A novel scanning laser wind radar

Abstract

This invention provides a novel scanning laser wind-measuring radar, employing a high-stability, narrow-linewidth semiconductor laser as the transmitting device. A high-speed optical switch precisely modulates the continuous laser in the time domain to generate ideal laser pulses. High-power amplifiers and low-noise amplifiers are used to enhance the transmitted power and echo signal quality, significantly compensating for the decrease in atmospheric echo power and improving range resolution and wind speed accuracy. The high-stability, narrow-linewidth laser improves the signal-to-noise ratio through a triple mechanism of increased coherence efficiency, reduced background noise, and sharpened spectral resolution, enabling long-range detection. When using a transceiver telescope system, it avoids a reduction in the scanning field of view due to a decrease in signal-to-noise ratio. The semiconductor laser solution is lighter than fiber lasers, suitable for airborne platforms, and enables miniaturized laser wind-measuring radar equipment. Furthermore, the high-stability, narrow-linewidth semiconductor laser used meets temperature and vibration stability requirements, ensuring the long-term reliability of the wind-measuring radar in field environments.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic instrument technology, and in particular to a novel scanning laser wind radar. Background Technology

[0002] Real-time measurement of atmospheric wind fields is a crucial component of atmospheric environmental monitoring. It directly impacts daily life and plays a vital role in environmental monitoring, aviation meteorological safety, atmospheric theory research, weather warnings, and wind farm performance evaluation. Particularly in meteorology, atmospheric wind field detection has a profound influence on research into monsoon climate change, atmospheric environmental systems, and numerical weather prediction. Studying the distribution characteristics of atmospheric wind fields provides essential data support for meteorological science. In wind energy development, wind resource assessment is fundamental to wind farm site selection and optimization. Real-time lidar scanning can acquire horizontal and vertical wind field distributions, generating wind field maps to optimize wind turbine layout and determine optimal operating conditions. In aviation safety, lidar wind measurement significantly improves the accuracy of low-altitude wind field warnings, providing early warnings of wind shear and microbursts, and real-time monitoring of turbulence and wake vortices, reducing the risk of aircraft loss of control or even damage. In meteorology and atmospheric dynamics, wind measurement radar contributes to refined weather forecasts and improves forecast accuracy. Precise atmospheric wind field measurements are crucial for revealing the mechanisms of Earth's environmental evolution and establishing macroclimate models. In addition, wind field information is of irreplaceable significance in fields such as pollutant diffusion monitoring, bridge construction safety assessment, and natural disaster early warning.

[0003] Currently, my country's wind field measurement equipment mainly includes microwave wind radar, wind profiler radar, and Doppler acoustic radar. Microwave wind radar is based on the interaction between microwaves and atmospheric particles, but it produces virtually no effective signals for small particles and atmospheric molecules, and its performance is only good in cloudy or rainy conditions, limiting its application under clear skies. Wind profiler radar retrieves wind fields by receiving signals reflected from atmospheric turbulence, but under clear skies, the system's signal-to-noise ratio is too low, making it susceptible to environmental noise interference and reducing detection accuracy. Furthermore, its large size makes miniaturization and portable deployment difficult. Doppler acoustic radar utilizes the interaction of sound waves with the atmosphere, but its detection range is limited, and its effective distance is short, resulting in significant shortcomings in long-range detection. Existing coherent wind lidar systems typically use fiber lasers as the light source. After the beam is emitted through a telescope, it can only achieve wind field measurements in a fixed direction or within a limited range, and cannot achieve three-dimensional scanning measurements of the atmospheric wind field. In addition, existing lidar systems have many problems in terms of signal-to-noise ratio, detection range, miniaturization, and reliability: fiber lasers are limited by the small optical mode field area, resulting in low output power and thus limited detection range; lidar detection is susceptible to multiple interferences such as ground clutter reflection, atmospheric turbulence disturbance, and internal system noise (such as 1 / f noise of the detector), especially in environments with low signal-to-noise ratio, making it extremely challenging to accurately capture wind field information. These interference factors may lead to a decrease in echo signal quality, affecting the accuracy and reliability of the final wind field data; at the same time, existing systems are insufficient in scanning mechanisms and real-time processing capabilities, making it difficult to meet the needs of airborne platforms or long-term field monitoring.

[0004] Therefore, there is an urgent need in this field to develop a laser wind radar system that can achieve high-precision, three-dimensional, real-time wind field measurement, while also having a high signal-to-noise ratio, long detection range, miniaturization, and high reliability, in order to overcome the limitations of existing technologies and meet the urgent need for comprehensive monitoring of atmospheric wind fields in scientific research and engineering applications. Summary of the Invention

[0005] The purpose of this invention is to provide a novel scanning laser wind measurement radar to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a novel scanning laser wind measurement radar, comprising a high-frequency stable narrow-linewidth laser, a high-speed optical switch, a first coupler, a high-power erbium-doped fiber amplifier, an acousto-optic modulator, a transceiver optical telescope, a low-noise erbium-doped fiber amplifier, a second coupler, a low-noise detector, a signal processing board, and an optomechanical control box, wherein: The output terminal of the high-frequency stable narrow-linewidth laser is connected to the first input terminal of the high-speed optical switch; The output terminal of the high-speed optical switch is connected to the input terminal of the first coupler; The first output terminal of the first coupler is connected to the input terminal of the high-power erbium-doped fiber amplifier, and the second output terminal is connected to the input terminal of the acousto-optic modulator; The output of the high-power erbium-doped fiber amplifier is connected to the first input of the transceiver optical telescope. The output end of the transceiver optical telescope is connected to the input end of the low-noise erbium-doped fiber amplifier. The first input terminal of the second coupler is connected to the output terminal of the acousto-optic modulator, the second input terminal is connected to the output terminal of the low-noise erbium-doped fiber amplifier, and the output terminal is connected to the input terminal of the low-noise detector. The output terminal of the low-noise detector is connected to the input terminal of the signal processing board; The first output terminal of the signal processing board is connected to the second input terminal of the high-speed optical switch, and the second output terminal is connected to the input terminal of the optomechanical control box. The output of the optomechanical control box is connected to the second input of the transceiver optical telescope.

[0007] Preferably, the high-frequency stable narrow-linewidth laser, the high-speed optical switch, the first coupler, the high-power erbium-doped fiber amplifier, the acousto-optic modulator, the transceiver optical telescope, the low-noise erbium-doped fiber amplifier, the second coupler, and the low-noise detector are connected by optical fibers.

[0008] Preferably, the low-noise detector is electrically connected to the signal processing board, the signal processing board is electrically connected to the high-speed optical switch, the signal processing board is electrically connected to the optomechanical control box, and the optomechanical control box is electrically connected to the transceiver optical telescope.

[0009] Preferably, the transceiver optical telescope is a non-common optical path transceiver optical telescope, including a primary mirror, a secondary mirror, and a transceiver splitter. Its internal transmission path is the transceiver splitter, the secondary mirror, and the primary mirror connected in sequence, and the reception path is the primary mirror, the secondary mirror, and the transceiver splitter connected in sequence.

[0010] Preferably, the transceiver splitter is used to physically separate the transmitted beam and the received beam from the same main optical path in space, forming two independent optical path channels, while achieving high isolation and high-efficiency transmission.

[0011] Preferably, the signal processing board includes a signal conditioning circuit, an ADC acquisition module, an FPGA processing core, a microcontroller or CPU, a high-speed memory, and a communication control interface.

[0012] Preferably, the acousto-optic modulator is used to shift the frequency of the input beam by 80MHz to avoid 1 / f noise from the detector, and to use the frequency-shifted beam as the local oscillator.

[0013] Preferably, the signal processing board is used to perform ADC acquisition, time-domain analysis, frequency-domain analysis, Doppler frequency shift extraction, and wind speed inversion. The frequency-domain analysis includes performing a fast Fourier transform on the signal to generate a power spectrum and extracting the Doppler frequency shift from the power spectrum.

[0014] Preferably, the optomechanical control box is used to receive scanning commands from the signal processing board, drive and control the scanning mechanism of the transceiver optical telescope, and realize three-dimensional scanning.

[0015] Preferably, the high-speed optical switch modulates continuous laser light into pulsed laser light under the control of the signal processing board, and precisely controls the pulse emission time and width.

[0016] The present invention achieves the following beneficial technical effects compared to the prior art: This invention provides a novel scanning laser wind radar that uses a high-stability, narrow-linewidth semiconductor laser as the transmitting device. A high-speed optical switch precisely modulates the continuous laser in the time domain to generate ideal laser pulses. High-power amplifiers and low-noise amplifiers are used to enhance the transmitted power and echo signal quality, significantly compensating for the decrease in atmospheric echo power and improving range resolution and wind speed accuracy. The high-stability, narrow-linewidth laser improves the signal-to-noise ratio through a triple mechanism of increased coherence efficiency, reduced background noise, and sharpened spectral resolution, enabling long-range detection. When using a transceiver telescope system, it avoids a reduction in the scanning field of view due to a decrease in signal-to-noise ratio. The semiconductor laser solution is lighter than fiber lasers, suitable for airborne platforms, and enables miniaturized laser wind radar equipment. Furthermore, the high-stability, narrow-linewidth semiconductor laser used meets temperature and vibration stability requirements, ensuring the long-term reliability of the wind radar in field environments. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the novel scanning laser wind measuring radar provided by the present invention; In the diagram: 1: High-stability, narrow-linewidth laser; 2: High-speed optical switch; 3: First coupler; 4: High-power erbium-doped fiber amplifier; 5: Acousto-optic modulator; 6: Transceiver optical telescope; 7: Low-noise erbium-doped fiber amplifier; 8: Second coupler; 9: Low-noise detector; 10: Signal processing board; 11: Optomechanical control box. Detailed Implementation

[0019] The component serial numbers used in this document, such as "first," "second," etc., are merely for distinguishing the described objects and have no sequential or technical meaning. Unless otherwise specified, the terms "connection" and "linkage" used in this application include both direct and indirect connections. In the description of this invention, it should be understood that the terms "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0020] In this invention, unless otherwise explicitly specified and limited, the first feature above or below the second feature may be in direct contact with the first feature, or indirect contact via an intermediate medium. Furthermore, "above," "over," and "on top" of the first feature may mean the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "beneath" of the first feature may mean the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The purpose of this invention is to provide a novel scanning laser wind measurement radar to solve the problems existing in the prior art.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1: Please see Figure 1As shown, this invention provides a novel scanning laser wind radar, comprising a high-stability, narrow-linewidth laser 1, a high-speed optical switch 2, a first coupler 3, a high-power erbium-doped fiber amplifier 4, an acousto-optic modulator 5, a transceiver optical telescope 6, a low-noise erbium-doped fiber amplifier 7, a second coupler 8, a low-noise detector 9, a signal processing board 10, and an optomechanical control box 11. These components work together through optical fiber and electrical connections to achieve high-precision three-dimensional scanning measurement of atmospheric wind fields.

[0025] Specifically, the high-frequency-stability, narrow-linewidth laser 1 outputs a stable, narrow-linewidth continuous laser, and its output end is connected to the first input end of the high-speed optical switch 2. Under the control of the signal processing board 10, the high-speed optical switch 2 modulates the continuous laser into a pulsed laser, and its output end is connected to the input end of the first coupler 3. The first coupler 3 splits the pulsed laser into two beams: the first output end is connected to the input end of the high-power erbium-doped fiber amplifier 4, amplifying the weak pulsed laser to high power as the emitted signal light; the second output end is connected to the input end of the acousto-optic modulator 5, inputting a portion of the laser as seed light into the acousto-optic modulator 5. The acousto-optic modulator 5 shifts the frequency of the seed light to generate a local oscillator light with a frequency shift of 80MHz. This design aims to avoid the significant 1 / f noise present in the low-noise detector 9 in the 0-10MHz frequency band. According to the Doppler frequency shift formula (where is the Doppler frequency shift, is the wind speed component in the line-of-sight direction, and is the laser wavelength, = 1550nm), a typical wind speed of 0.1m / s only produces a frequency shift of 0.129MHz. Traditional zero-difference detection schemes would completely annihilate this weak signal in the baseband noise. Choosing an 80MHz frequency shift value first shifts the signal to the electromagnetic silence zone. This frequency band avoids power frequency interference harmonics and is far away from the 5G communication frequency band, while also being lower than the detector's typical 100MHz cutoff frequency.

[0026] Furthermore, the output of the high-power erbium-doped fiber amplifier 4 is connected to the first input of the transceiver optical telescope 6, inputting the high-power pulsed laser into the telescope. The transceiver optical telescope 6 adopts a non-common optical path design, mainly including a primary mirror, a secondary mirror, and a transceiver splitter. Its internal transmission path consists of the transceiver splitter, the secondary mirror, and the primary mirror connected in sequence, while the receiving path consists of the primary mirror, the secondary mirror, and the transceiver splitter connected in sequence. The transceiver splitter physically separates the transmitted beam and the received beam from the same primary optical path in space, forming two independent optical path channels, achieving high isolation and high-efficiency transmission. The telescope collimates the high-power pulsed laser and emits it in a specific atmospheric scanning direction driven by the optomechanical control box 11, collecting weak laser signals carrying wind speed information reflected or scattered from aerosols or particulate matter in the atmosphere. The output of the telescope is connected to the low-noise erbium-doped fiber amplifier 7 via optical fiber, which amplifies the extremely weak atmospheric backscattered light signal with low noise.

[0027] Furthermore, the output of the low-noise erbium-doped fiber amplifier 7 is connected to the second input of the second coupler 8, while the first input of the second coupler 8 is connected to the output of the acousto-optic modulator 5. The second coupler 8 combines the amplified echo signal from the low-noise erbium-doped fiber amplifier 7 with the local oscillator light from the acousto-optic modulator 5 to generate a beat frequency optical signal. The output of the second coupler 8 is connected to the input of the low-noise detector 9, which converts the beat frequency optical signal into an analog electrical signal and outputs it to the input of the signal processing board 10.

[0028] Furthermore, the signal processing board 10 includes a signal conditioning circuit, an ADC acquisition module, an FPGA processing core, a microcontroller / CPU, a high-speed memory, and a communication control interface. The signal processing board 10 first performs high-speed, high-precision analog-to-digital conversion on the analog electrical signal output from the low-noise detector 9 through the ADC acquisition module to obtain a digital signal; then, it performs time-domain analysis, processing the digital signal with range gate control, pulse accumulation, etc.; next, it performs frequency-domain analysis, performing fast Fourier transform or other spectrum estimation algorithms on the signal within each range gate to convert the time-domain signal into a frequency-domain power spectrum; it identifies the offset of the signal peak relative to 80MHz in the power spectrum and extracts the Doppler frequency shift; finally, it calculates the radial wind speed component according to the Doppler frequency shift calculation formula. The signal processing board 10 is also responsible for system control: its first output terminal is connected to the second input terminal of the high-speed optical switch 2 to generate a precise timing pulse signal, controlling the switching time and pulse width of the high-speed optical switch 2; its second output terminal is connected to the input terminal of the optomechanical control box 11 to send scanning commands to the optomechanical control box 11, including target azimuth angle, elevation angle, scanning mode, and speed.

[0029] Furthermore, the output of the optomechanical control box 11 is connected to the second input of the transceiver optical telescope 6. After receiving the scanning command from the signal processing board 10, it drives and controls the scanning mechanism of the telescope to achieve precise rotation in the horizontal and vertical directions, thereby completing the three-dimensional scan. By repeating the above laser emission, signal reception, processing, and scanning control steps, the system can continuously scan and detect the field of view, ultimately constructing three-dimensional wind field information and outputting a wind field map.

[0030] This specific implementation clearly demonstrates how a novel scanning laser wind radar utilizes a high-frequency, narrow-linewidth laser to improve coherence efficiency and signal-to-noise ratio, achieves long-range detection through pulsed laser technology and precise scanning control, and extracts high-precision wind field data by combining advanced signal processing techniques. The system has a compact structure, making it suitable for airborne platforms and long-term field deployment, effectively solving the problems of short detection range, low signal-to-noise ratio, and insufficient scanning capability in existing technologies.

[0031] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0032] It should be noted that the components mentioned in the above embodiments are all general standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0033] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A novel scanning laser wind-measuring radar, characterized in that, The system includes a high-stability, narrow-linewidth laser, a high-speed optical switch, a first coupler, a high-power erbium-doped fiber amplifier, an acousto-optic modulator, a transceiver optical telescope, a low-noise erbium-doped fiber amplifier, a second coupler, a low-noise detector, a signal processing board, and an optomechanical control box, among which: The output terminal of the high-frequency stable narrow-linewidth laser is connected to the first input terminal of the high-speed optical switch; The output terminal of the high-speed optical switch is connected to the input terminal of the first coupler; The first output terminal of the first coupler is connected to the input terminal of the high-power erbium-doped fiber amplifier, and the second output terminal is connected to the input terminal of the acousto-optic modulator; The output of the high-power erbium-doped fiber amplifier is connected to the first input of the transceiver optical telescope. The output end of the transceiver optical telescope is connected to the input end of the low-noise erbium-doped fiber amplifier. The first input terminal of the second coupler is connected to the output terminal of the acousto-optic modulator, the second input terminal is connected to the output terminal of the low-noise erbium-doped fiber amplifier, and the output terminal is connected to the input terminal of the low-noise detector. The output terminal of the low-noise detector is connected to the input terminal of the signal processing board; The first output terminal of the signal processing board is connected to the second input terminal of the high-speed optical switch, and the second output terminal is connected to the input terminal of the optomechanical control box. The output of the optomechanical control box is connected to the second input of the transceiver optical telescope.

2. The novel scanning laser wind measuring radar according to claim 1, characterized in that, The high-frequency stable narrow-linewidth laser, the high-speed optical switch, the first coupler, the high-power erbium-doped fiber amplifier, the acousto-optic modulator, the transceiver optical telescope, the low-noise erbium-doped fiber amplifier, the second coupler, and the low-noise detector are connected by optical fibers.

3. The novel scanning laser wind measuring radar according to claim 1, characterized in that, The low-noise detector is electrically connected to the signal processing board, the signal processing board is electrically connected to the high-speed optical switch, the signal processing board is electrically connected to the optomechanical control box, and the optomechanical control box is electrically connected to the transceiver optical telescope.

4. The novel scanning laser wind measuring radar according to claim 1, characterized in that, The transceiver optical telescope is a non-common optical path transceiver optical telescope, including a primary mirror, a secondary mirror, and a transceiver splitter. Its internal transmission path is the transceiver splitter, the secondary mirror, and the primary mirror connected in sequence, and the reception path is the primary mirror, the secondary mirror, and the transceiver splitter connected in sequence.

5. The novel scanning laser wind measuring radar according to claim 4, characterized in that, The transceiver splitter is used to physically separate the transmitted beam and the received beam from the same main optical path in space, forming two independent optical path channels, while achieving high isolation and high-efficiency transmission.

6. The novel scanning laser wind-measuring radar according to claim 1, characterized in that, The signal processing board includes a signal conditioning circuit, an ADC acquisition module, an FPGA processing core, a microcontroller or CPU, a high-speed memory, and a communication control interface.

7. The novel scanning laser wind measuring radar according to claim 1, characterized in that, The acousto-optic modulator is used to shift the frequency of the input beam by 80MHz to avoid 1 / f noise from the detector, and to use the frequency-shifted beam as the local oscillator.

8. The novel scanning laser wind measuring radar according to claim 1, characterized in that, The signal processing board is used to perform ADC acquisition, time domain analysis, frequency domain analysis, Doppler frequency shift extraction, and wind speed inversion. The frequency domain analysis includes performing a fast Fourier transform on the signal to generate a power spectrum and extracting the Doppler frequency shift from the power spectrum.

9. The novel scanning laser wind measuring radar according to claim 1, characterized in that, The optomechanical control box is used to receive scanning commands from the signal processing board, drive and control the scanning mechanism of the transceiver optical telescope, and realize three-dimensional scanning.

10. The novel scanning laser wind-measuring radar according to claim 1, characterized in that, The high-speed optical switch, under the control of the signal processing board, modulates continuous laser light into pulsed laser light and precisely controls the pulse emission time and width.

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