Substation laser radar anti-interference ranging method

Abstract

The invention discloses a transformer substation laser radar anti-interference ranging method, and belongs to the technical field of transformer substation radar ranging. The method comprises the following steps of: compensating transmitting equipment in advance at a transmitting end; a true random sequence is generated through the environment photons, and the emission interval of laser pulses is obtained; a signal is sent by using a dual-frequency Bessel pulse with self-adaptive electric field intensity, and the interference of an environmental electric field is effectively resisted by using a dual-frequency characteristic; the dielectric property of the pollutant is calculated through the dual-wavelength reflectivity difference; acquiring the signal distance between the original transmitting end and the receiving end, and correcting the measured distance; and processing the received signal to obtain a final distance. According to the invention, the laser pulse emission interval is dynamically adjusted through the true random sequence; the influence of electromagnetic interference on a laser path can be effectively dealt with by combining advanced compensation of the micromirror; different types of pollutants are effectively distinguished by utilizing the reflection characteristic difference of different wavelengths to the material, the distance measurement is corrected according to the pollution type, and the distance measurement accuracy in the interference environment is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of substation radar ranging, and particularly relates to a substation laser radar anti-interference ranging method. BACKGROUND

[0002] The electromagnetic interference in a substation mainly comes from the operation of high-voltage equipment, switch operation and electromagnetic wave radiation in the external environment. Such interference may affect the path calculation of the laser radar system through electromagnetic field vectors, causing laser path deviation, and thus affecting the detection accuracy. In addition, the laser radar system is easily disturbed by abnormal reflected light in a complex environment, such as abnormal reflected light interference in a laser line scanning system, which will reduce the recognition ability of the system.

[0003] At present, the anti-interference methods for laser radar systems mainly include random emission of laser pulse sequences, regulation of detector arrays and signal processing techniques. For example, the emission order and time interval of the light sources in the light source array are randomized to reduce interference. However, this method often fails to completely eliminate interference when facing strong interference sources or complex environments, especially in high-noise environments, the signal-to-noise ratio of the signal will decrease significantly.

[0004] In addition, the compensation method for laser path deviation usually relies on real-time calculation of electromagnetic field vectors and adjustment of the laser path, but this method may not respond in time in a dynamically changing environment, resulting in untimely or inaccurate compensation. In terms of arc scattering suppression, the existing methods mostly use pulse forms with fixed parameters, lack adaptive adjustment capability, and are difficult to cope with interference under different working conditions.

[0005] Therefore, how to solve the problem of abnormal reflected light interference during laser radar ranging and improve the accuracy of ranging is a technical problem that the application wants to solve. SUMMARY

[0006] The purpose of the present application is to provide a substation laser radar anti-interference ranging method to solve the problems raised in the background.

[0007] The purpose of the present application is achieved by a substation laser radar anti-interference ranging method, characterized in that the method comprises the following steps:

[0008] Step S1: Adjust the emission device and perform pre-compensation on the emission device at the emission end;

[0009] Step S2: Generate a true random sequence through environmental photons, obtain the emission interval of the laser pulse, and use the randomness of the emission interval to solve the multi-radar mutual interference problem;

[0010] Step S3: sending signals by using electric field intensity adaptive dual-frequency Bessel pulse, effectively resisting environmental electric field interference by using dual-frequency characteristics;

[0011] Step S4: calculating the dielectric properties of pollutants by using dual-wavelength reflectivity difference, and classifying the pollutants;

[0012] Step S5: receiving the transmission signal of the transmitting end, obtaining the signal distance between the original transmitting end and the receiving end, and correcting the distance measurement according to the category of the pollutants;

[0013] Step S6: processing the received signal to obtain the final distance.

[0014] Preferably, the transmitting device is pre-compensated in the transmitting end in step S1, the electromagnetic field intensity is calculated and the laser deflection angle is calculated, and the micro-mirror is driven to pre-compensate the transmitting end, specifically:

[0015] Step S1-1: measuring real-time electromagnetic field intensity , according to the electromagnetic field intensity , the laser path offset is calculated by using the laser deflection angle:

[0016] ;

[0017] wherein, laser deflection angle, equivalent charge amount, equivalent mass, light speed, electric field intensity vector, magnetic induction intensity vector, light speed vector, path differential;

[0018] Step S1-2: driving the micro-mirror to compensate the displacement of the transmitting end: .

[0019] Preferably, the laser pulse transmission interval is obtained by using the transmission signal of the transmitting end in step S2, specifically:

[0020] Step S2-1: collecting photon flow and generating original binary sequence;

[0021] The environmental photons are collected by using a single-photon detector, and the photon count is subject to Poisson distribution: ;

[0022] wherein, photon count, photon flow density;

[0023] The photon arrival time is discretized into time windows , record whether the time window detects photon generation original binary sequence :

[0024] ;

[0025] Step S2-2: the method of generating a true random sequence by selecting the size of electromagnetic interference, specifically:

[0026] When the electromagnetic interference is small, a Gaussian integral model is used to generate a true random sequence, and the Gaussian integral model is:

[0027] ;

[0028] Wherein, Photon flux function, ;

[0029] Wherein, Impact function, Time window, Time, The current time window count, Electromagnetic interference coefficient, Time average, Base variance, Magnetic induction intensity; Natural base;

[0030] When the electromagnetic interference is large, a chaos enhancement model is used to generate a true random sequence, and the chaos enhancement model is:

[0031] ;

[0032] Step S2-3: use pulse control output laser pulse emission interval, true random sequence ensures the anti-interference performance of laser pulse emission interval, output laser pulse emission interval is:

[0033] ;

[0034] Wherein, Reference period.

[0035] Preferably, the step step S3 uses electric field intensity adaptive double frequency Bessel pulse sending signal, specifically:

[0036] Step S3-1: adjust the main frequency and auxiliary frequency energy ratio according to the electric field intensity, use the strong penetration characteristics of the main frequency, and the main frequency energy ratio is ≥ 90%;

[0037] The energy ratio is: ; When kV / m, the main frequency energy ratio is ≥ 90%;

[0038] Step S3-2: generating a time-domain waveform by a lithium niobate electro-optical modulator to realize Bessel pulse shaping;

[0039] The time-domain waveform is: ;

[0040] wherein, an electric field intensity amplitude, a main-to-auxiliary frequency energy ratio, a pulse time-domain intensity, is a time-domain basic waveform, a zero-order Bessel function, which suppresses environmental multiple reflection interference and reduces signal distortion;

[0041] Step S3-3: adjusting the electric field direction of the transmitting end to realize waveform adjustment of the transmitting end;

[0042] If the electric field direction change rate V / (m·s), the switching is a circularly polarized state waveform;

[0043] wherein, is the electric field change rate.

[0044] Preferably, in the step S4, the dielectric properties of the pollutants are calculated by the double-wavelength reflectivity difference to classify the pollutants, specifically:

[0045] Step S4-1: judging the type of the pollutants, specifically:

[0046] The dielectric properties of the pollutants are calculated according to the laser reflectivity difference by using double-wavelength laser alternating detection, and the dielectric property calculation formula is:

[0047] ;

[0048] wherein, is the refractive index imaginary part, is the dirt thickness, is the clean surface reflectivity, is the reflection intensity of the wavelength λ, is the initial reflection intensity;

[0049] When , it is a conductive pollutant, and the electromagnetic shielding coating is activated;

[0050] When , it is a non-conductive pollutant, and the electromagnetic shielding coating does not need to be activated;

[0051] Step S4-2: when the pollutants increase by 5% per minute, the pollutant removal tool is triggered;

[0052] wherein, , is the reflection intensity ratio; is the pollution attenuation coefficient, For time.

[0053] Preferably, in step S5, the transmission signal of the transmitting end is received, the signal distance between the original transmitting end and the receiving end is obtained, and the distance measurement is corrected according to the type of pollutant, specifically:

[0054] Step S5-1: Calibrate quantum efficiency using temperature control:

[0055] Real-time calculation of detection efficiency based on operating temperature: ;

[0056] in, Detector temperature, superconducting critical temperature;

[0057] Temperature control of superconducting nanowire arrays using a GM refrigerator , obtain the superconducting critical temperature;

[0058] when is the superconducting critical temperature, maintaining the superconducting energy gap , the superconducting material enters the superconducting state, the resistance suddenly drops to zero, and the thermal noise is low;

[0059] in, superconducting gap; is the Boltzmann constant, ;

[0060] Step S5-2: Determine the validity of the received signal;

[0061] When the count rate exceeds 3 standard deviations of the ambient noise, a valid signal is marked:

[0062] ; ;

[0063] in, Signal count rate, is the average value of the ambient noise, represents the standard deviation of ambient noise;

[0064] Step S5-3: Calculate the signal distance between the original transmitter and the receiver:

[0065] ;

[0066] The speed of light varies with temperature ;

[0067] is the temperature deviation from 20°C; the difference between the round trip time of the laser pulse from emission to reflection by the target and reception by the detector, ;

[0068] wherein, is the time stamp of the echo signal, generated after the echo pulse is detected by the superconducting detector, and is also the reception time; is the time stamp of the emission signal, and is also the transmission time;

[0069] Step S5-4: Correcting the ranging according to the pollutant category:

[0070] ;

[0071] ;

[0072] is a dynamic correction factor, a non-conductive correction coefficient, a non-conductive attenuation coefficient, a conductive correction coefficient, a conductive attenuation coefficient;

[0073] when, for weakly absorbing media such as dust and oil, the surface roughness causes the laser to undergo diffuse reflection, and the reflected signal intensity decreases nonlinearly with the thickness of the pollutant;

[0074] when, for strongly absorbing / scattering media such as metal particles and carbon powder, the free electron scattering dominates the signal attenuation, and the reflected signal decreases exponentially with the thickness of the pollutant.

[0075] Preferably, the received signal is processed in step S6 to obtain the final distance, specifically:

[0076] Step S6-1: millimeter wave radar signal transmission and reception, outputting millimeter wave radar polar coordinate data, specifically:

[0077] The millimeter wave radar signal is transmitted using the frequency-modulated continuous wave (FMCW) system, with a transmission frequency range , a bandwidth , and an electronic scanning function achieved through a phased array antenna, covering a horizontal spatial domain and a vertical field of view angle;

[0078] After receiving the echo signal, the millimeter wave radar signal is mixed with the local oscillator signal to generate an intermediate frequency signal; time synchronization with the laser radar is achieved through the IEEE 1588 Precision Time Protocol (PTP), with a synchronization accuracy , and the millimeter wave radar outputs polar coordinate data ;

[0079] Step S6-2: fuse laser and millimeter wave radar data to obtain original ranging results, specifically:

[0080] Step S6-1-1: align the laser and millimeter wave radar coordinate systems using the spatial registration coordinate system:

[0081] Laser coordinate system:

[0082] ;

[0083] Millimeter wave radar coordinate system:

[0084] ;

[0085] Align the laser and millimeter wave radar coordinate systems through a rotation matrix and a translation vector :

[0086] ;

[0087] wherein, and are calibrated through ground control points;

[0088] Establish a laser and millimeter wave coordinate conversion model for spatial registration:

[0089] ;

[0090] wherein, is a coordinate rotation angle, is a coordinate translation amount; corresponding to its three-dimensional coordinates in the Cartesian coordinate system, is a ranging result based on the Doppler effect, corresponding to its three-dimensional coordinates in the polar coordinate system;

[0091] Step S6-1-2: weighted fusion of the distances measured by the millimeter wave radar and the laser radar: the expression is: ;

[0092] wherein, is a laser radar ranging distance, ; is a millimeter wave radar ranging distance; is a weight dynamically assigned to the laser radar and the millimeter wave radar according to the intensity of environmental interference, , that is, the higher the signal-to-noise ratio SNR, the greater the weight of the laser radar, and when the SNR is lower than a threshold, switching to a millimeter wave dominant mode;

[0093] Step S6-3: Optimize the initial distance using Kalman filtering to obtain the final distance;

[0094] Step S6-4: Eliminate the final distance environment error through the meteorological compensation model.

[0095] Preferably, in step S6-3, the initial distance is optimized by using Kalman filtering, with a time step of The Kalman filter processing is as follows:

[0096] Step S6-3-1: Initialize the state and covariance matrices:

[0097] Initialization state: ;

[0098] Initial covariance matrix: ;

[0099] in, Initial distance, Initial velocity, The covariance matrix of the initial distances, Covariance moment of initial velocity;

[0100] Step S6-3-2: iterate the Kalman filter using the time step;

[0101] Step S6-3-2-1: Use time to update the state and covariance matrix prediction:

[0102] Status prediction: ;

[0103] Covariance matrix prediction: ;

[0104] in, Indicates that from the time step Time has come The predicted state vector at time , for The state vector at the moment, for The speed of time, is the time step, Indicates that from the time step Time has come Moment covariance prediction, for The covariance matrix at time t, is the model noise;

[0105] Step S6-3-2-2: Modify the state and covariance matrix:

[0106] Status correction: , realize fusion prediction value and measured value ;

[0107] Covariance matrix correction: , realize after correction uncertainty reduction;

[0108] Wherein, The Kalman gain is calculated, , using Kalman gain calculation to realize according to the prediction uncertainty and measurement noise , dynamic allocation weight;

[0109] Step S6-3-2-3: enter the next time step: the current state And the covariance matrix As the input of the next time step , repeat the steps S5-2-2-1 to S5-2-2-3 process;

[0110] Step S6-3-3: after Kalman filter optimization, the expression of the final distance is:

[0111] ;

[0112] Wherein, Indicates The optimization result after Kalman filtering, Indicates the result of iterative calculation of Kalman filtering algorithm.

[0113] Preferably, the step S6-4 eliminates the final distance environmental error by the meteorological compensation model, specifically:

[0114] The meteorological compensation model is: , the wavelength compensation is carried out on rain and fog attenuation;

[0115] Wherein, Humidity, Indicates The optimization result after Kalman filtering.

[0116] Compared with the prior art, the present application has the following improvements and advantages:

[0117] 1. True random sequence is generated by ambient photons, and the laser pulse emission interval is dynamically adjusted; combined with micro mirror advance compensation, the stability of laser signal is ensured, which can effectively cope with the influence of electromagnetic interference on laser path; at the same time, the double frequency Bessel pulse with adaptive emission electric field intensity is adopted, which can effectively suppress arc scattering interference and improve the clarity and transmission efficiency of signal.

[0118] 2. The method utilizes the difference in reflection characteristics of different wavelengths on materials, can effectively distinguish different types of pollutants, and corrects the ranging according to the pollution type, thereby improving the accuracy of ranging in an interference environment. BRIEF DESCRIPTION OF DRAWINGS

[0119] Figure 1 The figure is a flowchart of the method of the application.

[0120] Figure 2 The figure is a schematic diagram of the comparison of quantum anti-interference modulation performance.

[0121] Figure 3 The figure is a schematic diagram of the comparison of Kalman filter convergence time and distance RMSE improvement results.

[0122] Figure 4 The figure is a schematic diagram of the comparison of SNR data fusion performance effects.

[0123] Figure 5 The figure is a schematic diagram of the comparison of output signal-to-noise ratio characteristics performance in an arc interference scenario. DETAILED DESCRIPTION

[0124] The application is further described below in conjunction with the accompanying drawings.

[0125] As shown in Figure 1 , a substation laser radar anti-interference ranging method, the method comprising the following steps:

[0126] In step S1, the transmitting device is adjusted, and the transmitting device is pre-compensated at the transmitting end, specifically:

[0127] Step S1-1: measuring real-time electromagnetic field intensity According to the electromagnetic field vector , the laser deflection angle is used to calculate the laser path offset:

[0128] The electric field intensity The electric field intensity around the transmitter is measured in real time by a three-dimensional electric field sensor: ;

[0129] The magnetic field intensity is obtained by a magnetometer or a fluxmeter;

[0130] Step S1-2: ;

[0131] Wherein, the laser deflection angle, the equivalent charge amount, the equivalent mass, the speed of light, the electric field intensity vector, the magnetic induction intensity vector, Light speed vector, Path differential;

[0132] Step S1-2: displacement compensation is performed by using a piezoelectric micro mirror: .

[0133] In step S2, a true random sequence is generated by environmental photons, the emission interval of laser pulses is obtained, and the randomness of the emission interval is used to solve the multi-radar interference problem, specifically:

[0134] Step S2-1: photon stream collection is performed to generate an original binary sequence;

[0135] The environmental photons are collected by a single-photon detector, and the photon count follows a Poisson distribution: ;

[0136] Among them, Photon count, Photon flux density;

[0137] The photon arrival time is discretized into a time window , and whether a photon is detected in the time window is recorded to generate an original binary sequence :

[0138] ;

[0139] Step S2-2: a method for generating a true random sequence by selecting the electromagnetic interference size, specifically:

[0140] When the electromagnetic interference is small, a Gaussian integral model is used to generate a true random sequence, and the Gaussian integral model is:

[0141] ;

[0142] Among them, Photon flux function, ;

[0143] Among them, Impact function, Time window, Time, Current time window count, Electromagnetic interference coefficient, Time average, Base variance, Magnetic induction intensity; Natural base;

[0144] When the electromagnetic interference is large, a chaos enhancement model is used to generate a true random sequence, and the chaos enhancement model is:

[0145] ;

[0146] Step S2-1-2: output laser pulse emission interval is controlled by pulse, and the true random sequence ensures the anti-interference performance of the laser pulse emission interval, and the output laser pulse emission interval is:

[0147]

[0148] wherein, reference period.

[0149] Step S2-3: output laser pulse emission interval is controlled by pulse, and the true random sequence ensures the anti-interference performance of the laser pulse emission interval, and the output laser pulse emission interval is:

[0150]

[0151] wherein, reference period.

[0152] In step S3, the electric field intensity adaptive dual-frequency Bessel pulse sending signal is used, and the specific process is as follows:

[0153] Step S3-1: adjust the energy ratio of the main frequency and the auxiliary frequency according to the electric field intensity, and use the strong penetration characteristics of the main frequency, and the energy ratio of the main frequency is ≥ 90%;

[0154] The energy ratio is: When the electric field intensity is ≥ 10 kV / m, the energy ratio of the main frequency is ≥ 90%;

[0155] Step S3-2: generate time-domain waveform through lithium niobate electro-optic modulator to realize Bessel pulse shaping;

[0156] The time-domain waveform is:

[0157] wherein, amplitude of electric field intensity, energy ratio of main and auxiliary frequencies, pulse time-domain intensity, time-domain basic waveform, zero-order Bessel function, the zero-order Bessel function suppresses environmental multiple reflection interference and reduces signal distortion;

[0158] Step S3-3: adjust the electric field direction of the transmitting end to realize the waveform adjustment of the transmitting end;

[0159] If the electric field direction change rate is V / (m·s), switch to circularly polarized state waveform;

[0160] wherein, electric field change rate. ​​​​

[0161] In step S4, the dielectric properties of the contaminants are calculated by the dual-wavelength reflectivity difference, and the contaminants are classified, specifically as follows:

[0162] Step S4-1: judging the type of the contaminants, specifically as follows:

[0163] Dual-wavelength laser is used for alternate detection, and the dielectric properties of the contaminants are calculated according to the laser reflectivity difference. The dielectric property calculation formula is as follows:

[0164] ;

[0165] Wherein, is the imaginary part of the refractive index, is the thickness of the dirt, is the reflectivity of the clean surface, is the reflection intensity of the wavelength λ, is the initial reflection intensity.

[0166] When , it is a conductive contaminant, and the electromagnetic shielding coating is activated.

[0167] When , it is a non-conductive contaminant, and the electromagnetic shielding coating does not need to be activated.

[0168] In step S5, the transmission signal of the transmitting end is received, the original signal distance between the transmitting end and the receiving end is obtained, and the ranging is corrected according to the type of the contaminants, specifically as follows:

[0169] Step S5-1: calibrating the quantum efficiency by temperature control:

[0170] Based on the working temperature, the detection efficiency is calculated in real time: ;

[0171] Wherein, is the temperature of the detector, is the superconducting critical temperature.

[0172] The temperature of the superconducting nanowire array is controlled by the G-M refrigerator to obtain the superconducting critical temperature.

[0173] When is the superconducting critical temperature, the superconducting energy gap is maintained, the superconducting material enters the superconducting state, and the resistance suddenly changes to zero, and the thermal noise is low.

[0174] Wherein, is the superconducting energy gap, is the Boltzmann constant.

[0175] Step S5-2: judging the effectiveness of the received signal.

[0176] An effective signal is marked when the count rate exceeds the ambient noise by 3 standard deviations:

[0177] ; ;

[0178] where, the signal count rate, the mean of the ambient noise, the standard deviation of the ambient noise;

[0179] Step S5-3: Calculate the signal distance between the original transmitting end and the receiving end:

[0180] ;

[0181] The speed of light changes with temperature ;

[0182] The difference of temperature deviating from 20℃; The difference of round-trip time of laser pulse from emission to reflection by the target and then received by the detector, ;

[0183] where, the time stamp of the echo signal, generated after the superconducting detector detects the echo pulse, also the receiving time; the time stamp of the transmitting signal, also the sending time;

[0184] Step S5-4: Correct the ranging according to the pollutant category:

[0185] ;

[0186] ;

[0187] the dynamic correction factor, the non-conductive correction coefficient, the non-conductive attenuation coefficient, the conductive correction coefficient, the conductive attenuation coefficient;

[0188] When Applicable to weakly absorbing media such as dust and oil stains, the roughness of the surface causes the laser to occur diffuse reflection, and the intensity of the reflected signal decreases nonlinearly with the thickness of the pollutant;

[0189] When Applicable to strongly absorbing / scattering media such as metal particles and carbon powder, free electron scattering dominates the signal attenuation, and the reflected signal decreases exponentially with the thickness of the pollutant.

[0190] The received signal is processed in step S6 to obtain the final distance, specifically:

[0191] Step S6-1: millimeter wave radar signal transmission and reception, output millimeter wave radar polar coordinate data, specifically:

[0192] Millimeter wave radar signal transmission adopts frequency modulation continuous wave system, the transmission frequency range is , the bandwidth is , electronic scanning is realized through phased array antenna, covering horizontal space, vertical field of view angle;

[0193] After receiving the millimeter wave radar signal echo signal, it is mixed with the local oscillator signal to generate an intermediate frequency signal; through IEEE 1588 precise time protocol to realize time synchronization with laser radar, synchronization accuracy , the millimeter wave radar outputs polar coordinate data ;

[0194] Step S6-2: fuse laser and millimeter wave radar data to obtain original ranging result, specifically:

[0195] Step S6-1-1: align the laser and millimeter wave radar coordinate systems by using the space registration coordinate system:

[0196] Laser coordinate system:

[0197] ;

[0198] Millimeter wave radar coordinate system:

[0199] ;

[0200] Align the laser and millimeter wave radar coordinate systems by rotating matrix and translation vector :

[0201] ;

[0202] Wherein, and are calibrated by ground control points;

[0203] Establish a laser and millimeter wave coordinate conversion model to space registration:

[0204] ;

[0205] Wherein, coordinate rotation angle, coordinate translation amount; corresponding to the three-dimensional coordinates in its Cartesian coordinate system, The ranging results based on the Doppler effect, Corresponding to its three-dimensional coordinates in the polar coordinate system;

[0206] Step S6-1-2: Perform weighted fusion of the distances measured by the millimeter-wave radar and the lidar: The expression is: ;

[0207] in, is the laser radar ranging distance, ; Millimeter wave radar ranging distance; In order to dynamically allocate the weights of LiDAR and millimeter-wave radar according to the intensity of environmental interference, , That is, the higher the signal-to-noise ratio (SNR), the greater the lidar weight. When the SNR is lower than the threshold, it switches to the millimeter wave dominant mode.

[0208] Step S6-3: Use Kalman filter to optimize the initial distance, with time step The Kalman filter is processed to obtain the final distance, which is:

[0209] Step S6-3-1: Initialize the state and covariance matrices:

[0210] Initialization state: ;

[0211] Initial covariance matrix: ;

[0212] in, Initial distance, Initial velocity, The covariance matrix of the initial distances, Covariance moment of initial velocity;

[0213] Step S6-3-2: iterate the Kalman filter using the time step;

[0214] Step S6-3-2-1: Use time to update the state and covariance matrix prediction:

[0215] Status prediction: ;

[0216] Covariance matrix prediction: ;

[0217] in, Indicates that from the time step Time has come The predicted state vector at time , for The state vector at the moment, for the velocity at time t, is the time step, denotes the covariance prediction from time t to time t+1, denotes the covariance prediction from time t to time t+1, is the covariance matrix at time t, is the model noise;

[0218] Step S6-3-2-2: correct the state and the covariance matrix:

[0219] State correction: , the fusion of the predicted value and the measured value is realized;

[0220] Covariance matrix correction: , the uncertainty after correction is reduced;

[0221] wherein, is the Kalman gain calculation, the dynamic allocation of the weight according to the prediction uncertainty and the measurement noise is realized by the Kalman gain calculation;

[0222] Step S6-3-2-3: enter the next time step: take the current state and the covariance matrix as the input of the next time step , and repeat the process of steps S5-2-2-1 to S5-2-2-3;

[0223] Step S6-3-3: after the Kalman filtering optimization, the expression of the final distance is:

[0224] ;

[0225] wherein, denotes the optimization result after the Kalman filtering, denotes the result of the iterative calculation of the Kalman filtering algorithm.

[0226] Step S6-4: eliminate the final distance environmental error by the meteorological compensation model, specifically:

[0227] The meteorological compensation model is: , the wavelength compensation for rain and fog attenuation is performed;

[0228] wherein, is the humidity, denotes the optimization result after the Kalman filtering.

[0229] In order to verify the effectiveness and feasibility of the method of the application, the following operation is used for verification:

[0230] Single photon detector SPAD, Poisson distribution , photon flux density , time window , reference period ; electric field intensity By real-time measurement of three-dimensional sensor, maximum , magnetic field intensity ; RH is set to 80%, simulate rain and fog extreme environment; Laser radar wavelength 1310nm (main frequency), 1550nm (auxiliary frequency), sampling rate 10Hz; Millimeter wave radar frequency band: 24GHz, sampling rate: 20Hz.

[0231] As shown in Figure 2 , CG1 represents fixed frequency modulation, CG2 represents non-adaptive random sequence, CG2 represents non-adaptive random sequence, S1 represents the quantum modulation scheme of the application; The SIR of S1 scheme under strong interference is 30dB, which is 2dB higher than that of traditional chaotic modulation (CG3), and the SIR is improved by 2dB, which is equivalent to 1.6 times of the channel capacity (according to Shannon theorem), and the anti-interference ability in the multi-radar coexistence scene is significantly enhanced. The error line ±1dB shows that the experiment has good repeatability, and the stability of the dynamic modulation strategy is verified. By switching from Gaussian model to chaotic model (threshold ), avoid fixed modulation failure under strong interference.

[0232] The entropy value of the quantum modulation scheme of the application is 0.90, which is 6% higher than that of the traditional chaotic modulation (CG3, H=0.85), close to the ideal value 1, and the error line (±0.02) shows that the randomness of the sequence is controllable under the influence of environmental noise, and the time correlation is increased by the exponential term to generate aperiodic sequence and enhance the anti-interference characteristic.

[0233] As shown in Figure 3 , when SNR≥10dB, the convergence time is less than 2s, which meets the dynamic monitoring demand of the transformer substation, and in the low SNR scene (SNR=5dB), the convergence time is as long as 4.2s, because the sensor data noise is large and the data fluctuation is small, more iterations are needed for correction, and the data fusion of laser radar and millimeter wave radar ranging data is used to accelerate the convergence. When SNR=5dB, the RMSE after filtering is reduced from 0.82m to 0.09m (improvement rate 89%), and when SNR=20dB, the RMSE after filtering is reduced from 0.05m to 0.005m (improvement rate 95%), the error after filtering is reduced by 89%-95% compared with no filtering, and the all-weather high-precision ranging is realized by combining the meteorological compensation model;

[0234] Figure 4As shown in the figure, the switching lag time and data error rate of the weighted data of the lidar and millimeter-wave radar are dynamically switched based on the intensity of environmental interference. When the SNR is greater than 10dB, the switching lag time is less than 30ms, meeting the real-time requirements of dynamic monitoring of substation equipment. For every 5dB increase in SNR, the error rate decreases by approximately 50% (for example, the error rate is 4.2% at SNR = 10dB and 0.8% at SNR = 20dB). Millimeter-wave radar dominates at low SNRs (weight > 70%), while lidar dominates at high SNRs (weight > 90%), avoiding the limitations of a single sensor and demonstrating the effectiveness of complementary data fusion between millimeter-wave radar and lidar.

[0235] like Figure 5 The study shows the effect of main and sub-frequency adjustment on the signal-to-noise ratio in dual-frequency anti-interference emission. When the electric field strength increases from 20kV / m (switching not triggered) to 30kV / m (switching triggered), the signal-to-noise ratio increases by 3dB from 20dB to 23dB. At low field strength (<30kV / m), the signal-to-noise ratio improvement depends on the basic filtering, and the signal-to-noise ratio performance improvement is general. At high field strength (>30 kV / m), the main frequency energy proportion is increased by ≥90%, and the signal-to-noise ratio performance improvement is significantly better than before switching. This verifies that the dual-frequency collaborative improvement of the main frequency energy proportion can give full play to the main frequency's strong penetration and its characteristics of being suitable for strong electromagnetic interference environments.

[0236] This solution provides a reliable technical solution for substation radar ranging in complex electromagnetic environments and can be directly applied to substation equipment inspection and status monitoring scenarios.

[0237] The foregoing is merely an embodiment of the present invention and is not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are intended to be included within the scope of the claims of the present invention.

Claims

1. A substation laser radar anti-interference ranging method, characterized by: The method comprises the following steps: Step S1: Adjust the transmitting device and perform advance compensation on the transmitting end; Step S2: Generate a true random sequence through ambient photons to obtain the emission interval of the laser pulse, and use the randomness of the emission interval to solve the multi-radar interference problem; Step S3: using a dual-frequency Bessel pulse with adaptive electric field strength to send a signal, and using the dual-frequency characteristic to effectively resist environmental electric field interference; Step S4: Calculate the dielectric properties of pollutants by the difference in dual-wavelength reflectivity and classify the pollutants; Step S5: Receive the transmission signal from the transmitter, obtain the original signal distance between the transmitter and the receiver, and correct the distance measurement according to the type of pollutant; Step S6: Process the received signal to obtain the final distance.

2. The anti-interference ranging method for substation laser radar according to claim 1 is characterized in that: In step S1, the transmitting device is compensated in advance at the transmitting end, and the electromagnetic field intensity is used to calculate the laser deflection angle, and the micromirror is driven to compensate the transmitting end in advance, specifically: Step S1-1: Measuring real-time electromagnetic field strength , according to the electromagnetic field strength , use the laser deflection angle to calculate the laser path offset: ； in, Laser deflection angle, Equivalent charge, Equivalent mass, Speed ​​of light, The electric field strength vector, Magnetic induction intensity vector, Light speed vector, Path differentiation; Step S1-2: driving the micromirror to perform displacement compensation at the transmitting end: .

3. The anti-interference ranging method for substation laser radar according to claim 1, characterized in that: In step S2, the laser pulse emission interval is obtained by using the emission signal of the emission end, specifically: Step S2-1: Collect the photon flow and generate an original binary sequence; A single-photon detector is used to collect ambient photons, and the photon count follows a Poisson distribution: ; in, Photon counting, Photon flux density; Discretize photon arrival times into time windows , record whether the time window detects the photon to generate the original binary sequence : ； Step S2-2: A method for generating a true random sequence by selecting the magnitude of electromagnetic interference is as follows: When the electromagnetic interference is small, the Gaussian integral model is used to generate a true random sequence. The Gaussian integral model is: ； in, Photon flux function, ; in, is the shock function, is the time window, For time, is the count of the current time window, Electromagnetic interference coefficient, Time mean, Basis variance, Magnetic induction intensity; is the natural base; When the electromagnetic interference is large, the chaos enhancement model is enabled to generate a true random sequence. The chaos enhancement model is: ； Step S2-3: Use pulse control to output the laser pulse emission interval. The true random sequence ensures the anti-interference performance of the laser pulse emission interval. The output laser pulse emission interval is: ； in, Benchmark period.

4. The anti-interference ranging method for substation laser radar according to claim 1, characterized in that: In step S3, a signal is sent by using a dual-frequency Bessel pulse with adaptive electric field strength, specifically: Step S3-1: Adjust the energy ratio of the main frequency to the auxiliary frequency according to the electric field strength, taking advantage of the strong penetrating property of the main frequency, so that the main frequency energy ratio is ≥90%; The energy ratio is: ;when kV / m, the main frequency energy accounts for ≥90%; Step S3-2: Generate a time domain waveform through a lithium niobate electro-optic modulator to achieve Bessel pulse shaping; The time domain waveform is: ; in, The magnitude of the electric field strength, The energy ratio of main and auxiliary frequencies, Pulse time domain intensity, is the basic waveform in the time domain, Zero-order Bessel function: The zero-order Bessel function suppresses the interference of multiple environmental reflections and reduces signal distortion; Step S3-3: Adjust the electric field direction of the transmitter to adjust the waveform of the transmitter; If the rate of change of the electric field direction V / (m·s), switch to circular polarization waveform; in, is the rate of change of the electric field.

5. The anti-interference ranging method for substation laser radar according to claim 1 is characterized in that: In step S4, the dielectric properties of pollutants are calculated by the difference in dual-wavelength reflectivity to classify the pollutants, specifically: Step S4-1: Determine the type of pollutant, specifically: Using dual-wavelength laser alternating detection, the dielectric properties of the pollutants are calculated based on the difference in laser reflectivity. The dielectric properties calculation formula is: ； in, is the imaginary part of the refractive index, is the dirt thickness, is the reflectivity of the clean surface, is the wavelength The reflection intensity, is the initial reflection intensity; when When it is a conductive pollutant, the electromagnetic shielding coating is activated; when When the pollutant is non-conductive, there is no need to activate the electromagnetic shielding coating.

6. The anti-interference ranging method for substation laser radar according to claim 1, characterized in that: In step S5, the transmission signal of the transmitting end is received, the signal distance between the original transmitting end and the receiving end is obtained, and the distance measurement is corrected according to the type of pollutant, specifically: Step S5-1: Calibrate quantum efficiency using temperature control: Real-time calculation of detection efficiency based on operating temperature: ; in, Detector temperature, superconducting critical temperature; Temperature control of superconducting nanowire arrays using a GM refrigerator , obtain the superconducting critical temperature; when is the superconducting critical temperature, maintaining the superconducting energy gap , the superconducting material enters the superconducting state, the resistance suddenly drops to zero, and the thermal noise is low; in, superconducting gap; is the Boltzmann constant; Step S5-2: Determine the validity of the received signal; When the count rate exceeds 3 standard deviations of the ambient noise, a valid signal is marked: ； ； in, Signal count rate, is the average value of the ambient noise, represents the standard deviation of ambient noise; Step S5-3: Calculate the signal distance between the original transmitter and the receiver: ； The speed of light varies with temperature ; is the temperature deviation from 20°C; is the round-trip time difference between the laser pulse being emitted and the laser pulse being reflected by the target and received by the detector. ; in, is the timestamp of the echo signal, which is generated after the superconducting detector detects the echo pulse and is also the receiving time; It is the timestamp of the transmitted signal, also the sending time; Step S5-4: Correct the distance measurement based on the pollutant type: ； ； in, is the dynamic correction factor, Non-conductive correction factor, Non-conductive attenuation coefficient, Conductivity correction factor, Conductive attenuation coefficient; hour, Applicable to weakly absorbing media such as dust and oil. The surface roughness causes diffuse reflection of the laser, and the intensity of the reflected signal decays nonlinearly with the thickness of the pollutant. hour, Suitable for strong absorption / scattering media such as metal particles and carbon powder. Free electron scattering dominates the signal attenuation, and the reflected signal decreases exponentially with the thickness of the contaminant.

7. The anti-interference ranging method for substation laser radar according to claim 1, characterized in that: In step S6, the received signal is processed to obtain the final distance, specifically: Step S6-1: Send and receive millimeter-wave radar signals and output millimeter-wave radar polar coordinate data, specifically: Millimeter wave radar signal transmission adopts frequency modulation continuous wave system, and the transmission frequency range is ,bandwidth , electronic scanning is achieved through phased array antenna, covering horizontal Airspace, vertical Field of view; After receiving the echo signal, the millimeter wave radar signal is mixed with the local oscillator signal to generate an intermediate frequency signal; the time synchronization with the lidar is achieved through the IEEE1588 precision time protocol, and the synchronization accuracy is , millimeter wave radar outputs polar coordinate data ; Step S6-2: Fuse the laser and millimeter-wave radar data to obtain the original ranging results, specifically: Step S6-1-1: Align the laser and millimeter wave radar coordinate systems using the spatial registration coordinate system: Laser coordinate system: ； Millimeter wave radar coordinate system: ； Through the rotation matrix and translation vectors Align the laser and millimeter-wave radar coordinate systems: ； in, and Calibration through ground control points; Establishing laser and millimeter wave coordinate conversion model for spatial registration: ； in, Coordinate rotation angle, Coordinate translation amount; Corresponding to its three-dimensional coordinates in the Cartesian coordinate system, The ranging results based on the Doppler effect, Corresponding to its three-dimensional coordinates in the polar coordinate system; Step S6-1-2: Perform weighted fusion of the distances measured by the millimeter-wave radar and the lidar: The expression is: ; in, is the laser radar ranging distance, ; Millimeter wave radar ranging distance; In order to dynamically allocate the weights of LiDAR and millimeter-wave radar according to the intensity of environmental interference, , That is, the higher the signal-to-noise ratio (SNR), the greater the lidar weight. When the SNR is lower than the threshold, it switches to the millimeter wave dominant mode. Step S6-3: Optimize the initial distance using Kalman filtering to obtain the final distance; Step S6-4: Eliminate the final distance environment error through the meteorological compensation model.

8. The anti-interference ranging method for substation laser radar according to claim 7, characterized in that: In step S6-3, the initial distance is optimized by using Kalman filtering, with a time step The Kalman filter processing is as follows: Step S6-3-1: Initialize the state and covariance matrices: Initialization state: ; Initial covariance matrix: ; in, Initial distance, Initial velocity, The covariance matrix of the initial distances, Covariance moment of initial velocity; Step S6-3-2: iterate the Kalman filter using the time step; Step S6-3-2-1: Use time to update the state and covariance matrix prediction: Status prediction: ; Covariance matrix prediction: ; in, Indicates that from the time step Time has come The predicted state vector at time t, for The state vector at the moment, for The speed of time, is the time step, Indicates that from the time step Time has come Moment covariance prediction, for The covariance matrix at time t, is the model noise; Step S6-3-2-2: Modify the state and covariance matrix: Status correction: , to achieve fusion of predicted values ​​and measured values ; Covariance matrix correction: , achieving uncertainty reduction after correction; in, is the Kalman gain calculation, , the Kalman gain calculation is used to achieve the prediction uncertainty and measurement noise , dynamically assign weights; Step S6-3-2-3: Enter the next time step: set the current state and the covariance matrix As the next time step Input, repeat steps S5-2-2-1 to S5-2-2-3; Step S6-3-3: After Kalman filter optimization, the final distance expression is: ； in, express The optimization result after Kalman filtering is: Represents the result of iterative calculation of the Kalman filter algorithm.

9. The anti-interference ranging method for substation laser radar according to claim 7, characterized in that: In step S6-4, the final distance environment error is eliminated by using a meteorological compensation model, specifically: The meteorological compensation model is: , wavelength compensation for rain and fog attenuation; in, For humidity, express Optimization results after Kalman filtering.

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