A VHF-based lightning signal receiving system and method

Abstract

The present application provides a lightning signal receiving system and method based on very high frequency. The system includes at least six detection substations, each of which includes: an antenna, a filtering device, a signal amplifying device, a timing device, a collection device and a main control device; the antenna is connected to the input end of the filtering device, and the antenna is used to receive VHF frequency band electromagnetic radiation signals radiated by lightning; the output end of the filtering device is connected to the input end of the signal amplifying device, the output end of the signal amplifying device is connected to the input end of the collection device, the output end of the collection device is connected to the first input end of the main control device, the timing device is connected to the second input end of the main control device, the output end of the main control device is externally connected to a host computer, the filtering device includes a bandpass filtering module, and the main control device adjusts the center frequency of the bandpass filtering module based on the environmental spectrum analysis result obtained by performing environmental spectrum analysis on the electromagnetic radiation signal output by the collection device.

Description

Technical Field

[0001] The present application relates to the field of wireless signal measurement in the field of communications, and in particular to a lightning signal receiving system and method based on very high frequency. Background Art

[0002] Thunderstorm is a natural phenomenon that occurs between cumulonimbus clouds or clouds and ground. Strong thunderstorms are often accompanied by strong winds, rainfall or hail, which bring disasters and huge property losses to humans. Therefore, thunderstorms are an important research object in weather, meteorology and atmospheric science. Common ways to observe thunderstorms include manual observation, atmospheric electric field instruments, lightning location systems, radar systems and satellite systems.

[0003] When lightning strikes or lightning occurs, electromagnetic signals and lightning electromagnetic waves are radiated, which have energy distribution from several Hz to several GHz. Among them, the VHF radiation source of lightning usually occurs in the air breakdown process, which is often associated with the development of cloud flash, ground lightning pre-breakdown, leader, streamer and other processes. Lightning also has high radiation energy in the VHF band during the discharge process, which is usually associated with the breakdown discharge process. The lightning radiation in the VHF band is very rich. In addition to the high current return stroke process, almost the entire lightning discharge process is accompanied by VHF radiation, especially the signal in this frequency band generated by cloud flash is more abundant.

[0004] In the prior art, the operating frequency band of the electromagnetic radiation signal receiving system is from a few kHz to several hundred kHz, which is located in the VLF / LF band. On the one hand, the electromagnetic signal receiving capability of cloud flash radiation is relatively weak, resulting in low cloud flash detection efficiency. On the other hand, the radiation in the VLF / LF band mainly occurs in the discharge process with a large spatial scale, which is greatly affected by the ground conductivity, ionosphere changes, and terrain changes. The quality of the signal received by the system is poor, which ultimately leads to poor system reception time accuracy. However, there is no equipment for data collection in the VHF band in the prior art, and the corresponding VHF band data collection technology needs to be solved urgently. Summary of the invention

[0005] This application adopts the following technical solutions:

[0006] In a first aspect, a lightning signal receiving system based on very high frequency is provided, the system includes at least six detection substations, each detection substation includes: an antenna, a filtering device, a signal amplifying device, a timing device, a collecting device and a main control device; the antenna is connected to the input end of the filtering device, and the antenna is used to receive the VHF frequency band electromagnetic radiation signal radiated by lightning; the output end of the filtering device is connected to the input end of the signal amplifying device, the output end of the signal amplifying device is connected to the input end of the collecting device, the output end of the collecting device is connected to the first input end of the main control device, the timing device is connected to the second input end of the main control device, the output end of the main control device is externally connected to a host computer, the filtering device includes a bandpass filtering module, the main control device adjusts the center frequency of the bandpass filtering module based on the environmental spectrum analysis result obtained by performing environmental spectrum analysis on the electromagnetic radiation signal output by the collecting device, and the collecting device is used to continuously collect signals and interact with TOD data of the timing device.

[0007] According to the system described in the first aspect, since the phase-locked loop technology in the acquisition device can be used in conjunction with the timing module to accurately measure the time when the narrowband lightning radiation pulse in the frequency band arrives at the receiver position, the main control device can accurately identify the rising edge time, falling edge time, and pulse period of the received narrowband electromagnetic radiation pulse signal, thereby accurately calculating the peak time and amplitude of the narrowband electromagnetic radiation pulse signal, thereby realizing the identification and analysis of the complex charge distribution and lightning evolution in different types of thunderstorms, which is helpful to describe the development characteristics of thunderstorms.

[0008] In combination with the first aspect, in a possible design scheme, the filtering device includes: a cavity, a cover plate, a coaxial connector and the bandpass filtering module; the coaxial connector and the bandpass filtering module are arranged in the cavity, and the cover plate is connected to the cavity; the bandpass filtering module includes a plurality of bandpass filtering units, each of which includes a first capacitor, a second capacitor and an inductor, wherein one end of the first capacitor is determined as the input end of the bandpass filtering unit, one end of the second capacitor and the inductor are both connected in parallel with the other end of the first capacitor, and the other end of the first capacitor after passing through the second capacitor and the inductor is determined as the output end of the bandpass filtering unit, the output end of each bandpass filtering unit is respectively connected to the input end of the next bandpass filtering unit, and the input end of the first bandpass filtering unit is connected to the VHF band electromagnetic radiation signal radiated by lightning received by the antenna.

[0009] In combination with the first aspect, in a possible design scheme, the signal amplifying device includes: an amplifying circuit, a bias circuit, an input matching network and an output matching network, which are used to filter out interference noise or perform spectrum analysis; the input end of the input matching network is connected to the output signal of the filtering device, the output end of the input matching network is connected to the first input end of the amplifying circuit, the bias circuit is connected to the second input end of the amplifying circuit, the output end of the amplifying circuit is connected to the input end of the output matching network, and the output end of the output matching network is determined as the output end of the signal amplifying device.

[0010] In combination with the first aspect, in a possible design scheme, the amplifier circuit includes a first-stage low-noise amplifier chip and a second-stage low-noise amplifier chip, and the first-stage low-noise amplifier chip and the second-stage low-noise amplifier chip are cascaded to achieve low noise and high gain functions of the system.

[0011] In combination with the first aspect, in a possible design scheme, the timing device is a high-precision clock source and a high-time precision dual-mode timing module, which is used to provide accurate timing and position information for the system.

[0012] In combination with the first aspect, in a possible design scheme, the acquisition device includes: an ADC circuit, a buffer module, a phase-locked loop module, several Balun modules, an RS232 level conversion module, several radio frequency switches and an FMC connector; the signal output by the signal amplification device is divided into two paths and transmitted to the first input end and the second input end of the ADC circuit respectively through the radio frequency switch and the Balun module; the phase-locked loop module includes a first phase-locked loop chip and a second phase-locked loop chip, and the input crystal oscillator signal is copied into two outputs through the buffer module and transmitted to the first phase-locked loop chip and the second phase-locked loop chip respectively, the output end of the first phase-locked loop chip is connected to the third input end of the ADC circuit, the output end of the ADC circuit is connected to the first input end of the FMC connector, and the output end of the second phase-locked loop chip is connected to the second input end of the FMC connector; the RS232 level conversion module is connected to the third input end of the FMC connector; wherein the ADC circuit is used for collecting analog signals into digital signals, the Balun module is used for converting the output single-ended analog signal into a differential analog signal, and the radio frequency switch is used for limit protection of the ADC module.

[0013] In combination with the first aspect, in a possible design scheme, the main control device includes: a main control module, a storage module and several peripheral interfaces, the storage module and the several peripheral interfaces are all connected to the main control module, and the main control module includes: a processor system unit and a programmable logic unit.

[0014] In combination with the first aspect, in a possible design scheme, the antenna is a retractable omnidirectional whip antenna, which is used to adjust the antenna to different lengths to receive electromagnetic radiation signals of different frequencies; the antenna includes: a metal radiator with adjustable length and a downward matching circuit, the metal radiator has a relative top and bottom, and the bottom is connected to the downward matching circuit.

[0015] In combination with the first aspect, in a possible design scheme, a cylindrical antenna cover is provided on the outside of the metal radiator, and the cylindrical antenna cover is designed as an integrated structure using a fiberglass reinforced plastic material.

[0016] In the second aspect, the embodiment of the present application provides a lightning signal receiving method based on very high frequency, and the method is implemented based on the lightning signal receiving system based on very high frequency of the first aspect, and each detection substation in the system implements the following process: the antenna detects the pulse signal generated based on lightning weather; the pulse signal is sequentially input into the filtering device and the signal amplifying device to realize the bandpass filtering and signal amplification of the signal; the main control device controls the acquisition device to perform threshold trigger acquisition and receive the time and position data of the timing module, and judges whether the absolute value of the current acquisition value is greater than the preset threshold. If the judgment result is yes, the current time and the current subdivision time are latched, and the data collected within the preset time length after the current acquisition value is analyzed to identify the rising edge time, falling edge time and pulse period of the electromagnetic radiation pulse signal, and calculate the peak time and amplitude of the electromagnetic radiation pulse signal.

[0017] In the third aspect, the embodiment of the present application provides a lightning signal receiving device based on very high frequency. The lightning signal receiving device based on very high frequency includes: a detection module, which is used for the antenna to detect the pulse signal generated by lightning weather; a filtering and amplifying module, which is used to input the pulse signal into the filtering device and the signal amplifying device in sequence to realize the bandpass filtering and signal amplification of the signal; a processing module, which is used for the main control device to control the acquisition device to perform threshold trigger acquisition and receive the time and position data of the timing module, and judge whether the absolute value of the current acquisition value is greater than the preset threshold. If the judgment result is yes, the current time is latched and subdivided, and the data collected within the preset time after the current acquisition value is analyzed, and the rising edge time, falling edge time and pulse period of the electromagnetic radiation pulse signal are identified, and the peak time and amplitude of the electromagnetic radiation pulse signal are calculated.

[0018] In a fourth aspect, a computer-readable storage medium is provided, comprising: a computer program or instructions; when the computer program or instructions are run on a computer, the computer executes the method described in the second aspect.

[0019] According to a fifth aspect, a computer program product is provided, comprising a computer program or instructions, which, when executed on a computer, causes the computer to execute the method described in the second aspect.

[0020] The embodiments of the present application provide a lightning signal receiving system and method based on very high frequency. The lightning signal receiving system based on very high frequency can receive VHF band electromagnetic radiation signals radiated by lightning with a large dynamic range and high sensitivity. Through the acquisition device, the signal is collected without omission; through the narrowband digital filtering technology, all electromagnetic signals outside the narrowband are filtered out; the phase-locked loop technology is used in conjunction with the high-precision clock source and the high-time precision dual-mode timing module to ensure the accurate measurement of the time when the lightning radiation pulse arrives at the measuring station, which makes up for the lack of data acquisition in the VHF band in the field of lightning positioning. The phase-locked loop technology can be used in conjunction with the high-precision clock source and the high-time precision dual-mode timing module to accurately measure the time when the narrowband lightning radiation pulse in the VHF band arrives at the receiver position. The data content is rich, and through multi-station networking, the same lightning data can be obtained at multiple different detection substations. The current time and the current subdivision time are locked for multiple detection substations in the network at the same time, so that the mathematical model of the time relationship of the lightning occurrence position is constructed according to the current time and current subdivision time locked by each detection substation, thereby realizing lightning positioning, and identifying and analyzing the complex charge distribution and lightning evolution in different types of thunderstorms, which is helpful to describe the development characteristics of thunderstorms and improve the accuracy of lightning positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a lightning signal receiving system based on very high frequency provided in an embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of a detection substation provided in an embodiment of the present application;

[0023] Figure 3 A schematic diagram of the circuit principle of the bandpass filter module provided in an embodiment of the present application;

[0024] Figure 4 A schematic diagram of the circuit principle of the signal amplification device provided in an embodiment of the present application;

[0025] Figure 5 A schematic diagram of the circuit principle of the acquisition device provided in the embodiment of the present application;

[0026] Figure 6 A flowchart of a very high frequency based lightning signal receiving method provided in an embodiment of the application. DETAILED DESCRIPTION

[0027] The technical solution in this application is described below in conjunction with the accompanying drawings.

[0028] With the development of electronic technology and high-time precision GPS / Beidou technology, VHF radiation source positioning technology has also developed rapidly and has become the most accurate lightning positioning technology. It can detect and locate the radiation pulses of cloud-to-ground lightning within a certain range with high time resolution.

[0029] See also Figure 1 and Figure 2 The embodiment of the present application provides a lightning signal receiving system based on very high frequency. The system includes at least six detection substations, each of which includes: an antenna, a filtering device, a signal amplifying device, a timing device, a collection device and a main control device; the antenna is connected to the input end of the filtering device, and the antenna is used to receive the VHF band electromagnetic radiation signal radiated by lightning; the output end of the filtering device is connected to the input end of the signal amplifying device, the output end of the signal amplifying device is connected to the input end of the collection device, the output end of the collection device is connected to the first input end of the main control device, the timing device is connected to the second input end of the main control device, and the output end of the main control device is externally connected to a host computer, the filtering device includes a bandpass filtering module, and the main control device adjusts the center frequency of the bandpass filtering module based on the environmental spectrum analysis result obtained by performing environmental spectrum analysis on the electromagnetic radiation signal output by the collection device, and the collection device is used to continuously collect signals and interact with TOD data of the timing device.

[0030] In the above-mentioned VHF-based lightning signal receiving system, since the phase-locked loop technology in the acquisition device can be used in conjunction with the timing module to accurately measure the time when the narrow-band lightning radiation pulse in the frequency band arrives at the receiver position, the main control device can accurately identify the rising edge time, falling edge time, and pulse period of the received narrow-band electromagnetic radiation pulse signal, thereby accurately calculating the peak time and amplitude of the narrow-band electromagnetic radiation pulse signal, realizing the identification and analysis of the complex charge distribution and lightning evolution in different types of thunderstorms, which is helpful to describe the development characteristics of thunderstorms.

[0031] Specifically, the antenna is a retractable omnidirectional whip antenna, which is used to adjust the antenna length to receive electromagnetic radiation signals of different frequencies; the antenna includes: a metal radiator with adjustable length and a bottom matching circuit, the metal radiator has a top and a bottom relative to each other, and the bottom is connected to the bottom matching circuit. In other words, the signal of 30M-4GHz can be received by adjusting the length of the antenna, and antennas of different lengths correspond to different optimal center frequencies.

[0032] The adjustable structure of the metal radiator can ensure that the radiator can achieve omnidirectional and efficient radiation at one-quarter of its resonant wavelength at different frequency points within the band. The lower impedance matching circuit can achieve the impedance matching of the 50Ω input impedance of the antenna input port with the impedance of the feeder system, thereby achieving a good port standing wave ratio.

[0033] As a possible implementation method, a cylindrical antenna cover is provided on the outside of the metal radiator. The cylindrical antenna cover is designed as an integrated fiberglass material, which has the advantages of good wave transmission performance, effective wind and rain protection, corrosion resistance, high and low temperature resistance, and vibration and impact resistance.

[0034] See also Figure 3 As a possible implementation, the filtering device includes: a cavity, a cover plate, a coaxial connector and the bandpass filtering module; the coaxial connector and the bandpass filtering module are arranged in the cavity, and the cover plate is connected to the cavity; the bandpass filtering module includes a plurality of bandpass filtering units, each of which includes a first capacitor, a second capacitor and an inductor, wherein one end of the first capacitor is determined as the input end of the bandpass filtering unit, one end of the second capacitor and the inductor are connected in parallel with the other end of the first capacitor, and the other end of the first capacitor after passing through the second capacitor and the inductor is determined as the output end of the bandpass filtering unit, the output end of each bandpass filtering unit is respectively connected to the input end of the next bandpass filtering unit, and the input end of the first bandpass filtering unit is connected to the VHF band electromagnetic radiation signal radiated by lightning received by the antenna. The filtering device has the characteristics of small size, high integration, high external suppression and stable temperature characteristics.

[0035] Specifically, the received pulse signal is matched and transmitted through the frequency range of 30-300MHz within the filter band, and the frequency points outside 20MHz and 350MHz are suppressed, thereby realizing the filtering function. In the system, it is mainly used to filter out interference noise or perform spectrum analysis. It mainly realizes the product function through the integration of inductance and capacitance in the bandpass filter module, and then matches the coaxial connector for transmission.

[0036] See also Figure 4 As a possible implementation, the signal amplification device includes: an amplification circuit, a bias circuit, an input matching network and an output matching network, which are used to filter out interference noise or perform spectrum analysis; the input end of the input matching network is connected to the output signal of the filtering device, the output end of the input matching network is connected to the first input end of the amplification circuit, the bias circuit is connected to the second input end of the amplification circuit, the output end of the amplification circuit is connected to the input end of the output matching network, and the output end of the output matching network is determined as the output end of the signal amplification device. The signal amplification device amplifies the weak signal in the 30MHz to 300MHz frequency band received by the antenna, so that the subsequent electronic equipment can process the signal.

[0037] Specifically, the amplification circuit includes a first-stage low-noise amplifier chip and a second-stage low-noise amplifier chip, which are cascaded. The amplification circuit is composed of two-stage low-noise amplifier chips in cascade to ensure the low noise and high gain requirements of the link; the bias circuit provides appropriate bias current for the two-stage low-noise amplifier chips to determine the static operating points of each stage; the input and output matching networks improve the link gain and output while satisfying the low noise of the low-noise amplifier module.

[0038] As a possible implementation, the timing device is a high-precision clock source and a high-time precision dual-mode timing module, which is used to provide accurate timing and position information for the system.

[0039] See also Figure 5 As a possible implementation, the acquisition device includes: an ADC circuit, a buffer module, a phase-locked loop module, a plurality of Balun modules, an RS232 level conversion module, a plurality of radio frequency switches and an FMC connector; the signal output by the signal amplification device is divided into two paths and is transmitted to the first input end and the second input end of the ADC circuit respectively through the radio frequency switch and the Balun module; the phase-locked loop module includes a first phase-locked loop chip and a second phase-locked loop chip, the input crystal oscillator signal is copied into two outputs through the buffer module and then transmitted to the first phase-locked loop chip and the second phase-locked loop chip respectively, the output end of the first phase-locked loop chip is connected to the third input end of the ADC circuit, the output end of the ADC circuit is connected to the first input end of the FMC connector, and the output end of the second phase-locked loop chip is connected to the second input end of the FMC connector; the RS232 level conversion module is connected to the third input end of the FMC connector; wherein the ADC circuit is used for collecting analog signals into digital signals, the Balun module is used for converting the output single-ended analog signals into differential analog signals, and the radio frequency switch is used for limit protection of the ADC module.

[0040] In detail, the acquisition device adopts the FMC standard interface to realize the high-speed acquisition function of continuous and non-missing signals. It supports a dual-channel high-speed ADC to realize dual-channel 1Gsps sampling, internal and external reference clocks, 1PPS input and timing module TOD data input. Among them, the pin control of the RF switch ADC circuit mainly protects the back-end AD chip. When the AD detects that the signal amplitude is greater than the set value, the set value is less than the maximum value that the ADC can withstand, and the switch is disconnected; the FPGA pin and the I / O interface of the FMC board can be connected through the FMC connector, and the pin speed can reach several Gb / s.

[0041] It should be noted that the acquisition device also includes a JESD204B data interface. JESD204 is a serial interface standard based on SERDES, which is mainly used for data transmission between digital-to-analog converters and logic devices. The advantages of JESD204B are: reduced PCB layout space, reduced device pins and package size, simpler timing control, and fast transmission rate.

[0042] As a possible implementation, the control device includes: a main control module, a storage module and several peripheral interfaces, the storage module and the several peripheral interfaces are connected to the main control module, and the main control module includes: a processor system unit and a programmable logic unit.

[0043] Specifically, the main control device realizes the control of the acquisition device and the processing of its digital signals. The main control device mainly includes a main control chip, a storage module and multiple data interfaces. In the embodiment of the present application, the main control chip adopts the Zynq7000 series chip of Xilinx, and the chip can be divided into the processor system part Processor System (PS) and the programmable logic part Programmable Logic (PL). Two DDR3s are hung on the PS end of the ZYNQ7100 chip, and four DDR3s are hung on the PL end. The capacity of each DDR3 is up to 512M bytes, so that the ARM system and the FPGA system can independently process and store data. The 8GB eMMC FLASH storage chip and two 256Mb QSPIFLASH on the PS end are used to statically store the operating system, file system and user data of ZYNQ. The main control device has expanded a wealth of peripheral interfaces, including 1 Gigabit Ethernet interface, 1 USB2.0OTG interface, 1 UART serial port interface, 1 SD card interface, 1 FMC HPC expansion interface, 2 SMA interfaces and some buttons and LED lights.

[0044] In the embodiment of the present application, the lightning signal receiving system based on very high frequency mainly receives electromagnetic pulse signals in the VHF (30-300MHz) frequency band, and performs high-speed acquisition, processing and analysis on them, and finally outputs the data to the host computer.

[0045] See also Figure 6 The embodiment of the present application provides a lightning signal receiving method based on very high frequency. The method is implemented based on the above-mentioned lightning signal receiving system based on very high frequency. Each detection substation in the system implements the process: step S11, step S12 and step S13.

[0046] Step S11: The antenna detects a pulse signal generated by lightning weather;

[0047] Step S12: the pulse signal is sequentially input into the filtering device and the signal amplifying device to implement the signal bandpass filtering and signal amplification;

[0048] Step S13: The main control device controls the acquisition device to perform threshold-triggered acquisition and receive the time and position data of the timing module, and determines whether the absolute value of the current acquisition value is greater than the preset threshold. If the judgment result is yes, the current time and the current subdivision time are latched, and the data collected within the preset time after the current acquisition value is analyzed to identify the rising edge time, falling edge time and pulse period of the electromagnetic radiation pulse signal, and calculate the peak time and amplitude of the electromagnetic radiation pulse signal.

[0049] Specifically, the pulse signal is generated randomly and is detected only when there is a thunderstorm. The pulse signal is received by an omnidirectional whip antenna, which can receive electromagnetic signals from any direction.

[0050] After the signal passes through filtering and low-noise amplifier circuit, bandpass filtering and signal amplification are realized. The passive filter passband frequency band is 30-300MHz. The low-noise amplifier processing circuit realizes signal amplification between 30-300MHz and can receive signals with a large dynamic range.

[0051] The acquisition device uses a FMC standard interface high-speed acquisition card with a sampling frequency of 1GSPS.

[0052] The main control device receives the time and position information from the timing module and simultaneously subdivides the 1pps pulse into fine details.

[0053] The main control device performs continuous digital filtering on the digital signal to achieve band-pass filtering while controlling the acquisition device to acquire the data, wherein the filter is designed with a 300-order FIR window function.

[0054] The filtered data is collected in real time through threshold triggering. When the absolute value of the collected value is greater than the threshold, the latch time and subdivision time are timestamped. At the same time, the data collected within the preset time period is analyzed to identify the rising edge time, falling edge time and pulse period of the electromagnetic radiation pulse signal, and accurately calculate the peak time and amplitude of the electromagnetic radiation pulse signal.

[0055] The lightning signal receiving system based on very high frequency regularly performs spectrum analysis of the VHF band on the data before filtering once an hour to monitor the electromagnetic environment around the installation of the detection equipment; at the same time, the system will perform spectrum analysis once a minute after filtering to detect whether there is any interference in the narrowband bandwidth.

[0056] The lightning signal receiving system based on VHF will output three types of data: status data, acquisition data and spectrum analysis data, among which the status data mainly monitors and self-checks the status of the entire system; the acquisition data is the result of lightning pulse signal analysis; and the spectrum analysis data is the result of regular hourly spectrum analysis. In the embodiment of the present application, all data generated by the lightning signal receiving system based on VHF must be saved in a storage peripheral, including status data, acquisition data, spectrum analysis data and data within a period of time after the threshold is triggered.

[0057] The lightning signal receiving system based on VHF can receive VHF band electromagnetic radiation signals radiated by lightning in a large dynamic range and with high sensitivity. Through the acquisition device, the analog signal is converted into a digital signal and the signal is collected without omission; through the narrowband digital filtering technology, all electromagnetic signals outside the narrowband are filtered out; using the phase-locked loop technology with a high-precision clock source and a high-time precision dual-mode timing module, the arrival time of the lightning radiation pulse at the measuring station is accurately measured.

[0058] The embodiments of the present application provide a lightning signal receiving system and method based on very high frequency. The lightning signal receiving system based on very high frequency can receive VHF band electromagnetic radiation signals radiated by lightning with a large dynamic range and high sensitivity. Through the acquisition device, the signal is collected without omission; through the narrowband digital filtering technology, all electromagnetic signals outside the narrowband are filtered out; the phase-locked loop technology is used in conjunction with the high-precision clock source and the high-time precision dual-mode timing module to ensure the accurate measurement of the time when the lightning radiation pulse arrives at the measuring station, which makes up for the lack of data acquisition in the VHF band in the field of lightning positioning. The phase-locked loop technology can be used in conjunction with the high-precision clock source and the high-time precision dual-mode timing module to accurately measure the time when the narrowband lightning radiation pulse in the VHF band arrives at the receiver position. The data content is rich, and through multi-station networking, the same lightning data can be obtained at multiple different detection substations. The current time and the current subdivision time are locked for multiple detection substations in the network at the same time, so that the mathematical model of the time relationship of the lightning occurrence position is constructed according to the current time and current subdivision time locked by each detection substation, thereby realizing lightning positioning, and identifying and analyzing the complex charge distribution and lightning evolution in different types of thunderstorms, which is helpful to describe the development characteristics of thunderstorms and improve the accuracy of lightning positioning.

[0059] In summary, the embodiment of the present application provides a lightning signal receiving system and method based on VHF, including: an antenna, a filtering device, a signal amplifying device, a timing device, a collection device and a main control device; the antenna is connected to the input end of the filtering device, and the antenna is used to receive the VHF band electromagnetic radiation signal radiated by lightning; the output end of the filtering device is connected to the input end of the signal amplifying device, the output end of the signal amplifying device is connected to the input end of the collection device, the output end of the collection device is connected to the first input end of the main control device, the timing device is connected to the second input end of the main control device, and the output end of the main control device is externally connected to a host computer, wherein the filtering device includes a bandpass filtering module, and the collection device is used to continuously collect signals and interact with TOD data of the timing device.

[0060] It should be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0061] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state hard disk.

[0062] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship, but it may also indicate an "and / or" relationship. Please refer to the context for specific understanding.

[0063] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0064] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0065] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0066] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0067] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0068] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0069] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0070] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks or optical disks.

[0071] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A lightning signal receiving system based on very high frequency, characterized in that: The system includes at least six detection substations, each of which includes: an antenna, a filtering device, a signal amplifying device, a timing device, a collection device and a main control device; The antenna is connected to the input end of the filter device, and the antenna is used to receive VHF frequency band electromagnetic radiation signals radiated by lightning; The output end of the filtering device is connected to the input end of the signal amplifying device, the output end of the signal amplifying device is connected to the input end of the collecting device, the output end of the collecting device is connected to the first input end of the main control device, the timing device is connected to the second input end of the main control device, the output end of the main control device is externally connected to a host computer, the filtering device includes a bandpass filtering module, the main control device adjusts the center frequency of the bandpass filtering module based on the environmental spectrum analysis result obtained by performing environmental spectrum analysis on the electromagnetic radiation signal output by the collecting device, the collecting device is used to continuously collect signals and interact with the TOD data of the timing device; the main control device is used to control the collecting device to perform threshold triggering collection and receive the time and position data of the timing module, judge whether the absolute value of the current collection value is greater than the preset threshold, if the judgment result is yes, latch the current time and the current subdivision time, and analyze the data collected within the preset time length after the current collection value, identify the rising edge time, falling edge time and pulse period of the electromagnetic radiation pulse signal, and calculate the peak time and amplitude of the electromagnetic radiation pulse signal; The filtering device comprises: a cavity, a cover plate, a coaxial connector and the bandpass filtering module; The coaxial connector and the bandpass filter module are arranged in the cavity, and the cover plate is connected to the cavity; The band-pass filter module includes a plurality of band-pass filter units, each of which includes a first capacitor, a second capacitor and an inductor, wherein one end of the first capacitor is determined as the input end of the band-pass filter unit, one end of the second capacitor and the inductor are connected in parallel with the other end of the first capacitor, and the other end of the first capacitor after passing through the second capacitor and the inductor is determined as the output end of the band-pass filter unit, the output end of each band-pass filter unit is respectively connected to the input end of the next band-pass filter unit, and the input end of the first band-pass filter unit is connected to the VHF band electromagnetic radiation signal radiated by lightning received by the antenna; The antenna is a retractable omnidirectional whip antenna, which is used to adjust the antenna of different lengths to receive electromagnetic radiation signals of different frequencies; the antenna comprises: a metal radiator with adjustable length and a bottom matching circuit, the metal radiator has a top and a bottom relative to each other, and the bottom is connected to the bottom matching circuit; The acquisition device includes: an ADC circuit, a buffer module, a phase-locked loop module, a plurality of Balun modules, an RS232 level conversion module, a plurality of radio frequency switches and an FMC connector; The signal output by the signal amplifying device is divided into two paths and is transmitted to the first input end and the second input end of the ADC circuit respectively through the radio frequency switch and the Balun module in sequence; the phase-locked loop module includes a first phase-locked loop chip and a second phase-locked loop chip, and the input crystal oscillator signal is copied into two outputs by the buffer module and transmitted to the first phase-locked loop chip and the second phase-locked loop chip respectively, the output end of the first phase-locked loop chip is connected to the third input end of the ADC circuit, the output end of the ADC circuit is connected to the first input end of the FMC connector, and the output end of the second phase-locked loop chip is connected to the second input end of the FMC connector; the RS232 level conversion module is connected to the third input end of the FMC connector; wherein the ADC circuit is used for collecting analog signals into digital signals, the Balun module is used for converting the output single-ended analog signals into differential analog signals, and the radio frequency switch is used for limit protection of the ADC module; The lightning signal receiving system based on very high frequency performs spectrum analysis in the VHF band on the pre-filtered data every hour to monitor the electromagnetic environment around the installation of the detection equipment; at the same time, the system performs spectrum analysis on the filtered data every minute to detect whether there is interference within the narrowband bandwidth.

2. The VHF-based lightning signal receiving system according to claim 1, characterized in that: The signal amplification device includes: an amplification circuit, a bias circuit, an input matching network and an output matching network, which are used to filter out interference noise or perform spectrum analysis; The input end of the input matching network is connected to the output signal of the filtering device, the output end of the input matching network is connected to the first input end of the amplifier circuit, the bias circuit is connected to the second input end of the amplifier circuit, the output end of the amplifier circuit is connected to the input end of the output matching network, and the output end of the output matching network is determined as the output end of the signal amplifying device.

3. The VHF-based lightning signal receiving system according to claim 2, characterized in that: The amplifier circuit includes a first-stage low-noise amplifier chip and a second-stage low-noise amplifier chip, and the first-stage low-noise amplifier chip and the second-stage low-noise amplifier chip are cascade-connected to achieve low-noise and high-gain functions of the system.

4. The VHF-based lightning signal receiving system according to claim 1, characterized in that: The timing device is a high-precision clock source and a high-time precision dual-mode timing module, which is used to provide accurate timing and position information for the system.

5. The VHF-based lightning signal receiving system according to claim 1, characterized in that: The main control device comprises: a main control module, a storage module and a plurality of peripheral interfaces, the storage module and the plurality of peripheral interfaces are connected to the main control module, and the main control module comprises: a processor system unit and a programmable logic unit.

6. The VHF-based lightning signal receiving system according to claim 1, characterized in that: A cylindrical antenna cover is arranged outside the metal radiator, and the cylindrical antenna cover is designed in an integrated manner using a glass fiber reinforced plastic material.

7. A lightning signal receiving method based on very high frequency, characterized in that: The method is implemented based on the lightning signal receiving system based on very high frequency according to any one of claims 1 to 6, and each detection substation in the system implements the following process: The antenna detects pulse signals generated by lightning weather; The pulse signal is sequentially input into a filtering device and a signal amplifying device to implement signal bandpass filtering and signal amplification; The main control device controls the acquisition device to perform threshold-triggered acquisition and receive the time and position data of the timing module, and determines whether the absolute value of the current acquisition value is greater than the preset threshold. If the judgment result is yes, the current time and the current subdivision time are latched, and the data collected within the preset time length after the current acquisition value is analyzed to identify the rising edge time, falling edge time, and pulse period of the electromagnetic radiation pulse signal, and calculate the peak time and amplitude of the electromagnetic radiation pulse signal; the main control device adjusts the center frequency of the bandpass filter module based on the environmental spectrum analysis result obtained by performing environmental spectrum analysis on the electromagnetic radiation signal output by the acquisition device.

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