A substation laser radar anti-interference ranging method

Abstract

The application discloses a substation laser radar anti-interference ranging method, and belongs to the technical field of substation radar ranging; the method is: in the transmitting end, the transmitting equipment is compensated in advance; a true random sequence is generated through ambient photons to obtain the transmission interval of laser pulses; a double-frequency Bessel pulse signal is sent by using the electric field strength self-adaption, and the double-frequency characteristic is used to effectively resist the environmental electric field interference; the dielectric properties of pollutants are calculated through the double-wavelength reflectivity difference; the signal distance between the original transmitting end and the receiving end is obtained, and the ranging is corrected; the received signal is processed to obtain the final distance; the true random sequence is used to dynamically adjust the laser pulse transmission interval; in combination with the micro-mirror pre-compensation, the influence of electromagnetic interference on the laser path can be effectively coped with; the reflection characteristic difference of different wavelengths on materials is used to effectively distinguish different types of pollutants; according to the pollution type, the ranging is corrected, and the ranging 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 in the transmitting end is pre-compensated 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, is the time.

[0053] Preferably, the step S5 receives the transmission signal of the transmission end, acquires the signal distance between the original transmission end and the receiving end, and corrects the ranging according to the pollution category, specifically:

[0054] Step S5-1: calibrate the quantum efficiency by temperature control:

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

[0056] Wherein, the temperature of the detector, the superconducting critical temperature;

[0057] Control the temperature of the superconducting nanowire array by the G-M refrigerator , and obtain the superconducting critical temperature;

[0058] 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;

[0059] Wherein, the superconducting energy gap; is the Boltzmann constant, ;

[0060] Step S5-2: determine the effectiveness of the received signal;

[0061] When the count rate exceeds 3 standard deviations of the environmental noise, mark the effective signal:

[0062] ; ;

[0063] Wherein, the signal count rate, is the average value of the environmental noise, indicates the standard deviation of the environmental noise;

[0064] Step S5-3: calculate the signal distance between the original transmission end and the receiving end:

[0065] ;

[0066] The speed of light changes with temperature ;

[0067] is the difference of temperature deviation from 20℃; 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 environmental error through a meteorological compensation model.

[0095] Preferably, in step S6-3, the initial distance is optimized using Kalman filtering, with time steps... The Kalman filtering process is as follows:

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

[0097] Initialization state: ;

[0098] Initial covariance matrix: ;

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

[0100] Step S6-3-2: Iterate the Kalman filter using time steps;

[0101] Step S6-3-2-1: Predict the state and covariance matrix using time updates:

[0102] State prediction: ;

[0103] Covariance matrix prediction: ;

[0104] in, Indicates from time step Time's up The predicted state vector at time t. for Time-state vector for The speed of time, For time step, Indicates from time step Time's up Time covariance prediction for The covariance matrix at time t, This is model noise;

[0105] Step S6-3-2-2: Correct 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, Ranging results based on the Doppler effect, Corresponding to its three-dimensional coordinates in the polar coordinate system;

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

[0207] in, For lidar ranging distance, ; Millimeter-wave radar ranging range; To dynamically allocate the weights of lidar and millimeter-wave radar based on the intensity of environmental interference, , The higher the signal-to-noise ratio (SNR), the greater the weight of the lidar; when the SNR is below the threshold, it switches to millimeter-wave dominant mode.

[0208] Step S6-3: Optimize the initial distance using Kalman filtering, in time steps. The final distance is obtained by Kalman filtering, specifically:

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

[0210] Initialization state: ;

[0211] Initial covariance matrix: ;

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

[0213] Step S6-3-2: Iterate the Kalman filter using time steps;

[0214] Step S6-3-2-1: Predict the state and covariance matrix using time updates:

[0215] State prediction: ;

[0216] Covariance matrix prediction: ;

[0217] in, Indicates from time step Time's up The predicted state vector at time t. for Time-state vector 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, the study dynamically switches the switching lag time and data error rate of lidar and millimeter-wave radar data based on the environmental interference intensity. When SNR > 10dB, the switching lag time < 30ms meets the real-time requirements of substation equipment dynamic monitoring. For every 5dB increase in SNR, the error rate decreases by approximately 50% (e.g., 4.2% error rate at SNR = 10dB, and 0.8% at SNR = 20dB). Millimeter-wave radar dominates at low SNR (weight > 70%), while lidar dominates at high SNR (weight > 90%), avoiding the limitations of a single sensor and demonstrating the effectiveness of data fusion and complementarity between millimeter-wave radar and lidar.

[0235] like Figure 5 The study investigated the impact of main and secondary frequency adjustment on the signal-to-noise ratio (SNR) in dual-frequency anti-interference transmission. When the electric field strength increased from 20 kV / m (without triggering switching) to 30 kV / m (triggered switching), the SNR improved from 20 dB to 23 dB, an increase of 3 dB. At low field strength (<30 kV / m), the SNR improvement depended on the basic filter, resulting in a moderate improvement in SNR performance. At high field strength (>30 kV / m), the main frequency energy ratio was increased by ≥90%, and the SNR performance improvement was significantly better than before switching. This verifies that the dual-frequency synergistic enhancement of the main frequency energy ratio can fully utilize the main frequency's strong penetration and suitability for strong electromagnetic interference environments.

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

[0237] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for anti-jamming ranging of a substation lidar, characterized in that: The method comprises the following steps: Step S1: adjusting the transmitting device and pre-compensating the transmitting device at the transmitting end; Step S2: generating a true random sequence through ambient photons, obtaining a laser pulse transmission interval, and solving the multi-radar mutual interference problem by using the randomness of the transmission interval; The transmission signal of the transmitting end is used to obtain the laser pulse transmission interval, specifically: Step S2-1: photon stream collection to generate an original binary sequence; The ambient photons are collected by a single photon detector, and the photon count is subject to a Poisson distribution: ; wherein, photon counts, photon flux density; Discretizing the photon arrival times into time windows Recording whether a time window detected a photon generates a raw binary sequence : ； Step S2-2: a method for generating a true random sequence by selecting the electromagnetic interference size, specifically: When the electromagnetic interference is small, a Gaussian integral model is used to generate a true random sequence, and the Gaussian integral model is: ； wherein photon flux function, ; wherein, is an impact function, is a time window, is a time, is a count of the current time window, is an electromagnetic interference coefficient, is a time average, is a base variance, is a magnetic induction; is a natural base; When the electromagnetic interference is large, a chaos enhancement model is used to generate a true random sequence, and the chaos enhancement model is: ； Step S2-3: using pulse control to output the laser pulse transmission interval, and the true random sequence ensures the anti-interference performance of the laser pulse transmission interval, and the output laser pulse transmission interval is: ； wherein Reference period Step S3: transmitting a signal by using a dual-frequency Bessel pulse with adaptive electric field intensity, and effectively resisting environmental electric field interference by using the dual-frequency characteristic; Step S4: calculating the dielectric properties of pollutants by using the difference in dual-wavelength reflectivity to classify the pollutants; 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 ranging according to the pollutant category; Step S6: processing the received signal to obtain the final distance, specifically: Step S6-1: millimeter wave radar signal transmission and reception, outputting millimeter wave radar polar coordinate data, specifically: Millimeter wave radar signal transmission, using frequency modulation continuous wave system, transmission frequency range , bandwidth , through phased array antenna to realize electronic scanning, cover horizontal space, vertical field of view angle; After receiving the echo signal of the millimeter wave radar signal, the local oscillator signal is mixed to generate an intermediate frequency signal; through the IEEE1588 precision time protocol, time synchronization with the laser radar is realized, and the synchronization accuracy , the millimeter wave radar outputs polar coordinate data ; Step S6-2: fusing laser and millimeter wave radar data to obtain the original ranging result, specifically: Step S6-1-1: aligning the laser and millimeter wave radar coordinate systems by using a spatial registration coordinate system: Laser coordinate system: ； Millimeter wave radar coordinate system: ； By rotating matrix And translation vector Aligning laser and millimeter wave radar coordinate systems: ； wherein, and by ground control point calibration; Establishing a laser and millimeter wave coordinate conversion model for spatial registration: ； wherein, a coordinate rotation angle, a coordinate translation amount; corresponding to its three-dimensional coordinates in a Cartesian coordinate system, a ranging result based on Doppler effect, corresponding to its three-dimensional coordinates in a polar coordinate system; Step S6-1-2: Weighted fusion of the distances measured by the millimeter wave radar and the laser radar: expression is ; wherein, is the laser radar ranging distance, ; is the millimeter wave radar ranging distance; is the weight of the laser radar and the millimeter wave radar according to the environmental interference intensity, , 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 value, switching to a millimeter wave dominant mode; Step S6-3: optimizing the initial distance by using Kalman filtering to obtain the final distance; Step S6-4: eliminating the environmental error of the final distance by using a meteorological compensation model.

2. The method of claim 1, wherein: In step S1, the transmitting device at the transmitting end is pre-compensated at the transmitting end, the electromagnetic field intensity is calculated, and the laser deflection angle is calculated to drive the micro-mirror to pre-compensate the transmitting end, specifically: Step S1-1: Measure real-time electromagnetic field intensity , according to electromagnetic field intensity , calculate laser path offset amount using laser deflection angle: ； wherein, laser deflection angle, equivalent charge quantity, equivalent mass, speed of light, electric field intensity vector, magnetic induction intensity vector, light speed vector, path differential; Step S1-2: driving the micro-mirror to perform displacement compensation of the transmitting end: .

3. The method of claim 1, wherein: In step S3, the signal is transmitted by using a dual-frequency Bessel pulse with adaptive electric field intensity, specifically: Step S3-1: adjusting the primary frequency and auxiliary frequency energy ratio according to the electric field intensity, and using the strong penetration characteristic of the primary frequency, the primary frequency energy ratio is greater than or equal to 90%; Energy ratio is: When kV / m, the main frequency energy ratio is ≥90%. Step S3-2: generating a time-domain waveform by using a lithium niobate electro-optic modulator to realize Bessel pulse shaping; The time-domain waveform is: ; Wherein, Electric field intensity amplitude, Main auxiliary frequency energy ratio, Pulse time domain intensity, Is the time domain basic waveform, Zero order Bessel function, zero order Bessel function suppresses environmental multiple reflection interference, reduces signal distortion; Step S3-3: adjusting the electric field direction of the transmitting end to realize waveform adjustment of the transmitting end; If the rate of change of the direction of the electric field V / (m·s), the waveform is switched to a circularly polarized state. wherein is the rate of change of the electric field.

4. The method of claim 1, wherein: In step S4, the dielectric properties of pollutants are calculated by using the difference in dual-wavelength reflectivity to classify the pollutants, specifically: Step S4-1: judging the type of pollutants, specifically: Dual-wavelength laser is used for alternative detection, and the dielectric properties of pollutants are calculated according to the difference in laser reflectivity, and the dielectric property calculation formula is: ； wherein, is the imaginary part of the refractive index, is the thickness of the dirt, is the reflectivity of the clean surface, is the wavelength is the reflected intensity, is the initial reflected intensity; When the electromagnetic shielding coating is activated for electrically conductive contaminants. When the electromagnetic shielding coating is not activated for non-conductive contaminants.

5. The method of claim 1, wherein: The step S5 receives the transmission signal of the transmission end, acquires the signal distance of the original transmission end and the receiving end, and corrects the distance measurement according to the pollutant category, specifically: Step S5-1: calibrating quantum efficiency by temperature control: Real-time calculation of detection efficiency based on working temperature: ; wherein probe temperature, superconducting critical temperature; Controlling superconducting nanowire array temperature by g-m refrigerator , obtaining a superconducting critical temperature; When Tc is the superconducting critical temperature, and Δ is the superconducting energy gap , the superconducting material enters a superconducting state, the resistance abruptly becomes zero, and the thermal noise is low; wherein superconducting energy gap; is the Boltzmann constant; Step S5-2: judging the effectiveness of the received signal; Marking an effective signal when the count rate exceeds the environmental noise by 3 standard deviations: ； ； wherein signal count rate, is the average value of the ambient noise, denotes the standard deviation of the ambient noise; Step S5-3: calculating the signal distance of the original transmission end and the receiving end: ； Speed of light as a function of temperature ; is the difference in temperature from 20°C; is the difference in round trip time for a laser pulse from emission to detection by the detector after reflection by the target, ; wherein, is a timestamp of the echo signal, generated by the superconducting detector upon detection of the echo pulse, and is also the reception time; is a timestamp of the transmitted signal, and is also the transmission time; Step S5-4: correcting the distance measurement according to the pollutant category: ； ； wherein, a dynamic correction factor, a non-conductive correction factor, a non-conductive decay factor, a conductive correction factor, a conductive decay factor; Time, Weak absorption medium of dust and oil stain, surface roughness leads to diffuse reflection of laser, and the reflected signal intensity is nonlinearly attenuated with the thickness of pollutants; Time, Suitable for metal particles, carbon powder, strong absorption / scattering medium, free electron scattering dominant signal attenuation, the reflection signal with the thickness of the pollutant exponentially down.

6. The method of claim 1, wherein: The step S6-3 utilizes Kalman filtering to optimize the initial distance, with time step The Kalman filtering process is specifically as follows: Step S6-3-1: initializing the state and covariance matrix: Initialization state: ; Initial covariance matrix: ; wherein, initial distance, initial velocity, covariance matrix of the initial distance, covariance matrix of the initial velocity; Step S6-3-2: iterating Kalman filtering by time step: Step S6-3-2-1: predicting the state and covariance matrix by time update: State prediction: ; Covariance matrix prediction: ; wherein, denotes the predicted state vector from time step to time step , is the state vector at , is the velocity at , is the time step, denotes the covariance prediction from time step to time step , is the covariance matrix at , is the model noise; Step S6-3-2-2: correcting the state and covariance matrix: State correction: , implementing the fusion of the predicted and measured values ; Covariance matrix correction: , achieving reduced uncertainty after correction; wherein is the Kalman gain, , the Kalman gain is calculated to achieve the prediction uncertainty and measurement noise , dynamically allocate weights; Step S6-3-2-3: Enter next time step: the current state and covariance matrix are used as input for the next time step , the procedure of steps S5-2-2-1 to S5-2-2-3 is repeated; Step S6-3-3: after Kalman filtering optimization, the expression of the final distance is: ； wherein, represents the optimization result after Kalman filtering, represents the result of iterative calculation of Kalman filtering algorithm.

7. The substation laser radar anti-jamming ranging method according to claim 1, characterized in that: In the step S6-4, the final distance environmental error is eliminated by a meteorological compensation model, specifically: The weather compensation model is: Wavelength compensation is performed on rain and fog attenuation; wherein for humidity, denotes Optimized results after Kalman filtering.

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