Continuous interferometer high-precision positioning method and device, electronic equipment and storage medium

Abstract

The application provides a continuous interferometer high-precision positioning method and device, electronic equipment and storage medium, and relates to the technical field of lightning detection. The application acquires a very high frequency original signal collected by an antenna array and extracts a signal envelope. A pulse event is detected based on the signal envelope, the number of pulses is counted, and a pulse density parameter is calculated. The waveform window length is dynamically matched according to the pulse density parameter, time domain oversampling is performed on the original signal in the window, high-precision time delay between antennas is obtained through cross-correlation calculation, a nonlinear equation is constructed based on the time delay and the geometric layout of the antenna array, the direction cosine of the radiation source is obtained by iterative solution, and the direction cosine is converted into an azimuth and elevation coordinate. The application adaptively matches the window length through the pulse density, solves the internal contradiction that a fixed window length cannot simultaneously meet the processing requirements of dense and sparse pulse areas, breaks through the limitation of the hardware sampling rate on the time delay estimation accuracy, and improves the positioning accuracy and channel continuity of the lightning radiation source.

Description

Technical Field

[0001] This invention relates to the field of lightning detection technology, and in particular to a high-precision positioning method, device, electronic equipment, and storage medium for a continuous interferometer. Background Technology

[0002] Lightning is a transient atmospheric discharge phenomenon accompanied by intense electromagnetic radiation. Its radiation signal contains rich spatiotemporal evolution information from initial breakdown and leader development to the return stroke. In the study of lightning physics, the radiation signal in the Very High Frequency (VHF) band mainly originates from small-scale air breakdown processes and is a key observational object for finely characterizing the details of lightning leader development and revealing the discharge process within clouds. Currently, high-precision localization techniques for VHF lightning radiation sources mainly include Time Difference of Arrival (TDOA) localization technology and interferometric measurement technology. Compared to TDOA systems that rely on multiple distant stations, interferometric measurement technology, which uses a compact antenna array, determines the direction of the radiation source by analyzing the phase difference or time difference between signals received by different antennas. It has higher time resolution and has become an important technique for continuously observing the physical processes of lightning discharge.

[0003] However, existing broadband interferometers still face several insurmountable technical bottlenecks in pursuing high spatiotemporal positioning accuracy. On the one hand, practical systems use analog-to-digital converters to discretize continuous analog signals, and their temporal resolution is limited by the physical sampling rate of the hardware. In short baseline time difference (SLD) positioning schemes, the accuracy of time delay estimation directly determines the microscopic positioning capability of the radiation source, and the limited sampling rate introduces quantization errors, restricting further improvements in positioning accuracy. On the other hand, VHF signals generated by lightning discharges exhibit typical strong non-stationary characteristics, with drastic changes in pulse density in the time domain—during the discharge burst phase, radiation pulses appear densely with extremely short intervals; while in the initial breakdown or leader interval phase, the signal is relatively sparse with a low signal-to-noise ratio. To address this characteristic, traditional processing methods typically use fixed-length time windows to segment the signal and then perform cross-correlation time delay estimation based on these segments. However, the fixed window length strategy faces an inherent contradiction between temporal resolution and the stability of time delay estimation: if the window is too long, multiple independent radiation events will be superimposed in the pulse-dense region, resulting in distorted localization trajectory smoothness and blurred details; if the window is too short, the signal-to-noise ratio of cross-correlation estimation will decrease due to insufficient effective data in the sparse signal region, leading to divergence of localization points and poor stability. A single fixed processing mode cannot simultaneously take into account the complex characteristics of the high-density burst region and the low signal-to-noise ratio sparse region during lightning discharge, making it difficult for existing interferometer techniques to clearly characterize the microscopic topological evolution process of lightning channels, such as the spatial branching and competition mechanisms in the leader development process. Summary of the Invention

[0004] This invention provides a high-precision positioning method, device, electronic device, and storage medium for a continuous interferometer, which solves the defects of existing interferometers that use a fixed window length processing strategy, which cannot simultaneously meet the time resolution requirements of lightning VHF signals in the pulse-dense region and the time delay estimation stability requirements in the sparse region, and are limited by the quantum error introduced by the hardware sampling rate, resulting in insufficient positioning accuracy and channel continuity.

[0005] This invention provides a high-precision positioning method for a continuous interferometer, comprising: Acquire the raw VHF signals collected by each antenna in the continuous interferometer array, and extract the signal envelope from the raw VHF signals; Based on the signal envelope, pulse events in the original signal are detected, the number of pulse events within a preset time window is counted, and a pulse density parameter characterizing the signal radiation intensity is calculated based on the number of pulse events. The waveform window length is dynamically matched according to the pulse density parameter. Within the waveform window length, the VHF original signal is subjected to time-domain oversampling processing. Cross-correlation calculation is performed on the oversampled signal. Based on the peak position of the cross-correlation result, the high-precision time delay between any two antennas is obtained. Based on the high-precision time delay and the geometric layout of the antenna array, a nonlinear equation between the direction cosine of the radiation source and the theoretical time delay is constructed. The direction cosine of the radiation source is obtained by iteratively solving the nonlinear equation, and the direction cosine of the radiation source is converted into the azimuth and elevation coordinates of the radiation source.

[0006] According to the high-precision positioning method for a continuous interferometer provided by the present invention, the extraction of the signal envelope from the VHF original signal includes: A bandpass filter is used to filter the VHF raw signal to extract the signal within a preset frequency band range, thereby filtering out low-frequency noise and FM broadcast interference. The discrete instantaneous envelope of the filtered signal is calculated using the Hilbert transform. An adaptive threshold is set based on the statistical characteristics of noise, and regions in the instantaneous envelope whose amplitude exceeds the adaptive threshold are marked as impulse events.

[0007] According to the high-precision positioning method for a continuous interferometer provided by the present invention, the step of detecting pulse events in the original signal based on the signal envelope includes: An adaptive threshold is set based on the statistical characteristics of noise, and regions in the signal envelope whose amplitude exceeds the adaptive threshold are marked as pulse candidate points. Calculate the time gap between adjacent pulse candidate regions. When the time gap is less than a preset fusion threshold, merge multiple discrete pulse candidate regions. The system searches outwards from the pulse peak value. When the envelope amplitude of multiple consecutive sampling points is lower than the envelope mean, the true boundary of the pulse is determined, and the corresponding pulse event is output.

[0008] According to the high-precision positioning method for a continuous interferometer provided by the present invention, the calculation of the pulse density parameter characterizing the signal radiation intensity based on the number of pulse events includes: Divide the continuous signal into data blocks of fixed length along the time axis; The total number of pulse events contained within each data block is counted, and the total number of pulse events contained within the data block is used as the pulse density parameter corresponding to that data block.

[0009] According to the high-precision positioning method for a continuous interferometer provided by the present invention, the step of dynamically matching the waveform window length according to the pulse density parameter and performing time-domain oversampling processing on the VHF original signal within the waveform window length includes: Multiple density thresholds and multiple candidate window lengths are preset, with each density threshold interval corresponding to a candidate window length; The pulse density parameter is compared with the plurality of density thresholds to determine the density threshold range to which the pulse density parameter belongs; Based on the correspondence between the density threshold range and the candidate window length, select a waveform window length that matches the current pulse density parameter; Within the selected waveform window length, the VHF original signal is subjected to time-domain oversampling processing to refine the time grid between the original sampling points.

[0010] According to the high-precision positioning method for a continuous interferometer provided by the present invention, the step of performing cross-correlation calculation on the oversampled signal includes: The oversampled signal is subjected to energy normalization to eliminate the influence of lightning signal amplitude fluctuations on the cross-correlation results; Calculate the energy-normalized cross-correlation function; Extract the delay index corresponding to the global maximum value of the cross-correlation function, and use it as the delay estimate under the oversampling grid; The delay estimate is converted into the actual time delay based on the oversampling factor.

[0011] According to the high-precision positioning method for a continuous interferometer provided by the present invention, the step of constructing the nonlinear equation between the radiation source direction cosine and the theoretical time delay based on the high-precision time delay and the geometric layout of the antenna array includes: Obtain the baseline vector between any two antennas in the antenna array; Based on the direction cosine vector of the radiation source and the baseline vector, a linear relationship equation between the theoretical time delay and the direction cosine is constructed. The difference between the measured high-precision time delay and the theoretical time delay is used as the residual to establish a nonlinear equation about the direction cosine vector.

[0012] The present invention also provides a high-precision positioning device for a continuous interferometer, comprising: The extraction module is used to acquire the VHF raw signals collected by each antenna in the continuous interferometer array, and extract the signal envelope from the VHF raw signals. The calculation module is used to detect pulse events in the original signal based on the signal envelope, count the number of pulse events within a preset time window, and calculate the pulse density parameter characterizing the signal radiation intensity based on the number of pulse events. The acquisition module is used to dynamically match the waveform window length according to the pulse density parameter, perform time-domain oversampling processing on the VHF original signal within the waveform window length, perform cross-correlation calculation on the oversampled signal, and obtain the high-precision time delay between any two antennas based on the peak position of the cross-correlation result. The solution module is used to construct a nonlinear equation between the direction cosine of the radiation source and the theoretical time delay based on the high-precision time delay and the geometric layout of the antenna array. The direction cosine of the radiation source is obtained by iteratively solving the nonlinear equation, and the direction cosine of the radiation source is converted into the azimuth and elevation coordinates of the radiation source.

[0013] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the high-precision positioning method for a continuous interferometer as described in any of the preceding claims.

[0014] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the high-precision positioning method for a continuous interferometer as described above.

[0015] The present invention provides a high-precision positioning method, apparatus, electronic device, and storage medium for a continuous interferometer. This method acquires the raw VHF signals collected by each antenna in a continuous interferometer array and extracts the signal envelope from the raw VHF signals. Based on the signal envelope, it detects pulse events in the raw signals, counts the number of pulse events within a preset time window, and calculates a pulse density parameter characterizing the signal radiation intensity based on the number of pulse events. It dynamically matches the waveform window length according to the pulse density parameter, performs time-domain oversampling processing on the raw VHF signals within the waveform window length, performs cross-correlation calculation on the oversampled signals, and calculates the peak value based on the cross-correlation result. The system obtains the high-precision time delay between any two antennas. Based on this high-precision time delay and the geometric layout of the antenna array, a nonlinear equation is constructed between the direction cosine of the radiation source and the theoretical time delay. The direction cosine of the radiation source is obtained by iteratively solving the nonlinear equation, and the direction cosine of the radiation source is converted into the azimuth and elevation coordinates of the radiation source. By adaptively matching the waveform window length with pulse density, the inherent contradiction that a fixed window length cannot simultaneously meet the processing requirements of pulse-dense and sparse regions is resolved. At the same time, by performing time-domain oversampling processing on the original signal, the limitation of hardware sampling rate on the time delay estimation accuracy is broken, thereby improving the positioning accuracy and channel continuity of the lightning radiation source. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the high-precision positioning method for a continuous interferometer provided in an embodiment of the present invention; Figure 2 A schematic diagram of the incident plane wave of the radiation source and a schematic diagram of the spatial angle geometry provided in the embodiments of the present invention; Figure 3 This is a functional structure diagram of the high-precision positioning device for a continuous interferometer provided in an embodiment of the present invention; Figure 4 This is a functional structure diagram of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0019] Figure 1 A flowchart of the high-precision positioning method for a continuous interferometer provided in an embodiment of the present invention is shown below. Figure 1 As shown, the high-precision positioning method for a continuous interferometer provided in this embodiment of the invention includes: Step 101: Obtain the VHF raw signals collected by each antenna in the continuous interferometer array, and extract the signal envelope from the VHF raw signals; Step 102: Detect pulse events in the original signal based on the signal envelope, count the number of pulse events within a preset time window, and calculate the pulse density parameter characterizing the signal radiation intensity based on the number of pulse events; Step 103: Dynamically match the waveform window length according to the pulse density parameter, perform time-domain oversampling processing on the VHF original signal within the waveform window length, perform cross-correlation calculation on the oversampled signal, and obtain the high-precision time delay between any two antennas based on the peak position of the cross-correlation result. Step 104: Based on the high-precision time delay and the geometric layout of the antenna array, construct a nonlinear equation between the direction cosine of the radiation source and the theoretical time delay. Obtain the direction cosine of the radiation source by iteratively solving the nonlinear equation, and convert the direction cosine of the radiation source into the azimuth and elevation coordinates of the radiation source.

[0020] Traditional, single, fixed processing methods cannot simultaneously capture the complex characteristics of both the high-density burst region and the low signal-to-noise ratio sparse region during lightning discharge. This contradiction makes it difficult for existing interferometer techniques to clearly characterize the microscopic topological changes in lightning channels.

[0021] The high-precision positioning method for a continuous interferometer provided in this invention involves acquiring the raw VHF signals collected by each antenna in a continuous interferometer array and extracting the signal envelope from the raw VHF signals; detecting pulse events in the raw signals based on the signal envelope, counting the number of pulse events within a preset time window, and calculating a pulse density parameter characterizing the signal radiation intensity based on the number of pulse events; dynamically matching the waveform window length according to the pulse density parameter; performing time-domain oversampling processing on the raw VHF signals within the waveform window length; performing cross-correlation calculation on the oversampled signals; and obtaining the target position based on the peak position of the cross-correlation result. A high-precision time delay between two antennas is achieved. Based on this high-precision time delay and the geometric layout of the antenna array, a nonlinear equation is constructed between the direction cosine of the radiation source and the theoretical time delay. The direction cosine of the radiation source is obtained by iteratively solving the nonlinear equation, and the direction cosine of the radiation source is converted into the azimuth and elevation coordinates of the radiation source. By adaptively matching the waveform window length with pulse density, the inherent contradiction that a fixed window length cannot simultaneously meet the processing requirements of pulse-dense and sparse regions is resolved. At the same time, by performing time-domain oversampling processing on the original signal, the limitation of hardware sampling rate on the time delay estimation accuracy is broken, thereby improving the positioning accuracy and channel continuity of the lightning radiation source.

[0022] This invention employs a very high frequency broadband continuous interferometer array, consisting of three high-sensitivity disc-cone antennas arranged in a non-uniform short baseline configuration. After signal processing by the receiver (bandwidth 30-80MHz), the signal is recorded by a high-speed acquisition device at a sampling rate of no less than 200MS / s and stamped with a high-precision timestamp.

[0023] Based on any of the above embodiments, the extraction of the signal envelope from the original VHF signal includes: Step 201: Use a bandpass filter to filter the VHF original signal and extract the signal within a preset frequency band range to filter out low-frequency noise and FM broadcast interference. Step 202: Calculate the discrete instantaneous envelope of the filtered signal using Hilbert transform; Step 203: Based on the statistical characteristics of noise, set an adaptive threshold and mark the region in the instantaneous envelope whose amplitude exceeds the adaptive threshold as a pulse event.

[0024] This invention preprocesses the raw non-stationary VHF data acquired by each antenna. After reading continuously acquired waveform data blocks, the system uses a bandpass filter to extract... to The effective physical frequency band is used to filter out background low-frequency noise and FM broadcast interference. Subsequently, the instantaneous envelope of the discrete signal is calculated using Hilbert transform, and an adaptive threshold is set based on noise statistical characteristics to detect pulse events in the original waveform, specifically including: Read the raw waveforms acquired continuously from the three channels. Extract the waveforms using a Butterworth or similar bandpass filter. The signal is processed in a frequency band to filter out low-frequency noise and FM radio interference from the environment. The preprocessed signal is then subjected to Hilbert transform to calculate the analytic signal, thereby obtaining the instantaneous envelope. :

[0025] in, This represents the nth discrete signal sample value after bandpass filtering.

[0026] To adapt to noise fluctuations during different lightning processes, a dynamic threshold strategy is employed in this embodiment, based on the noise standard deviation of the current data block. and detection factor Real-time calculation of main detection threshold :

[0027] Any region whose envelope amplitude exceeds the threshold is marked as a candidate point for radiation pulse to be analyzed.

[0028] Based on any of the above embodiments, the step of detecting pulse events in the original signal based on the signal envelope includes: Step 301: Based on the noise statistical characteristics, set an adaptive threshold and mark the regions in the signal envelope whose amplitude exceeds the adaptive threshold as pulse candidate points; Step 302: Calculate the time gap between adjacent pulse candidate regions. When the time gap is less than a preset fusion threshold, merge multiple discrete pulse candidate regions. Step 303: Search outwards from the pulse peak value. When the envelope amplitude of multiple consecutive sampling points is lower than the envelope mean, determine the true boundary of the pulse and output the corresponding pulse event.

[0029] This invention performs neighborhood fusion judgment on detected pulses, merging adjacent pulses when the gap between them is less than a preset tolerance to avoid excessive segmentation caused by waveform oscillation. The total number of effective pulses within a certain time interval is counted, and a pulse density index, which quantitatively describes the radiation intensity, is calculated. .

[0030] After obtaining the signal envelope, the system performs a refined pulse identification and feature fusion process. To overcome the "over-segmentation" phenomenon caused by high-frequency oscillations in the lightning radiation waveform, the algorithm introduces an iterative neighborhood fusion strategy: calculating the time interval between adjacent candidate pulse regions. If the gap is smaller than the preset fusion tolerance If the sampling point threshold is reached, multiple discrete segments are merged into a single complete physical discharge event. After merging, the system locates the peak point within each pulse region and searches both sides until the amplitude drops below the envelope mean, thereby accurately pinpointing the pulse's starting index. and end index Subsequently, the system divides the continuous lightning signals along the time axis into data blocks of fixed length (uniformly set to N sampling points, corresponding to signal length T). For each individual data block, the algorithm counts the total number of valid pulses contained within it, and then derives a pulse density parameter that reflects the activity level of that data block. .

[0031] Based on any of the above embodiments, the calculation of the pulse density parameter characterizing the signal radiation intensity based on the number of pulse events includes: Step 401: Divide the continuous signal into data blocks of fixed length along the time axis; Step 402: Count the total number of pulse events contained in each data block, and use the total number of pulse events contained in the data block as the pulse density parameter corresponding to the data block.

[0032] Based on any of the above embodiments, the step of dynamically matching the waveform window length according to the pulse density parameter, and performing time-domain oversampling processing on the VHF original signal within the waveform window length, includes: Step 501: Preset multiple density thresholds and multiple candidate window lengths, with each density threshold interval corresponding to a candidate window length; Step 502: Compare the pulse density parameter with the plurality of density thresholds to determine the density threshold range to which the pulse density parameter belongs; Step 503: Based on the correspondence between the density threshold range and the candidate window length, select a waveform window length that matches the current pulse density parameter; Step 504: Within the selected waveform window length, perform time-domain oversampling processing on the original VHF signal to refine the time grid between the original sampling points.

[0033] This invention establishes a pulse density-based system. An adaptive window decision model is proposed, which dynamically adjusts the waveform window length used for each cross-correlation calculation based on the lightning pulse density. A four-level gradient window length decision model is established based on the quantized pulse density to achieve optimal adaptation for different discharge stages. The window length refers to the number of discrete signal sampling points used for a single cross-correlation function calculation and extraction of the arrival time difference when traversing the current data block for segmented processing. The model presets three empirical density thresholds. The signal activity level is categorized into four levels: sparse, moderate, dense, and bursty. Based on the pulse density assessment results of the current data block, the system will automatically select the optimal window length from the four levels of 512, 1024, 2048, and 4096 sampling points. Applied to this data block:

[0034] when When determining whether a signal is sparse or weak, the system selects 4096 points (approximately 20.48). The long window, utilizing long-time integration, significantly improves the stability of phase estimation; as pulse density increases, the window length decreases progressively; when... At that time, the signal was determined to be in a high-density burst state, and the system automatically switched to point 512 (approximately 2.56). The short window of the pulse density window ensures effective separation of closely adjacent independent events in pulse-dense regions and maximally suppresses noise interference in pulse-sparse regions, thus approaching the optimal balance point of time-frequency uncertainty throughout the entire time period.

[0035] In this embodiment of the invention, the cross-correlation calculation of the oversampled signal includes: Step 601: Perform energy normalization processing on the oversampled signal to eliminate the influence of lightning signal amplitude fluctuations on the cross-correlation results; Step 602: Calculate the energy-normalized cross-correlation function; Step 603: Extract the delay index corresponding to the global maximum value of the cross-correlation function, and use it as the delay estimate under the oversampling grid; Step 604: Convert the estimated delay value into the actual time delay based on the oversampling factor.

[0036] Within a waveform window of selected length, cubic spline interpolation is used to perform a 50-fold time-domain oversampling of the original signal. The oversampled high-density signal is then normalized, and cross-correlation is calculated to obtain the peak position of the cross-correlation result and to calculate the precise time delay.

[0037] This invention improves waveform timing accuracy through "pre-sampling with high magnification". Unlike simple linear interpolation schemes, the algorithm uses a method with continuous second derivatives (…). Continuous cubic splines as interpolation kernel functions While maintaining waveform smoothness, it approximates the actual physical changes of band-limited lightning signals as closely as possible. This is achieved by setting an upsampling factor. The time grid of the signal is changed from Significantly refined to approximately The reconstructed high-density signal Obtained by convolution of the original sequence and the interpolation kernel:

[0038] in, The first discrete signal is the first discrete signal. Each sample value, This is the index of the discrete-time sampling points after oversampling.

[0039] Subsequently, the energy-normalized generalized cross-correlation function is calculated. To eliminate the impact of drastic fluctuations in the amplitude of lightning signals, and to extract [the necessary parameters] under a high-density grid. The global maximum value is used to determine the arrival time difference. , The time grid interval is the time interval after oversampling. This method avoids systematic biases introduced by incorrect assumptions in the fitted model.

[0040] Based on any of the above embodiments, constructing the nonlinear equation between the radiation source direction cosine and the theoretical time delay based on the high-precision time delay and the geometric layout of the antenna array includes: Step 701: Obtain the baseline vector between any two antennas in the antenna array; Step 702: Based on the direction cosine vector of the radiation source and the baseline vector, construct a linear relationship equation between the theoretical time delay and the direction cosine. Step 703: Using the difference between the measured high-precision time delay and the theoretical time delay as the residual, establish a nonlinear equation about the direction cosine vector.

[0041] After obtaining the signal time delay between any two antennas among the three antennas, a nonlinear equation is first constructed based on the geometric layout of the antenna array, relating the direction cosine vector of the radiation source to the theoretical time delay of each baseline. Next, by comprehensively utilizing the initial value of the direction cosine, the antenna position coordinates, and the measured observation time difference, a nonlinear least-squares objective function is constructed to minimize the relationship between the observation delay and the theoretical time delay. Subsequently, while ensuring that the physical constraints of the direction cosine are met, a trust domain reflection algorithm is used for global iterative optimization to search for and obtain the optimal direction cosine solution that minimizes the residual. Finally, the direction cosine solution is transformed into the azimuth and elevation coordinates of the radiation source according to the coordinate transformation formula. The positioning results are then subjected to quality control screening based on the closure error and cross-correlation coefficient, thereby achieving high-precision spatial positioning of the lightning radiation source.

[0042] For a non-uniformly distributed triangular antenna array, the time difference between any two antenna signals can be obtained. (in The value range is 1-3), and the direction cosine vector of the inverted discharge radiation source is retrieved. . No. The theoretical time delay between antennas The projection equation gives:

[0043] in For baseline vector, At the speed of light, Let x be the direction cosine of the angle between the radiation source direction and the x-axis. The direction cosine of the angle between the radiation source direction and the y-axis Let be the baseline length of antenna i and antenna j in the x-direction. Let be the baseline length of antenna i and antenna j in the y direction.

[0044] The specific geometric relationship of plane wave incident is as follows: Figure 2 As shown.

[0045] Subsequently, the objective function is constructed. :

[0046] The objective function is iteratively optimized, and physical constraints are imposed. Ultimately, the azimuth angle of the radiation source... With elevation angle It can be exported as: arctan .

[0047] The high-precision positioning method for continuous interferometers provided in this invention reduces the average azimuth error from 0.1855° to 0.0906° and the elevation error from 0.1562° to 0.0823°, resulting in an overall error reduction of approximately half. It effectively solves the problems of discontinuous positioning trajectories during the pulse burst phase and point divergence in weak signal regions caused by the fixed window algorithm. It achieves smooth reconstruction of the lightning channel to eliminate detail blurring caused by the fixed window length, suppresses sampling quantization errors, and enables high-precision observation of the microscopic physical processes of lightning.

[0048] Figure 3 This is a schematic diagram of the structure of the high-precision positioning device for a continuous interferometer provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the high-precision positioning device for a continuous interferometer provided in this embodiment of the invention includes: Extraction module 301 is used to acquire the VHF raw signals collected by each antenna in the continuous interferometer array, and extract the signal envelope from the VHF raw signals; The calculation module 302 is used to detect pulse events in the original signal based on the signal envelope, count the number of pulse events within a preset time window, and calculate the pulse density parameter characterizing the signal radiation intensity based on the number of pulse events. The acquisition module 303 is used to dynamically match the waveform window length according to the pulse density parameter, perform time-domain oversampling processing on the VHF original signal within the waveform window length, perform cross-correlation calculation on the oversampled signal, and obtain the high-precision time delay between any two antennas based on the peak position of the cross-correlation result. The solver module 304 is used to construct a nonlinear equation between the direction cosine of the radiation source and the theoretical time delay based on the high-precision time delay and the geometric layout of the antenna array. The direction cosine of the radiation source is obtained by iteratively solving the nonlinear equation, and the direction cosine of the radiation source is converted into the azimuth and elevation coordinates of the radiation source.

[0049] The high-precision positioning device for a continuous interferometer provided in this invention acquires the VHF raw signals collected by each antenna in the continuous interferometer array and extracts the signal envelope from the VHF raw signals; detects pulse events in the raw signals based on the signal envelope, counts the number of pulse events within a preset time window, and calculates a pulse density parameter characterizing the signal radiation intensity based on the number of pulse events; dynamically matches the waveform window length according to the pulse density parameter, performs time-domain oversampling processing on the VHF raw signals within the waveform window length, performs cross-correlation calculation on the oversampled signals, and obtains any position based on the peak position of the cross-correlation result. A high-precision time delay between two antennas is achieved. Based on this high-precision time delay and the geometric layout of the antenna array, a nonlinear equation is constructed between the direction cosine of the radiation source and the theoretical time delay. The direction cosine of the radiation source is obtained by iteratively solving the nonlinear equation, and the direction cosine of the radiation source is converted into the azimuth and elevation coordinates of the radiation source. By adaptively matching the waveform window length with pulse density, the inherent contradiction that a fixed window length cannot simultaneously meet the processing requirements of pulse-dense and sparse regions is resolved. At the same time, by performing time-domain oversampling processing on the original signal, the limitation of hardware sampling rate on the time delay estimation accuracy is broken, thereby improving the positioning accuracy and channel continuity of the lightning radiation source.

[0050] Figure 4 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 4As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430, and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 communicate with each other through the communication bus 440. The memory 430 includes a computer program, an operating system, and acquired data. The processor 410 can call the logical instructions in the memory 430 to execute a high-precision positioning method for a continuous interferometer. This method includes: acquiring the VHF raw signals collected by each antenna in the continuous interferometer array and extracting the signal envelope from the VHF raw signals; detecting pulse events in the raw signals based on the signal envelope, counting the number of pulse events within a preset time window, and calculating a pulse density parameter characterizing the signal radiation intensity based on the number of pulse events; dynamically matching the waveform window length according to the pulse density parameter, performing time-domain oversampling processing on the VHF raw signals within the waveform window length, performing cross-correlation calculation on the oversampled signals, and obtaining the high-precision time delay between any two antennas based on the peak position of the cross-correlation result; constructing a nonlinear equation between the radiation source direction cosine and the theoretical time delay based on the high-precision time delay and the geometric layout of the antenna array, obtaining the radiation source direction cosine by iteratively solving the nonlinear equation, and converting the radiation source direction cosine into the azimuth and elevation coordinates of the radiation source.

[0051] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to related technologies, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0052] On the other hand, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the high-precision positioning method for a continuous interferometer provided by the methods described above. The method includes: acquiring VHF raw signals collected by each antenna in a continuous interferometer array and extracting the signal envelope from the VHF raw signals; detecting pulse events in the raw signals based on the signal envelope, counting the number of pulse events within a preset time window, and calculating a pulse density parameter characterizing the signal radiation intensity based on the number of pulse events; dynamically matching the waveform window length according to the pulse density parameter, performing time-domain oversampling processing on the VHF raw signals within the waveform window length, performing cross-correlation calculation on the oversampled signals, and obtaining a high-precision time delay between any two antennas based on the peak position of the cross-correlation result; constructing a nonlinear equation between the direction cosine of the radiation source and the theoretical time delay based on the high-precision time delay and the geometric layout of the antenna array, obtaining the direction cosine of the radiation source by iteratively solving the nonlinear equation, and converting the direction cosine of the radiation source into the azimuth and elevation coordinates of the radiation source.

[0053] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0054] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of software products. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision positioning method for a continuous interferometer, characterized in that, include: Acquire the raw VHF signals collected by each antenna in the continuous interferometer array, and extract the signal envelope from the raw VHF signals; Based on the signal envelope, pulse events in the original signal are detected, the number of pulse events within a preset time window is counted, and a pulse density parameter characterizing the signal radiation intensity is calculated based on the number of pulse events. The waveform window length is dynamically matched according to the pulse density parameter. Within the waveform window length, the VHF original signal is subjected to time-domain oversampling processing. Cross-correlation calculation is performed on the oversampled signal. Based on the peak position of the cross-correlation result, the high-precision time delay between any two antennas is obtained. Based on the high-precision time delay and the geometric layout of the antenna array, a nonlinear equation between the direction cosine of the radiation source and the theoretical time delay is constructed. The direction cosine of the radiation source is obtained by iteratively solving the nonlinear equation, and the direction cosine of the radiation source is converted into the azimuth and elevation coordinates of the radiation source. The step of dynamically matching the waveform window length according to the pulse density parameter, and performing time-domain oversampling processing on the VHF original signal within the waveform window length, includes: Multiple density thresholds and multiple candidate window lengths are preset, with each density threshold interval corresponding to a candidate window length; The pulse density parameter is compared with the plurality of density thresholds to determine the density threshold range to which the pulse density parameter belongs; Based on the correspondence between the density threshold range and the candidate window length, select a waveform window length that matches the current pulse density parameter; Within the selected waveform window length, the VHF original signal is subjected to time-domain oversampling processing to refine the time grid between the original sampling points; Establish based on pulse density An adaptive window decision model is proposed, which dynamically adjusts the waveform window length used for each cross-correlation calculation time delay based on the lightning pulse density. Based on the quantized pulse density, a four-level gradient window length decision model is established to achieve optimal adaptation for different discharge stages. The window length refers to the number of discrete signal sampling points used for single cross-correlation function calculation and extraction of arrival time difference when traversing the current data block for segmented processing. The model presets three empirical density thresholds. The signal activity level is divided into four levels: sparse, medium, dense, and burst. Based on the pulse density evaluation results of the current data block, the system will automatically select the optimal window length from the four levels of 512, 1024, 2048, and 4096 sampling points. Applied to this data block: when When the signal is in a sparse or weak state, the system selects a long window of 4096 points and uses long-time integration to significantly improve the stability of phase estimation; as the pulse density increases, the window length decreases step by step; when When the signal is determined to be in a high-density burst state, the system automatically switches to a short window of 512 points.

2. The high-precision positioning method for a continuous interferometer according to claim 1, characterized in that, The extraction of the signal envelope from the original VHF signal includes: A bandpass filter is used to filter the VHF original signal to extract the signal within a preset frequency band range, thereby filtering out low-frequency noise and FM broadcast interference. The discrete instantaneous envelope of the filtered signal is calculated using the Hilbert transform. An adaptive threshold is set based on the statistical characteristics of noise, and regions in the instantaneous envelope whose amplitude exceeds the adaptive threshold are marked as impulse events.

3. The high-precision positioning method for a continuous interferometer according to claim 1, characterized in that, The detection of pulse events in the original signal based on the signal envelope includes: An adaptive threshold is set based on the statistical characteristics of noise, and regions in the signal envelope whose amplitude exceeds the adaptive threshold are marked as pulse candidate points. Calculate the time gap between adjacent pulse candidate regions. When the time gap is less than a preset fusion threshold, merge multiple discrete pulse candidate regions. The system searches outwards from the pulse peak value. When the envelope amplitude of multiple consecutive sampling points is lower than the envelope mean, the true boundary of the pulse is determined, and the corresponding pulse event is output.

4. The high-precision positioning method for a continuous interferometer according to claim 1, characterized in that, The pulse density parameter characterizing the signal radiation intensity based on the number of pulse events includes: Divide the continuous signal into data blocks of fixed length along the time axis; The total number of pulse events contained within each data block is counted, and the total number of pulse events contained within the data block is used as the pulse density parameter corresponding to that data block.

5. The high-precision positioning method for a continuous interferometer according to claim 1, characterized in that, The cross-correlation calculation of the oversampled signal includes: The oversampled signal is subjected to energy normalization to eliminate the influence of lightning signal amplitude fluctuations on the cross-correlation results; Calculate the energy-normalized cross-correlation function; Extract the delay index corresponding to the global maximum value of the cross-correlation function, and use it as the delay estimate under the oversampling grid; The delay estimate is converted into the actual time delay based on the oversampling factor.

6. The high-precision positioning method for a continuous interferometer according to claim 1, characterized in that, The nonlinear equations relating the radiation source direction cosine and the theoretical time delay, based on the high-precision time delay and the geometric layout of the antenna array, include: Obtain the baseline vector between any two antennas in the antenna array; Based on the direction cosine vector of the radiation source and the baseline vector, a linear relationship equation between the theoretical time delay and the direction cosine is constructed. The difference between the measured high-precision time delay and the theoretical time delay is used as the residual to establish a nonlinear equation about the direction cosine vector.

7. A high-precision positioning device for a continuous interferometer, applicable to the high-precision positioning method for a continuous interferometer as described in any one of claims 1 to 6, characterized in that, include: The extraction module is used to acquire the VHF raw signals collected by each antenna in the continuous interferometer array, and extract the signal envelope from the VHF raw signals. The calculation module is used to detect pulse events in the original signal based on the signal envelope, count the number of pulse events within a preset time window, and calculate the pulse density parameter characterizing the signal radiation intensity based on the number of pulse events. The acquisition module is used to dynamically match the waveform window length according to the pulse density parameter, perform time-domain oversampling processing on the VHF original signal within the waveform window length, perform cross-correlation calculation on the oversampled signal, and obtain the high-precision time delay between any two antennas based on the peak position of the cross-correlation result. The solution module is used to construct a nonlinear equation between the direction cosine of the radiation source and the theoretical time delay based on the high-precision time delay and the geometric layout of the antenna array. The direction cosine of the radiation source is obtained by iteratively solving the nonlinear equation, and the direction cosine of the radiation source is converted into the azimuth and elevation coordinates of the radiation source.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the high-precision positioning method for a continuous interferometer as described in any one of claims 1 to 6.

9. A non-transitory readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the high-precision positioning method for a continuous interferometer as described in any one of claims 1 to 6.

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