WO2018036280A1

WO2018036280A1 - Method of using mobile terminal to detect and cooperatively position lightning

Info

Publication number: WO2018036280A1
Application number: PCT/CN2017/091667
Authority: WO
Inventors: 伍楷舜; 刘巍峰; 邹永攀; 王璐
Original assignee: 深圳大学
Priority date: 2016-08-26
Filing date: 2017-07-04
Publication date: 2018-03-01
Also published as: CN107490781B; CN107490781A; CN106324562A

Abstract

The invention relates to the field of positioning of thunder and lightning. Provided is a method using a mobile terminal to detect and cooperatively position lightning. The method comprises the following steps: S1. using a magnetometer of an intelligent device to collect thunder and lightning data at a given frequency (S1); S2. performing processing on the data collected by the magnetometer (S21, S22); and S3. performing time domain analysis (S31A) and frequency domain analysis (S31B) on divided frame data. The method using a mobile terminal to detect and cooperatively position lightning can obtain a precise lightning distance, and has high cost performance and a wide range of applications.

Description

Method for detecting and co-locating lightning using a mobile terminal

Technical field

The present invention relates to the field of lightning positioning, and more particularly to a method for detecting and co-locating lightning using a mobile terminal.

Background technique

Lightning is a strong discharge between clouds and clouds, between clouds and ground, or between various parts of the cloud (generally in cumulonimbus). Usually, the storm cloud (cumulonimbus) generates electric charge, the bottom layer is negative electricity, the top layer is positive electricity, and it also produces positive charges on the ground, moving along with the clouds. Positive and negative charges attract each other, but air is not a good conductor. Positive charges rush to the tops of trees, hills, tall buildings, and even the human body, in an attempt to meet the negatively charged clouds; the negatively charged branches extend downward and extend closer to the ground. Finally, the positive and negative charges are finally connected to overcome the obstacle of the air. The huge current flows from the ground to the clouds along a conducting airway, creating a bright flash of light.

The process of lightning seen by the naked eye is very complicated. When the thunderstorm cloud moves to somewhere, the middle and lower part of the cloud is a strong negative charge center, and the opposite underlying surface of the cloud becomes a positive charge center, forming a strong electric field between the cloud bottom and the ground. In the case where the electric charge accumulates more and the electric field becomes stronger, the cloud bottom first appears as a gas column in which the atmosphere is strongly ionized, which is called a step pilot. The ionized gas column extends step by step to the ground. Each stage of the cascade is a dim light column with a diameter of about 5 meters, a length of 50 meters and a current of about 100 amps. It is extended at a high speed of about 150,000 meters per second. To the ground, when the ground is about 5-50 meters away from the ground, the ground suddenly hits back. The channel of the return is from the ground to the bottom of the cloud, and the ionization channel is opened along the steps of the above-mentioned steps. The backlash rushed from the ground to the bottom of the cloud at a higher speed of 50,000 km/s, emitting a bright beam of light, lasting 40 microseconds, and the current exceeded 10,000 amps, which was the first flash. A few hundredths of a second, from a cloud of a dim light column, carrying a huge current, flying along the path of the first flash to the ground, called the direct pilot, when it is off the ground 5 - When it is about 50 meters, the ground will strike back again, and then a bright light column will be formed. This is the second flash. Then, the third and fourth flashes are generated similarly to the second time. A lightning process is usually formed by 3-4 flashes. A lightning process lasted about 0.25 seconds. In this short period of time, a huge narrow electric lightning channel would release huge electric energy, thus forming a strong explosion, generating a shock wave, and then forming sound waves to spread around. This is thunder or saying " Thunder", at the same time at the moment of discharge will produce EMP (electromagnetic pulse), lightning electromagnetic pulse is the electromagnetic radiation associated with lightning discharge. Lightning electromagnetic radiation is very similar to nuclear explosion electromagnetic radiation. The electromagnetic waves radiated from VLF (very low frequency) to UHF (very high frequency), very wide electromagnetic pulses, the generated electric and magnetic fields can be coupled into electrical or electronic systems. , thereby generating an intrusive surge current or surge voltage. Electromagnetic pulses have a strong interference with precision electronic components and even burn out electronic components.

Lightning hazard

Because the energy contained in lightning is huge, the powerful lightning current flows through the organism after the lightning strikes. The thermal and biological effects generated in this process are the main cause of injury. Because the human body has a certain resistance, a powerful current flows through the human body. In a moment, a large amount of heat is generated, which causes the human skin and internal organs to be carbonized, which is "burnt", and the biological effect is that when the current flows through the heart, the myocardial fiber vibrates, causing the heartbeat to stop. Every year, people are killed by electric shocks, and lightning has a great impact on human production activities.

Existing lightning detection technology

1. Lightning detection network such as: U.S. National Lighting Detecting Network, China National Lightning Monitoring and Positioning Network.

NLDN detects lightning by means of a number of sensor nodes located in different regions. It provides services to the US power system, weather forecasting systems and other government departments, as well as some commercial sectors, including real-time data and historical data. . However, NLDN needs to deploy dedicated sensor nodes, and the general public needs to pay for it.

2. Commercial personal portable lightning detection equipment

One of the more popular ones is the use of battery-based pager-sized personal lightning detection equipment, which is used outdoors. Among the working people are popular, such as golfers, campers, sportsmen and some other outdoor sportsmen. This device determines the distance of lightning from the user by detecting the intensity of the EMP (electromagnetic pulse), but it has the disadvantage that it is easy to misjudge the distance, and of course it cannot locate the location where the lightning occurs. There are also other professional lightning detection equipment that perform better but are expensive.

Summary of the invention

In order to overcome the deficiencies in the prior art referred to above, the present invention provides a method for detecting and co-locating lightning using a mobile terminal, which solves the above problem of easily misjudged distance in the prior art.

The present invention is achieved by the following technical solution: a method for detecting and co-locating lightning using a mobile terminal, comprising the following steps:

S1. Collect lightning data at a certain frequency by using a magnetometer disposed on the mobile terminal;

S2: processing data collected by the magnetometer, and dividing the data into a plurality of frame data having a set time length in time sequence;

S3, performing time domain analysis and frequency domain analysis on the divided frame data to obtain a plurality of characteristic parameters of the data; and determining, by using the obtained characteristic parameter, whether the magnetic induction data formed by lightning, and determining the lightning formation time, and Turn on the microphone to receive the thunder signal;

S4. The processing unit of the smart device calculates a distance between the lightning discharge position and the mobile terminal by using a lightning formation time and a thunder receiving time, and simultaneously numbers the lightning terminal, the distance from the discharge position, the lightning formation time, and The mobile terminal location information is uploaded to the server through the wireless network;

S5. The server uses the above information uploaded by the multiple mobile terminals to locate the location of the lightning discharge at a certain moment according to the geometric principle, and generates a lightning discharge heat map to return to the plurality of mobile terminals.

As a further improvement of the present invention, the step S2 comprises:

S21. Divide the magnetic induction signal output by the magnetometer, and divide it into multiple segments according to a set time interval, each segment being adjacent on the time axis and having the same length of time; each segment of the magnetic induction signal is a data frame. For each data frame Give its start time as its time stamp;

S22: Perform noise reduction processing on each of the data frames, and filter the signal using a filter to remove noise.

As a further improvement of the present invention, the step S3 includes:

S31A, performing time domain analysis on the signal data in each data frame to obtain time domain characteristics, where the time domain features include signal amplitude, signal energy, and signal statistics;

S31B: performing Fourier transform on the data signal in the data frame by using a short-time Fourier transform function, and analyzing the frequency domain of the signal to obtain a frequency domain characteristic thereof, where the frequency domain features include: Spectral centroid, spectral entropy, bandwidth, spectral flux, and spectral roll-off;

S32. Combining the time domain feature and the frequency domain feature of the data frame to obtain a parameter set of the data frame, and using the parameter set to determine whether a discharge and a discharge time exist in the data frame, and if so, triggering the microphone to collect data;

S33. Perform time-frequency analysis on the sound signal collected by the microphone to detect the arrival time of the thunder.

As a further improvement of the present invention, in step S32, by comparing the obtained feature parameter set with the previously stored plurality of feature parameter sets one by one, a plurality of the same types in the two feature parameter sets being compared When the difference between the characteristic parameters is less than the set threshold, it is determined that the lightning discharge exists, and the time stamp corresponding to the currently obtained feature parameter set is taken as the discharge time.

As a further improvement of the present invention, in the step S5, the server determines, according to the information uploaded by the different mobile terminals, the data uploaded by the mobile terminal detecting the lightning in the discharge location area of the lightning discharge according to the discharge time, and combines the data in the area The distance information uploaded by the mobile terminal locates the location of the lightning discharge by geometric principle, generates a lightning discharge heat map according to different lightning information located at different moments, and transmits it to the client of the smart device.

As a further improvement of the present invention, the client of the smart device receives the information returned by the server through the network, and gives the user a security prompt according to the information, and provides the client to view the lightning information in the vicinity.

The invention has the beneficial effects that the lightning distance can be accurately obtained by the method of the invention, and the utility model has the advantages of high cost performance and wide application.

DRAWINGS

1 is a schematic diagram of a scenario application of the present invention;

Figure 2 is a schematic view of the steps of the present invention.

detailed description

The invention will now be further described with reference to the drawings and embodiments.

A method for detecting and co-locating lightning using a mobile terminal, the steps of which include:

S1, collecting lightning data by using a magnetometer of the smart device at a certain frequency;

S2, processing data collected by the magnetometer;

S3, performing time domain analysis and frequency domain analysis on the divided frame data;

S4. The processing unit of the smart device calculates the distance of the lightning discharge position from the mobile terminal, and simultaneously uploads the lightning ID, the distance, the time stamp, and the location information of the mobile terminal to the server through the wireless network;

S5. The server locates the location of the lightning discharge at a certain moment, and generates a lightning discharge heat map to return to the smart device client;

S6. The smart device client receives the information returned by the server.

The step S2 includes:

S21. First, the magnetometer signals collected in step S1 are framed, and each window data is processed;

S22. Perform noise reduction processing on the collected magnetometer signal, and filter the signal by using a filter to remove noise.

The step S3 includes:

S31A, performing time domain analysis on the signal data obtained in step S2;

S31B, performing a Fourier transform on the data signal obtained in step S2 using a short-time Fourier transform function to analyze the frequency domain of the signal;

S32. Analyze the time domain information and the frequency domain information obtained through the analysis in steps S31A and S31B, extract features, determine a discharge time, and trigger a microphone to collect data;

In the step S5, the server determines, according to the information uploaded by the mobile terminal, the data uploaded by the mobile terminal that detects the lightning in the discharge location area during the lightning discharge according to the timestamp, and combines the distance information uploaded by the mobile terminal in the area. The geometric principle locates the location of the lightning discharge, generates a lightning discharge heat map according to different lightning information located at different times, and transmits it back to the client of the smart device.

In the step S6, the client of the smart device receives the information returned by the server through the network, and gives the user a security prompt according to the information, and provides the client to view the lightning information in the vicinity.

The method uses a combination of sensors and microphones built into the phone to detect and measure lightning and to locate lightning in conjunction with multiple handsets in the area.

In a specific embodiment, as shown in FIG. 1, a method for detecting and co-locating lightning using a mobile terminal includes the following steps:

S1, collecting data at a certain frequency by using a magnetometer of the smart device;

S2, processing the data collected by the magnetometer. First, the collected signal is framed, then the signal is denoised, and the signal is filtered by using a filter;

S3, performing time domain analysis on the divided frame data, and performing time-frequency domain transform on the time-series frame data by using a short-time Fourier transform, and generating an extremely high-energy electromagnetic pulse due to lightning discharge (lightning electromagnetic pulse) ), because the electromagnetic pulse with strong energy in a short period of time has high energy, the precision sensor (magnetometer) of the smart device is affected by the short-time high-energy electromagnetic pulse, which causes the collected magnetometer data to be abnormal, and This kind of interference has a certain mode. By combining the analysis of the time domain and the frequency domain of the signal, the interference is detected and the lightning discharge time is determined. Since the propagation speed of the electromagnetic pulse is equal to the speed of light, the speed is extremely fast, and the error in a certain area is negligible. Except when the discharge is detected, the speaker is triggered to collect sound data. Due to the time-frequency characteristics of the thunder, there is also a certain mode, and the time when the thunder arrives is detected by an algorithm;

S4, the processing unit of the smart device calculates the distance of the lightning discharge position from the mobile phone according to the time difference between the arrival of the LEMP and the thunder, and uploads the lightning ID, distance, time stamp, mobile phone location and the like to the server through the wireless network;

S5. The server uses the geometric positioning method to locate the position of the lightning discharge at a certain moment according to the information uploaded by the mobile phone at different positions in the same area, and generates a lightning discharge heat map to return the smart device according to the lightning discharge times of different lightning positions. Client

S6: The client receives the information returned by the server, and gives the user an active security prompt, and the user can also view the lightning history discharge information in the vicinity through the client.

Because the electromagnetic pulse generated by lightning will produce instantaneous electromagnetic interference to the precise sensor, resulting in data anomaly, the EMP interference of this mode is detected to determine the time of lightning discharge, while the lightning discharge, in the lightning channel, the current Extremely strong, the temperature can rise to 20,000 degrees Celsius, the air pressure suddenly increases, causing the air to expand rapidly, forming a shock, producing thunder, and the speed of thunder and electromagnetic waves is different, so the electromagnetic pulse and thunder arrive at different times. The TOA is used to calculate the distance from the mobile phone when the lightning is discharged. When the mobile phone in the area detects the lightning signal, the distance of the lightning and its position information and time stamp are uploaded to the server through the network through the network, and the server passes through different locations. The data uploaded by the mobile phone is used to locate the lightning, and generate a heat map of the lightning discharge distribution, and then return the information to the mobile terminal display, and the user can judge the lightning information by the neighbor information, and keep away from the dangerous area in time to protect personal safety.

In general, in the embodiment, the lightning data is collected at a certain frequency by using a magnetometer disposed on the mobile terminal; the data collected by the magnetometer is processed, and is divided into a plurality of devices according to chronological order. a frame data of a predetermined length of time; performing time domain analysis and frequency domain analysis on the divided frame data to obtain a plurality of characteristic parameters of the data; and determining whether the magnetic induction data formed by the lightning is obtained by using the obtained characteristic parameter, and if so, Determining a lightning formation time and turning on a microphone to receive a thunder signal; the processing unit of the smart device calculates a distance between the lightning discharge position and the mobile terminal by a lightning formation time and a thunder reception time, and simultaneously numbers the mobile terminal with the lightning The distance of the above discharge position, the lightning formation time and the position information of the mobile terminal are uploaded to the server through the wireless network; the server transmits the above information of the plurality of mobile terminals, and locates the position of the lightning discharge at a certain moment according to the geometric principle to generate a lightning discharge heat. The graph returns to the plurality of mobile terminals. Basically, it is to use a plurality of mobile terminals (ie, smart devices) loaded in the lightning generating area to perform the above functions, and firstly detect whether a magnetic induction signal caused by lightning occurs, and if so, Determine the lightning time and start the microphone to detect the audio signal of the thunder. If detected, you can know the time difference between the lightning and thunder signals reaching the location of the mobile terminal. This basically can obtain the distance from the location where the lightning occurs to the location of the mobile terminal; when such a mobile terminal detects the distance, the server can determine the specific location of the lightning occurrence by the data uploaded by the mobile terminal, and then can use the same. Users of these softwares send out warning signals.

More specifically, in the above embodiment, the processing of the magnetic induction signal includes: dividing the magnetic induction signal output by the magnetometer, and dividing it into a plurality of segments according to a set time interval, each segment being adjacent on the time axis And each segment has the same length of time; a magnetic induction signal is a data frame, and each data frame is given its start time as its time stamp; each of the data frames is subjected to noise reduction processing, and the filter is used to filter the signal. To remove noise. One of the purposes of segmentation is to more accurately determine when lightning strikes.

And determining whether the lightning occurs includes performing time domain analysis on the signal data in each data frame to obtain a time domain characteristic thereof, the time domain characteristic including a signal amplitude, a signal energy, and a signal statistic; and the data frame In the signal data, the data signal is Fourier transformed using a short-time Fourier transform function, and the frequency domain of the signal is analyzed to obtain frequency domain characteristics, the frequency domain features include: spectral centroid, spectral entropy, Bandwidth, spectral flux and spectral roll-off; combining the above time domain features and frequency domain features of a data frame to obtain a parameter set of the data frame, and using the parameter set to determine whether there is a discharge and discharge time in the data frame, and if so, The microphone is triggered to collect data; the time-frequency analysis of the sound signal collected by the microphone is performed to detect the arrival time of the thunder. It is worth mentioning that the analysis processing of the above time domain and frequency domain is parallel.

When the foregoing parameter set is used for the judgment, the obtained feature parameter set is compared with the previously stored plurality of feature parameter sets one by one, and the plurality of the same type of features in the compared two feature parameter sets are compared. When the difference between the parameters is less than the set threshold, it is determined that the lightning discharge exists, and the time stamp corresponding to the currently obtained feature parameter set is taken as the discharge time.

When the server determines the specific location of the lightning occurrence, the server according to the information uploaded by different mobile terminals, according to the The discharge time determines the data uploaded by the mobile terminal detecting lightning in the discharge position area of a lightning discharge, and combines the distance information uploaded by the mobile terminal in the area to locate the position of the lightning discharge by geometric principle, according to different positions at different times. Lightning information, generate a lightning discharge heat map, and pass it back to the client of the smart device. The client of the smart device receives the information returned by the server through the network, and gives the user a security prompt according to the information, and provides the client to view the lightning information nearby.

Since smart phones (ie smart devices or mobile terminals) have built-in rich sensors such as gyroscopes, accelerometers, magnetometers, microphones, light sensors and distance sensors. Based on these sensors, the above method can be easily implemented by the cooperation of a plurality of mobile terminals.

The above content is further described in connection with the specific implementation manner, and it should not be construed that the specific implementation of the present invention is limited to the above description. It will be apparent to those skilled in the art that the present invention may be practiced without departing from the spirit and scope of the invention.

Claims

A method for detecting and co-locating lightning using a mobile terminal, comprising: the following steps:

S1. Collect lightning data at a certain frequency by using a magnetometer disposed on the mobile terminal;

S2: processing data collected by the magnetometer, and dividing the data into a plurality of frame data having a set time length in time sequence;

S3, performing time domain analysis and frequency domain analysis on the divided frame data to obtain a plurality of characteristic parameters of the data; and determining, by using the obtained characteristic parameter, whether the magnetic induction data formed by lightning, and determining the lightning formation time, and Turn on the microphone to receive the thunder signal;

S4. The processing unit of the smart device calculates a distance between the lightning discharge position and the mobile terminal by using a lightning formation time and a thunder receiving time, and simultaneously numbers the lightning terminal, the distance from the discharge position, the lightning formation time, and The mobile terminal location information is uploaded to the server through the wireless network;

S5. The server uses the above information uploaded by the multiple mobile terminals to locate the location of the lightning discharge at a certain moment according to the geometric principle, and generates a lightning discharge heat map to return to the plurality of mobile terminals.
The method for detecting and co-locating lightning using a mobile terminal according to claim 1, wherein the step S2 comprises:

S21. Divide the magnetic induction signal output by the magnetometer, and divide it into multiple segments according to a set time interval, each segment being adjacent on the time axis and having the same length of time; each segment of the magnetic induction signal is a data frame. Each data frame is given its start time as its time stamp;

S22: Perform noise reduction processing on each of the data frames, and filter the signal using a filter to remove noise.
The method for detecting and co-locating lightning using a mobile terminal according to claim 2, wherein the step S3 comprises:

S31A, performing time domain analysis on the signal data in each data frame to obtain a time domain characteristic thereof, where the time domain characteristic includes a letter Number amplitude, signal energy, and signal statistics;

S31B: performing Fourier transform on the data signal in the data frame by using a short-time Fourier transform function, and analyzing the frequency domain of the signal to obtain a frequency domain characteristic thereof, where the frequency domain features include: Spectral centroid, spectral entropy, bandwidth, spectral flux, and spectral roll-off;

S32. Combining the time domain feature and the frequency domain feature of the data frame to obtain a parameter set of the data frame, and using the parameter set to determine whether a discharge and a discharge time exist in the data frame, and if so, triggering the microphone to collect data;

S33. Perform time-frequency analysis on the sound signal collected by the microphone to detect the arrival time of the thunder.
The method for detecting and co-locating lightning using a mobile terminal according to claim 3, wherein in step S32, the obtained feature parameter set and the previously stored plurality of characteristic parameter sets are performed one by one In contrast, when the difference between the plurality of feature parameters of the same type in the two characteristic parameter sets that are compared is less than the set threshold, it is determined that the lightning discharge exists, and the time mark corresponding to the currently obtained feature parameter set is used as the discharge time.
The method for detecting and co-locating lightning using a mobile terminal according to claim 4, wherein in the step S5, the server determines, according to the information uploaded by the different mobile terminals, a discharge position region during a lightning discharge according to the discharge time thereof. The data uploaded by the mobile terminal detecting the lightning is combined with the distance information uploaded by the mobile terminal in the area to locate the location of the lightning discharge by geometric principle, and generate a lightning discharge heat map according to different lightning information located at different times, and return Passed to the client of the smart device.
The method for detecting and co-locating lightning using a mobile terminal according to claim 5, wherein the client of the smart device receives the information returned by the server through the network, and gives the user a security prompt according to the information, and simultaneously provides the client to view the nearby Lightning information.