Visibility measuring device and method based on transmission method

Abstract

The invention provides a visibility measurement device and method based on a transmission method, and relates to the technical field of optical measurement, the device is provided with a DDS adjustable signal generator realized by FPGA logic programming at a transmitting end, sine wave modulation signals with adjustable frequency and amplitude can be generated, signal parameters can be flexibly adjusted according to an actual measurement environment, and the visibility measurement accuracy is improved. Interference frequency bands are effectively avoided, and the purity of measurement signals is improved; a digital lock-in amplification signal processor is arranged at the receiving end, the frequency of a target signal can be accurately locked through the digital lock-in amplification technology, interference signals of other frequencies are effectively restrained, and it is ensured that useful signals can still be accurately extracted under complex environment light interference. And meanwhile, high-precision amplification processing can be carried out on weak light signals subjected to atmospheric attenuation, the signal-to-noise ratio of the signals is increased, and the accuracy and reliability of measurement are further improved.

Description

Technical Field

[0001] The present application relates to the field of optical measurement technology, and in particular to a visibility measurement device and method based on a transmission method. Background Art

[0002] Visibility is an extremely important parameter in the field of atmospheric meteorology. It plays a key role in weather forecasting, meteorological information collection, climate analysis, scientific research, and meteorological services, and provides an indispensable basis for related work. In visibility measurement technology, the core issue lies in the measurement of the atmospheric extinction coefficient. The atmospheric extinction coefficient is mainly caused by atmospheric aerosol particles, which is the most important factor in atmospheric extinction. From a physical principle, the extinction coefficient is equal to the sum of the absorption coefficient and the scattering coefficient. Therefore, accurate measurement of the atmospheric extinction coefficient is the key link to achieve high-precision visibility measurement.

[0003] However, in the existing visibility measurement technology, a measurement method based on the transmission method is usually used. Specifically, this method uses a fixed-frequency modulation signal. The transmitter sends out a modulated light signal. After the receiving end collects the signal, the light signal of the corresponding frequency is demodulated through a filter of the corresponding frequency. Although this method can measure visibility to a certain extent, due to the use of a fixed-frequency modulation signal and a relatively simple light intensity detection circuit, this method cannot effectively avoid possible interference from the same-frequency light signal. This interference will cause errors in the intensity of the received detection, which will affect the final detection accuracy. Summary of the invention

[0004] In view of the above problems, the present application provides a visibility measurement device and method based on the transmission method, including the following contents: In a first aspect, the present application provides a visibility measuring device based on a transmission method, the device comprising: Transmitter, receiver and computing module; The transmitting end includes a DDS adjustable signal generator, a light source driving circuit, and a light intensity detection and AD acquisition circuit; the DDS adjustable signal generator is implemented by FPGA logic programming and is used to generate a sine wave modulation signal with adjustable frequency and amplitude; the transmitting end is used to generate initialization light; The receiving end includes an atmospheric attenuated light intensity detection circuit, a high-pass filter and AD acquisition module, a digital phase-locked amplification signal processor and a low-pass filter module; the receiving end is used to receive and detect the atmospheric attenuated light; the digital phase-locked amplification signal processor is used to amplify the atmospheric attenuated light received by the receiving end; The calculation module is used to calculate the transmittance and the optical range MOR according to the light intensity value of the initial light emitted by the transmitting end and the light intensity value of the light attenuated by the atmosphere received and processed by the receiving end.

[0005] Optionally, the DDS adjustable signal generator and the digital lock-in amplifier signal processor are implemented by the same FPGA logic programming; The signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor to ensure clock synchronization and signal homology between the transmitting end and the receiving end, thereby improving the measurement accuracy and anti-interference ability of the system; the digital phase-locked amplifier signal processor is used to perform phase-sensitive detection on the received AC signal using the same reference signal as the transmitting end.

[0006] Optionally, the device further comprises: The low-pass filtering light intensity saturation detection module is used to perform light intensity saturation or top distortion detection on the signal output by the atmospheric attenuation light intensity detection circuit.

[0007] Optionally, the atmospheric attenuation light intensity detection circuit is specifically used to receive the optical signal after atmospheric attenuation and divide the atmospheric attenuation light signal into two processing paths, one path is sent to the high-pass filter and AD acquisition module, and the AC signal is retained, and after being collected by the AD acquisition module, it enters the digital phase-locked amplification signal processor; the other path is processed by the low-pass filter light intensity saturation detection module, the DC signal is retained and the DC signal is monitored to monitor whether there is light intensity saturation or top distortion.

[0008] Optionally, the signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor in the phase-locked amplifier signal processing circuit on the one hand, and is used to drive the light source at the transmitting end after amplitude adjustment on the other hand, so as to meet the requirement that the input signal of the digital phase-locked amplifier signal processor and the reference signal are homologous.

[0009] In a second aspect, the present application provides a visibility measurement method based on a transmission method, which is applied to a visibility measurement device based on a transmission method, wherein the device comprises a transmitting end, a receiving end and a computing module; the transmitting end comprises a DDS adjustable signal generator, a light source driving circuit and a light intensity detection and AD acquisition circuit; the receiving end comprises a light intensity detection circuit attenuated by the atmosphere, a high-pass filter and AD acquisition module, a digital phase-locked amplification signal processor and a low-pass filter module, and the method comprises: The transmitting end transmits a modulated optical signal; The receiving end detects the optical signal after atmospheric attenuation; the signal is extracted through the phase-locked amplification signal processing circuit; The calculation module calculates the transmittance and the optical range MOR according to the light intensity value of the initial light emitted by the transmitting end and the light intensity value of the light attenuated by the atmosphere received and processed by the receiving end.

[0010] Optionally, the DDS adjustable signal generator and the digital lock-in amplifier signal processor are implemented by the same FPGA logic programming; The signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor to ensure clock synchronization and signal homology between the transmitting end and the receiving end, thereby improving the measurement accuracy and anti-interference ability of the system; the digital phase-locked amplifier signal processor is used to perform phase-sensitive detection on the received AC signal using the same reference signal as the transmitting end.

[0011] Optionally, the device further includes a low-pass filtering light intensity saturation detection module, and the method further includes: The low-pass filtering light intensity saturation detection module is used to perform light intensity saturation or top distortion detection on the signal output by the atmospheric attenuation light intensity detection circuit.

[0012] Optionally, the atmospheric attenuation light intensity detection circuit receives the atmospheric attenuation light signal and divides the atmospheric attenuation light signal into two processing paths, one path is sent to the high-pass filter and AD acquisition module, and the AC signal is retained, and after being collected by the AD acquisition module, it enters the digital phase-locked amplification signal processor; the other path is processed by the low-pass filter light intensity saturation detection module, the DC signal is retained and the DC signal is monitored to monitor whether there is light intensity saturation or top distortion.

[0013] Optionally, the signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor in the phase-locked amplifier signal processing circuit on the one hand, and is used to drive the light source at the transmitting end after amplitude adjustment on the other hand, so as to meet the requirement that the input signal of the digital phase-locked amplifier signal processor and the reference signal are homologous.

[0014] In a third aspect, the present application provides a device comprising a memory and a processor, wherein the memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device performs the visibility measurement method based on the transmission method introduced in any implementation of the aforementioned second aspect.

[0015] In a fourth aspect, the present application provides a computer-readable storage medium having codes stored therein. When the codes are executed, the device executing the codes implements the visibility measurement method based on the transmission method introduced in any implementation of the aforementioned second aspect.

[0016] The present application provides a visibility measurement device based on the transmission method. The device includes a transmitting end, a receiving end, and a calculation module. The transmitting end includes a DDS tunable signal generator, a light source driving circuit, and a light intensity detection and AD acquisition circuit; the DDS tunable signal generator is implemented by FPGA logic programming and is used to generate a sine wave modulation signal with adjustable frequency and amplitude; the transmitting end is used to generate initialization light; the receiving end includes an atmospheric attenuation light intensity detection circuit, a high-pass filter and AD acquisition module, a digital lock-in amplifier signal processor, and a low-pass filter module; the receiving end is used to receive and detect the light after atmospheric attenuation; the digital lock-in amplifier signal processor is used to amplify the light after atmospheric attenuation received by the receiving end; the calculation module is used to calculate the transmittance and the meteorological optical range (MOR) according to the light intensity value of the initialization light emitted by the transmitting end and the light intensity value of the light after atmospheric attenuation received and processed by the receiving end. Among them, a DDS tunable signal generator is provided at the transmitting end. The DDS tunable signal generator implemented by FPGA logic programming can generate a sine wave modulation signal with adjustable frequency and amplitude, can flexibly adjust the signal parameters according to the actual measurement environment, effectively avoid the interference frequency band, and improve the purity of the measurement signal. In addition, the signal generated by DDS technology has high precision and high stability, can provide a high-quality basic signal for visibility measurement, and significantly improve the measurement accuracy; the digital lock-in amplifier signal processor provided at the receiving end can accurately lock the target signal frequency through digital lock-in amplification technology, effectively suppress the interference signals of other frequencies, and ensure that useful signals can still be accurately extracted under the interference of complex ambient light. At the same time, it can perform high-precision amplification processing on the weak light signal after atmospheric attenuation, improve the signal-to-noise ratio of the signal, and further improve the accuracy and reliability of the measurement.

[0017] In summary, by adopting the DDS tunable signal generator and the digital lock-in amplifier signal processor, the present application significantly improves the measurement accuracy, anti-interference ability, measurement range and adaptability, measurement efficiency and stability of the visibility measurement device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of a visibility measurement device provided by an embodiment of the present application; Figure 2 It is a schematic structural diagram of a visibility measurement device based on the transmission method provided by an embodiment of the present application; Figure 3 A design schematic diagram of a digital phase-locked amplifier signal processor based on FPGA provided in an embodiment of the present application; Figure 4 A flow chart of a visibility measurement method based on the transmission method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] Figure 1 A schematic diagram of the structure of a visibility measurement device provided in an embodiment of the present application is shown in FIG. Figure 1 As shown in the figure, it includes the transmitter and receiver as well as the transmittance and MOR calculation module. The transmitter consists of a fixed-frequency signal generator, a light source driving circuit, and an initial light intensity detection and AD acquisition circuit; the receiver consists of a light intensity detection circuit after atmospheric attenuation and a filtering and AD acquisition circuit. The transmitter drives the light source through a fixed-frequency modulation signal, and the receiver collects the signal and demodulates the corresponding frequency light signal through a filter. However, since the fixed-frequency modulation signal and the simple light intensity detection circuit are difficult to avoid interference from the same-frequency light signal, there is an error in the received light intensity, which affects the measurement accuracy.

[0022] Based on this, the present application proposes a new visibility measuring device based on the transmission method. The visibility measuring device based on the transmission method in the present application is specifically introduced below in combination with specific embodiments: Figure 2 The following is a schematic diagram of a visibility measurement device based on a transmission method provided in an embodiment of the present application. Figure 2 As shown, the visibility measuring device provided in this embodiment includes a transmitting end, a receiving end and a computing module, and the device can be used as a transmissometer.

[0023] The transmitting end includes a DDS adjustable signal generator, a light source driving circuit, and an initial light intensity detection and AD acquisition circuit. The DDS adjustable signal generator is implemented by FPGA logic programming and can generate a sine wave modulation signal with adjustable frequency and amplitude. In this way, the signal generator can flexibly adjust the frequency and amplitude of the signal according to the actual measurement environment and needs. For example, the light intensity frequency is set to 1355Hz. This uncommon frequency can effectively reduce the problem of light source interference, because the common ambient light interference frequency is usually concentrated in certain specific frequency bands. By selecting atypical frequencies, the impact of interference signals on the measurement signal can be significantly reduced. In addition, the adjustable amplitude feature enables the signal generator to adjust the amplitude of the modulation signal in real time through the light intensity feedback mechanism. In this way, the constant output of the driving circuit is guaranteed, thereby ensuring the stability of the light intensity of the light source.

[0024] In this embodiment, the DDS signal generator adopts a design with a phase width of 16 bits, a minimum frequency of 0.4 Hz, and a maximum frequency of 12 kHz. This design can provide a sufficiently wide frequency range to adapt to different measurement conditions and environmental requirements. At the same time, in order to minimize the orthogonal error of the sine and cosine reference signals, the signal source adopts high-precision DDS technology. The reduction of orthogonal error helps to improve the quality of the signal and the accuracy of the measurement, because the orthogonal error may cause signal distortion, which in turn affects the accuracy of the measurement result.

[0025] The signal generated by DDS is used as the reference signal of the digital phase-locked amplifier signal processor on the one hand, and is used to drive the LED light source after amplitude adjustment on the other hand. This design meets the requirement that the input signal of the digital phase-locked amplifier signal processor is homologous to the reference signal, ensuring the consistency and stability of the signal. In addition, DDS also uses Taylor series correction technology to improve the signal-to-noise ratio. The improvement of the signal-to-noise ratio means that the strength of the useful signal is relatively stronger at the same noise level, so that the signal detection and processing can be performed more accurately, further improving the accuracy and reliability of the measurement.

[0026] The transmitter divides the system clock and sends it to the receiving end of the transmissometer through optical fiber. After being phase-locked and multiplied by PLL, it is used as the system clock of the receiving end of the transmissometer. This design ensures that the clocks at both ends of the transmissometer are of the same source, and thus the reference signal frequencies of the digital phase-locked amplifier signal processors at both ends of the transmissometer are the same. Clock homology is crucial to ensure the synchronization and accuracy of the measurement, because asynchronous clocks may cause phase differences in the signal, thereby affecting the accuracy of the measurement results. Transmitting the clock signal through optical fiber can effectively reduce interference and attenuation during signal transmission, ensuring the stability and reliability of the clock signal.

[0027] The light source driving circuit is used to drive the light source to emit light. The driver and light source used in this embodiment are both wide temperature, high stability and high current types. This design can ensure that the signal has sufficient dynamic range under different ambient temperatures and baseline conditions. For example, under a baseline length of 75m, it can be ensured that the voltage amplitude of the detection signal light intensity is greater than 1V. Sufficient dynamic range means that under different measurement conditions, the intensity of the signal can be accurately detected and processed, thereby ensuring the accuracy and reliability of the measurement. The driver and light source with wide temperature, high stability and high current can adapt to various complex environmental conditions, ensuring that the measuring device can work stably in different application scenarios.

[0028] The initial light intensity detection circuit and AD acquisition circuit are mainly used to detect the initial light intensity at the transmitting end. The circuit is integrated inside the device, is not subject to external interference, has a single signal, and a simple detection circuit can meet the requirements. The detection circuit converts the light intensity signal into a sine wave signal with the same frequency as the modulation signal, and then enters the AD acquisition circuit, converts it into a digital signal and sends it to the calculation module to calculate the initial light intensity value. This design ensures the accurate measurement of the initial light intensity and provides reliable basic data for subsequent visibility calculations. Because the transmittance is the ratio of the initial light intensity to the light intensity after atmospheric attenuation, and the MOR is calculated based on the transmittance, the accurate initial light intensity value is crucial for calculating the transmittance and optical range (MOR). Any error in the initial light intensity measurement may lead to inaccurate calculations of the transmittance and MOR, thereby affecting the final result of the visibility measurement.

[0029] The receiving end includes a light intensity detection circuit after atmospheric attenuation, a high-pass filter and AD acquisition module, a digital phase-locked amplifier signal processor and a low-pass filter module; the receiving end is used to receive and detect light after atmospheric attenuation; the digital phase-locked amplifier signal processor is used to amplify the light after atmospheric attenuation received by the receiving end.

[0030] The atmospheric attenuated light intensity detection circuit is used to detect the light signal after atmospheric attenuation. Since the aerosol particles, water vapor and other components in the atmosphere will cause the light signal to attenuate during the propagation process, the circuit needs to have high sensitivity and low noise characteristics to ensure that the weak light signal can be accurately detected and can work effectively even in low visibility conditions. The detector of this detection circuit is the same as the detector at the transmitting end to ensure that the spectral width of the detection light source at both ends is consistent. This design ensures that the spectral characteristics of the transmitting end and the receiving end match, thereby improving the accuracy and consistency of the measurement. The weak photocurrent signal is first converted into a voltage signal through a transimpedance amplifier. Since the detector at the receiving end will receive signals of various light intensities from the outside world, the signal output by the signal detection circuit needs to be primary filtered to remove noise and interference components to ensure the signal quality of subsequent processing.

[0031] The high-pass filter and AD acquisition module is used to perform high-pass filtering on the received optical signal to remove low-frequency noise and interference signals. The high-pass filter can effectively suppress low-frequency interference and ensure the purity of the signal. Subsequently, the signal passes through the analog-to-digital conversion (AD) module to convert the analog signal into a digital signal for subsequent digital signal processing.

[0032] The digital phase-locked amplifier signal processor is used to amplify the optical signal received by the receiving end after atmospheric attenuation. The digital phase-locked amplifier signal processor can accurately lock the frequency and phase of the target signal, thereby extracting weak useful signals in a complex noise environment.

[0033] The signal after digital phase-locked amplification is further processed by the low-pass filter module. The low-pass filter can remove high-frequency noise and interference to ensure the stability and accuracy of the final output signal. The function of the low-pass filter module is to smooth the signal and remove possible high-frequency fluctuations, thereby providing high-quality measurement data for the subsequent calculation module.

[0034] Through the coordinated work of the above modules, the receiving end can accurately receive and process the optical signal after atmospheric attenuation, providing a reliable basis for the precise measurement of visibility.

[0035] The calculation module is used to calculate the transmittance and the optical range MOR according to the light intensity value of the initial light emitted by the transmitting end and the light intensity value of the light attenuated by the atmosphere received and processed by the receiving end.

[0036] The calculation module is the core part of the visibility measurement device. It is used to calculate the transmittance and optical range (MOR) based on the light intensity value of the initial light emitted by the transmitter and the light intensity value of the light received and processed by the receiver after atmospheric attenuation. The transmittance is the ratio of the initial light intensity to the light intensity after atmospheric attenuation, which reflects the attenuation degree of the light signal when it propagates in the atmosphere. The MOR is calculated based on the transmittance and is used to represent the quantitative index of visibility. The calculation module analyzes and processes the collected light intensity data through precise mathematical models and algorithms to obtain accurate transmittance and MOR values. These values ​​have important application value for weather forecasting, meteorological information, climate analysis, scientific research and meteorological services.

[0037] The above-mentioned visibility measurement device based on the transmission method realizes visibility measurement with high precision, high stability and high anti-interference ability by adopting advanced technologies such as DDS adjustable signal generator and digital phase-locked amplifier signal processor. The DDS adjustable signal generator at the transmitting end can flexibly adjust the signal frequency and amplitude, effectively reduce the interference problem of the light source, and ensure the stability of the light intensity of the light source. The digital phase-locked amplifier signal processor at the receiving end has high sensitivity and low noise characteristics, and can accurately detect and process weak light signals after atmospheric attenuation. The calculation module obtains accurate transmittance and optical range (MOR) values ​​through precise calculation models. These characteristics enable this device to achieve high-precision visibility measurement under complex environmental conditions, providing strong technical support for meteorological observations and related applications.

[0038] In one implementation of the embodiment of the present application, the DDS adjustable signal generator and the digital phase-locked amplifier signal processor are both implemented by the same FPGA logic programming. This design ensures the clock synchronization and signal homology of the transmitting end and the receiving end, thereby significantly improving the measurement accuracy and anti-interference ability of the system.

[0039] The signal generated by the DDS adjustable signal generator is not only used to drive the light source, but also serves as a reference signal for the digital phase-locked amplifier signal processor. In this way, the signals at the transmitter and receiver always remain homologous, avoiding phase differences and frequency drift problems caused by different signal sources. This homologous design ensures the consistency and stability of the signal, providing a basis for high-precision measurement.

[0040] The digital phase-locked amplifier signal processor uses the same reference signal as the transmitter to perform phase-sensitive detection on the received AC signal. Phase-sensitive detection is a high-precision signal processing technology that can effectively extract the signal component in phase with the reference signal while suppressing signals and noise in other phases. In this way, the digital phase-locked amplifier signal processor can accurately extract weak target signals in complex noise environments, thereby improving the system's anti-interference ability and measurement accuracy.

[0041] This design can effectively improve the accuracy and reliability of visibility measurement under complex environmental conditions, providing strong technical support for meteorological observations and related applications.

[0042] Figure 3 The schematic diagram of the design of a digital phase-locked amplifier signal processor based on FPGA provided in the embodiment of the present application, wherein the DDS adjustable signal generator outputs a sinusoidal reference signal v_ref_sin, where v_ref_sin=sin(ω n ), ω is the discrete reference angular frequency. The sine reference signal is processed by the inverter to obtain the cosine reference signal v_ref_cos=cos(ωn ). Another sinusoidal reference signal is converted by DAC to drive the external system, i.e. the transmitter. The system response signal is expressed as v_sig=Vsin(ωn+θ), where V is the system response amplitude and θ is the system response phase.

[0043] After the receiving end receives the system response signal v_sig from the transmitting end, the system response signal is taken as the digital signal v_sig to be processed and enters the multiplier for mixing, and is processed by the digital phase-locked amplifier signal processor. After mixing and low-pass filtering, the double frequency signal component of ω is attenuated, and only the DC components X and Y are left in the signal, where X=1 / 2Vcosθ, Y=1 / 2Vsinθ, and the final signal amplitude is , where (sin 2 θ+cos 2 θ = 1).

[0044] It can be seen that the amplitude of the system response signal is independent of the phase after being processed by the digital phase-locked amplifier signal processor, and the signal components of other frequencies are attenuated by the low-pass filter. The system's acquisition accuracy, stability and anti-interference ability can be greatly improved.

[0045] In order to test the performance of the digital phase-locked amplifier signal processor, a sine wave with an output frequency of 1000±N(Hz) (N=0,1,2,…,200) from the Agilent function generator 33250A was used as the input signal of the signal acquisition board. The amplitude was collected and normalized to obtain the test results, in which the Q value (quality factor) of the digital phase-locked amplifier signal processor was 147.93. It is shown that the digital phase-locked amplifier signal processor in this application has a very narrow bandwidth and strong frequency selectivity near the main frequency, and can effectively amplify the main frequency signal while suppressing or attenuating other frequency components other than the main frequency; in addition, due to the high Q value, the digital phase-locked amplifier signal processor has a strong frequency resolution ability near the main frequency. This enables it to accurately identify and extract the target frequency signal in a complex frequency environment, even if the signal is very weak. Finally, due to the low noise of the acquisition board of the digital phase-locked amplifier signal processor, combined with the high Q value characteristics of the digital phase-locked amplifier signal processor, the entire system can identify and amplify weak signals while effectively suppressing noise interference. This is crucial for extracting useful signals in a noisy environment.

[0046] In one implementation of the embodiment of the present application, the device further includes: a low-pass filtering light intensity saturation detection module, which is used to perform light intensity saturation or top distortion detection on the signal output by the atmospheric attenuation light intensity detection circuit.

[0047] The atmospheric attenuation light intensity detection circuit is specifically used to receive the optical signal after atmospheric attenuation, and divide the atmospheric attenuation light signal into two processing paths: the first signal is sent to the high-pass filter and AD acquisition module, and the AC signal is retained. After the signal is collected by the AD acquisition module, it enters the digital phase-locked amplifier signal processor to calculate the useful light intensity amplitude after demodulation. The second signal is processed by the low-pass filter light intensity saturation detection module, retains the DC signal and monitors the DC signal to monitor whether there is light intensity saturation or top distortion. When strong external light is irradiated (such as sunlight), it is easy to generate a large DC signal, resulting in saturation or top distortion of the detection signal. Therefore, the device also has the function of monitoring light intensity saturation distortion, and can generate an alarm log when an abnormality occurs to directly locate the problem.

[0048] The above is an introduction to the visibility measuring device based on the transmission method in the present application. The present application also provides a visibility measuring method based on the transmission method, which is applied to the visibility measuring device based on the transmission method. The device includes a transmitting end, a receiving end and a computing module; the transmitting end includes a DDS adjustable signal generator, a light source driving circuit and a light intensity detection and AD acquisition circuit; the receiving end includes a light intensity detection circuit attenuated by the atmosphere, a high-pass filter and AD acquisition module, a digital phase-locked amplification signal processor and a low-pass filter module. Figure 4 A flow chart of a visibility measurement method based on the transmission method provided in an embodiment of the present application. Figure 4 As shown, the visibility measurement method based on the transmission method provided in the embodiment of the present application may include: S401. The transmitting end transmits a modulated optical signal.

[0049] S402: The receiving end detects the optical signal after atmospheric attenuation, and extracts the signal through a phase-locked amplification signal processing circuit.

[0050] S403, the calculation module calculates the transmittance and the optical range MOR according to the light intensity value of the initial light emitted by the transmitting end and the light intensity value of the light attenuated by the atmosphere received and processed by the receiving end.

[0051] In one implementation of the embodiment of the present application, the DDS adjustable signal generator and the digital lock-in amplifier signal processor are implemented by the same FPGA logic programming; The signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor to ensure clock synchronization and signal homology between the transmitting end and the receiving end, thereby improving the measurement accuracy and anti-interference ability of the system; the digital phase-locked amplifier signal processor is used to perform phase-sensitive detection on the received AC signal using the same reference signal as the transmitting end.

[0052] In an implementation of the embodiment of the present application, the device further includes a low-pass filtering light intensity saturation detection module, and the method further includes: The low-pass filtering light intensity saturation detection module is used to perform light intensity saturation or top distortion detection on the signal output by the atmospheric attenuation light intensity detection circuit.

[0053] In one implementation of the embodiment of the present application, the atmospheric attenuation light intensity detection circuit receives the atmospheric attenuation light signal and divides the atmospheric attenuation light signal into two processing paths, one path is sent to the high-pass filter and AD acquisition module, and the AC signal is retained, and after being collected by the AD acquisition module, it enters the digital phase-locked amplification signal processor; the other path is processed by the low-pass filter light intensity saturation detection module, the DC signal is retained and the DC signal is monitored to monitor whether there is light intensity saturation or top distortion.

[0054] In one implementation of the embodiment of the present application, the signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor in the phase-locked amplifier signal processing circuit on the one hand, and is used to drive the light source of the transmitting end after amplitude adjustment on the other hand, so as to meet the requirement that the input signal of the digital phase-locked amplifier signal processor and the reference signal are homologous.

[0055] The embodiments of the present application also provide corresponding devices and computer storage media for implementing the solutions provided by the embodiments of the present application.

[0056] The device includes a memory and a processor, the memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes the method described in any embodiment of the present application.

[0057] The computer storage medium stores codes, and when the codes are executed, a device executing the codes implements the method described in any embodiment of the present application.

[0058] Through the description of the above implementation methods, it can be known that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a general hardware platform. Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, and the computer software product can be stored in a storage medium, such as a read-only memory (ROM) / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network communication device such as a router) to execute the methods described in each embodiment of the present application or some parts of the embodiments.

[0059] 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 existence of other identical elements in the process, method, article or device including the elements.

[0060] It should also be noted that the various embodiments in this specification are described in a progressive manner, and the same and similar parts between the various embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device and apparatus embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiments. The device and apparatus embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components indicated as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0061] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A visibility measuring device based on transmission method, characterized in that: The device comprises a transmitting end, a receiving end and a computing module; The transmitting end includes a DDS adjustable signal generator, a light source driving circuit, and a light intensity detection and AD acquisition circuit; the DDS adjustable signal generator is implemented by FPGA logic programming and is used to generate a sine wave modulation signal with adjustable frequency and amplitude; the transmitting end is used to generate initialization light; The receiving end includes an atmospheric attenuated light intensity detection circuit, a high-pass filter and AD acquisition module, a digital phase-locked amplification signal processor and a low-pass filter module; the receiving end is used to receive and detect the atmospheric attenuated light; the digital phase-locked amplification signal processor is used to amplify the atmospheric attenuated light received by the receiving end; The calculation module is used to calculate the transmittance and the optical range MOR according to the light intensity value of the initial light emitted by the transmitting end and the light intensity value of the light attenuated by the atmosphere received and processed by the receiving end.

2. The device according to claim 1, characterized in that The DDS adjustable signal generator and the digital phase-locked amplifier signal processor are implemented by the same FPGA logic programming; The signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor to ensure clock synchronization and signal homology between the transmitting end and the receiving end, thereby improving the measurement accuracy and anti-interference ability of the system; the digital phase-locked amplifier signal processor is used to perform phase-sensitive detection on the received AC signal using the same reference signal as the transmitting end.

3. The device according to claim 1, characterized in that The device also includes: The low-pass filtering light intensity saturation detection module is used to perform light intensity saturation or top distortion detection on the signal output by the atmospheric attenuation light intensity detection circuit.

4. The device according to claim 3, characterized in that The atmospheric attenuated light intensity detection circuit is specifically used to receive the atmospheric attenuated light signal and divide the atmospheric attenuated light signal into two processing paths, one path is sent to the high-pass filter and AD acquisition module, and the AC signal is retained. After being collected by the AD acquisition module, it enters the digital phase-locked amplification signal processor; the other path is processed by the low-pass filter light intensity saturation detection module, the DC signal is retained and the DC signal is monitored to monitor whether there is light intensity saturation or top distortion.

5. The device according to claim 1, characterized in that The signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor in the phase-locked amplifier signal processing circuit on the one hand, and is used to drive the light source at the transmitting end after amplitude adjustment on the other hand, so as to meet the requirement that the input signal of the digital phase-locked amplifier signal processor and the reference signal are of the same source.

6. A visibility measurement method based on transmission method, characterized in that: The device is applied to a visibility measurement device based on the transmission method, the device comprises a transmitting end, a receiving end and a computing module; the transmitting end comprises a DDS adjustable signal generator, a light source driving circuit and a light intensity detection and AD acquisition circuit; the receiving end comprises a light intensity detection circuit attenuated by the atmosphere, a high-pass filter and AD acquisition module, a digital phase-locked amplification signal processor and a low-pass filter module, and the method comprises: The transmitting end transmits a modulated optical signal; The receiving end detects the optical signal after atmospheric attenuation; the signal is extracted through the phase-locked amplification signal processing circuit; The calculation module calculates the transmittance and the optical range MOR according to the light intensity value of the initial light emitted by the transmitting end and the light intensity value of the light attenuated by the atmosphere received and processed by the receiving end.

7. The method according to claim 6, characterized in that The DDS adjustable signal generator and the digital phase-locked amplifier signal processor are implemented by the same FPGA logic programming; The signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor to ensure clock synchronization and signal homology between the transmitting end and the receiving end, thereby improving the measurement accuracy and anti-interference ability of the system; the digital phase-locked amplifier signal processor is used to perform phase-sensitive detection on the received AC signal using the same reference signal as the transmitting end.

8. The method according to claim 6, characterized in that The device further includes a low-pass filtering light intensity saturation detection module, and the method further includes: The low-pass filtering light intensity saturation detection module is used to perform light intensity saturation or top distortion detection on the signal output by the atmospheric attenuation light intensity detection circuit.

9. The method according to claim 8, characterized in that The atmospheric attenuated light intensity detection circuit receives the atmospheric attenuated light signal and divides the atmospheric attenuated light signal into two processing paths, one path is sent to the high-pass filter and AD acquisition module, and the AC signal is retained. After being collected by the AD acquisition module, it enters the digital phase-locked amplification signal processor; the other path is processed by the low-pass filter light intensity saturation detection module, the DC signal is retained and the DC signal is monitored to monitor whether there is light intensity saturation or top distortion.

10. The method according to claim 6, characterized in that The signal generated by the DDS adjustable signal generator is used as a reference signal of the digital phase-locked amplifier signal processor in the phase-locked amplifier signal processing circuit on the one hand, and is used to drive the light source at the transmitting end after amplitude adjustment on the other hand, so as to meet the requirement that the input signal of the digital phase-locked amplifier signal processor and the reference signal are of the same source.

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