All time photon counting laser radar apparatus and method

A technology of laser radar and photon counting, which is applied in the directions of measuring devices, electromagnetic wave re-radiation, and utilization of re-radiation, etc., can solve the problems of high price, large gap between laser radar detection performance and night time, detection distance and accuracy limitation, etc. Effect of low, daytime detection signal-to-noise ratio and detection distance improvement, high-performance working ability

Inactive Publication Date: 2008-05-14
OCEAN UNIV OF CHINA
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Problems solved by technology

Most importantly, even if the filter with the narrowest bandwidth is used, the solar background light that is consistent with the emitted laser wavelength still enters the receiving system, which makes the detection performance of the lidar during the day far from that at night, which greatly limits its application in the business field. Applications
[0004] In short, the current lidar system is affected by strong background light, and the detection distance and accuracy are greatly limited; and the existing background light filter is difficult to complete 24-hour continuous observation (that is, all-day measurement) with the same performance, and the structure Complex, expensive, difficult to promote to practical applications

Method used

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  • All time photon counting laser radar apparatus and method

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Embodiment 1

[0029] Take, for example, a photon-counting lidar device operating at 518.362 nm for measuring the extinction coefficient of the atmosphere.

[0030] The wavelength of the laser matches the 518.362nm Fraunhofer line of the Mg element in the solar spectrum. The Fraunhofer line bandwidth of Mg element at 518.362nm is 0.1584nm. In order to make the Fraunhofer and Fernando line bandwidth greater than or equal to the linewidth of the emitted laser, the usual interferometer mode selection method is adopted for the laser, so that the laser linewidth is less than 0.01nm, even if the emission linewidth of the laser is much smaller than the Fraunhofer and Fernando line bandwidth, This causes the laser to emit in the dark window of the solar spectrum. The laser can be an OPO tunable laser, such as the Surelite OPO PLUS laser from Continuum in the United States, which is pumped by a 355nm laser and whose output wavelength can be tuned at 518.362nm.

[0031] The telescope 5 can be a commer...

Embodiment 2

[0037] Take a photon-counting lidar device operating at 526.955 nm for measuring the extinction coefficient of atmospheric aerosols as an example.

[0038] The wavelength of the laser is selected to match the Fraunhofer line 526.955nm of the Fe element in the solar spectrum. The laser can be an OPO tunable laser, such as the VIBRANT (B) 355 II laser of OPOTEK in the United States, which is pumped by a 355nm laser and whose output wavelength can be tuned at 526.955nm. .

[0039] The telescope 5 can be a commercially available general-purpose telescope such as reflective and refracting telescopes, such as the 91024 8-inch Schmidt-Cassegrain telescope produced by Celestron Corporation of the United States. The beam expander 2 is a BE10M-A 10x beam expander from THORLABS, USA. Reflector 3 is a general optical lens coated with a 526.955nm anti-reflection film.

[0040] Optical filter 6 is a serial combination of a bandpass interference filter and a Fabry-Perot etalon. In the so...

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Abstract

The invention relates to a whole day photon counting laser radar device and a method, which comprises an emission system consisting of a laser, an expander and a reflector, a receiving system consisting of a telescope, an optics filter and a photoelectric detector, and a central control device connected with the photoelectric detector with a software. The invention is characterized in that the wavelength of the laser and the optics filter are chosen to match with the fraunhofer absorption line wavelength of the solar spectrum; the intense absorption is adopted to reduce the intensity of a solar back light by 80 to 90 percent and to lead the laser radar to have good photon counting ability under the back light condition in days. The invention is characterized in that the day detection signal-noise ratio and the detection distance are greatly improved, which effectively improves the whole day high-performance working ability. Besides, the invention is widely suitable for the laser radarof detecting weak signal such as Mie dispersion, Rayleigh dispersion, Raman dispersion and atom resonance fluorescence, etc.

Description

technical field [0001] The present invention relates to a laser radar device, more specifically, a laser radar device that can still normally perform photon counting measurement under strong background light during the day—all-day photon counting laser radar device. Background technique [0002] Lidar detects various atmospheric parameters by receiving backscattering signals of laser light from scatterers (atmosphere, water bodies, targets). Since the scattered signal is very weak, lidar usually uses photon counting for weak signal detection. Through long-term accumulation, the signal photons are captured from the dark background, and the signal-to-noise ratio and detection distance are improved. Due to the influence of the strong solar background light, the detection signal-to-noise ratio and detection distance of lidar during the day are greatly different from those at night, and it is impossible to observe the diurnal changes of atmospheric physical and chemical paramete...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S17/95G01S7/481
CPCY02A90/10
Inventor 吴松华刘智深张凯临
Owner OCEAN UNIV OF CHINA
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