler velocimetry system, which includes a laser 1, a polarization beam splitter 2, a mechanical switch 3, a first convex lens 4, a second convex lens 6, a multimode optical fiber 7, and a third convex lens 8 , polarization beam splitter prism 9, fourth convex lens 10, mirror 11, fifth convex lens 12, first optical fiber phase modulator 13, second optical fiber phase modulator 14, driver 15, signal generator 16, sixth convex lens 17, the first optical fiber phase modulator Seven-convex lens 18, first beam expander 19, second beam expander 20, F-P etalon 21, eighth convex lens 22, first photomultiplier tube 23, ninth convex lens 24, second photomultiplier tube 25, right-angle mirror 26, data acquisition card 27, output card 28 and computer 29;

[0036] When the mechanical switch 3 is turned on, the laser 1 sends signal light, and the signal light is...

specific Embodiment approach 2

[0050] Specific embodiment two, based on the dual edge phase modulation laser Doppler velocimetry method of specific embodiment one, it comprises the following steps:

[0051] Step 1. When the mechanical switch 3 is in the closed state, use the computer 29 to control the output card 28 to adjust the output frequency of the laser 1, that is: the frequency ω of the signal light, and use the computer 29 to collect the different laser frequencies collected by the data acquisition card 27. The output current i of the first photomultiplier tube 23 1 and the output current i of the second photomultiplier tube 25 2 Carry out calculations and draw the frequency discrimination parameter lA 1 (ω) and frequency discrimination parameter lA 2 (ω) frequency shift curve;

[0052] Step 2, when the mechanical switch 3 is closed, the output current i of the first photomultiplier tube 23 collected by the computer to the data acquisition card 27 1 (t 0 ) and the output current i of the second...

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Abstract

The invention discloses a double-margin phase modulation laser Doppler velocimetry system and method and relates to the Doppler velocimetry technique. The problems of existing phase modulation laser Doppler velocimetry systems that Doppler shift information in a signal light double modulation frequency beat frequency signal phase can not be utilized simultaneously and Doppler shift information in all echo signal light can not be fully utilized are solved. A polarization splitting prism is adopted for dividing echo signal light into two beams according to position, sinusoidal phase modulation is conducted on all signal light beams in the same way, and detection is conducted on all signal light beams with photomultipliers respectively. Two frequency discrimination parameters lA1(omega) and lA2(omega) are obtained through two current values i1 and i2, and by means of the two frequency discrimination parameters lA1(omega) and lA2(omega), a new frequency discrimination parameter sA(omega) is established to serve as the frequency discrimination parameter of the double-margin structure, wherein sA(omega)=lA1(omega)-lA2(omega). The system and method are suitable for double-margin phase modulation laser Doppler velocimetry.

Description

technical field [0001] The present invention relates to Doppler velocity measuring technology. Background technique [0002] A beam of laser with a stable frequency is irradiated on the moving target. Due to the Doppler effect, the backscattered light of the target will produce a certain frequency shift. By measuring the Doppler frequency shift of the backscattered light, the moving target can be obtained. Velocity information along the beam direction, this is the basic principle of the laser Doppler velocimeter. Due to the unparalleled measurement accuracy of the laser Doppler velocimeter, it has broad application prospects in various fields such as military affairs and industry. At present, laser Doppler velocimeter mainly adopts two methods of measuring Doppler frequency shift, coherent detection and direct detection. Although these two methods each have significant advantages, they also have disadvantages that are difficult to overcome. Coherent detection is to use th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S17/58G01S7/481
CPCG01S7/4818G01S17/58
Inventor 杜军李世明杨娜张海波丁云鸿周国辉牛智萌刘艺丹
Owner HARBIN NORMAL UNIVERSITY
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