CN107490781A - Use mobile terminal detection and the method for co-located lightning - Google Patents

Abstract

The present invention relates to the field of lightning positioning, which discloses a method for detecting and coordinating lightning using a mobile terminal, including the following steps: S1, collecting lightning data at a certain frequency by using a magnetometer of an intelligent device; S2, analyzing the magnetic force Processing the data collected by the meter; S3, performing time domain analysis and frequency domain analysis on the divided frame data. Beneficial effects of the present invention: the lightning distance can be accurately obtained through the method of the present invention, and the cost performance is high, and the method is widely used.

Description

Method for detecting and co-locating lightning using mobile terminals

technical field

The invention relates to the field of lightning location, in particular to a method for using a mobile terminal to detect and coordinate lightning location.

Background technique

Lightning is a strong discharge phenomenon between clouds, between clouds and the ground, or between various parts of the cloud body (generally occurs in cumulonimbus clouds). Usually, storm clouds (cumulonimbus clouds) generate charges, the bottom layer is negative electricity, the top layer is positive electricity, and also generates positive charges on the ground, moving with the cloud like a shadow. Positive and negative charges attract each other, but air is not a good conductor. Positive charges rush to trees, hills, tops of tall buildings and even human bodies, trying to meet negatively charged clouds; negatively charged branch-like tentacles extend downward, closer to the ground. Finally, the positive and negative charges finally overcome the air barrier and connect. A huge electric current surged from the ground to the cloud along a conductive airway, producing a bright and dazzling flash.

The process of lightning seen by the naked eye is very complicated. When the thundercloud moves to a certain place, the middle and lower part of the cloud is a strong negative charge center, and the opposite underlying surface of the cloud base becomes a positive charge center, forming a strong electric field between the cloud base and the ground. When the electric charge accumulates more and more and the electric field becomes stronger and stronger, a section of gas column whose atmosphere is strongly ionized first appears at the bottom of the cloud, which is called the step leader. This ionized gas column extends to the ground step by step. Each step is led by a dim light column with a diameter of about 5 meters, a length of 50 meters, and a current of about 100 amperes. It extends step by step at an average speed of about 150,000 m/s To the ground, when it is about 5-50 meters above the ground, the ground suddenly strikes back upwards, and the channel of the counterattack is from the ground to the bottom of the cloud, along the ionization channel opened by the leader of the above-mentioned steps. The return strike traveled from the ground to the bottom of the cloud at a higher speed of 50,000 kilometers per second, emitting an incomparably bright beam of light, which lasted for 40 microseconds, and passed a current of more than 10,000 amperes. This was the first lightning strike. After a few hundredths of a second, a dim beam of light from the cloud, carrying a huge current, galloped towards the ground along the path of the first lightning strike, called the direct flight leader. When it was about 5-50 meters away from the ground, the ground went up again. Hit back, and then form an incomparably bright beam of light, this is the second lightning strike. Then the third and fourth lightning strikes were produced similarly to the second time. Usually, a lightning process is composed of 3-4 lightning strikes. A lightning process lasts about 0.25 seconds. In this short period of time, a huge amount of electric energy will be released on the narrow lightning channel, thus forming a strong explosion, generating shock waves, and then forming sound waves to spread around. This is the sound of thunder or " At the same time, EMP (Electromagnetic Pulse) will be generated at the moment of discharge, which is the electromagnetic radiation associated with lightning discharge. Lightning electromagnetic radiation is very similar to nuclear explosion electromagnetic radiation. The radiated electromagnetic waves range from VLF (very low frequency) to UHF (very high frequency), very wide frequency electromagnetic pulses, and the generated electric and magnetic fields can be coupled to electrical or electronic systems. , resulting in disturbing surge current or surge voltage. Electromagnetic pulses have strong interference to precision electronic components, and even burn out electronic components.

lightning hazard

Due to the huge energy contained in lightning, a strong lightning current flows through the organism after the lightning strikes. The thermal effect and biological effect generated in this process are the main causes of damage. Since the human body has a certain resistance, when a strong current flows through the human body In an instant, a large amount of heat will be generated, which will carbonize the skin and internal organs of the human body, that is, "burnt". The biological effect is that when the current flows through the heart, the myocardial fibers will vibrate, causing the heart to stop beating. Every year, people are killed by electric shock, and lightning has a great impact on human production activities.

Existing Lightning Detection Techniques

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

NLDN detects lightning by deploying many sensor nodes in different regions. It provides services for the US power system department, weather forecast system and some other government departments, as well as some commercial departments, including real-time data and historical data. . However, NLDN needs to deploy dedicated sensor nodes, and ordinary people need to pay for it.

2. Commercial personal portable lightning detection equipment

One of the more popular is the pager-sized personal lightning detection device that uses batteries. This device is more popular among people who work outdoors, such as golfers, campers, sports players and some other outdoor sports. By. This device judges the distance of lightning relative to the user by detecting the intensity of EMP (Electromagnetic Pulse), but it has the disadvantage that it is easy to misjudge the distance, and of course it cannot locate the location of lightning. There are some other professional lightning detection equipment with better performance but expensive.

Contents 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 problem of easy misjudgment of distance in the above-mentioned prior art.

The present invention is achieved through the following technical solutions: a method for using a mobile terminal to detect and cooperatively locate lightning, comprising the following steps:

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

S2. Process the data collected by the magnetometer, and divide it into a plurality of frame data with a set time length in chronological order;

S3. Carry out time-domain analysis and frequency-domain analysis on the divided frame data respectively to obtain a plurality of characteristic parameters of the data; and judge whether the magnetic induction data of lightning is formed by the characteristic parameters obtained, if so, determine the lightning formation time and Turn on the microphone to receive the thunder signal;

S4. The processing unit of the smart device calculates the distance between the lightning discharge position and the mobile terminal through the lightning formation time and the thunder reception time, and at the same time, the number of the lightning, the distance from the mobile terminal to the discharge position, the lightning formation time and The location information of the mobile terminal is uploaded to the server through the wireless network;

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

As a further improvement of the present invention: said step S2 includes:

S 21. Divide the magnetic induction signal output by the magnetometer, divide it into multiple segments according to the set time interval, each segment is adjacent on the time axis and the time length of each segment is the same; a segment of the magnetic induction signal is a data frame , give each data frame its start time as its time stamp;

S 22. Perform noise reduction processing on each of the data frames, and use a filter to filter the signal to remove noise.

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

S31A. Perform time-domain analysis on the signal data in each data frame to obtain its time-domain features, where the time-domain features include signal amplitude, signal energy, and signal statistics;

S31B. For the signal data in the data frame, use a short-time Fourier transform function to perform Fourier transform on the data signal, analyze the frequency domain of the signal, and obtain its frequency domain characteristics, and the frequency domain characteristics include: Spectral centroid, spectral entropy, bandwidth, spectral flux, and spectral roll-off;

S32. Combining the above-mentioned time-domain features and frequency-domain features of a data frame to obtain a parameter set of the data frame, using the parameter set to determine whether there is discharge and discharge time in the data frame, and if so, triggering a microphone to collect data;

S33. Detect the arrival time of the thunder by performing time-frequency analysis on the sound signal collected by the microphone.

As a further improvement of the present invention: in step S32, by comparing the obtained feature parameter set with the existing multiple feature parameter sets stored in advance one by one, multiple identical type When the difference between the characteristic parameters is less than the set threshold, it is judged that the lightning discharge exists, and the time stamp corresponding to the currently obtained characteristic parameter set is used 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 different mobile terminals and according to the discharge time of a certain lightning discharge, the data uploaded by the mobile terminal that detects lightning in the discharge location area, and combines the data uploaded by the mobile terminal in the area. The distance information uploaded by the mobile terminal of the mobile terminal locates the location of lightning discharge through geometric principles, and generates a heat map of lightning discharge according to different lightning information located at different times, and sends it back 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 safety reminder according to the information, and at the same time provides the client to view nearby lightning information.

Beneficial effects of the present invention: the lightning distance can be accurately obtained through the method of the present invention, and the cost performance is high, and the method is widely used.

Description of drawings

Fig. 1 is a schematic diagram of the scene application of the present invention;

Fig. 2 is a schematic diagram of the steps of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

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

S1. Collect lightning data at a certain frequency by using the magnetometer of the smart device;

S2, processing the data collected by the magnetometer;

S3. Perform time-domain analysis and frequency-domain analysis on the divided frame data;

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

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

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

Described step S2 comprises:

S 21. First, the magnetometer signal collected in step S1 is divided into frames, and each window data is processed;

S 22. Perform noise reduction processing on the collected magnetometer signal, and use a filter to filter the signal to remove noise.

Described step S3 comprises:

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

S31B. For the data signal obtained in step S2, perform Fourier transform on the data signal using a short-time Fourier transform function, and analyze the frequency domain of the signal;

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

S33. Detect the arrival time of the thunder by performing time-frequency analysis on the sound signal collected by the microphone.

In the step S5, according to the information uploaded by different mobile terminals, the server determines the data uploaded by the mobile terminal that detects lightning in the discharge location area when a certain lightning is discharged according to the time stamp, and combines the distance information uploaded by the mobile terminal in the area to pass The geometric principle locates the location of lightning discharge, and generates a heat map of lightning discharge according to different lightning information located at different times, and sends 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 safety reminder according to the information, and at the same time provides the client to view nearby lightning information.

In this method, the built-in sensor and microphone of the mobile phone are combined to detect and measure the lightning, and combine multiple mobile phones in the area to locate the lightning.

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

S1. Collect data at a certain frequency by using the magnetometer of the smart device;

S2. Processing the data collected by the magnetometer. First, frame the collected signal, then denoise the signal, and filter the signal by using a filter;

S3. Perform time-domain analysis on the divided frame data, and use short-time Fourier transform to analyze the time-frequency domain transformation of the time-series frame data, because lightning discharges instantly generate extremely high-energy electromagnetic pulses (lightningelectromagnetic pulse) , due to the high energy of the electromagnetic pulse with extremely strong energy in a short period of time, the precision sensor (magnetometer) of the smart device will be affected by this short-term high-energy electromagnetic pulse, resulting in abnormalities in the collected magnetometer data, and this This kind of interference has a certain pattern. By combining the analysis of the time domain and 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 can be ignored. , when a discharge is detected, the speaker is triggered to collect sound data. Due to the time-frequency characteristics of thunder, it also has a certain pattern, and the arrival time of thunder is detected through an algorithm;

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

S5. Based on the information uploaded back by mobile phones in different locations in the same area, the server uses the geometric positioning method to locate the location of lightning discharge at a certain moment, and generates a heat map of lightning discharge according to the number of lightning discharges at different locations of different locations and returns it to the smart device. client;

S6. The client receives the information returned by the server, and gives the user an active safety reminder, and the user can also check the nearby lightning historical discharge information through the client.

Since the electromagnetic pulse generated by lightning will produce instantaneous strong electromagnetic interference to the precise sensor, resulting in abnormal data, the time of lightning discharge can be determined by detecting this mode of EMP interference. At the same time, when lightning discharges, in the lightning channel, the current Extremely strong, the temperature can suddenly rise to 20,000 degrees Celsius, and the sudden increase in air pressure will cause the air to expand violently, form a shock, and produce thunder. The speed of propagation of thunder and electromagnetic waves is different, so the arrival time of electromagnetic pulses and thunder is different. Use TOA to calculate the distance from the mobile phone when the lightning discharge occurs. When the mobile phone in the area detects the lightning signal, it uploads the lightning distance, its own location information and time stamp to the server 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 for display. The user can judge the lightning information based on the information, and stay away from the dangerous area in time to protect personal safety.

Generally speaking, in this embodiment, the lightning data is collected at a certain frequency by using the magnetometer installed on the mobile terminal; the data collected by the magnetometer is processed and divided into multiple Frame data of fixed time length; Carry out time domain analysis and frequency domain analysis respectively to the divided frame data, obtain a plurality of characteristic parameters of this data; And judge whether the magnetic induction data that lightning is formed by the characteristic parameter that obtains described, if so, Determine the lightning formation time and turn on the microphone to receive the thunder signal; the processing unit of the smart device calculates the distance between the lightning discharge position and the mobile terminal through the lightning formation time and the thunder reception time, and at the same time the number of the mobile terminal to the lightning, and The distance of the above-mentioned discharge location, the formation time of lightning, and the location information of the mobile terminal are uploaded to the server through the wireless network; the server uses the above-mentioned information uploaded by multiple mobile terminals to locate the location of the lightning discharge at a certain moment according to geometric principles, and generate lightning discharge heat. The graph returns the plurality of mobile terminals. Basically, it uses multiple mobile terminals (i.e., smart devices) equipped with the above-mentioned functions in the lightning occurrence area to first detect whether there is a magnetic induction signal caused by lightning. If so, determine the time of lightning occurrence and activate the microphone to detect thunder If the audio signal is detected, the time gap between the arrival of the lightning and the thunder signal can be known for the location of the mobile terminal. This can basically get the distance from the place where the lightning occurs to the location of the mobile terminal; if multiple such mobile terminals detect this distance, the server can determine the specific location of the lightning from the data uploaded by these mobile terminals, and then can use Users of these software are sending warning signs.

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

And the judgment for whether lightning occurs includes: time-domain analysis is carried out to the signal data in each data frame to obtain its time-domain characteristics, and the time-domain characteristics include signal amplitude, signal energy and signal statistics; In the signal data, use the short-time Fourier transform function to perform Fourier transform on the data signal, analyze the frequency domain of the signal, and obtain its frequency domain characteristics, and the frequency domain characteristics include: spectral centroid, spectral entropy, Bandwidth, spectral flux and spectral roll-off; combine the above-mentioned time-domain features and frequency-domain features of a data frame to obtain a parameter set of the data frame, and use the parameter set to determine whether there is discharge and discharge time in the data frame, and if so, Trigger the microphone to collect data; through the time-frequency analysis of the sound signal collected by the microphone, the arrival time of thunder is detected. It is worth mentioning that the analysis and processing of the above-mentioned time domain and frequency domain are parallel.

When using the above parameter sets for judgment, it is by comparing the obtained feature parameter sets with the existing multiple feature parameter sets stored in advance one by one, and multiple features of the same type in the compared two feature parameter sets When the difference between the parameters is less than the set threshold, it is judged that the lightning discharge exists, and the time stamp corresponding to the currently acquired feature parameter set is used as the discharge time.

When the server judges the specific location of the lightning, the server determines the discharge location of a certain lightning according to the information uploaded by different mobile terminals and the discharge time according to the data uploaded by the mobile terminals in the area where lightning is detected The uploaded distance information locates the location of lightning discharge through geometric principles, and generates a heat map of lightning discharge according to different lightning information located at different times, and sends 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 safety tips based on the information, and at the same time provides the client to view nearby lightning information.

Since a smart phone (that is, a smart device or a mobile terminal) has built-in a wealth of sensors, such as a gyroscope, an accelerometer, a magnetometer, a microphone, a light sensor, and a distance sensor. Based on these sensors, the above method can be easily realized through the cooperation of multiple mobile terminals.

The above content is a further elaboration of the present invention in combination with specific implementation methods, and it should not be assumed that the specific implementation of the present invention is limited to the above description. For those skilled in the art, without departing from the concept of the present invention, some simple deductions or substitutions can be made, which should be deemed to be within the scope of protection determined by the claims submitted in the present invention.

Claims (6)

1. a kind of use mobile terminal detection and the method for co-located lightning, it is characterised in that：Comprise the following steps：

S1, by using setting magnetometer on mobile terminals with certain frequency collection Lightning data；

S2, the data that magnetometer collects are handled, and it is divided into sequentially in time multiple there is setting time The frame data of length；

S3, time-domain analysis and frequency-domain analysis are carried out respectively to the frame data after division, obtain multiple characteristic parameters of the data；And Judge whether the magnetic induction data of lightning formation by the obtained characteristic parameter, in this way, determine that lightning forms the time and beaten Drive microphone and receive thunder signal；

S4, smart machine processing unit by lightning formed time and thunder receive the time calculate lightning discharge position with it is described The distance of mobile terminal, while during by the mobile terminal to the numbering of the lightning, with the distance of above-mentioned discharge position, lightning formation Between and location information of mobile terminal service end is uploaded to by wireless network；

The above- mentioned information that S5, service end are uploaded by multiple mobile terminals, a certain moment lightning discharge is positioned according to geometrical principle Position, generation lightning discharge thermal map returns to the multiple mobile terminal.

2. according to claim 1 use mobile terminal detection and the method for co-located lightning, it is characterised in that described Step S2 includes：

S 21, the magnetic strength induction signal to magnetometer output are divided, and it is divided into multistage at set time intervals, Every section of adjacent on a timeline and every section time span is identical；One section of magnetic strength induction signal is a data frame, to each data Frame assigns its initial time and marked as its time；

S 22, noise reduction process is carried out to each data frame, using wave filter to signal filtering process, remove noise.

3. according to claim 2 use mobile terminal detection and the method for co-located lightning, it is characterised in that described Step S3 includes：

S31A, time-domain analysis is carried out to the signal data in each data frame, obtain its temporal signatures, the temporal signatures include Signal amplitude, signal energy and signal statistics amount；

S31B, to the signal data in the data frame, use Short Time Fourier Transform function pair data-signal to carry out Fourier Conversion, analyzes the frequency domain of signal, obtains its frequency domain character, the frequency domain character includes：Spectral centroid, spectrum entropy, bandwidth, Compose flux and spectrum roll-off；

S32, the above-mentioned temporal signatures and frequency domain character for combining a data frame, obtain the parameter set of the data frame, use the ginseng Manifold determines in this way, to trigger microphone gathered data with the presence or absence of electric discharge and discharge time in the data frame；

S33, time frequency analysis, the time that detection thunder reaches are carried out by the voice signal collected to microphone.

4. according to claim 3 use mobile terminal detection and the method for co-located lightning, it is characterised in that in step In rapid S32, by the way that the characteristic parameter collection of acquirement and the existing multiple characteristic parameter collection being previously stored are carried out pair one by one Than, when the difference between the characteristic parameter for multiple same types that two characteristic parameters compared are concentrated is less than given threshold, Judge that lightning discharge is present, and time mark corresponding to the characteristic parameter collection that this is currently obtained is as discharge time.

5. according to claim 4 use mobile terminal detection and the method for co-located lightning, it is characterised in that described In step S5, information that server uploads according to different mobile terminal determines to put during a certain lightning discharge according to its discharge time The data that the mobile terminal of lightning uploads, and the distance letter that the mobile terminal in calmodulin binding domain CaM uploads are detected in electric position region Breath orients the position of lightning discharge by geometrical principle, according to the different lightning informations navigated at different moments, generates lightning Discharge thermal map, and passes back to the client of smart machine.

6. according to claim 5 use mobile terminal detection and the method for co-located lightning, it is characterised in that intelligence The information that the client of equipment is returned by network the reception server, and user security prompting is given according to information, provide simultaneously Client checks neighbouring lightning information.