CN103116083B - Very low frequency (VLF) / low frequency (LF) frequency range ground lightening detection positioning system - Google Patents

Abstract

The invention discloses a VLF/LF frequency band ground lightning detection and positioning system, which can accurately estimate the direction of arrival (DOA) of the ground lightning signal generated by the ground lightning radiation source and propagated along the ground surface. Upload the ground lightning signal waveform data files calculated by different detection and processing sub-stations to the central processing station through the wide area network, and calculate the arrival time difference corresponding to the same ground lightning signal between any two detection and processing sub-stations at the central processing station ( TDOA estimation), and then use the DOA and TDOA information to jointly determine the two-dimensional plane coordinate position of the ground lightning lightning radiation source. The present invention can carry out high-precision and super-resolution observation on the direction of arrival of the ground lightning signal generated by the ground lightning radiation source and propagates along the ground surface; it greatly reduces the consistency requirement for the amplitude characteristics of the receiver channel; The TDOA estimation error problem caused by the different channel group delays of different detection and processing sub-station systems.

Description

A VLF/LF frequency band ground lightning detection and positioning system

technical field

The invention belongs to the research field of ground lightning monitoring and early warning technology, and relates to a very low frequency/low frequency (VLF/LF) frequency band ground lightning detection and positioning system.

Background technique

The lightning location system originated in the late 1970s. The United States realized the construction of a large-scale lightning location system (LLS, Lightning Location System) based on modern lightning remote location technology, and networked the lightning location systems distributed in various states to form the current U.S. The National Lightning Detection Network (NLDN, National Lightning Detection Network) has realized comprehensive and complete monitoring of lightning activities in the coverage area. In the mid-1980s, the French Vaisala company developed the SAFIR3000V2 ground lightning and lightning location system, which was put into use in many countries and regions.

my country also successfully developed a ground lightning and lightning positioning system in the late 1980s, and began to build a ground lightning and lightning positioning monitoring network all over the country in the late 1990s. After more than 20 years of development, my country's current monitoring network system has covered It covers most of the country and provides a large amount of practical data for the national power grid transmission, meteorological monitoring and other departments.

Contents of the invention

The purpose of the present invention is to design and implement a VLF/LF frequency band ground lightning detection and positioning system, which can accurately estimate the direction of arrival (DOA) of ground lightning signal propagation along the ground surface produced by ground lightning radiation sources.

A VLF/LF frequency band ground lightning detection and positioning system provided by the present invention is characterized in that the system includes a central processing station and a plurality of detection and processing sub-stations located at different positions; different detection and processing sub-stations and the central processing station All are connected to the wide area network through wireless or wired methods to form a combined system;

Each detection and processing substation is used to complete GPS/Beidou satellite timing and clock synchronization, system channel group delay calculation, reception and synchronous acquisition of ground lightning lightning signals, channel amplitude inconsistency calibration, ground lightning lightning detection and signal direction of arrival estimation , and then frame the obtained real-time ground lightning waveform data, direction finding angle information, system state parameter information and time stamp information to form a ground lightning lightning signal waveform data file, and upload the data file to the central processing station through the wide area network ;

The central processing station realizes remote monitoring of the working status of each detection and processing sub-station through the wide area network; the central processing station is also used to receive the data files uploaded by each detection and processing sub-station, and according to the ground lightning signal waveform of each detection and processing sub-station at the same time period The data file calculates the time difference between the arrival of the same ground lightning signal at any two detection and processing sub-stations, and then calculates the ground lightning radiation source by using the direction of arrival information and arrival time difference information of each detection and processing sub-station corresponding to the same ground lightning signal The plane coordinate position of .

The present invention can carry out high-precision and super-resolution observation on the direction of arrival of the ground lightning signal generated by the ground lightning radiation source and propagates along the ground surface; it greatly reduces the consistency requirement for the amplitude characteristics of the receiver channel; The TDOA estimation error problem caused by the different channel group delays of different detection and processing sub-station systems; the present invention can also continuously record the lightning waveform data of VLF/LF frequency band ground lightning for a long time, which is the characteristics of VLF/LF frequency band ground lightning lightning signal Analysis provides detailed basic data. Specifically, the system of the present invention has the following characteristics:

(1) Constitute a complete VLF/LF frequency band ground lightning detection and positioning system, which can realize continuous and uninterrupted observation and positioning of VLF/LF frequency band ground lightning lightning signals. The time to record continuous lightning signals can be as long as several hours without data loss;

(2) The hardware complexity of the system is low, the cost of network construction and system operation is low, and the scalability is strong;

(3) The detection and processing sub-station adopts non-coherent energy detection, which improves the detection efficiency of lightning signals to the ground;

(4) The detection and processing sub-station can perform high-precision and super-resolution observation of the incoming wave direction of the ground lightning lightning signal, and at the same time upload the waveform data file of the ground lightning lightning signal to the central processing station, and then directly solve the ground lightning signal at the central processing station. The time difference (TDOA) between the arrival of lightning and lightning signals at any two detection and processing sub-stations does not require the detection and processing sub-stations to provide time-of-arrival (TOA) information of ground lightning and lightning signals;

(5) The detection and processing sub-station can effectively estimate the delay of the system channel group, and add the delay information of the system channel group into the lightning signal waveform data file and upload it to the central processing station. When the central processing station performs TDOA calculation, it uses The system channel group delay information of each detection and processing sub-station compensates the time stamp information of the ground lightning and lightning waveform data used for TDOA calculation, thereby minimizing the difference in system channel group delay of different detection and processing sub-stations The resulting positioning error;

(6) The central processing station uses combined DOA and TDOA information to calculate the two-dimensional plane coordinates of the ground lightning radiation source; it can also only use TDOA information to calculate the position of the ground lightning radiation source, and use DOA information to distinguish and eliminate false positioning point.

Description of drawings

Fig. 1 is the overall structure of the VLF/LF frequency band ground lightning detection and positioning system referred to in the present invention;

Fig. 2 is a block diagram of the functional unit of the detection processing substation;

Fig. 3 is a structural diagram of an ultra-wideband receiving antenna in the VLF/LF band;

Fig. 4 is the system channel group delay calculation process;

Fig. 5 is a functional unit block diagram of the central processing station;

Fig. 6 is a block diagram of the functional unit of the digital processing subsystem of the detection processing substation;

Fig. 7 is a block diagram of the analog channel functional unit of the detection processing substation.

Detailed ways

A VLF/LF frequency band ground lightning detection and positioning system proposed by the present invention uses a VLF/LF frequency band ultra-wideband receiving antenna and a VLF/LF frequency band multi-channel receiving and synchronous acquisition unit to receive and collect ground lightning lightning radiation sources. The receiving bandwidth of VLF/LF ground lightning and lightning signal is 0~2.5MHz. After analog-to-digital conversion, corresponding digital signal processing is carried out, and then the extracted ground lightning and lightning parameters are uploaded to the central processing station for positioning and calculation of ground lightning and lightning signals. .

As shown in Figure 1, a VLF/LF frequency band ground lightning detection and positioning system proposed by the present invention includes a central processing station 20 and N detection and processing sub-stations 11, 12, 13, ..., 1N located in different positions. , N is a positive integer greater than or equal to 3, indicating the number of detection processing sub-stations. The distance between the detection and processing sub-stations 11, 12, 13, . The detection and processing sub-stations 11, 12, 13, ..., 1N are respectively connected to the WAN through wireless or wired methods such as 3G/4G wireless base stations and wired routers, and the central processing station 20 is connected to the WAN through dedicated optical fiber lines to form a joint ground flash Lightning detection and positioning system.

Each detection and processing substation completes GPS/Beidou satellite timing and clock synchronization, system channel group delay calculation, ultra-wideband high-speed reception of VLF/LF frequency band ground lightning lightning signals, synchronous acquisition, channel amplitude inconsistency calibration, ground lightning lightning signal detection and signal direction of arrival estimation, and then frame the obtained real-time ground lightning signal waveform data, direction finding angle information, system state parameter information and time stamp information, etc., cache them in the SDRAM memory stick, and then upload them through the PXI interface To the local hard disk of the embedded controller of the detection and processing sub-station, the ground lightning lightning signal waveform data file is formed, and finally the above-mentioned data file is uploaded to the central processing station through the wide area network using the file transfer protocol (FTP).

After the central processing station 20 receives the ground lightning lightning signal waveform data files uploaded by each detection processing sub-station 11, 12, 13, ..., 1N, store it in the ground lightning lightning database according to the format of the data frame, and then from the database Take out the ground lightning waveform data corresponding to each detection and processing sub-station in the same period and calculate the time difference between the same ground lightning signal arriving at any two detection and processing sub-stations, and then use each detection and processing sub-station to correspond to the same ground lightning lightning signal The DOA information and TDOA information are used to establish a combined positioning equation, and finally calculate the plane coordinate position of the lightning radiation source of the ground lightning.

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. It should be noted here that the descriptions of these embodiments are used to help understand the present invention, but are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not constitute a conflict with each other.

As shown in Figure 2, each detection processing sub-station includes at least the following units: time-frequency unit 101, VLF/LF frequency band ultra-wideband receiving antenna unit 102, VLF/LF frequency band multi-channel receiving and synchronous acquisition unit 103, detection processing sub-station The digital processing subsystem 104 and the embedded controller 105 of the detection processing substation.

The time frequency unit 101 adopts GPS/Beidou satellite timing synchronization technology to provide 50MHz synchronous clock signal, standard second pulse signal (1PPS pulse) and universal coordinated time information (UTC information). Among them, the 1PPS pulse and UTC information are sent to the digital processing subsystem 104 of the detection processing sub-station through a general-purpose serial interface; the rising edge jitter average value of the 1PPS pulse is less than 50 ns, so that the time stamp resolution of the detection processing sub-station reaches 20 ns, each detection processing The clock synchronization accuracy between sub-stations is better than 50ns, thus ensuring the synchronization performance of the entire ground lightning detection and positioning system.

The structural block diagram of the VLF/LF frequency band ultra-broadband receiving antenna unit 102 is shown in Figure 3, and three symmetrically placed support rods 33 support three different receiving antennas respectively: the monopole antenna 34 is perpendicular to the horizontal plane and is used for receiving Electric field channel signal; GPS/Beidou satellite antenna 35, used to receive GPS/Beidou satellite signal; Two orthogonal loop antennas 31 and 32 cross vertically, and each ring plane is all perpendicular to the horizontal plane, wherein, the loop antenna 31 is aligned with the geographic east-west direction Coincident, the loop antenna 32 coincides with the geographical north-south direction, and the two receive the magnetic field east-west loop channel signal and the magnetic field north-south loop channel signal respectively; adopt the coaxial cable to provide the magnetic field east-west loop channel signal, magnetic field north-south loop channel signal and electric field channel signal to the VLF /LF frequency band multi-channel receiving and synchronous acquisition unit 103, also adopts coaxial cable to send GPS/Beidou satellite signal to time frequency unit 101; The coaxial cable of the transmitted magnetic field east-west ring channel signal, magnetic field north-south ring channel signal and electric field channel signal also includes impedance matching, lightning surge protection, differential to single-ended, low-pass filtering and impedance conversion circuits connected in series.

The three analog receiving channels in the VLF/LF frequency band multi-channel receiving and synchronous acquisition unit 103, after lightning surge protection, band-pass filtering, program-controlled gain, and active filter amplification, the VLF/LF frequency band ultra-wideband receiving antenna unit 102 The output magnetic field east-west loop channel signal, magnetic field north-south loop channel signal and electric field channel signal are subjected to ultra-wideband analog reception and amplification, and the signal bandwidth is 0-2.5MHz; then 50MHz synchronous sampling and quantization (quantization digits) are performed through the ADC analog-to-digital conversion circuit After not less than 10bit), the VLF/LF digital signal with a frequency range of 0-2.5MHz is obtained, which is serially input into the digital processing subsystem 104 of the detection processing substation, and the data flow rate of the three serial digital signals is equal to Not less than 500Mbps.

As shown in Fig. 6, the digital processing subsystem 104 of the detection processing substation includes at least a time stamp module 401, a digital preprocessing module 402, a system channel group delay calculation module 403, a channel amplitude inconsistency calibration module 404, a ground lightning signal detection Module 405 , Signal Direction of Arrival Estimation Module 406 , Data Framing Buffer and Transmission Control Module 407 .

The time stamp module 401 mainly completes receiving and analyzing the serial 1PPS pulse and UTC information output by the time frequency unit 101, and obtains the year, month, day, hour, minute and second information; simultaneously uses the 50MHz clock signal output by the time frequency unit 101 to count, and uses The rising edge of the 1PPS pulse clears the counter to obtain a synchronous second pulse count value with an accuracy of 20ns. Together with the year, month, day, hour, minute, and second information, a complete time stamp information is formed for use by subsequent modules. In addition, the time stamp module also completes the frequency division and multiplication processing of the 50MHz clock signal, and generates homologous clock signals of different frequencies that are required by other modules of the digital processing subsystem of the detection processing substation.

The digital preprocessing module mainly completes the synchronous reception and decimation and filtering of the three high-speed serial data streams of the magnetic field east-west loop channel (EW), magnetic field north-south loop channel (NS), and electric field channel (EF), and the three-way data rate is 5Msps The digital signal x _EW (n), x _NS (n), x _{EF (} n). Among them, x _EW (n), x _NS (n), and x _EF (n) are the magnetic field east-west ring channel signal, magnetic field north-south ring channel signal and electric field channel signal at the nth sampling point after digital preprocessing, respectively. The specific process is as follows:

① Synchronous reception of three high-speed serial data streams: first execute the test mode to obtain the clock phase deviation between the three high-speed serial data streams, and then lock the bit clock phase of each serial data stream receiver through the clock phase fine-tuning mechanism , to realize the synchronous reception of three serial digital signals with a rate not lower than 500Mbps, and then through serial-to-parallel conversion, to obtain three parallel digital signals with a rate of 50Msps.

②Decimate and filter processing: firstly, perform DC component removal processing on the three-way parallel digital signals obtained above; then perform low-pass filtering and 5-fold decimation to obtain parallel digital signals with a rate of 10Msps and a bandwidth of 0-5M; The digital signals of the three channels are further low-pass filtered and decimated by 2 times to obtain a parallel digital signal with a rate of 5Msps and a bandwidth of 0-2.5M; finally, high-pass filtering is performed on the three-channel signal to obtain a parallel digital signal with a rate of 5Msps and a bandwidth of 10K-2.5M Three digitally preprocessed signals x _EW (N), x _NS (N), x _EF (N).

In this example, the process shown in Figure 4 can be used to calculate the time delay of the system channel group: the 1PPS pulse output by the time frequency unit 101 is sent to the pulse sequence generator and the time stamp module in the digital processing subsystem 104 of the detection processing substation respectively 401; The pulse sequence generator can generate VLF/LF pulse modulation signal, which generates VLF/LF pulse modulation signal under the synchronous modulation of the rising edge of 1PPS pulse, and then conducts electromagnetic radiation to the space through the signal transmitting antenna; the transmitting antenna is made of copper core The loop antenna made of wire winding, the VLF/LF pulse modulation signal is input to the two input ends of the transmitting antenna to radiate to the space; the VLF/LF frequency band ultra-wideband receiving antenna unit 102 passes the received VLF/LF The LF pulse modulation signal is sent to the VLF/LF frequency band multi-channel receiving and synchronous acquisition unit 103 for synchronous acquisition and reception, and finally enters the system channel group delay calculation after passing through the digital preprocessing module in the digital processing subsystem 104 of the detection processing substation Module; system channel group delay module uses 1PPS pulse rising edge for synchronous detection, the time difference between the moment when the threshold pulse modulation signal is detected and the arrival time of 1PPS pulse rising edge is the group delay of the entire signal loop. In the case of ignoring the difference between the transmit path and the receive path of the pulse modulation signal, the group delay result of the entire signal loop measured above is divided by 2 to obtain the system channel group delay value.

The channel amplitude inconsistency calibration module includes an amplitude inconsistency coefficient calculation module and a channel amplitude inconsistency compensation module;

① The amplitude inconsistency coefficient calculation module, when each detection and processing sub-station is built, uses a random signal generator to generate a Gaussian white noise signal, and sends it to the magnetic field of the VLF/LF frequency band ultra-wideband receiving antenna unit 102 through a 1-2 power divider The coaxial cable connection port of the north-south loop channel and the magnetic field east-west loop channel, and then calculate the magnetic field dual-channel amplitude inconsistency coefficient α for the digital signal x _EW (n) and x _NS (n) after digital preprocessing

$\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; =</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; wxya</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; nS</span>}}}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; E\; W</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}{\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; NS</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}}$

Among them, M is a positive integer, indicating the total number of sampling points contained in each sampling data block, M≥200; x _EW (n), x _NS (n)) are respectively in a sampling data block, after digital preprocessing The magnetic field east-west loop channel signal and the magnetic field north-south loop channel signal of the nth sampling point; P _nEW and P _nNS are respectively the short-term energy of the magnetic field east-west loop channel signal and the magnetic field north-south loop channel signal in a sampling data block;

② In the channel amplitude inconsistency compensation module, the inconsistency compensation is performed on the amplitudes of the three signals output by the digital preprocessing module according to the following formula, and the digital signal after calibration and compensation is obtained

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; E\; W</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; E\; W</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; NS</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; E\; W</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; EF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; EF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>\end{array}\right.$

Among them, y _EW (n) is the digital signal of the east-west ring channel signal of the magnetic field after amplitude inconsistency compensation, and its amplitude compensation coefficient is 1; y _NS (n) is the digital signal of the magnetic field north-south ring channel signal after amplitude inconsistency compensation , its amplitude compensation coefficient is α; y _EF (n) is the digital signal of the electric field channel signal after amplitude inconsistency compensation, and its amplitude compensation coefficient is 1. The reason why the amplitude inconsistency compensation is also performed on the magnetic field east-west loop channel signal and the electric field channel signal is to ensure that the magnetic field east-west loop channel signal x _EW (n) and the magnetic field north-south loop channel signal x _NS ( n) and strict data synchronization between the electric field channel signal x _EF (n).

The ground lightning lightning signal detection module includes a state switching control module, a background noise energy calculation module, a short-term energy calculation module, and a dynamic threshold detection module;

①The state switching control module performs periodic switching control between the background noise energy calculation and the normal sampling receiving state according to the preset background noise energy calculation and normal sampling receiving time ratio; the system in this embodiment performs automatic switching every hour Once, the duration of each background noise energy calculation state is 1s, and the other time is the normal sampling receiving state;

② The noise floor energy calculation module is used to perform short-term energy statistical calculations on the calibrated and compensated digital signals y _EW (n), y _NS (n) according to the following formula during the noise floor energy calculation state

${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; noise</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; E\; W</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; NS</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>$

Among them, E _noise is the noise floor energy, M is a positive integer, indicating the total number of sampling points contained in each sampling data block, M≥200, K is a positive integer, indicating the sampling data block used to calculate the noise floor energy The number of K, the value range of K is [1, 1024]; the reason for counting the cumulative sum of K×M points here is to obtain as many general statistical laws of background noise energy in a long period of time as possible .

③The short-term energy calculation module performs short-term energy calculation on the calibrated and compensated digital signals y _EW (n), y _NS (n) according to the following formula under normal sampling and receiving status

${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; sample</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; E\; W</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; NS</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>$

Among them, E _sample is short-term energy, M is a positive integer, indicating the total number of sampling points contained in each sample data block, M≥200;

④ The dynamic threshold detection module correlates the calculated background noise energy value E _noise with the detection threshold signal-to-noise ratio setting value to obtain the dynamic energy detection threshold

E _ref ＝k*E _noise /K

Among them, k is the detection threshold signal-to-noise ratio setting value, E _ref is the dynamic energy detection threshold; compare the short-term energy E _sample with the detection threshold E _ref , when E _sample ≥ E _ref , it is determined that the data block contains ground flashes Lightning pulse signal, otherwise it does not include ground lightning lightning pulse signal.

The signal direction of arrival estimation module performs tangent angle calculation, arc tangent angle table lookup, and quadrant fuzzy judgment on the data segment containing the ground lightning pulse signal detected under the normal sampling receiving state, so as to obtain the direction of arrival information:

①The tangent angle calculation module uses the following formula to calculate the tangent value information of the direction of arrival

$<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; the\; tan</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; |</span>\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; E\; W</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span>}{<span\; class="notranslate">\; |</span>\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; NS</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span>}$

Among them, θ is the direction of arrival, |tanθ| is the absolute value of its tangent, M is a positive integer, indicating the total number of sampling points contained in each sample data block, M≥200;

② The arc tangent look-up module performs a one-dimensional arc tangent look-up table according to the |tanθ| obtained in the aforementioned tangent angle calculation module to obtain the projection |θ| of the direction of arrival θ in the first quadrant, where the independent variable is the tangent value, and the The value is an angle, and the function value covers 0° to 90°, and the step size of the angle in this embodiment is 0.5°;

③In the de-quadrant fuzzy judgment module, the positive and negative polarity information of the three-channel signals is obtained by calculating the amplitude sum of the magnetic field east-west ring channel signal, the magnetic north-south ring channel signal and the electric field channel signal, and then the quadrant removal is performed according to the following rules Fuzzy judgment to get the real direction of arrival calculation result θ:

in, is the cumulative sum of signal amplitudes in the east-west loop channel of the magnetic field, is the cumulative sum of signal amplitudes of the magnetic field north and south ring channels, It is the cumulative sum of the signal amplitude of the electric field channel, M is a positive integer, indicating the total number of sampling points contained in each sampling data block, M≥200.

Data group framing cache and transmission control module, the electric field channel signal data y _EF (n) corresponding to the data segment that contains the ground lightning pulse signal detected in the aforementioned ground lightning lightning signal detection module, together with the aforementioned signal direction of arrival estimation module The calculated direction of arrival and positive and negative polarity information, as well as system channel group delay information, detection threshold signal-to-noise ratio setting value, and background noise energy value are framed, and marked with a high-precision time stamp output by the time stamp module information to form a complete lightning signal waveform data frame, and then cache it in the SDRAM memory stick. When the data frame size reaches 640KB, it will be uploaded to the embedded control of the detection processing substation through PXI upload control In the local hard disk of device 105, form a ground lightning lightning signal waveform data file.

The detection processing sub-station detection processing sub-station embedded controller 105 in Fig. 2 uploads the ground lightning lightning signal waveform data file stored in the local hard disk to the central processing station 20 in Fig. 1 according to the file transfer protocol (FTP) mode .

As shown in Figure 5, the central processing station at least includes the following units: router 201, firewall 202, communication and monitoring server 203, switch 204, ground lightning database 205, TDOA calculation server 206 and ground lightning location solution server 207.

The lightning detection data files obtained by each detection processing sub-station 11, 12, 13, ..., 1N are transmitted to the router 201 through the wide area network through the high-speed optical fiber dedicated line, and after the invalid IP data packets are isolated by the firewall 202, the valid IP data packets are sent to the communication and monitoring server 203, and then stored in the ground lightning database 205 through the switch 204.

The TDOA calculation server 206 accesses the ground lightning lightning database 205 through the switch 204, obtains the ground lightning lightning signal waveform data frame with time stamp information, and then calculates the time difference Δτ _pq of the ground lightning lightning signal arriving at any two detection processing sub-stations p, q , and then put the TDOA information and DOA information in the same time period into one data set, and obtain the TDOA/DOA data set (Δτ _pq , θ _p ) corresponding to the same ground lightning radiation source, where θ _p represents the pth A detecting and processing substation measures the direction of arrival of the ground lightning lightning signal, and re-stores the calculation result in the ground lightning lightning database 205. The duration of each time period in this embodiment is 40us.

The ground lightning lightning location solution server 207 accesses the ground lightning lightning database 205 through the switch 204, reads the DOA and TDOA data therein, and then uses these data to establish a combined positioning based on the direction of arrival DOA and time difference of arrival TDOA information of the ground lightning lightning signal The two-dimensional plane coordinates (x, y) of the ground lightning lightning radiation source are obtained through iterative calculation. The established combined positioning equations include the following two types:

① Rotational symmetry hyperbolic equation established based on the time difference information of ground lightning lightning signal arriving at any two detection and processing sub-stations:

$\sqrt{{(x_p-x)}^2+{({\mathrm{the\; y}}_p-\mathrm{the\; y})}^2}-\sqrt{{(x_q-x)}^2+{({\mathrm{the\; y}}_q-\mathrm{the\; y})}^2}=c\&Center\; Dot;{\mathrm{\&Delta;\&tau;}}_{\mathrm{pq}},$ p, q=1, 2, ..., p≠q

② The azimuth plane equation established based on the azimuth angle information of the ground lightning lightning signal arriving at any detection and processing substation:

(xx _p )sinθ _p -(yy _p )cosθ _p = 0, p = 1, 2, ...

Among them, (x, y) is the two-dimensional plane coordinates of the ground lightning radiation source, (x _p , y _p ), (x _q , y _q ) are the two-dimensional planes of the pth and qth detection and processing sub-stations Position coordinates, Δτ _pq is the time difference between the arrival of the ground lightning lightning signal at the pth and qth detection and processing sub-stations, θ _p is the direction of arrival of the ground lightning lightning signal obtained by the p-th detection and processing sub-station, and c represents the propagation of electromagnetic waves speed.

In a word, the system of the present invention utilizes VLF/LF frequency band ultra-wideband receiving antenna, VLF/LF frequency band multi-channel reception and synchronous acquisition board, digital signal processing hardware platform composed of FPGA, SDRAM, PCI controller, etc., and PXI embedded industrial computer etc. Constitute a complete ground lightning detection and processing sub-station to complete the reception, processing, transmission and control of VLF/LFF frequency band ground lightning signals. The system accurately estimates the direction of arrival (DOA) of the lightning signal generated by the ground lightning radiation source and propagates along the ground surface. In addition, the system also uses GPS/Beidou satellite high-precision timing technology and file transfer protocol (FTP) network transmission technology to upload the ground lightning lightning waveform with high-precision time stamp information and the above-mentioned obtained ground lightning lightning signal direction of arrival data. to the central processing station. Then the central processing station calculates the time difference of arrival (TDOA) estimation corresponding to the same ground lightning signal between any two detection and processing sub-stations, and realizes the two-dimensional plane positioning of the ground lightning radiation source based on DOA and TDOA information. The central processing station is composed of multiple interconnected general-purpose computers. The file transfer protocol (FTP) is used between the detection processing sub-station and the central processing station to complete the transmission of lightning waveform data files, and the transmission control protocol/Internet protocol (TCP /IP) to complete the two-way monitoring information of the ground lightning detection and processing sub-station.

The present invention is not limited to the above-mentioned specific embodiments. Those skilled in the art can implement the present invention by adopting other various specific embodiments according to the disclosed content of the present invention. Changes or modified designs all fall within the protection scope of the present invention.

Claims (10)

1. VLF/LF frequency range ground dodges a lightening detection positioning system, it is characterized in that, this system comprises a center processing station and multiple detection processing substation that is positioned at diverse location; Different detection processing substations and center processing station all form the system of an associating by wireless or wired mode access wide area network;

Each survey process substation be used for the time service of GPS/ big-dipper satellite and clock synchronous, system channel group delay calculate, dodge the reception of thunder and lightning signal and synchronous acquisition, the calibration of channel amplitude inconsistency, dodge that thunder and lightning detects and the estimation of signal direction of arrival, then the lightning wave of the sudden strain of a muscle in real time graphic data, direction finding angle information, system state parameter information and the time tag information that obtain are carried out after framing, form ground and dodge thunder and lightning signal waveform data file, by wide area network, this data file is uploaded to center processing station;

Center processing station is realized each is surveyed to the remote monitoring of processing substation duty by wide area network; Data file that upload processing substation is also surveyed for receiving each in center processing station, and each is surveyed ground of processing substation and dodges thunder and lightning signal waveform data file and calculate and dodge thunder and lightning signal and arrive any two and survey the mistiming of processing substations according to the same period samely, re-use each survey process substation corresponding to same direction of arrival information of dodging thunder and lightning signal and time of arrival poor information dodge the planimetric coordinates position in radiation of lightening discharge source with calculating.

2. a kind of VLF/LF frequency range according to claim 1 ground dodges lightening detection positioning system, it is characterized in that, each detection is processed substation and is all at least comprised with lower unit: temporal frequency unit (101), VLF/LF frequency range ultra broadband receiving antenna unit (102), the reception of VLF/LF frequency range hyperchannel and synchronous acquisition unit (103), detection are processed substation digital processing subsystem (104) and surveyed and process substation embedded controller (105);

VLF/LF frequency range ultra broadband receiving antenna unit (102) dodges thunder and lightning signal and GPS/ Big Dipper satellite signal for receiving, ground is dodged to thunder and lightning signal and offer the reception of VLF/LF frequency range hyperchannel and synchronous acquisition unit (103), GPS/ Big Dipper satellite signal is offered to temporal frequency unit (101);

Resolve the GPS/ Big Dipper satellite signal receiving temporal frequency unit (101), obtains standard second pulse signal and UTC information, and offer detection processing substation digital processing subsystem (104); Also local clock signal is synchronously processed, synchronizing clock signals is offered respectively to the reception of VLF/LF frequency range hyperchannel and synchronous acquisition unit (103) and detection and process substation digital processing subsystem (104);

VLF/LF frequency range hyperchannel receives and synchronous acquisition unit (103) carry out synchronized sampling and quantification treatment according to synchronizing clock signals to the ground sudden strain of a muscle thunder and lightning signal receiving, and dodges thunder and lightning digital signal with obtaining and sends into detection processing substation digital processing subsystem (104);

Survey processing substation digital processing subsystem (104) the ground sudden strain of a muscle thunder and lightning digital signal of input is carried out to digital processing, dodge lightning wave graphic data file with obtaining, be cached in to survey and process in substation embedded controller (105);

Survey processing substation embedded controller (105) the ground sudden strain of a muscle lightning wave graphic data file being stored in local hard drive is uploaded to center processing station in file transfer protocol (FTP) (FTP) mode.

3. a kind of VLF/LF frequency range according to claim 1 ground dodges lightening detection positioning system, it is characterized in that, center processing station at least comprise router (201), fire wall (202), communication and monitoring server (203), switch (204), dodge lightning data storehouse (205), TDOA calculation server (206) and ground and dodge thunder and lightning positioning calculation server (207);

Communication receives each detection with monitoring server (203) by router (201) and fire wall (202) and processes the ground sudden strain of a muscle thunder and lightning signal waveform data file that substation provides, lightening detection data are dodged in parsing with obtaining, this ground dodges lightening detection data and comprises ground sudden strain of a muscle lightning wave graphic data and the DOA data with time tag information, and dodge lightning data storehouse (205) storage of classifying by switch (204) with offering, communication also surveys to each remote monitoring of processing substation duty for completing with monitoring server (203);

TDOA calculation server (206) dodges lightning data storehouse (205) by switch (204) access, obtain dodging lightning wave graphic data with the ground of time tag information, then calculating ground sudden strain of a muscle thunder and lightning signal arrives any two and surveys the mistiming of processing substations, obtain TDOA data, and TDOA data are dodged in lightning data storehouse (205) again with being stored in;

Ground dodges thunder and lightning positioning calculation server (207) and dodges lightning data storehouse (205) by switch (204) access, read DOA and TDOA data wherein, dodge the two dimensional surface coordinate of thunder and lightning origination point or area of space according to read data with calculating.

4. a kind of VLF/LF frequency range according to claim 2 ground dodges lightening detection positioning system, it is characterized in that, VLF/LF frequency range ultra broadband receiving antenna unit (102) comprises monopole antenna (34), GPS/ big-dipper satellite antenna (35) and two orthogonal magnetic loop antenna (31, 32), wherein two orthogonal loop antennas (31, 32) overlap with geographical east-west direction and North and South direction respectively, be used for receiving magnetic field thing ring channel signal and north and south, magnetic field ring channel signal, monopole antenna (34) is vertical with surface level, receive electric field channel signal, and adopt concentric cable and magnetic field thing ring channel signal, north and south, magnetic field ring channel signal and electric field channel signal are offered to VLF/LF frequency range hyperchannel receive and synchronous acquisition unit (103), that impedance matching, lightening surge preventing, the difference that magnetic field thing loop antenna passage, north and south, magnetic field loop antenna passage and electric field antenna channels include successively series connection turns is single-ended, low-pass filtering and impedance inverter circuit, VLF/LF frequency range hyperchannel receives and synchronous acquisition unit (103) middle three corresponding simulation receiving cables include series connection successively lightening surge preventing, bandpass filtering, programme-controlled gain, active power filtering amplify and ADC analog to digital conversion circuit,

GPS/ big-dipper satellite antenna (35) is for receiving GPS/ Big Dipper satellite signal, and offers temporal frequency unit (101).

5. a kind of VLF/LF frequency range according to claim 2 ground dodges lightening detection positioning system, it is characterized in that, survey processing substation digital processing subsystem (104) three railway digital signals of input are carried out after digital pre-service, obtain magnetic field thing ring passage numeral preprocessed signal, north and south, magnetic field ring passage numeral preprocessed signal and the digital preprocessed signal of electric field passage; Then carry out the calibration of channel amplitude inconsistency, dodge thunder and lightning input, the estimation of signal direction of arrival, time mark, data buffer storage and control, dodged in real time lightning wave graphic data, magnetic field passage inconsistency calibration factor and signal wave and reached directional data, then after framing buffer memory, upload to survey and process substation embedded controller (105).

6. a kind of VLF/LF frequency range according to claim 3 ground dodges lightening detection positioning system, it is characterized in that, the concrete processing procedure that TDOA calculation server (206) and ground dodge thunder and lightning positioning calculation server (207) is respectively:

TDOA calculation server (206) dodges lightning data storehouse (205) by switch (204) access, obtain dodging thunder and lightning signal waveform data frame with the ground of time tag information, then calculating ground sudden strain of a muscle thunder and lightning signal arrives any two and surveys the mistiming Δ τ that processes substation p, q _pq, then the TDOA information, the DOA information that are positioned at the same time period are put in to a data centralization, obtain TDOA/DOA data acquisition (the Δ τ that dodges thunder and lightning signal corresponding to same _pq, θ _p), wherein, θ _prepresent that p is surveyed the direction of arrival of processing the ground that records, substation and dodge thunder and lightning signal, and by this data acquisition (Δ τ _pq, θ _p) again dodge in lightning data storehouse (205) with being stored in;

Ground dodge thunder and lightning positioning calculation server (207) utilize direction of arrival DOA and time of arrival poor TDOA information set up based on ground dodge thunder and lightning signal direction of arrival DOA and time of arrival poor TDOA information integrated positioning equation, finally resolve the two dimensional surface coordinate that dodges thunder and lightning origination point or area of space with obtaining;

Described integrated positioning system of equations comprises following two class positioning equations:

1. dodge thunder and lightning signal based on ground and arrive any two Rotational Symmetry Hyperbolic Equations of surveying the time difference information of processing substation and set up:

$\sqrt{{(x_p-x)}^2+{(y_p-y)}^2}-\sqrt{{(x_q-x)}^2+{(y_q-y)}^2}=c\&CenterDot;{\mathrm{\&Delta;\&tau;}}_{\mathrm{pq}},p,q=\mathrm{1,2},...,p\&NotEqual;q$

P, q survey the sequence number of processing substation;

2. dodge thunder and lightning signal based on ground and arrive the aximuthpiston equation of surveying arbitrarily the azimuth information of processing substation and set up:

(x-x _p)sinθ _p-(y-y _p)cosθ _p＝0,p＝1,2,…

Wherein, (x, y) dodges the two dimensional surface coordinate in radiation of lightening discharge source, (x with being _p, y _p), (x _q, y _q) be the two dimensional surface position coordinates that p and q survey processing substation, Δ τ _pqfor dodging thunder and lightning signal, ground arrives p and q the mistiming of surveying processing substation, θ _pbe p and survey the ground sudden strain of a muscle thunder and lightning signal direction of arrival that processing substation obtains, c represents electromagnetic wave propagation speed.

7. a kind of VLF/LF frequency range according to claim 2 ground dodges lightening detection positioning system, it is characterized in that, survey process substation digital processing subsystem (104) at least comprise time mark module (401), digital pretreatment module (402), system channel group delay computing module (403), channel amplitude inconsistency calibration module (404), dodge thunder and lightning signal detection module (405), signal direction of arrival estimation module (406), data framing buffer memory and transmission control module (407);

Numeral pretreatment module (402) is carried out synchronous reception and filtering extraction processing for completing to three railway digital signals of input, and data after treatment are offered to channel amplitude inconsistency calibration module (404) and system channel group delay computing module (403);

Channel amplitude inconsistency calibration module (404) is to the magnetic field thing ring passage numeral preprocessed signal obtaining, the amplitude of north and south, magnetic field ring passage numeral preprocessed signal and electric field passage numeral preprocessed signal is carried out Inconsistency compensation processing, obtain digital signal and magnetic field binary channels amplitude inconsistency coefficient after compensation for calibrating errors, and the magnetic field thing ring channel digital signal after compensation for calibrating errors and north and south, magnetic field ring channel digital signal are dodged to thunder and lightning signal detection module (405) with offering, simultaneously by the magnetic field thing ring passage numeral preprocessed signal after compensation for calibrating errors, north and south, magnetic field ring passage numeral preprocessed signal and electric field passage numeral preprocessed signal offer signal direction of arrival estimation module (406),

Ground dodges thunder and lightning signal detection module (405) and utilizes magnetic field thing ring passage numeral preprocessed signal and north and south, magnetic field ring passage numeral preprocessed signal after compensation for calibrating errors to carry out short-time energy calculating, obtain the detection of dynamic thresholding Mobile state over-threshold detection of going forward side by side, and testing result is offered to signal direction of arrival estimation module (406);

The signal that signal direction of arrival estimation module (406) utilization receives carries out arctangent computation, obtains direction of arrival information, and offers data framing buffer memory and transmission control module (407);

Data framing buffer memory and transmission control module (407) are by direction of arrival information, together with corresponding electric field passage numeral preprocessed signal and temporal information, and magnetic field binary channels amplitude inconsistency coefficient, dynamic monitoring threshold information carry out framing, local cache, then upload to survey and process substation embedded controller (105);

Time mark module (401) receives from temporal frequency unit (101) output 1PPS pulse and UTC information, and above-mentioned detecting dodged to lightening pulse signal data segment mark temporal information with comprising; Time mark module (401) also receives the synchronous clock information from temporal frequency unit (101) output, provides clock signal for surveying other modules of processing substation digital processing subsystem.

8. a kind of VLF/LF frequency range according to claim 7 ground dodges lightening detection positioning system, it is characterized in that, channel amplitude inconsistency calibration module (404) comprises amplitude inconsistency coefficients calculation block and channel amplitude Inconsistency compensation module;

Amplitude inconsistency coefficients calculation block is used for calculating magnetic field binary channels amplitude inconsistency factor alpha:

$\mathrm{\&alpha;}=\sqrt{\frac{P_{\mathrm{nEW}}}{P_{\mathrm{nNS}}}}=\sqrt{\frac{\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{\mathrm{EW}}^2\left(n\right)}{\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{\mathrm{NS}}^2\left(n\right)}}$

Wherein, M is positive integer, represents total sampling number that each sampled data piece comprises, M>=200; x _eW(n), x _nS(n) be respectively in a sampled data piece, through the magnetic field of pretreated n the sampled point of numeral thing ring channel signal and north and south, magnetic field ring channel signal; P _nEWand P _nNSbe respectively the short-time energy of magnetic field thing ring channel signal and north and south, magnetic field ring channel signal in a sampled data piece;

Channel amplitude Inconsistency compensation module is carried out Inconsistency compensation for the amplitude of the three railway digital signals to digital pretreatment module output

$\left\{\begin{array}{c}{y}_{\mathrm{EW}}\left(n\right)=1\&CenterDot;x_{\mathrm{EW}}\left(n\right)\\ y_{\mathrm{NS}}\left(n\right)=\mathrm{\&alpha;}\&CenterDot;x_{\mathrm{EW}}\left(n\right)\\ y_{\mathrm{EF}}\left(n\right)=1\&CenterDot;x_{\mathrm{EF}}\left(n\right)\end{array}\right.$

Wherein, y _eW(n) be the digital signal of magnetic field thing ring channel signal after amplitude Inconsistency compensation, its Amplitude Compensation coefficient is 1; y _nS(n) be the digital signal of north and south, magnetic field ring channel signal after amplitude Inconsistency compensation, its Amplitude Compensation coefficient is α, y _eF(n) be the digital signal of electric field channel signal after amplitude Inconsistency compensation, its Amplitude Compensation coefficient is 1; x _eWand x (n) _nS(n) channel signal, x are encircled in the pretreated magnetic field of representative digit thing ring channel signal and north and south, magnetic field respectively _eF(n) the pretreated electric field channel signal of representative digit.

9. a kind of VLF/LF frequency range according to claim 7 ground dodges lightening detection positioning system, it is characterized in that, ground dodges thunder and lightning signal detection module (405) and comprises state switching controls module, background noise energy computing module, short-time energy computing module and dynamic over-threshold detection module;

State switching controls module is calculated according to default background noise energy and normal sampling time of reception ratio, calculates between normal sampling accepting state and carries out periodic switching controls at background noise energy;

Background noise energy computing module is for during background noise energy computing mode, to the digital signal y after compensation for calibrating errors _eW(n), y _nS(n) carry out according to the following equation short-time energy statistical computation

$E_{\mathrm{noise}}=\underset{n=0}{\overset{K\&times;M}{\mathrm{\&Sigma;}}}[y_{\mathrm{EW}}^2\left(n\right)+y_{\mathrm{NS}}^2\left(n\right)]$

Wherein, E _noisefor background noise energy, M is positive integer, represents total sampling number that each sampled data piece comprises, M>=200, and K is positive integer, represents the number for calculating background noise energy sampled data piece used, the span of K is [1,1024];

Short-time energy computing module is under normal sampling accepting state, to the digital signal y after compensation for calibrating errors _eW(n), y _nS(n) carry out according to the following equation short-time energy calculating

$E_{\mathrm{sample}}=\underset{n=0}{\overset{M}{\mathrm{\&Sigma;}}}[y_{\mathrm{EW}}^2\left(n\right)+y_{\mathrm{NS}}^2\left(n\right)]$

Wherein, E _samplefor short-time energy, M is positive integer, represents total sampling number that each sampled data piece comprises, M>=200;

Dynamically over-threshold detection module is by the background noise energy value E calculating _noisecarry out relevant treatment with detection threshold signal-to-noise ratio settings value, obtain dynamic power detection threshold

E _ref＝k*E _noise/K

Wherein, k is detection threshold signal-to-noise ratio settings value, E _reffor dynamic power detection threshold; By short-time energy E _samplewith detection threshold E _refcompare, work as E _sample>=E _reftime, judge that this data block dodges lightening pulse signal with comprising, otherwise do not dodge lightening pulse signal with comprising;

1PPS pulse and the UTC temporal information of mark temporal information module frequency cells service time (101) output, be temporal information on the electric field channel signal mark dodging after the corresponding compensation for calibrating errors of the data segment of lightening pulse by aforementioned detection with comprising, form ground and dodge lightening detection data.

10. a kind of VLF/LF frequency range according to claim 7 ground dodges lightening detection positioning system, it is characterized in that, signal direction of arrival estimation module (406) comprises tangent angle computing module, arc tangent angle table look-up module and goes quadrant fuzzy Judgment module;

Tangent angle computing module utilizes following formula to calculate the absolute value information of the tangent value of direction of arrival θ | tan θ |

$\left|\tan \mathrm{\&theta;}\right|=\frac{\left|\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)\right|}{\left|\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)\right|}$

Wherein, θ is direction of arrival, | tan θ | be the absolute value of its tangent value, M is positive integer, represents total sampling number that each sampled data piece comprises, M >=200;

Arc tangent table look-up module is according to obtaining in aforementioned tangent angle computing module | tan θ | carry out one dimension arc tangent and table look-up, obtain the absolute value of direction of arrival | θ |, wherein independent variable is tangent value, and functional value is angle, and functional value covers 0 °～90 °;

Go in quadrant fuzzy Judgment module, calculate the amplitude cumulative sum value of magnetic field thing ring channel signal, north and south, magnetic field ring channel signal and electric field channel signal after amplitude Inconsistency compensation, obtain the positive-negative polarity information of triple channel signal, then go quadrant fuzzy Judgment to obtain real direction of arrival result of calculation θ according to following rule:

$\left\{\begin{array}{c}\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)>0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)>0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EF}}\left(n\right)<0\\ \underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)<0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)<0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EF}}\left(n\right)>0\end{array}\right.$ Corresponding first quartile: θ=| θ |

$\left\{\begin{array}{c}\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)<0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)>0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EF}}\left(n\right)>0\\ \underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)>0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)<0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EF}}\left(n\right)<0\end{array}\right.$ Corresponding the second quadrant: θ=180 °-| θ |

$\left\{\begin{array}{c}\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)>0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)>0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EF}}\left(n\right)>0\\ \underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)<0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)<0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EF}}\left(n\right)<0\end{array}\right.$ Corresponding third quadrant: θ=180 °+| θ |

$\left\{\begin{array}{c}\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)>0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)<0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EF}}\left(n\right)>0\\ \underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EW}}\left(n\right)<0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{NS}}\left(n\right)>0,\underset{n=1}{\overset{M}{\mathrm{\&Sigma;}}}{y}_{\mathrm{EF}}\left(n\right)<0\end{array}\right.$ Corresponding fourth quadrant: θ=360 °-| θ |

Wherein, for the magnetic field thing ring channel signal amplitude cumulative sum value after amplitude Inconsistency compensation, for north and south, the magnetic field ring channel signal amplitude cumulative sum value after amplitude Inconsistency compensation, for the electric field channel signal amplitude cumulative sum value after amplitude Inconsistency compensation, M is positive integer, represents total sampling number that each sampled data piece comprises, M>=200.