Composite anti-interference radar level measurement method and system based on laser calibration

Abstract

This invention relates to the field of level detection technology and proposes a composite anti-interference radar level measurement method and system based on laser calibration. The method includes: performing spatial distortion correction on environmental parameters to obtain laser calibration reference data, and performing spectral analysis on medium characteristic parameters to obtain a radar wave frequency adjustment reference; based on the radar wave frequency adjustment reference, performing frequency modulation on the initial radar transmission signal to obtain a wide-area scanning radar signal; based on the laser calibration reference data, performing beam pointing correction on the wide-area scanning radar signal to obtain a radar echo signal; determining a dynamic interference suppression threshold based on the radar echo signal; performing logical identification and filtering processing on the radar echo signal based on the dynamic interference suppression threshold to obtain a clean level echo sequence; and fitting the waveform characteristics of the clean level echo sequence and the laser calibration reference data to obtain a high-precision level distance. This invention can improve the efficiency of anti-interference radar level measurement.

Description

Technical Field

[0001] This invention relates to the field of level detection technology, and in particular to a composite anti-interference radar level measurement method and system based on laser calibration. Background Technology

[0002] In current gas holder level and piston status monitoring scenarios, single laser level devices are easily affected by on-site temperature, humidity, and suspended particulate matter, resulting in measurement deviations. Radar detection alone suffers from beam pointing deviations and significant clutter interference. When both types of devices work independently, it is difficult to balance measurement accuracy and anti-interference capabilities. When facing the dynamic operating conditions of gas holders, the overall measurement stability is insufficient, and the data error is relatively large.

[0003] Traditional monitoring methods lack integrated calibration of laser and radar technologies, and their signal correction and interference suppression methods are relatively simple. These methods cannot effectively adapt to the dusty, complex, and wide-ranging operating environments of gas holders, resulting in unreliable measurement data and insufficient overall equipment efficiency to meet field requirements. Therefore, improving the accuracy, anti-interference capability, and operational stability of gas holder level and piston status monitoring has become an urgent problem to be solved. Summary of the Invention

[0004] This invention provides a composite anti-interference radar level measurement method and system based on laser calibration to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides a composite anti-interference radar level measurement method based on laser calibration, comprising: D1. Perform spatial distortion correction on the environmental parameters of the object under test to obtain the laser calibration reference data of the object under test, and perform spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test. D2. Based on the radar wave frequency adjustment reference, the initial radar transmission signal of the object under test is frequency modulated to obtain the wide-area scanning radar signal of the object under test. D3. Based on the laser calibration reference data, the beam pointing of the wide-area scanning radar signal is corrected to obtain the radar echo signal of the object under test. D4. Determine the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal. D5. Based on the dynamic interference suppression threshold, perform logical identification on the radar echo signal to obtain the interference feature components of the object under test, and filter out the interference feature components to obtain the pure level echo sequence of the object under test. D6. Fit the waveform characteristics of the pure material level echo sequence with the laser calibration reference data to obtain the high-precision material level distance of the object under test.

[0006] In a preferred embodiment, the step of spatially distorting the environmental parameters of the object under test to obtain laser calibration reference data for the object under test includes: The temperature, humidity, air pressure, and atmospheric particulate matter concentration of the space where the object under test is located are collected in real time to obtain the environmental parameters of the object under test. The environmental parameters are spatially gridded to obtain a spatial distribution sequence of the environmental parameters. Distortion features are identified in the spatial distribution sequence to obtain the spatial distortion mapping spectrum of the object under test; Based on the spatial distortion mapping map, local deviation compensation is performed on the environmental parameters to obtain the distortion correction parameters of the object under test; Based on the distortion correction parameters, the initial laser scanning data of the object under test is geometrically corrected to obtain the laser calibration reference data of the object under test.

[0007] In a preferred embodiment, the step of performing spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test includes: The medium characteristic parameters of the object under test are continuously sampled to obtain the medium parameter sampling sequence of the object under test; Extract the spectral energy distribution of the medium parameter sampling sequence and perform smooth fitting on the spectral energy distribution to obtain the medium response spectral envelope of the object under test; Based on the envelope of the medium response spectrum, the primary resonant frequency and secondary resonant frequency of the object under test are identified. The frequency difference between the primary resonant frequency point and the secondary resonant frequency point is calculated to obtain the frequency offset indication of the object under test. The intrinsic frequency distribution of the medium of the object under test is obtained by performing spectral analysis on the sampled sequence of the medium parameters. The frequency offset indication is compared with the intrinsic frequency distribution of the medium on a frequency-by-frequency basis to obtain the radar wave frequency adjustment reference of the object under test.

[0008] In a preferred embodiment, the step of frequency modulating the initial radar transmission signal of the object under test based on the radar wave frequency adjustment reference to obtain the wide-area scanning radar signal of the object under test includes: Based on the radar wave frequency adjustment reference, the initial radar transmission signal of the object under test is phase compensated to obtain the phase correction signal of the object under test. Based on the phase correction signal, the initial radar transmission signal is nonlinearly frequency modulated to obtain the modulated signal of the object under test; The modulation signal is spectrally expanded to obtain the wide-area scanning radar signal of the object under test.

[0009] In a preferred embodiment, the step of performing beam pointing correction on the wide-area scanning radar signal based on the laser calibration reference data to obtain the radar echo signal of the object under test includes: Spatial discretization sampling is performed on the laser calibration reference data to obtain the spatial pointing feature sequence of the laser calibration reference data; The spatial position deviation in the spatial pointing feature sequence is mapped to a phase offset, and the phase correction factor of the wide-area scanning radar signal is obtained based on the phase offset. Based on the phase correction factor, point-by-point phase compensation is performed on the wide-area scanning radar signal to obtain the phase compensation signal of the wide-area scanning radar signal. The phase compensation signals are coherently superimposed to obtain the radar echo signal of the object under test.

[0010] In a preferred embodiment, the phase compensation signal is calculated using the following formula: ; in, The phase compensation signal is... For wide-area scanning radar signals, The phase correction factor is... Represents an imaginary number.

[0011] In a preferred embodiment, determining the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal includes: The amplitude of the radar echo signal is statistically analyzed to obtain the average amplitude and amplitude fluctuation range of the radar echo signal; Based on the average amplitude, the amplitude fluctuation range is divided into intervals to obtain the high amplitude signal segment and low amplitude signal segment of the radar echo signal; The mean value of clutter in the low-amplitude signal band is used as the background noise reference value of the radar echo signal; Based on the background noise baseline value, the overall signal-to-noise ratio of the radar echo signal is evaluated to obtain the dynamic interference suppression threshold of the object under test.

[0012] In a preferred embodiment, the step of logically identifying the radar echo signal based on the dynamic interference suppression threshold to obtain the interference feature components of the object under test, and filtering out the interference feature components to obtain the clean level echo sequence of the object under test, includes: The radar echo signal is segmented by a sliding window to obtain echo signal segments of the radar echo signal; Based on the dynamic interference suppression threshold, the amplitude of the echo signal segment is compared to obtain the interference characteristic component of the echo signal segment, and the interference characteristic component is the signal segment that exceeds the threshold. The amplitude of the echo signal segment corresponding to the interference feature component is zeroed out, and the zeroed echo signal segment is time-series spliced ​​with the echo signal segment not marked as the interference feature component to obtain the pure level echo sequence of the object under test.

[0013] In a preferred embodiment, the step of fitting the waveform features of the pure level echo sequence with the laser calibration reference data to obtain the high-precision level distance of the object under test includes: Local extrema extraction is performed on the pure material level echo sequence to obtain the echo peak position sequence of the object under test; Based on the laser calibration reference data, the echo peak position sequence is spatially aligned to obtain the aligned radar echo characteristics of the object under test. Based on the aligned radar echo characteristics, the echo peak position sequence is refined by sub-pixel level interpolation to obtain the refined echo peak position of the object under test. The deviation between the refined echo peak position and the laser calibration reference data is obtained, and the deviation is used to correct the refined echo peak position to obtain the high-precision position distance of the object under test.

[0014] To address the above problems, the present invention also provides a composite anti-interference radar level measurement system based on laser calibration, the system comprising: The reference generation module is used to perform spatial distortion correction on the environmental parameters of the object under test, obtain the laser calibration reference data of the object under test, and perform spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test. An adaptive frequency modulation module is used to frequency modulate the initial radar transmission signal of the object under test based on the radar wave frequency adjustment reference, so as to obtain the wide-area scanning radar signal of the object under test. The beam pointing calibration module is used to correct the beam pointing of the wide-area scanning radar signal based on the laser calibration reference data, so as to obtain the radar echo signal of the object under test. The dynamic interference threshold construction module is used to determine the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal. The signal purification module is used to perform logical identification on the radar echo signal based on the dynamic interference suppression threshold, obtain the interference feature components of the object under test, and filter out the interference feature components to obtain the clean level echo sequence of the object under test. A high-precision ranging module is used to fit the waveform characteristics of the pure level echo sequence with the laser calibration reference data to obtain the high-precision level distance of the object to be measured.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention combines the advantages of precise laser ranging and radar wave measurement. It conducts environmental parameter spatial distortion correction and medium characteristic spectrum analysis for gas holder measurement scenarios, establishing a dual measurement benchmark. Furthermore, it optimizes signal quality through radar signal frequency modulation and laser beam pointing correction, effectively resisting interference factors such as dust and temperature / humidity changes inside the gas holder, ensuring continuous and stable measurement signals. Combined with dynamic interference suppression, interference component filtering, and waveform fitting processing, it fully leverages the high-precision positioning of laser and the strong environmental adaptability of radar, significantly improving the detection accuracy of parameters such as gas holder position, piston tilt, drift, and torsion.

[0016] 2. This invention integrates a laser calibration unit and radar level detection, combining the advantages of a small laser beam angle and accurate positioning with radar wavelength adaptability to solid media and strong tolerance to harsh working conditions. It can meet the large-span measurement requirements of gas holders. The system supports multi-channel signal output and on-site debugging and remote operation and maintenance functions, improving overall operating efficiency and equipment protection performance. It can continuously and stably complete the all-time level and equipment status monitoring work in the explosion-proof and multi-interference working environment of gas holders. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a composite anti-interference radar level measurement method based on laser calibration, provided in an embodiment of the present invention. Figure 2 A functional block diagram of a laser-calibrated composite anti-interference radar level measurement system provided in an embodiment of the present invention; The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] This application provides a laser-calibrated composite anti-interference radar level measurement method. The executing entity of the laser-calibrated composite anti-interference radar level measurement method includes, but is not limited to, at least one of the following electronic devices that can be configured to execute the method provided in this application: a server, a terminal, etc. In other words, the laser-calibrated composite anti-interference radar level measurement method can be executed by software or hardware installed on a terminal device or a server device. The server includes, but is not limited to, a single server, a server cluster, a cloud server, or a cloud server cluster. The server can be an independent server or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery networks (CDN), and big data and artificial intelligence platforms.

[0020] Reference Figure 1 The diagram shown is a flowchart illustrating a laser-calibrated composite anti-interference radar level measurement method according to an embodiment of the present invention. In this embodiment, the laser-calibrated composite anti-interference radar level measurement method includes: D1. Perform spatial distortion correction on the environmental parameters of the object under test to obtain the laser calibration reference data of the object under test, and perform spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test. In this embodiment of the invention, the step of performing spatial distortion correction on the environmental parameters of the object under test to obtain laser calibration reference data for the object under test includes: The temperature, humidity, air pressure, and atmospheric particulate matter concentration of the space where the object under test is located are collected in real time to obtain the environmental parameters of the object under test. The environmental parameters are spatially gridded to obtain a spatial distribution sequence of the environmental parameters. Distortion features are identified in the spatial distribution sequence to obtain the spatial distortion mapping spectrum of the object under test; Based on the spatial distortion mapping map, local deviation compensation is performed on the environmental parameters to obtain the distortion correction parameters of the object under test; Based on the distortion correction parameters, the initial laser scanning data of the object under test is geometrically corrected to obtain the laser calibration reference data of the object under test.

[0021] The step of performing spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test includes: The medium characteristic parameters of the object under test are continuously sampled to obtain the medium parameter sampling sequence of the object under test; Extract the spectral energy distribution of the medium parameter sampling sequence and perform smooth fitting on the spectral energy distribution to obtain the medium response spectral envelope of the object under test; Based on the envelope of the medium response spectrum, the primary resonant frequency and secondary resonant frequency of the object under test are identified. The frequency difference between the primary resonant frequency point and the secondary resonant frequency point is calculated to obtain the frequency offset indication of the object under test. The intrinsic frequency distribution of the medium of the object under test is obtained by performing spectral analysis on the sampled sequence of the medium parameters. The frequency offset indication is compared with the intrinsic frequency distribution of the medium on a frequency-by-frequency basis to obtain the radar wave frequency adjustment reference of the object under test.

[0022] Dedicated sensing equipment is deployed to complete data acquisition across the entire space. The sensing equipment continuously captures temperature, humidity, air pressure, and atmospheric particulate matter concentration information within the space according to a predetermined working mode. The collected environmental information is integrated and summarized to form complete environmental parameters for the object under test. All collected content is organized and stored in a unified format to ensure that subsequent processing can be carried out in an orderly manner based on complete environmental parameters.

[0023] According to the spatial region division rules, the acquired environmental parameters are divided into multiple independent grid units of uniform specifications. The environmental parameters are matched to each grid unit, and the parameters are arranged in sequence according to the spatial arrangement of the grid. The parameters are then combined to form a complete and orderly spatial distribution sequence of environmental parameters. This sequence strictly corresponds to the actual environmental state of each grid location.

[0024] A comprehensive distortion feature identification process is conducted on the spatial distribution sequence of established environmental parameters. The normal state of parameters in each grid cell is compared with the actual acquisition state to accurately locate the parts of the sequence where data offset or abnormal state occurs. The spatial location and change form of each abnormal content are recorded. All the distortion-related information obtained is integrated and sorted out according to the spatial position relationship. Finally, a spatial distortion mapping map that can completely reflect the distortion situation in the whole domain is generated. The map can intuitively show the location and specific manifestation of distortion in the entire space.

[0025] Referring to the generated spatial distortion mapping map, the corresponding grid regions with distortion problems are marked in the map. For each region with distortion, linear interpolation compensation is used to carry out local deviation compensation. The corresponding compensation method is matched with the degree of distortion recorded in the mapping map, and the environmental parameters in the region are corrected one by one to eliminate various deviation problems in the environmental parameters. After comprehensive compensation and correction, all correction results are sorted out to obtain the distortion correction parameters for subsequent correction work.

[0026] The distortion correction parameters are used to perform geometric correction on the initial laser scanning data. According to the correction standards marked by the distortion correction parameters, the spatial position offset and shape deviation in the laser scanning data are adjusted. The entire set of initial laser scanning data is uniformly corrected to match the actual spatial state of the site. After all the correction work is completed, the standard and usable laser calibration reference data is finally obtained.

[0027] Relying on a dedicated sampling device, the medium characteristic parameters of the object under test are continuously collected without interruption. The sampling work maintains a stable collection rhythm, and various characteristic information of the medium is picked up sequentially at fixed time intervals. The contents collected each time are arranged and combined in chronological order, and continuously spliced ​​to form a complete and coherent medium parameter sampling sequence. The sequence completely records the various changes in the medium characteristics over time.

[0028] Fast Fourier Transform is used to extract the spectral energy distribution contained in the sampling sequence of medium parameters. The energy proportion and energy change of different frequency bands in the sequence are sorted out. The sorted spectral energy distribution is subjected to 5th order polynomial smoothing fitting to sort out the overall trend of energy change, smooth out the scattered fluctuations in the distribution, and keep the overall change law continuous and smooth. After the complete fitting operation, a medium response spectral envelope that can reflect the overall energy change law of the medium is generated.

[0029] Frequency point identification is carried out based on the established dielectric response spectrum envelope. On the spectrum envelope, the position with the highest energy concentration and the most prominent signal performance can be located. The main resonant frequency point is identified by the criterion that the energy proportion of a single frequency band is >30%, and the point with the energy proportion between 10% and 30% is identified as the secondary resonant frequency point. The frequency difference between the two types of frequency points is calculated by the frequency difference calculation formula to generate a frequency offset indicator.

[0030] Frequency difference calculation is performed on the identified primary and secondary resonant frequency points. The positional difference and response difference between the two types of frequency points are compared to quantify the frequency difference between them. Combining the magnitude of the difference with the medium response characteristics corresponding to the frequency points, relevant information is integrated to generate a frequency offset indicator that can intuitively reflect the frequency offset. This indicator can accurately reflect the overall frequency offset caused by the medium.

[0031] A comprehensive spectral analysis is performed on the sampled sequence of medium parameters, breaking down all the frequency components contained within the sequence, distinguishing the medium response performance corresponding to different frequencies, sorting out the distribution range and existence state of each independent frequency, and arranging them in a regular manner according to the frequency arrangement order, so as to completely sort out the intrinsic frequency distribution of the medium corresponding to the object under test and clearly present the inherent frequency composition of the medium itself.

[0032] The calculated frequency offset indication and the analyzed intrinsic frequency distribution of the medium are compared point by point. The offset status of each intrinsic frequency point is checked in turn. The adaptation of each frequency point is judged based on the comparison results. The frequency adjustment standard adapted to the state of the medium under test is integrated based on the overall comparison results. In this way, the radar wave frequency adjustment benchmark that can guide the adjustment of radar signals is determined.

[0033] The beneficial effects are that the entire processing flow can comprehensively collect and correct spatial distortion problems caused by complex on-site environments. Relying on multi-level data processing, it forms accurate and reliable laser calibration reference data and radar wave frequency adjustment reference, which is fully adapted to the medium characteristics and environmental conditions under complex working conditions such as gas holders. It reduces measurement interference caused by temperature, humidity, air pressure, suspended particulate matter and the characteristics of the medium itself from the source, laying a solid foundation for subsequent radar signal modulation, beam correction and level calculation work, and effectively improving the accuracy, stability and environmental adaptability of the overall measurement work.

[0034] D2. Based on the radar wave frequency adjustment reference, the initial radar transmission signal of the object under test is frequency modulated to obtain the wide-area scanning radar signal of the object under test.

[0035] In this embodiment of the invention, the step of frequency modulating the initial radar transmission signal of the object under test based on the radar wave frequency adjustment reference to obtain the wide-area scanning radar signal of the object under test includes: Based on the radar wave frequency adjustment reference, the initial radar transmission signal of the object under test is phase compensated to obtain the phase correction signal of the object under test. Based on the phase correction signal, the initial radar transmission signal is nonlinearly frequency modulated to obtain the modulated signal of the object under test; The modulation signal is spectrally expanded to obtain the wide-area scanning radar signal of the object under test.

[0036] According to the adjustment standard corresponding to the radar wave frequency adjustment reference, the phase deviation problem existing in the initial radar transmission signal is investigated. The phase compensation operation is performed on the entire signal according to the phase correction range and correction direction defined by the reference. The phase content of the signal is corrected segment by segment, so that the signal phase returns to the standard state. After all the compensation operations are completed, a phase correction signal with a regular state is formed.

[0037] Based on the generated phase correction signal as a reference, nonlinear frequency modulation is performed on the original initial radar transmission signal. The frequency state is adjusted according to the transmission characteristics of different signal intervals. Instead of using a uniform adjustment amplitude to complete the entire range, the signal frequency parameters are changed segment by segment in combination with the standard state reflected by the phase correction signal. After completing the full-domain frequency adjustment, a modulation signal that meets the adjustment requirements is generated.

[0038] The modulated signal is subjected to spectrum expansion to broaden the frequency range of the signal coverage, allowing the signal to cover a larger monitoring area and improve the scanning coverage capability. After complete spectrum expansion processing, a wide-area scanning radar signal capable of large-scale detection is finally formed.

[0039] The beneficial effects are that, with a predetermined frequency reference as the core, the signal phase and frequency are optimized in multiple layers, the signal spectrum coverage is gradually expanded, and it can adapt to the needs of large-scale level detection in complex field environments. It effectively improves the transmission quality and scanning capability of radar transmitted signals, reduces signal loss caused by phase deviation and frequency mismatch, and allows radar signals to stably complete full-domain scanning operations, further enhancing the detection coverage effect and operational reliability of the measurement system under complex working conditions.

[0040] D3. Based on the laser calibration reference data, the beam pointing of the wide-area scanning radar signal is corrected to obtain the radar echo signal of the object under test. In this embodiment of the invention, the step of performing beam pointing correction on the wide-area scanning radar signal based on the laser calibration reference data to obtain the radar echo signal of the object under test includes: Spatial discretization sampling is performed on the laser calibration reference data to obtain the spatial pointing feature sequence of the laser calibration reference data; The spatial position deviation in the spatial pointing feature sequence is mapped to a phase offset, and the phase correction factor of the wide-area scanning radar signal is obtained based on the phase offset. Based on the phase correction factor, point-by-point phase compensation is performed on the wide-area scanning radar signal to obtain the phase compensation signal of the wide-area scanning radar signal. The phase compensation signals are coherently superimposed to obtain the radar echo signal of the object under test.

[0041] The formula for calculating the phase compensation signal is as follows: ; in, The phase compensation signal is... For wide-area scanning radar signals, The phase correction factor is... Represents an imaginary number.

[0042] Spatial discretization sampling is performed on the laser calibration reference data according to a fixed spatial sampling interval. Sampling points are evenly distributed within the complete space covered by the laser, and beam pointing data corresponding to each sampling point is extracted in sequence. All the extracted data are arranged and integrated in an orderly manner according to the spatial arrangement of the sampling points, and finally a complete spatial pointing feature sequence of the laser calibration reference data is formed.

[0043] Extract the spatial position deviation information recorded in the spatial pointing feature sequence, convert and map each position deviation according to the correspondence between spatial position and signal phase during beam transmission, convert the spatial position deviation into the signal phase offset, integrate the phase offset information of all points and perform unified regularization, and finally form a phase correction factor suitable for wide-area scanning radar signals.

[0044] Based on the correction standard corresponding to the phase correction factor, phase compensation is performed on each signal point of the wide-area scanning radar signal one by one. The phase state of each signal point is adjusted according to the requirements of the correction factor to eliminate various phase deviation problems in the signal. After the compensation processing of all points is completed, the phase compensation signal of the wide-area scanning radar signal is generated.

[0045] The wide-area scanning radar signal originates from the wide-area scanning radar signal generated after phase compensation, nonlinear frequency modulation, and spectrum expansion are sequentially performed on the initial radar transmission signal. It is the original input signal for this phase correction process. The phase correction factor is derived from the phase correction factor obtained by mapping the spatial position deviation in the spatial pointing feature sequence of the laser calibration reference data into a phase offset and integrating it. It is the core basis for controlling the phase compensation amplitude. The imaginary number is a general identifier for time-domain complex signal processing and is used to characterize the operational properties of phase rotation. The phase compensation signal is the final output quantity of this processing. All physical quantities involved in the processing are within a unified time-domain signal system, and their dimensions are completely matched and unified.

[0046] The significance of this process is to apply corresponding phase rotation correction to each time-domain sampling point of the wide-area scanning radar signal in the complex signal domain, adjust the phase state of the original signal according to the value of the phase correction factor, offset the signal phase shift problem caused by beam pointing deviation, and finally obtain a phase-compensated signal with phase calibration, providing a phase-accurate signal basis for subsequent coherent superposition and radar echo signal generation.

[0047] When the beam pointing deviation corresponding to the wide-area scanning radar signal increases, the corresponding value of the phase correction factor increases synchronously, and the phase correction amplitude of the processed phase compensation signal increases accordingly. When the beam pointing deviation decreases, the value of the phase correction factor decreases synchronously, and the correction amplitude of the phase compensation signal decreases synchronously. The correction amplitude of the entire processing process is always positively correlated with the degree of beam pointing deviation, and the output phase compensation signal always maintains the accurate state after phase calibration.

[0048] The multiple signal components contained in the phase compensation signal are merged according to the rules of coherent superposition. The effective signal components with the same phase are superimposed and enhanced, while the interference components with mismatched phases cancel each other out. After complete superposition and integration, the radar echo signal of the object under test is finally obtained.

[0049] The beneficial effects are that this process relies on the precise spatial data obtained from laser calibration to correct the direction of the radar beam. Through a complete processing chain of discrete sampling, phase mapping, point-by-point compensation, and coherent superposition, it accurately corrects the direction deviation of the radar beam, effectively improves the focus and signal strength of the radar echo signal, reduces the measurement error caused by beam offset, and allows the radar echo to accurately reflect the true state of the object under test. This provides a high-quality signal foundation for subsequent interference suppression and level calculation, further enhancing the accuracy and operational reliability of the radar level measurement system.

[0050] D4. Determine the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal. In this embodiment of the invention, determining the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal includes: The amplitude of the radar echo signal is statistically analyzed to obtain the average amplitude and amplitude fluctuation range of the radar echo signal; Based on the average amplitude, the amplitude fluctuation range is divided into intervals to obtain the high amplitude signal segment and low amplitude signal segment of the radar echo signal; The mean value of clutter in the low-amplitude signal band is used as the background noise reference value of the radar echo signal; Based on the background noise baseline value, the overall signal-to-noise ratio of the radar echo signal is evaluated to obtain the dynamic interference suppression threshold of the object under test.

[0051] The entire time interval of the radar echo signal from start to finish is traversed, covering all sampling points without missing any signal nodes. The signal amplitude value corresponding to each sampling point is extracted one by one. After summing the amplitude data of all points, the sum of all values ​​is calculated. The sum is divided by the total number of sampling points to obtain the average amplitude of the radar echo signal. At the same time, the maximum and minimum amplitude values ​​are compared and selected from all amplitude values. The minimum amplitude is used as the starting point and the maximum amplitude is used as the ending point to define a complete range of numerical variation. This range is the amplitude fluctuation range of the radar echo signal.

[0052] Using the calculated average amplitude as the sole dividing criterion for interval division, all numerical intervals within the amplitude fluctuation range that are greater than or equal to the average amplitude are defined as high-amplitude intervals. Continuous or discrete signal segments in the radar echo signal whose amplitudes fall within the high-amplitude intervals are extracted according to the chronological order of the signals. All extracted signal segments are then sequentially spliced ​​together in chronological order to form the high-amplitude signal segment of the radar echo signal. Simultaneously, all numerical intervals within the amplitude fluctuation range that are less than the average amplitude are defined as low-amplitude intervals. All signal segments in the radar echo signal whose amplitudes fall within the low-amplitude intervals are extracted according to the same chronological order and then spliced ​​together in chronological order to form the low-amplitude signal segment of the radar echo signal.

[0053] There are no effective echo signals carrying level information in the low-amplitude signal segment. All of them are composed of environmental clutter and the basic noise of the equipment itself. The clutter amplitude values ​​corresponding to all sampling points in the low-amplitude signal segment are extracted one by one. All clutter amplitude values ​​are summed and the sum is calculated. The sum is divided by the total number of sampling points in the low-amplitude signal segment to obtain the clutter mean of the low-amplitude signal segment. This clutter mean is directly set as the background noise reference value of the radar echo signal.

[0054] Using the background noise baseline as the core reference for on-site noise intensity, and combining the conventional amplitude characteristics of the effective level echo in the radar echo signal, an overall signal-to-noise ratio (SNR) assessment is conducted. The critical amplitude standard that can clearly distinguish the effective echo signal from interference clutter is calculated to ensure that signals below this standard belong to the category of interference clutter, and signals above this standard can be stably determined as effective level echoes. Finally, this critical amplitude standard is determined as the dynamic interference suppression threshold of the object under test. The dynamic interference suppression threshold is the product of the background noise baseline and the SNR coefficient. The SNR coefficient ranges from 1.5 to 3.0, and the higher the dust concentration, the larger the coefficient value.

[0055] The beneficial effects are that this processing flow dynamically generates interference suppression thresholds based on the amplitude characteristics of the echo signal itself, which can match the noise changes in complex on-site environments in real time, avoid the shortcomings of fixed thresholds that cannot adapt to changing working conditions, accurately delineate the judgment boundary between effective echoes and interference clutter, and provide accurate and reliable judgment basis for subsequent interference component identification and filtering work, effectively improve the environmental anti-interference capability of radar level measurement system and the accuracy of level measurement results, and better adapt to the complex level monitoring needs of industrial sites.

[0056] D5. Based on the dynamic interference suppression threshold, perform logical identification on the radar echo signal to obtain the interference feature components of the object under test, and filter out the interference feature components to obtain the pure level echo sequence of the object under test. In this embodiment of the invention, the step of logically identifying the radar echo signal based on the dynamic interference suppression threshold to obtain the interference feature components of the object under test, and filtering out the interference feature components to obtain the clean level echo sequence of the object under test, includes: The radar echo signal is segmented by a sliding window to obtain echo signal segments of the radar echo signal; Based on the dynamic interference suppression threshold, the amplitude of the echo signal segment is compared to obtain the interference characteristic component of the echo signal segment, and the interference characteristic component is the signal segment that exceeds the threshold. The amplitude of the echo signal segment corresponding to the interference feature component is zeroed out, and the zeroed echo signal segment is time-series spliced ​​with the echo signal segment not marked as the interference feature component to obtain the pure level echo sequence of the object under test.

[0057] A sliding window length and sliding step size adapted to the total duration of the radar echo signal are preset. The window length is 50 sampling points, the sliding step size is 10 sampling points, and the window overlap rate is 80%. The sliding window is placed starting from the beginning of the radar echo signal time. All signal content within the time interval covered by the window is captured as the first echo signal segment. Then, the sliding window moves backward at a constant speed along the time axis according to the predetermined sliding step size. Each time the step distance is completed, the signal content within the current window coverage area is captured to generate a new echo signal segment. The moving and capturing operation is repeated until the sliding window completely covers the entire time interval of the radar echo signal, ensuring that all signal content is included in the corresponding segment without omission. All captured independent signal segments are arranged in the order of their generation time to form the echo signal segments of the radar echo signal.

[0058] The established dynamic interference suppression threshold is used as the criterion for judging the interference signal. The amplitude comparison and verification work is carried out one by one according to the time arrangement of the echo signal segments. The peak amplitude of each echo signal segment is extracted and compared with the criterion. When the amplitude of three or more consecutive sampling points exceeds the threshold, it is marked. These marked signal segments are uniformly classified as interference feature components. After completing the verification and screening of all segments, the interference feature components of the object under test are obtained.

[0059] Locate the echo signal segments corresponding to all interference characteristic components, perform amplitude zeroing processing on all signal sampling points within these segments, adjust the signal amplitude of each sampling point within the segment to the zero level, completely eliminate the signal influence of the interference segments, and after completing the zeroing operation of all interference segments, sequentially connect and splice the zeroed signal segments with normal signal segments not marked as interference characteristic components according to the original time sequence, ensuring that the spliced ​​signal maintains complete time continuity and there is no time sequence misalignment problem, and finally splicing to form a pure level echo sequence of the object under test.

[0060] The beneficial effects are that this processing flow achieves refined unit processing of echo signals through a sliding window segmentation method, and completes the accurate identification and thorough filtering of interference components by combining dynamically adapted interference suppression thresholds. It can adapt to the complex interference environment of dynamic changes in the field in real time, accurately remove abnormal interference signal components that exceed the threshold, and retain the complete waveform characteristics and time dimension information of the effective level echo to the greatest extent. This effectively improves the purity and reliability of the echo signal, provides a high-quality signal foundation for subsequent waveform feature fitting and level distance calculation, and further enhances the anti-interference capability and measurement accuracy of the radar level measurement system under complex industrial conditions.

[0061] D6. Fit the waveform characteristics of the pure material level echo sequence with the laser calibration reference data to obtain the high-precision material level distance of the object under test.

[0062] In this embodiment of the invention, the step of fitting the pure level echo sequence with the laser calibration reference data to obtain the high-precision level distance of the object under test includes: Local extrema extraction is performed on the pure material level echo sequence to obtain the echo peak position sequence of the object under test; Based on the laser calibration reference data, the echo peak position sequence is spatially aligned to obtain the aligned radar echo characteristics of the object under test. Based on the aligned radar echo characteristics, the echo peak position sequence is refined by sub-pixel level interpolation to obtain the refined echo peak position of the object under test. The deviation between the refined echo peak position and the laser calibration reference data is obtained, and the deviation is used to correct the refined echo peak position to obtain the high-precision position distance of the object under test.

[0063] The entire sampling point is traversed point by point along the time axis of the pure level echo sequence from the beginning to the end. The signal amplitude of each sampling point is compared with the amplitude of the five sampling points before and after it. When the amplitude of a certain sampling point is greater than the amplitude of all the sampling points before and after it, the point is marked as a local extreme peak point. The time position information corresponding to each peak point is recorded synchronously. After the entire sequence is traversed, false peak points with amplitudes lower than the valid signal judgment standard are removed. All the retained valid peak points are arranged in chronological order to obtain the echo peak position sequence of the object under test.

[0064] The standard spatial coordinate system and precise object level reference point information contained in the laser calibration reference data are retrieved. The time position information of each peak point in the echo peak position sequence is converted into initial spatial position coordinates according to the correspondence between radar wave transmission speed and spatial distance. Then, all the converted initial spatial coordinates are matched and calibrated one by one with the standard coordinate system of the laser calibration reference data to eliminate the coordinate system offset and origin deviation between the two types of data, so that the spatial coordinates of the radar echo peak and the reference coordinates of the laser calibration are under the same standard system. After the coordinate calibration of all peak points is completed, the corresponding feature information is integrated to finally obtain the aligned radar echo characteristics of the object under test.

[0065] Based on the standard coordinate accuracy requirements corresponding to the aligned radar echo features, bicubic interpolation is used to refine the local signal interval where each peak point in the echo peak position sequence is located, performing subpixel-level interpolation. Sufficient subdivision points are inserted between adjacent sampling points around the peak point. By fitting the amplitude change trend of the local signal, the amplitude corresponding to each subdivision point is calculated. The precise position with the highest amplitude is located from all subdivision points, replacing the coarse peak position under the original sampling accuracy. After completing the refinement of all peak points, all precise position information is regularized, and finally the refined echo peak position of the object under test is obtained.

[0066] By comparing the spatial differences between the refined echo peak position and the corresponding reference point in the laser calibration benchmark data, the deviation values ​​between the two types of positions are extracted. These deviation values ​​are then added as correction values ​​to the calculation results of the refined echo peak position to offset the positional deviation caused by environmental factors during radar signal transmission. After correcting the deviations of all peak positions, the corrected peak positions are converted into corresponding level distance values ​​by combining the distance conversion rules of radar level measurement, and finally, the high-precision level distance of the object under test is obtained.

[0067] The beneficial effects are that this processing flow, through a complete processing link of peak extraction, coordinate alignment, sub-pixel refinement and deviation correction, deeply fuses and fits radar echo signals with laser calibration reference data, giving full play to the high-precision calibration role of laser measurement and the strong environmental adaptability of radar measurement. Sub-pixel-level refinement effectively improves the resolution of peak positioning, and then systematic deviation correction is completed based on laser reference data, further reducing measurement errors caused by environmental interference and sampling accuracy limitations. This can significantly improve the measurement accuracy and reliability of level distance, and better meet the actual needs of high-precision level monitoring in complex industrial scenarios such as gas holders.

[0068] like Figure 2 The diagram shown is a functional block diagram of a composite anti-interference radar level measurement system based on laser calibration provided in an embodiment of the present invention.

[0069] The laser-calibrated composite anti-interference radar level measurement system 100 of this invention can be installed in an electronic device. Depending on the functions implemented, the laser-calibrated composite anti-interference radar level measurement system 100 may include a reference generation module 101, an adaptive frequency modulation module 102, a beam pointing calibration module 103, a dynamic interference threshold construction module 104, a signal purification module 105, and a high-precision ranging module 106. The module described in this invention can also be called a unit, referring to a series of computer program segments that can be executed by the processor of an electronic device and perform a fixed function, stored in the memory of the electronic device.

[0070] In this embodiment, the functions of each module / unit are as follows: The reference generation module 101 is used to perform spatial distortion correction on the environmental parameters of the object under test to obtain the laser calibration reference data of the object under test, and to perform spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test. The adaptive frequency modulation module 102 is used to frequency modulate the initial radar transmission signal of the object under test based on the radar wave frequency adjustment reference to obtain the wide-area scanning radar signal of the object under test. The beam pointing calibration module 103 is used to correct the beam pointing of the wide-area scanning radar signal based on the laser calibration reference data to obtain the radar echo signal of the object under test. The dynamic interference threshold construction module 104 is used to determine the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal. The signal purification module 105 is used to perform logical identification on the radar echo signal based on the dynamic interference suppression threshold, obtain the interference feature components of the object under test, and filter out the interference feature components to obtain the pure level echo sequence of the object under test. The high-precision ranging module 106 is used to fit the waveform features of the pure level echo sequence and the laser calibration reference data to obtain the high-precision level distance of the object to be measured.

[0071] In the several embodiments provided by this invention, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the system embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and other division methods may be used in actual implementation.

[0072] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0073] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in the form of hardware plus software functional modules.

[0074] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0075] This application embodiment can acquire and process relevant data based on artificial intelligence technology. Artificial intelligence is the theory, method, technology, and application system that uses digital computers or machines controlled by digital computers to simulate, extend, and expand human intelligence, perceive the environment, acquire knowledge, and use that knowledge to obtain optimal results.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A composite anti-interference radar level measurement method based on laser calibration, characterized in that, The method includes: D1. Perform spatial distortion correction on the environmental parameters of the object under test to obtain the laser calibration reference data of the object under test, and perform spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test. D2. Based on the radar wave frequency adjustment reference, the initial radar transmission signal of the object under test is frequency modulated to obtain the wide-area scanning radar signal of the object under test. D3. Based on the laser calibration reference data, the beam pointing of the wide-area scanning radar signal is corrected to obtain the radar echo signal of the object under test. D4. Determine the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal. D5. Based on the dynamic interference suppression threshold, perform logical identification on the radar echo signal to obtain the interference feature components of the object under test, and filter out the interference feature components to obtain the pure level echo sequence of the object under test. D6. Fit the waveform characteristics of the pure material level echo sequence with the laser calibration reference data to obtain the high-precision material level distance of the object under test.

2. The composite anti-interference radar level measurement method based on laser calibration as described in claim 1, characterized in that, The environmental parameters of the object under test are spatially distorted to obtain laser calibration reference data for the object under test, including: The temperature, humidity, air pressure, and atmospheric particulate matter concentration of the space where the object under test is located are collected in real time to obtain the environmental parameters of the object under test. The environmental parameters are spatially gridded to obtain a spatial distribution sequence of the environmental parameters. Distortion features are identified in the spatial distribution sequence to obtain the spatial distortion mapping spectrum of the object under test; Based on the spatial distortion mapping map, local deviation compensation is performed on the environmental parameters to obtain the distortion correction parameters of the object under test; Based on the distortion correction parameters, the initial laser scanning data of the object under test is geometrically corrected to obtain the laser calibration reference data of the object under test.

3. The composite anti-interference radar level measurement method based on laser calibration as described in claim 1, characterized in that, The step of performing spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test includes: The medium characteristic parameters of the object under test are continuously sampled to obtain the medium parameter sampling sequence of the object under test; Extract the spectral energy distribution of the medium parameter sampling sequence and perform smooth fitting on the spectral energy distribution to obtain the medium response spectral envelope of the object under test; Based on the envelope of the medium response spectrum, the primary resonant frequency and secondary resonant frequency of the object under test are identified. The frequency difference between the primary resonant frequency point and the secondary resonant frequency point is calculated to obtain the frequency offset indication of the object under test. The intrinsic frequency distribution of the medium of the object under test is obtained by performing spectral analysis on the sampled sequence of the medium parameters. The frequency offset indication is compared with the intrinsic frequency distribution of the medium on a frequency-by-frequency basis to obtain the radar wave frequency adjustment reference of the object under test.

4. The composite anti-interference radar level measurement method based on laser calibration as described in claim 1, characterized in that, The step of frequency modulation of the initial radar transmission signal of the object under test based on the radar wave frequency adjustment reference to obtain the wide-area scanning radar signal of the object under test includes: Based on the radar wave frequency adjustment reference, the initial radar transmission signal of the object under test is phase compensated to obtain the phase correction signal of the object under test. Based on the phase correction signal, the initial radar transmission signal is nonlinearly frequency modulated to obtain the modulated signal of the object under test; The modulation signal is spectrally expanded to obtain the wide-area scanning radar signal of the object under test.

5. The composite anti-interference radar level measurement method based on laser calibration as described in claim 1, characterized in that, The step of correcting the beam pointing of the wide-area scanning radar signal based on the laser calibration reference data to obtain the radar echo signal of the object under test includes: Spatial discretization sampling is performed on the laser calibration reference data to obtain the spatial pointing feature sequence of the laser calibration reference data; The spatial position deviation in the spatial pointing feature sequence is mapped to a phase offset, and the phase correction factor of the wide-area scanning radar signal is obtained based on the phase offset. Based on the phase correction factor, point-by-point phase compensation is performed on the wide-area scanning radar signal to obtain the phase compensation signal of the wide-area scanning radar signal. The phase compensation signals are coherently superimposed to obtain the radar echo signal of the object under test.

6. The composite anti-interference radar level measurement method based on laser calibration as described in claim 5, characterized in that, The formula for calculating the phase compensation signal is as follows: ； in, The phase compensation signal is... For wide-area scanning radar signals, The phase correction factor is... Represents an imaginary number.

7. The composite anti-interference radar level measurement method based on laser calibration as described in claim 1, characterized in that, The step of determining the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal includes: The amplitude of the radar echo signal is statistically analyzed to obtain the average amplitude and amplitude fluctuation range of the radar echo signal; Based on the average amplitude, the amplitude fluctuation range is divided into intervals to obtain the high amplitude signal segment and low amplitude signal segment of the radar echo signal; The mean value of clutter in the low-amplitude signal band is used as the background noise reference value of the radar echo signal; Based on the background noise baseline value, the overall signal-to-noise ratio of the radar echo signal is evaluated to obtain the dynamic interference suppression threshold of the object under test.

8. The composite anti-interference radar level measurement method based on laser calibration as described in claim 1, characterized in that, The step of logically identifying the radar echo signal based on the dynamic interference suppression threshold to obtain the interference feature components of the object under test, and filtering out the interference feature components to obtain the clean level echo sequence of the object under test, includes: The radar echo signal is segmented by a sliding window to obtain echo signal segments of the radar echo signal; Based on the dynamic interference suppression threshold, the amplitude of the echo signal segment is compared to obtain the interference characteristic component of the echo signal segment, and the interference characteristic component is the signal segment that exceeds the threshold. The amplitude of the echo signal segment corresponding to the interference feature component is zeroed out, and the zeroed echo signal segment is time-series spliced ​​with the echo signal segment not marked as the interference feature component to obtain the pure level echo sequence of the object under test.

9. The composite anti-interference radar level measurement method based on laser calibration as described in claim 1, characterized in that, The step of fitting the waveform features of the pure material level echo sequence with the laser calibration reference data to obtain the high-precision material level distance of the object under test includes: Local extrema extraction is performed on the pure material level echo sequence to obtain the echo peak position sequence of the object under test; Based on the laser calibration reference data, the echo peak position sequence is spatially aligned to obtain the aligned radar echo characteristics of the object under test. Based on the aligned radar echo characteristics, the echo peak position sequence is refined by sub-pixel level interpolation to obtain the refined echo peak position of the object under test. The deviation between the refined echo peak position and the laser calibration reference data is obtained, and the deviation is used to correct the refined echo peak position to obtain the high-precision position distance of the object under test.

10. A composite anti-interference radar level measurement system based on laser calibration, characterized in that, For implementing the laser-calibrated composite anti-interference radar level measurement method of claim 1, the system comprises: The reference generation module is used to perform spatial distortion correction on the environmental parameters of the object under test, obtain the laser calibration reference data of the object under test, and perform spectral analysis on the medium characteristic parameters of the object under test to obtain the radar wave frequency adjustment reference of the object under test. An adaptive frequency modulation module is used to frequency modulate the initial radar transmission signal of the object under test based on the radar wave frequency adjustment reference, so as to obtain the wide-area scanning radar signal of the object under test. The beam pointing calibration module is used to correct the beam pointing of the wide-area scanning radar signal based on the laser calibration reference data, so as to obtain the radar echo signal of the object under test. The dynamic interference threshold construction module is used to determine the dynamic interference suppression threshold of the object under test based on the multidimensional characteristics of the radar echo signal. The signal purification module is used to perform logical identification on the radar echo signal based on the dynamic interference suppression threshold, obtain the interference feature components of the object under test, and filter out the interference feature components to obtain the clean level echo sequence of the object under test. A high-precision ranging module is used to fit the waveform characteristics of the pure material level echo sequence with the laser calibration reference data to obtain the high-precision material level distance of the object to be measured.

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