CN216209906U

CN216209906U - Three-dimensional environment monitoring polarization laser radar system

Info

Publication number: CN216209906U
Application number: CN202122481625.2U
Authority: CN
Inventors: 宋耀东; 刘洋; 赵凯; 张凯
Original assignee: Hefei Zhongke Environmental Monitoring Technology National Engineering Laboratory Co ltd
Current assignee: Hefei Zhongke Environmental Monitoring Technology National Engineering Laboratory Co ltd
Priority date: 2021-10-14
Filing date: 2021-10-14
Publication date: 2022-04-05
Anticipated expiration: 2031-10-14

Abstract

The utility model relates to the technical field of atmospheric environment remote sensing monitoring, and discloses a three-dimensional environment monitoring polarization laser radar system, which comprises a laser emitting system, a polarization laser receiving system and a polarization laser receiving system, wherein the laser emitting system is used for emitting laser to the air; a rotating polarizer rotatable about an optical axis; the lens is positioned at the rear side of the rotary polarizing device and is used for scattering aerosol in the air and converging the laser passing through the rotary polarizing device to the spectroscope; the spectroscope divides the laser into the CCD and the detector according to the proportion; the CCD is used for detecting the distribution of the transverse polarization profile when the rotary polarization device works in a rotating mode; the detector is used for detecting the distribution of the longitudinal polarization profile when the rotary polarization device works in a rotating mode; when the rotary polarization device does not rotate to work and the polarization direction of the rotary polarization device is consistent with that of the laser emitted by the laser emission system, the detector is used for detecting an extinction profile; the measurement of extinction profile, horizontal, vertical polarization profile is realized, need not a plurality of detectors, saves channel number and cost.

Description

Three-dimensional environment monitoring polarization laser radar system

Technical Field

The utility model relates to the technical field of atmospheric environment remote sensing monitoring, in particular to a three-dimensional environment monitoring polarization laser radar system.

Background

As shown in fig. 2, in the current distribution detection of atmospheric particulates, a laser active detection meter scattering principle is generally adopted, a laser beam is emitted into the atmosphere, the laser beam scatters aerosol molecules in the air, and a telescope is adopted to receive scattered echo signals at a backward scattering position. The echo signal intensity of the backscattering can be different at different distances and different aerosol extinction coefficients. The Mie scattering laser radar can analyze aerosol extinction profiles at different heights, but can not distinguish the types of pollutants. As shown in fig. 3, a conventional laser radar having polarization detection is also used, and the polarization ratio of the emitted laser light is known, and the vertical and parallel paths of the return light are separated by a PBS, and the light intensities in both directions are detected by a photomultiplier PMT, so that the depolarization ratio can be calculated.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problems, the utility model provides a three-dimensional environment monitoring polarization laser radar system which can simultaneously realize measurement of an aerosol extinction profile, a transverse polarization profile and a longitudinal polarization profile in a remote sensing mode without a plurality of detectors.

In order to solve the technical problems, the utility model adopts the following technical scheme:

a stereoscopic environment monitoring polarized lidar system, comprising:

the laser emission system is used for emitting laser to the air;

a rotating polarizer rotatable about an optical axis;

the lens is positioned at the rear side of the rotary polarizing device and is used for scattering aerosol in the air and converging the laser passing through the rotary polarizing device to the spectroscope;

the spectroscope divides the laser into the CCD and the detector according to the proportion;

the CCD is used for detecting the distribution of the transverse polarization profile when the rotary polarization device works in a rotating mode;

the detector is used for detecting the distribution of the longitudinal polarization profile when the rotary polarization device works in a rotating mode; when the rotary polarization device does not rotate to work and the rotary polarization device is consistent with the polarization direction of the laser emitted by the laser emitting system, the detector is used for detecting the extinction profile.

Further, the rotating polarization device is a linear polarization device.

Further, the beam splitter splits the laser light to the CCD and the detector according to a ratio of 50: 50.

Furthermore, the laser emission system comprises a laser, a first reflecting mirror and a second reflecting mirror, wherein the first reflecting mirror adjusts the light spot of the laser emitted by the laser to the middle position of the second reflecting mirror, and the direction of the emitted laser is parallel to the direction of the optical axis of the rotary polarization device by adjusting the angle of the second reflecting mirror.

Compared with the prior art, the utility model has the beneficial technical effects that:

the polarization device can be rotated, is arranged at the foremost end of the receiving system and is vertical incidence, and the measurement of the extinction profile, the transverse polarization profile and the longitudinal polarization profile can be realized by rotating the polarization device to operate in a rotating state and a non-rotating state, so that a plurality of detectors are not needed, and the channel number and the cost are saved.

Drawings

FIG. 1 is a schematic diagram of a radar system according to the present invention;

FIG. 2 is a schematic diagram of a prior art atmospheric environment monitoring device;

fig. 3 is a schematic diagram of an atmospheric environment monitoring device in the prior art.

Detailed Description

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

The polarized laser radar system can not only remotely sense the distribution of aerosol in the air, but also judge the type information of pollutants, and respectively judge the distribution types of the pollutants from the longitudinal direction and the transverse direction.

The type of the particles is longitudinally judged, namely the depolarization degrees of the particles at the profiles with different heights are judged, and experimental observation shows that the depolarization effects of the particles are different due to different ovalities. The spherical particles do not basically change the polarization characteristics of the laser, and the depolarization characteristic effect of the backward scattering of the non-spherical particles is very obvious. The spherical particles are secondary particles (local pollution) formed by oxidizing, adsorbing and condensing gaseous pollutants such as VOC and the like generally; the non-spherical particles are mostly dust and sand, which is transported externally. Longitudinal judgment enables analysis of the particulate contamination category at vertical height.

The transverse judgment of the category is realized according to the optical imaging characteristic and the polarization detection principle of polarized light, an object plane is imaged on the surface of the CCD3 through the lens 2, the CCD3 records light intensity information, the polarization device 1 is rotated at the same time, the polarization characteristics at different angles are recorded, the polarization information of different positions of the object plane can be solved according to the Stokes equation, and therefore the transverse polarization distribution characteristic is judged, and the category of the substance is judged.

As shown in fig. 1, the polarization lidar system for monitoring a three-dimensional environment in the present invention includes a laser, a first reflecting mirror 8, a second reflecting mirror 9, a rotating polarization device 1, a lens 2, a beam splitter 10, a CCD3, an aperture stop 4, a collimating mirror 5, an optical filter 6, a detector 7, an analog-to-digital conversion module, a main control, and an upper computer. The lens is positioned at the rear side of the rotating polarization device.

Wherein the laser, the first reflector 8 and the second reflector 9 form a laser emitting system; the receiving system consists of a rotary polarizing device 1, a lens 2, a spectroscope 10, a CCD3, an aperture diaphragm 4, a collimating mirror 5, an optical filter 6 and a detector 7. The detector 7 is a photomultiplier tube (PMT).

The emergent light of the laser is emergent after being reflected by the two reflectors, the first reflector 8 adjusts the laser spot to the middle position of the second reflector 9, and the coaxial emergent laser beam and a receiving system are realized by adjusting the angle of the second reflector 9. Laser emitted into the air is scattered by the action of aerosol and then enters a rotating polarization device 1, the rotating polarization device 1 is a linear polarization device and can rotate around an optical axis, the polarized light passing through the rotating polarization device is received and converged by a lens 2, and is split by a beam splitter 50:50, and part of the polarized light enters a CCD3 for imaging, and when the rotating polarization device 1 rotates to work, the CCD3 can detect the distribution of transverse polarization profiles; the other part passes through the spectroscope 10, the small aperture diaphragm 4, the collimating mirror 5 and the optical filter 6 and reaches the surface of the detector 7, and when the rotary polarizing device 1 rotates to work, the other part detects the longitudinal polarization profile distribution; when the rotating polarization device 1 does not rotate and the rotating polarization device 1 is consistent with the polarization direction of the emitted laser light, the detector 7 is used for detecting the extinction profile. The specific workflow is as follows.

A polarization detection process:

(1) the laser is started, and laser enters the atmosphere and is scattered;

(2) the rotating polarization device 1 rotates to work, and the scattered light enters a receiving system and changes in intensity;

(3) the photomultiplier and the CCD3 collect optical signals, perform photoelectric conversion, and collect the optical signals through a digital-to-analog conversion module to enter an upper computer for operation;

(4) and outputting the longitudinal polarization profile distribution and the transverse polarization profile distribution.

Extinction detection process:

(1) the rotary polarization device 1 rotates to the same polarization direction as the emergent laser;

(2) the laser is started, and laser enters the atmosphere and is scattered;

(3) the scattered light enters a receiving system and changes in intensity;

(4) the photomultiplier collects optical signals, performs photoelectric conversion, and collects the optical signals through a digital-to-analog conversion module to enter an upper computer for operation;

(5) and outputting an extinction profile.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not intended to be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A stereoscopic environment monitoring polarized lidar system, comprising:

the laser emission system is used for emitting laser to the air;

a rotating polarizer rotatable about an optical axis;

2. The stereographic environment monitoring polarized lidar system of claim 1, wherein: the rotating polarization device is a linear polarization device.

3. The stereographic environment monitoring polarized lidar system of claim 1, wherein: the beam splitter splits the laser light to the CCD and the detector at a ratio of 50: 50.

4. The stereographic environment monitoring polarized lidar system of claim 1, wherein: the laser emission system comprises a laser, a first reflector and a second reflector, wherein the first reflector adjusts a light spot of laser emitted by the laser to the middle position of the second reflector, and the direction of the emitted laser is parallel to the optical axis direction of the rotary polarization device by adjusting the angle of the second reflector.