Wind laser radar calibration method, device, equipment and storage medium

Abstract

The present application discloses a wind laser radar calibration method, device, equipment and storage medium, which relates to the field of wind speed measurement technology, including: dividing the energy of a target seed source to obtain a first laser signal, a second laser signal and a local oscillator signal; the energy of the first laser signal is higher than the energy of the second laser signal and the local oscillator signal; the first laser signal is sequentially passed through a target acousto-optic modulator, a target amplifier, a first circulator and a first light output mirror group to obtain a first output light signal, and the second laser signal is sequentially passed through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator and a second light output mirror group to obtain a second output light signal; an echo signal is determined from the first output light signal and the second output light signal, and a target frequency domain signal is obtained using the echo signal and the local oscillator signal; the target frequency domain signal is sent to a control terminal so as to be calibrated based on the target frequency domain signal. The present application realizes the calibration of a wind laser radar.

Description

Technical Field

[0001] The present invention relates to the technical field of wind speed measurement, and in particular to a wind speed laser radar calibration method, device, equipment and storage medium. Background Art

[0002] At present, the speed measurement accuracy of the coherent wind laser radar is determined by analyzing the spectrum of the echo signals with different energies and frequencies. The echo signals with different energies will cause the signal-to-noise ratio of the radar detection to decrease, resulting in a decrease in the speed measurement accuracy. Different frequency-shifted echo signals, different detection bandwidths of the inspection system and different wind speeds correspond to different spectra, which requires different system bandwidths. To fully simulate the real radar speed measurement accuracy and performance, it is necessary to perform different attenuation on the echo and move the echo frequency accordingly. Usually, when calibrating the coherent wind laser radar, the whole machine is often measured by hard targets. Hard target signals with different positions, different reflectivities and different movement speeds are selected to obtain different return signals, and the return signals are used to calibrate the radar under test. However, when tracking and irradiating the dynamic hard target signal, it is difficult to control the laser emitted by the radar under test to be relative to the center of the dynamic hard target signal, and it is also difficult to achieve precise control of the changing angle when calibrating the angle using external mechanical methods, resulting in very complicated calibration processes and facilities.

[0003] Therefore, how to simplify the process and facilities for calibrating wind lidar and improve the calibration accuracy is an urgent problem to be solved. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a wind laser radar calibration method, device, equipment and storage medium, which can simplify the process and facilities for calibrating the wind laser radar and improve the calibration accuracy. The specific scheme is as follows:

[0005] In a first aspect, the present application discloses a wind laser radar calibration method, comprising:

[0006] Dividing the energy of the target seed source based on a preset division ratio to obtain a first laser signal, a second laser signal and a local oscillator signal; wherein the energy of the first laser signal is higher than the energy of the second laser signal and the local oscillator signal;

[0007] The first laser signal is sequentially passed through a target acousto-optic modulator, a target amplifier, a first circulator and a first light output mirror group to obtain a first output light signal, and the second laser signal is sequentially passed through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator and a second light output mirror group to obtain a second output light signal; wherein the angle of the first light output mirror group and the angle of the second light output mirror group are controlled by a servo system;

[0008] Determine an echo signal from the first outgoing light signal and the second outgoing light signal, and collect and process the echo signal and the local oscillator signal to obtain a target frequency domain signal;

[0009] The target frequency domain signal is sent to a control terminal so that the control terminal performs calibration based on the target frequency domain signal.

[0010] Optionally, the step of sequentially passing the first laser signal through a target acousto-optic modulator, a target amplifier, a first circulator, and a first light output mirror group to obtain a first output light signal includes:

[0011] Determining a target acousto-optic modulator based on a target modulation bandwidth, and controlling the on-off state of the first laser signal based on a first preset transmission frequency using the control terminal;

[0012] The first laser signal passes through the target acousto-optic modulator, the target amplifier, the first circulator and the first light output mirror group in sequence to obtain a first output light signal whose emission frequency is the first preset emission frequency.

[0013] Optionally, the step of sequentially passing the second laser signal through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator, and a second light output mirror assembly to obtain a second output optical signal includes:

[0014] Using the control terminal to adjust the optical frequency shift modulator based on the second preset transmission frequency and the preset pulse frequency to obtain the target optical frequency shift modulator;

[0015] The second laser signal passes through the target optical frequency shift modulator, the target amplifier attenuator, the second circulator and the second light output mirror group in sequence to obtain a second output optical signal with an emission frequency of the second preset emission frequency and a pulse frequency of the preset pulse frequency.

[0016] Optionally, determining an echo signal from the first outgoing light signal and the second outgoing light signal includes:

[0017] The first outgoing optical signal and the second outgoing optical signal are input to a 2*1 optical switch, so that the control terminal determines an echo signal from the first outgoing optical signal and the second outgoing optical signal through the 2*1 optical switch.

[0018] Optionally, collecting and processing the echo signal and the local oscillator signal to obtain a target frequency domain signal includes:

[0019] The echo signal and the local oscillator signal are coupled by a fiber coupler to obtain a target coupled signal;

[0020] The target coupling signal is input into a balanced detector to obtain a target electrical signal corresponding to the target coupling signal, and a signal acquisition processor is used to acquire and process the target electrical signal to obtain the target frequency domain signal.

[0021] Optionally, the calibration based on the target frequency domain signal includes:

[0022] Servo system calibration, frequency-shift wind speed calibration and acquisition position calibration are performed based on the target frequency domain signal.

[0023] Optionally, the control terminal performs calibration based on the target frequency domain signal, including:

[0024] Performing calibration based on the target frequency domain signal by the control terminal, and determining whether the calibration is completed;

[0025] If the calibration is not completed, the control terminal determines the parameters to be adjusted based on a preset parameter adjustment method, and adjusts the parameters to be adjusted, so that the wind measurement lidar is calibrated based on the target frequency domain signal using the adjusted parameters through the control terminal.

[0026] In a second aspect, the present application discloses a wind laser radar calibration device, comprising:

[0027] An energy division module, used to divide the energy of the target seed source based on a preset division ratio to obtain a first laser signal, a second laser signal and a local oscillator signal; wherein the energy of the first laser signal is higher than the energy of the second laser signal and the local oscillator signal;

[0028] an output light signal acquisition module, configured to sequentially pass the first laser signal through a target acousto-optic modulator, a target amplifier, a first circulator, and a first light output mirror group to obtain a first output light signal, and sequentially pass the second laser signal through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator, and a second light output mirror group to obtain a second output light signal; wherein the angle of the first light output mirror group and the angle of the second light output mirror group are controlled by a servo system;

[0029] A frequency domain signal acquisition module, used to determine an echo signal from the first outgoing optical signal and the second outgoing optical signal, and collect and process the echo signal and the local oscillator signal to acquire a target frequency domain signal;

[0030] The calibration module is used to send the target frequency domain signal to the control terminal so that the control terminal performs calibration based on the target frequency domain signal.

[0031] In a third aspect, the present application discloses an electronic device, including:

[0032] Memory, used to store computer programs;

[0033] The processor is used to execute the computer program to implement the above-mentioned wind laser radar calibration method.

[0034] In a fourth aspect, the present application discloses a computer-readable storage medium for storing a computer program, wherein the computer program implements the aforementioned wind laser radar calibration method when executed by a processor.

[0035] In the present application, when calibrating the wind measuring laser radar, the energy of the target seed source is divided based on a preset division ratio to obtain a first laser signal, a second laser signal and a local oscillator signal; wherein the energy of the first laser signal is higher than the energy of the second laser signal and the local oscillator signal; the first laser signal is sequentially passed through a target acousto-optic modulator, a target amplifier, a first circulator and a first light output mirror group to obtain a first output light signal, and the second laser signal is sequentially passed through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator and a second light output mirror group to obtain a second output light signal; wherein the angle of the first light output mirror group and the angle of the second light output mirror group are controlled by a servo system; an echo signal is determined from the first output light signal and the second output light signal, and the echo signal and the local oscillator signal are collected and processed to obtain a target frequency domain signal; the target frequency domain signal is sent to a control terminal so that the control terminal performs calibration based on the target frequency domain signal. It can be seen that when calibrating the wind measuring laser radar, the present application adopts a laser source as the target seed source, divides the energy emitted by the target seed source into three parts, respectively as the first laser signal, the second laser signal and the local oscillator signal, and inputs the first laser signal into the acoustic target optical modulator so that the first output optical signal is modulated through a fixed modulation bandwidth, and the second laser signal input into the target optical frequency shift modulator can perform corresponding frequency modulation on the second laser signal according to the change of the input microwave frequency, and uses an amplifier attenuator with different parameters to process the second laser signal to simulate echo signals in various weather conditions and detection distances, which is fast and stable, avoiding the tedious operation of irradiating the radar's entire emission light beam with hard targets at different positions when calibrating the entire radar system, and at the same time, uses a programmable optical frequency shift modulator to generate echo signals of different wind speeds, and the generated echo signal has high frequency shift accuracy, thereby simplifying the process and facilities for calibrating the wind measuring laser radar and improving the calibration accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0037] Figure 1 A flow chart of a wind laser radar calibration method disclosed in this application;

[0038] Figure 2 A schematic diagram of a wind laser radar calibration method disclosed in this application;

[0039] Figure 3 This is a schematic diagram of the structure of a wind measurement laser radar servo system disclosed in this application;

[0040] Figure 4 A schematic diagram of a specific wind laser radar calibration process disclosed in this application;

[0041] Figure 5 A schematic diagram of a specific wind laser radar angle calibration process disclosed in this application;

[0042] Figure 6 A schematic diagram of a specific wind speed calibration process of a wind laser radar frequency shifting disclosed in this application;

[0043] Figure 7 This is a schematic diagram of the structure of a wind laser radar calibration device disclosed in this application;

[0044] Figure 8 This is a structural diagram of an electronic device disclosed in this application. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] At present, when calibrating a coherent wind laser radar, in order to simulate the real radar speed measurement accuracy and performance, the whole machine is often used to measure hard targets, and hard targets with different positions and different reflectivities are selected to simulate echo signals with different attenuation and different frequencies, and the hard targets need to be moved at different speeds. However, it is difficult to control the speed of the hard target and it is difficult to find echo signals of different powers, which makes the calibration process and facilities very complicated. In order to solve the above technical problems, the present application discloses a wind laser radar calibration method, which can simplify the process and facilities for calibrating the wind laser radar and improve the calibration accuracy.

[0047] See also Figure 1 As shown, an embodiment of the present invention discloses a wind laser radar calibration method, comprising:

[0048] Step S11, dividing the energy of the target seed source based on a preset division ratio to obtain a first laser signal, a second laser signal and a local oscillator signal; wherein the energy of the first laser signal is higher than the energy of the second laser signal and the local oscillator signal.

[0049] In this embodiment, the target seed source can provide a laser radar light source seed light with narrow line width and low intensity noise, which can be used to emit continuous laser. Figure 2 As shown, the laser emitted by the target seed source can be divided by an integrated optical splitter based on a preset division ratio to obtain a first laser signal, a second laser signal and a local oscillator signal. The energy of the first laser signal is the highest energy signal among the three signals, and is used for signal acquisition in practical applications; the second laser signal is used for calibration, and the local oscillator signal is connected to the fiber coupler as the local oscillator light for calibration.

[0050] Step S12, passing the first laser signal sequentially through a target acousto-optic modulator, a target amplifier, a first circulator and a first light output mirror group to obtain a first output light signal, and passing the second laser signal sequentially through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator and a second light output mirror group to obtain a second output light signal; wherein the angle of the first light output mirror group and the angle of the second light output mirror group are controlled by a servo system.

[0051] In this embodiment, Figure 2As shown, before the first laser signal passes through the target AOM, the target amplifier, the first circulator and the first light output mirror group in sequence, the target AOM can be determined based on the target modulation bandwidth, and then the first laser signal passes through the target AOM, the target amplifier, the first circulator and the first light output mirror group in sequence to obtain the first output light signal, so as to control the on-off state of the first laser signal based on the first preset emission frequency by using the control terminal. Since the modulation bandwidth of the target AOM is known, the first laser signal is modulated into a pulse light with a known frequency and pulse width and an output light frequency of the first preset emission frequency after passing through the target AOM, and then the pulse light is further amplified by the amplifier, and finally emitted through the first circulator and the first light output mirror group to obtain the first output light signal with a known frequency and pulse width and an output light frequency of the first preset emission frequency. At the same time, since the angle of the first light output mirror group and the angle of the second light output mirror group are determined by the following formula: Figure 3 The servo system shown is controlled, so the angle of each light-emitting mirror group can be adjusted by the servo system to achieve radial wind speed measurement at different angles.

[0052] It should be pointed out that Figure 3 The servo system shown is a dual-axis system, which is divided into an azimuth rotation axis (which can rotate within the range of 0° to 360°) and a pitch rotation axis (which can rotate within the range of 0° to 360°). A first light output mirror group (i.e., light output mirror 1) is installed on the pitch rotation axis. Two reflectors (total reflectors, the placement angles of which have taken into account the reflection direction of the light path) are also installed inside the dual-axis servo system, which are used to reflect the light path inside the radar body onto the light output mirror 1. A second light output mirror group (i.e., light output mirror 2) is also installed on the radar body. The axis of the light output path of light output mirror 2 is vertically upward relative to the radar body, and when the axis of the light output path of light output mirror 1 is also vertically upward relative to the radar body, the light output axes of the two light output mirrors should be approximately parallel, and the relative angle should be less than 0.1°.

[0053] In this embodiment, Figure 2As shown, before the second laser signal passes through the target optical frequency shift modulator, the target amplifier attenuator, the second circulator and the second light output mirror group in sequence to obtain the second output light signal, the control terminal can adjust the optical frequency shift modulator based on the second preset emission frequency and the preset pulse frequency to obtain the target optical frequency shift modulator, and then the second laser signal passes through the target optical frequency shift modulator, the target amplifier attenuator, the second circulator and the second light output mirror group in sequence to obtain the second output light signal with the emission frequency of the second preset emission frequency and the pulse frequency of the preset pulse frequency. Since the optical frequency shift modulator can arbitrarily control the frequency shift amount of light and modulate the frequency-shifted light, the second laser signal becomes a pulse light with a known frequency and pulse width and an output light frequency of the second preset emission frequency after passing through the target optical frequency shift modulator, and then the pulse light is amplified or attenuated by the target amplifier attenuator, the energy of the pulse light is quantitatively adjusted to obtain the adjusted pulse light, and the adjusted pulse light is emitted through the second circulator and the second light output mirror group, thereby obtaining the second output light signal with a known frequency and pulse width and an output light frequency of the second preset emission frequency. In addition, the control terminal can obtain the offset time relative to the system time reference by adjusting the optical frequency shift modulator, thereby determining the arrival position of the second outgoing optical signal, and use the pulse light emitted by the target optical frequency shift modulator to simulate a high-precision echo signal with a known frequency, and use the target amplifier attenuator to quantitatively simulate echo signals with different signal-to-noise ratios, thereby speeding up the calibration process of the coherent wind measurement lidar while ensuring the speed measurement accuracy.

[0054] Step S13: determining an echo signal from the first outgoing optical signal and the second outgoing optical signal, and collecting and processing the echo signal and the local oscillator signal to obtain a target frequency domain signal.

[0055] In this embodiment, the first outgoing light signal can be used for signal acquisition in actual application scenarios, that is, the coherent wind laser radar in this application is used to detect the Doppler frequency shift of the target speed measurement object to the first outgoing light signal to measure the radial wind speed; the second outgoing light signal is used to calibrate the coherent wind laser radar in this application, so the echo signal can be determined from the first outgoing light signal and the second outgoing light signal according to user needs. Figure 2 As shown, the specific process may include: inputting the first outgoing optical signal and the second outgoing optical signal into the 2*1 optical switch, so that the control terminal determines the echo signal from the first outgoing optical signal and the second outgoing optical signal through the 2*1 optical switch. After the 2*1 optical switch inputs the first outgoing optical signal and the second outgoing optical signal, the control terminal selects one of the outgoing optical signals as the echo signal, and the 2*1 optical switch outputs the echo signal.

[0056] It should be noted that after the echo signal is determined, the echo signal and the local oscillator signal need to be collected and processed to obtain the target frequency domain signal. Figure 2 As shown, the specific process of obtaining the target frequency domain signal may include: coupling the echo signal and the local oscillator signal through the optical fiber coupler to obtain the target coupled signal, then inputting the target coupled signal into the balanced detector to obtain the target electrical signal corresponding to the target coupled signal, and using the signal acquisition processor to collect and process the target electrical signal to obtain the target frequency domain signal. That is, the optical fiber coupler inputs the target coupled signal obtained by coupling the echo signal and the local oscillator signal into the balanced detector for photoelectric conversion and amplification, thereby obtaining the target electrical signal, and then using the signal acquisition processor to collect the target electrical signal, and processing the collected target electrical signal, including but not limited to converting the target electrical signal from the time domain to the frequency domain, to obtain the target frequency domain signal.

[0057] Step S14: Send the target frequency domain signal to a control terminal so that the control terminal performs calibration based on the target frequency domain signal.

[0058] In this embodiment, the control terminal performs calibration based on the target frequency domain signal, which may specifically include: servo system calibration, frequency-shifted wind speed calibration, acquisition position calibration, and weather simulation system calibration based on the target frequency domain signal. When performing calibration, the control terminal first performs calibration based on the target frequency domain signal, and determines whether the calibration is completed; if the calibration is not completed, the control terminal determines the parameters to be adjusted based on the preset parameter adjustment method, and adjusts the parameters to be adjusted, so that the control terminal uses the adjusted parameters and calibrates the wind laser radar based on the target frequency domain signal.

[0059] In a specific implementation, the servo system calibration, frequency-shifted wind speed calibration, acquisition position calibration and weather simulation system calibration can be performed in sequence based on the calibration time corresponding to each calibration item. Figure 4 As shown, during calibration, the servo system can be calibrated first, that is, the angle of each light output mirror group can be calibrated, and after each calibration of the servo system, it is determined whether the servo system calibration is completed. If the servo system calibration is not completed and the preset servo system calibration time is not exceeded, the parameters to be adjusted can be determined based on the preset parameter adjustment method and the parameters to be adjusted can be adjusted, so that the servo system of the wind measurement laser radar can be calibrated by using the adjusted parameters through the control terminal and based on the target frequency domain signal.

[0060] It is understandable that the larger the fiber mode field, the smaller the effect of the lateral offset on the optical coupling efficiency, and the larger the angle deviation, the greater the effect on the optical coupling efficiency. Based on this principle, the optical coupling efficiency can be used to calibrate the servo angle, the lateral offset can be used to calibrate the angle of the azimuth rotation axis, and the angle deviation of the two light-emitting mirrors can be used to calibrate the angle deviation of the pitch. Figure 5As shown, the specific process of calibrating the servo system may include: at the beginning of the calibration, the first light output mirror group and the second light output mirror group are adjusted to a preset calibration position, then the echo signal is collected, and it is determined whether the signal-to-noise ratio of the echo signal exceeds the preset signal-to-noise ratio threshold according to the energy of the collected echo signal; if the signal-to-noise ratio of the echo signal exceeds the preset signal-to-noise ratio threshold, the pointing direction of the first light output mirror group is adjusted at intervals of 0.1° in both azimuth and elevation, and the step of collecting the echo signal is jumped again until the signal-to-noise ratio of the echo signal is not greater than the preset signal-to-noise ratio threshold, that is, the servo system calibration is completed, or the calibration time exceeds the preset servo system calibration time, and then the next calibration is performed.

[0061] like Figure 6 As shown, according to the formula The frequency-shifted wind speed is calibrated, where is the wind speed change, is the wavelength of light, is the frequency shift of the light. Since the frequency shift of the echo signal is known and the pulse frequency is known, the wind speed change can be calculated according to this formula.

[0062] When performing frequency-shift wind speed calibration, the control terminal controls the optical frequency-shift modulator to modify the frequency-shift parameters, that is, adjusts the parameters of the optical frequency-shift modulator based on the preset pulse frequency adjustment method to obtain the target optical frequency-shift modulator, and transmits the second output light emitted by the second light-emitting mirror group to the first light-emitting mirror, and then selects the optical signal output by the first circulator as the output of the 2*1 optical switch, that is, the echo signal, and uses the echo signal to calculate the actual measured wind speed, and judge whether the difference between the actual measured wind speed and the theoretical wind speed corresponding to the preset pulse frequency is less than the preset error (such as 0.1m / s). If the difference between the actual measured wind speed and the theoretical wind speed corresponding to the preset pulse frequency is greater than or equal to the preset error, jump to the step of adjusting the parameters of the optical frequency-shift modulator based on the preset pulse frequency adjustment method until the difference between the actual measured wind speed and the theoretical wind speed corresponding to the preset pulse frequency is less than the preset error, that is, the frequency-shift wind speed calibration is completed, or the calibration time exceeds the preset frequency-shift wind speed calibration time, and then the next calibration is performed. In addition, Figure 6 What is given is a process of calibrating the frequency-shifted wind speed by emitting an optical signal from the light output mirror 2 to the light output mirror 1. Accordingly, the present application can realize the calibration of the frequency-shifted wind speed by emitting an optical signal from the light output mirror 1 to the light output mirror 2. The frequency-shifted wind speed can be calibrated by simply adjusting the energy of the target amplifier to a preset amplification factor to ensure that the energy of the output optical signal is not sufficient to damage the optical fiber.

[0063] When the collection position is calibrated based on the constant light speed theory, the collection position can be calculated or calibrated by adjusting the difference between the light emission time and the collection time. That is, the collection position can be calculated based on the time difference between the received echo signal and the emitted light signal of the light output mirror group, and then the difference between the light emission time and the collection time can be adjusted based on the preset parameter adjustment method to adjust the collection position, and the calibration of the collection position is completed, or the calibration time exceeds the preset collection position calibration time, and the collection position calibration is ended.

[0064] In addition, after completing the acquisition position calibration, the present application can also be used to simulate and restore echo signals under different weather conditions, using a target optical frequency shift modulator and a target amplifier attenuator to simulate the atmospheric echo intensity under different weather conditions, and passing the second laser signal through the target optical frequency shift modulator and the target amplifier attenuator to obtain echo signals under different weather conditions, and determine whether the echo signal simulates the echo signal under similar weather conditions, so as to adjust the relevant parameters of the target optical frequency shift modulator and the target amplifier attenuator, thereby constructing a large model of echo signals corresponding to different weather conditions. Using this model, the echo intensity under different weather conditions and the form of the echo signal corresponding to the echo intensity can be inferred, so as to study the impact of weather on the echo signal.

[0065] Through Figure 4 The calibration process shown in the figure, the present application realizes automatic correction of the calibration wind speed, wind speed collection position and servo angle deviation, improves the calibration efficiency of the wind measuring lidar, and realizes the large-scale application of the wind measuring lidar.

[0066] It can be seen that when calibrating the wind measuring laser radar, the present application adopts a laser source as the target seed source, divides the energy emitted by the target seed source into three parts, respectively as the first laser signal, the second laser signal and the local oscillator signal, and inputs the first laser signal into the acoustic target optical modulator so that the first output optical signal is modulated through a fixed modulation bandwidth, and the second laser signal input into the target optical frequency shift modulator can perform corresponding frequency modulation on the second laser signal according to the change of the input microwave frequency, and uses an amplifier attenuator with different parameters to process the second laser signal to simulate echo signals in various weather conditions and detection distances, which is fast and stable, avoiding the tedious operation of irradiating the radar's entire emission light beam with hard targets at different positions when calibrating the entire radar system, and at the same time, uses a programmable optical frequency shift modulator to generate echo signals of different wind speeds, and the generated echo signal has high frequency shift accuracy, thereby simplifying the process and facilities for calibrating the wind measuring laser radar and improving the calibration accuracy.

[0067] Based on the above embodiment, it can be seen that the present application discloses a wind laser radar calibration method, which can simplify the process and facilities for calibrating the wind laser radar and improve the calibration accuracy. Next, the specific calibration process will be described.

[0068] like Figure 2 As shown, the light emitted by the seed source is divided into a first laser signal, a second laser signal and a local oscillator signal by an integrated beam splitter, and the first laser signal is modulated and amplified by an acousto-optic modulator and an amplifier to obtain a first modulated signal, and the first modulated signal is output through a circulator 1 and a light output mirror 1 to obtain a first output light signal. Since the acousto-optic modulator and the amplifier perform a fixed frequency shift and amplification on the first laser signal, and the control terminal can control the on-off state of the acousto-optic modulator on the first laser signal, the first output light signal is a pulsed laser with a fixed emission frequency and a fixed pulse width, which can be used to measure radial wind speed in practical applications.

[0069] At the same time, the second laser signal is input to the optical frequency shift modulator for frequency shift modulation, and the signal energy is adjusted through the amplifier attenuator, and then output through the circulator 2 and the light output mirror 2 to obtain the second output light signal. Since the frequency shift amount and frequency shift accuracy of the optical frequency shift modulator are mainly determined by the RF power signal, as long as the stability of the RF power signal can be guaranteed, the frequency shift accuracy can be very high, and the influence of the ambient temperature is also very small. The frequency shift can be easily controlled by changing the external electrical signal, and the amplification and attenuation ratio of the signal by the amplifier attenuator can be arbitrarily adjusted, so the second output light signal can be used to simulate a high-precision echo signal with a known frequency and signal-to-noise ratio.

[0070] Both the first outgoing optical signal and the second outgoing optical signal can be input into the optical switch, and then the control terminal selects one of the signals as the echo signal and outputs it through the optical switch, so that the optical fiber coupler couples and mixes the echo signal and the local oscillator signal, and mixes and detects the obtained target coupled signal through a balanced detector to obtain a target electrical signal, and then uses a signal acquisition processor to process the target electrical signal to obtain a target frequency domain signal, and the control terminal analyzes the target frequency domain signal and calibrates it based on the analysis result.

[0071] During calibration, Figure 3 The servo system shown adjusts the angle of each light output mirror group, such as adjusting the light output mirror 1 by 0.1° in both azimuth and pitch dimensions to adjust the direction of the light output mirror 1 when the signal-to-noise ratio of the echo signal is higher than the preset signal-to-noise ratio threshold, and ends the servo system calibration when the signal-to-noise ratio of the acquired echo signal is not higher than the preset signal-to-noise ratio threshold, or the calibration time has exceeded the preset servo system calibration time.

[0072] When performing frequency-shift wind speed calibration, it is only necessary to set a suitable amplification ratio for the amplifier, and then the first output light signal can be emitted to the light output mirror 2, and the signal output by the circulator 2 can be selected as the echo signal, or the second output light signal can be emitted to the light output mirror 1, and the signal output by the circulator 1 can be selected as the echo signal, so as to determine based on the echo signal whether the difference between the actual measured wind speed and the theoretical wind speed corresponding to the frequency of the output light signal is less than the preset error, and automatically adjust the parameters to be adjusted within the preset frequency-shift wind speed calibration time until the difference between the actual measured wind speed and the theoretical wind speed is less than the preset error or the calibration times out, thereby terminating the frequency-shift wind speed calibration.

[0073] In addition, the collection position can be calculated based on the time difference between the received echo signal and the output light signal of the light output mirror group to calibrate the collection position; the target optical frequency shift modulator and the target amplifier attenuator are used to simulate the atmospheric echo intensity under different weather conditions, and the second laser signal is passed through the target optical frequency shift modulator and the target amplifier attenuator to obtain the echo signals under different weather conditions, and it is judged whether the echo signal simulates the echo signal under similar weather conditions, so as to adjust the relevant parameters of the target optical frequency shift modulator and the target amplifier attenuator, thereby constructing a large model of the echo signal corresponding to different weather conditions. The model can be used to infer the echo intensity under different weather conditions and the form of the echo signal corresponding to the echo intensity, so as to study the influence of weather on the echo signal.

[0074] In a specific embodiment, the seed source can be a commercial light laser, such as a high-power pulsed fiber laser with a narrow linewidth (less than 15KHz, indicative value), a pulse energy of 50 uJ (indicative value), and a repetition frequency of 10KHz (adjustable). The circulator can be a PM1550 polarization-maintaining circulator, and the insertion loss of the circulator is less than 1dB. The telescope (lens tube ①) of the servo system has a focal length of 400mm and a receiving aperture of 100mm, and the telescope (lens tube ②) has a focal length of 200mm and a receiving aperture of 80mm. A low-noise pin detector can be selected as a balanced detector. The 2*2 fiber coupler can be a PM1550nm fiber coupler, and the focal length of the coupling lens group is 200mm and the receiving aperture is 100mm. The amplifier attenuator consists of two parts: an amplifier and an attenuator. The light first passes through the amplifier and then through the attenuator. The attenuator can be a PM1550 optical fiber with an attenuation range of 10 to 70dB. The built-in signal generator of the control terminal adopts an arbitrary waveform generator with a frequency output range of 10 to 500MHz. It can also be a waveform generator with a preset centralized fixed waveform to save costs. The acousto-optic modulator can be an acousto-optic modulator of lithium niobate crystal. The signal acquisition processor and the control terminal are independently developed computer systems. The control terminal is the computing center of the entire control system, controlling the entire process, data recording and data analysis, and intelligent judgment for calibration.

[0075] It can be seen that the present application can simulate high-precision, known frequency echo signals by using optical frequency shift modulators and amplifiers and attenuators to calibrate the measurement accuracy of the radar system. At the same time, the optical amplifier and attenuator can quantitatively simulate echo signals with different signal-to-noise ratios, and can also simulate echo signals under different weather conditions and at different detection locations, avoiding the cumbersome operation of irradiating hard targets at different positions with the radar system when calibrating the radar system, speeding up the process of calibrating the radial velocity of the coherent wind laser radar while ensuring the calibration accuracy. At the same time, the servo system can be used to adjust the angle of the light-emitting mirror group to measure radial wind speeds at different angles, and the horizontal wind speed and wind direction can be calculated using the results of multi-angle radial measurements. The angle deviation of the two light-emitting mirrors can also be used to calibrate the angle deviation of the pitch. In addition, the difference between the light-emitting time and the acquisition time can be adjusted based on the constant light speed theory to calculate the acquisition position, and the acquisition position can also be calibrated; and the above calibration process can be intelligently controlled by the control terminal, recording relevant data, automatically correcting the calibration wind speed, wind speed acquisition position and servo angle deviation, and completing the calibration process.

[0076] See also Figure 7 As shown, the embodiment of the present application discloses a wind laser radar calibration device, including:

[0077] An energy division module 11 is used to divide the energy of the target seed source based on a preset division ratio to obtain a first laser signal, a second laser signal and a local oscillator signal; wherein the energy of the first laser signal is higher than the energy of the second laser signal and the local oscillator signal;

[0078] An output light signal acquisition module 12 is used to sequentially pass the first laser signal through a target acousto-optic modulator, a target amplifier, a first circulator and a first light output mirror group to obtain a first output light signal, and sequentially pass the second laser signal through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator and a second light output mirror group to obtain a second output light signal; wherein the angle of the first light output mirror group and the angle of the second light output mirror group are controlled by a servo system;

[0079] A frequency domain signal acquisition module 13, used to determine an echo signal from the first outgoing optical signal and the second outgoing optical signal, and collect and process the echo signal and the local oscillator signal to acquire a target frequency domain signal;

[0080] The calibration module 14 is used to send the target frequency domain signal to the control terminal so that the control terminal performs calibration based on the target frequency domain signal.

[0081] It can be seen that when calibrating the wind measuring laser radar, the present application adopts a laser source as the target seed source, divides the energy emitted by the target seed source into three parts, respectively as the first laser signal, the second laser signal and the local oscillator signal, and inputs the first laser signal into the acoustic target optical modulator so that the first output optical signal is modulated through a fixed modulation bandwidth, and the second laser signal input into the target optical frequency shift modulator can perform corresponding frequency modulation on the second laser signal according to the change of the input microwave frequency, and uses an amplifier attenuator with different parameters to process the second laser signal to simulate echo signals in various weather conditions and detection distances, which is fast and stable, avoiding the tedious operation of irradiating the radar's entire emission light beam with hard targets at different positions when calibrating the entire radar system, and at the same time, uses a programmable optical frequency shift modulator to generate echo signals of different wind speeds, and the generated echo signal has high frequency shift accuracy, thereby simplifying the process and facilities for calibrating the wind measuring laser radar and improving the calibration accuracy.

[0082] In a specific embodiment, the outgoing light signal acquisition module 12 may specifically include:

[0083] A first signal on-off control unit, used to determine a target acousto-optic modulator based on a target modulation bandwidth, and control the on-off state of the first laser signal based on a first preset emission frequency using the control terminal;

[0084] The first signal output unit is used to sequentially pass the first laser signal through the target acousto-optic modulator, the target amplifier, the first circulator and the first light output mirror group to obtain a first output light signal whose emission frequency is the first preset emission frequency.

[0085] In a specific embodiment, the outgoing light signal acquisition module 12 may specifically include:

[0086] A parameter adjustment unit, configured to use the control terminal to adjust the optical frequency shift modulator based on the second preset transmission frequency and the preset pulse frequency to obtain the target optical frequency shift modulator;

[0087] The second signal output unit is used to pass the second laser signal through the target optical frequency shift modulator, the target amplifier attenuator, the second circulator and the second light output mirror group in sequence to obtain a second output optical signal with an emission frequency of the second preset emission frequency and a pulse frequency of the preset pulse frequency.

[0088] In a specific embodiment, the frequency domain signal acquisition module 12 may specifically include:

[0089] The echo signal determination unit is used to input the first outgoing optical signal and the second outgoing optical signal into a 2*1 optical switch, so that the control terminal determines an echo signal from the first outgoing optical signal and the second outgoing optical signal through the 2*1 optical switch.

[0090] In a specific embodiment, the frequency domain signal acquisition module 13 may specifically include:

[0091] A signal coupling unit, used for coupling the echo signal and the local oscillator signal through an optical fiber coupler to obtain a target coupling signal;

[0092] The frequency domain signal acquisition unit is used to input the target coupling signal into a balanced detector to acquire a target electrical signal corresponding to the target coupling signal, and use a signal acquisition processor to acquire and process the target electrical signal to acquire the target frequency domain signal.

[0093] In a specific embodiment, the calibration module 14 may specifically include:

[0094] The first calibration unit is used to perform servo system calibration, frequency-shifted wind speed calibration and acquisition position calibration based on the target frequency domain signal.

[0095] In a specific embodiment, the calibration module 14 may specifically include:

[0096] A calibration result judgment unit, configured to perform calibration based on the target frequency domain signal through the control terminal, and judge whether the calibration is completed;

[0097] The second calibration unit is used to determine the parameters to be adjusted based on a preset parameter adjustment method through the control terminal if the calibration is not completed, and adjust the parameters to be adjusted, so as to calibrate the wind measurement laser radar based on the target frequency domain signal using the adjusted parameters through the control terminal.

[0098] Furthermore, the present application also discloses an electronic device. Figure 8 This is a structural diagram of an electronic device 20 according to an exemplary embodiment. The content in the diagram cannot be regarded as any limitation on the scope of use of the present application.

[0099] Figure 8A schematic diagram of the structure of an electronic device 20 provided in an embodiment of the present application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 is used to store a computer program, which is loaded and executed by the processor 21 to implement the relevant steps in the wind laser radar calibration method disclosed in any of the aforementioned embodiments. In addition, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0100] In this embodiment, the power supply 23 is used to provide working voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and the external device, and the communication protocol it follows is any communication protocol that can be applied to the technical solution of the present application, and is not specifically limited here; the input and output interface 25 is used to obtain external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs and is not specifically limited here.

[0101] In addition, the memory 22 as a carrier for storing resources may be a read-only memory, a random access memory, a disk or an optical disk, etc. The resources stored thereon may include an operating system 221, a computer program 222, etc., and the storage method may be temporary storage or permanent storage.

[0102] The operating system 221 is used to manage and control the hardware devices and computer program 222 on the electronic device 20, which can be Windows Server, Netware, Unix, Linux, etc. In addition to the computer program that can be used to complete the wind laser radar calibration method performed by the electronic device 20 disclosed in any of the aforementioned embodiments, the computer program 222 can further include computer programs that can be used to complete other specific tasks.

[0103] Furthermore, the present application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, the aforementioned wind laser radar calibration method is implemented. The specific steps of the method can refer to the corresponding contents disclosed in the aforementioned embodiments, and will not be repeated here.

[0104] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0105] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0106] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0107] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0108] The technical solution provided by the present application is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for general technicians in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A wind laser radar calibration method, characterized in that: include: Dividing the energy of the target seed source based on a preset division ratio to obtain a first laser signal, a second laser signal and a local oscillator signal; wherein the energy of the first laser signal is higher than the energy of the second laser signal and the local oscillator signal; The first laser signal is sequentially passed through a target acousto-optic modulator, a target amplifier, a first circulator and a first light output mirror group to obtain a first output light signal, and the second laser signal is sequentially passed through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator and a second light output mirror group to obtain a second output light signal; wherein the angle of the first light output mirror group and the angle of the second light output mirror group are controlled by a servo system; Inputting the first outgoing optical signal and the second outgoing optical signal into a 2*1 optical switch, so that the control terminal determines an echo signal from the first outgoing optical signal and the second outgoing optical signal through the 2*1 optical switch, and collects and processes the echo signal and the local oscillator signal to obtain a target frequency domain signal; The target frequency domain signal is sent to the control terminal so that the control terminal performs calibration based on the target frequency domain signal.

2. The wind laser radar calibration method according to claim 1, characterized in that: The step of sequentially passing the first laser signal through a target acousto-optic modulator, a target amplifier, a first circulator, and a first light output mirror group to obtain a first output light signal includes: Determine a target acousto-optic modulator based on a target modulation bandwidth, and use the control terminal to control the on / off state of the first laser signal based on a first preset transmission frequency; The first laser signal passes through the target acousto-optic modulator, the target amplifier, the first circulator and the first light output mirror group in sequence to obtain a first output light signal whose emission frequency is the first preset emission frequency.

3. The wind laser radar calibration method according to claim 1, characterized in that: The step of sequentially passing the second laser signal through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator, and a second light output mirror assembly to obtain a second output light signal includes: Using the control terminal to adjust the optical frequency shift modulator based on the second preset transmission frequency and the preset pulse frequency to obtain the target optical frequency shift modulator; The second laser signal passes through the target optical frequency shift modulator, the target amplifier attenuator, the second circulator and the second light output mirror group in sequence to obtain a second output optical signal with an emission frequency of the second preset emission frequency and a pulse frequency of the preset pulse frequency.

4. The wind laser radar calibration method according to claim 1, characterized in that: The collecting and processing the echo signal and the local oscillator signal to obtain a target frequency domain signal includes: The echo signal and the local oscillator signal are coupled by a fiber coupler to obtain a target coupled signal; The target coupling signal is input into a balanced detector to obtain a target electrical signal corresponding to the target coupling signal, and a signal acquisition processor is used to acquire and process the target electrical signal to obtain the target frequency domain signal.

5. The wind laser radar calibration method according to claim 1, characterized in that: The calibration based on the target frequency domain signal includes: Servo system calibration, frequency-shift wind speed calibration and acquisition position calibration are performed based on the target frequency domain signal.

6. The wind laser radar calibration method according to any one of claims 1 to 5, characterized in that: The control terminal performs calibration based on the target frequency domain signal, including: Performing calibration based on the target frequency domain signal by the control terminal, and determining whether the calibration is completed; If the calibration is not completed, the control terminal determines the parameters to be adjusted based on a preset parameter adjustment method, and adjusts the parameters to be adjusted, so that the control terminal uses the adjusted parameters and calibrates the wind measurement lidar based on the target frequency domain signal.

7. A wind laser radar calibration device, characterized in that: include: An energy division module, used to divide the energy of the target seed source based on a preset division ratio to obtain a first laser signal, a second laser signal and a local oscillator signal; wherein the energy of the first laser signal is higher than the energy of the second laser signal and the local oscillator signal; an output light signal acquisition module, configured to sequentially pass the first laser signal through a target acousto-optic modulator, a target amplifier, a first circulator, and a first light output mirror group to obtain a first output light signal, and sequentially pass the second laser signal through a target optical frequency shift modulator, a target amplifier attenuator, a second circulator, and a second light output mirror group to obtain a second output light signal; wherein the angle of the first light output mirror group and the angle of the second light output mirror group are controlled by a servo system; a frequency domain signal acquisition module, configured to input the first outgoing optical signal and the second outgoing optical signal into a 2*1 optical switch, so that the control terminal determines an echo signal from the first outgoing optical signal and the second outgoing optical signal through the 2*1 optical switch, and collects and processes the echo signal and the local oscillator signal to obtain a target frequency domain signal; The calibration module is used to send the target frequency domain signal to the control terminal so that the control terminal performs calibration based on the target frequency domain signal.

8. An electronic device, characterized in that: include: Memory, used to store computer programs; A processor, used to execute the computer program to implement the wind laser radar calibration method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: Used to store a computer program, wherein when the computer program is executed by a processor, the wind laser radar calibration method according to any one of claims 1 to 6 is implemented.

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