An earthquake rescue positioning method, system, device and storage medium

Abstract

The embodiment of the application relates to the technical field of communication, in particular to a post-earthquake search and rescue positioning method, system and device and a storage medium, the method comprising the following steps: first, generating an induction signal according to a mobile communication network protocol, and inducing a mobile terminal of a rescue target to send a signal to access a network; next, synchronously collecting electromagnetic signals in a post-earthquake environment by multiple signal collection nodes; finally, simultaneously positioning and analyzing multiple rescue targets to obtain position information of the rescue targets and signal strengths of the mobile terminals corresponding to the rescue targets. The post-earthquake search and rescue positioning method provided by the embodiment of the application can obtain accurate position positioning of the rescue targets in a small number of iteration processes, has less calculation time consumption, and can be used for simultaneously, widely and efficiently searching and positioning multiple trapped personnel in real time.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of communication, in particular to a post-earthquake search and rescue positioning method, system, device and storage medium. BACKGROUND

[0002] Earthquake disaster sites usually have the following characteristics: complex environment, unpredictable; sudden disasters and their derivative events threaten the life safety of trapped personnel at any time; there is not enough time and sufficient rescue personnel for a net search; support conditions are lacking, and disaster sites often lack power and communication support. In the case of very limited rescue forces after a large-scale natural disaster, life rescue becomes the primary goal of emergency rescue, so whether trapped personnel can be quickly searched and located is a key problem to reduce casualties.

[0003] Currently, the life search and positioning method of trapped personnel can be divided into two categories: positioning based on human life characteristics and positioning based on carried beacons. Among them, positioning based on human life characteristics refers to directly searching for human characteristics or signals emitted by the human body using various instruments and equipment, mainly acoustic positioning methods, optical positioning methods, infrared positioning methods, and life radar positioning methods. These search technologies are universal, but in the ruins environment of earthquakes and other disasters, due to the complex terrain environment, combined with the small signal strength emitted by the human body, the positioning difficulty is large, and it is difficult to meet the demand of large-scale and rapid search and positioning. The positioning method based on beacons can search and locate according to the beacons carried by trapped personnel, indirectly find the location of trapped personnel, and has the advantages of high efficiency and large range. Since everyone carries a mobile phone in today's society, mobile phone beacon positioning has a great advantage.

[0004] Currently, there are many mobile phone positioning technologies, but most mobile positioning technologies are aimed at Location-Based Service (LBS) applications and have developed accordingly, and few of them are aimed at disaster scenarios. In disaster scenarios, infrastructure such as base stations is destroyed, and mobile phone users cannot operate their phones, making it extremely difficult to locate the phone. Passive mobile phone detection methods are limited to conditions where there is a network, and the owner of the phone has the ability to operate the phone for communication. Therefore, due to the inability to accurately locate trapped personnel, search and rescue work is difficult to carry out smoothly. SUMMARY

[0005] Embodiments of the present application provide a post-earthquake search and rescue positioning method, system, device and storage medium, which is used in a legal scenario to simultaneously, widely and efficiently search and locate multiple trapped personnel in real time.

[0006] To solve the above technical problems, in a first aspect, the embodiments of the present application provide a post-earthquake search and rescue positioning method, comprising the following steps: first, generating an induction signal according to a mobile communication network protocol, and inducing a mobile terminal of a rescue target to send a signal to access a network; next, synchronously collecting electromagnetic signals in a post-earthquake environment by a plurality of signal collection nodes; finally, simultaneously performing positioning analysis on a plurality of rescue targets to obtain position information of the rescue targets and signal strengths of mobile terminals corresponding to the rescue targets.

[0007] In some example embodiments, the simultaneously performing positioning analysis on the plurality of rescue targets to obtain the position information of the rescue targets and the signal strengths of the mobile terminals corresponding to the rescue targets comprises: constructing a post-earthquake ruin electromagnetic scene model, calculating a sensing matrix and initializing search and rescue positioning parameters; simultaneously obtaining position information of the mobile terminals of the plurality of rescue targets, selecting a support set, and calculating signal strength values corresponding to the position information support set; based on the position information support set and the signal strength values, obtaining the position information of the rescue targets and the signal strengths of the mobile terminals corresponding to the rescue targets through iterative calculation.

[0008] In some example embodiments, the constructing a post-earthquake ruin electromagnetic scene model, calculating a sensing matrix and initializing search and rescue positioning parameters comprises: constructing a post-earthquake ruin electromagnetic scene model by assuming a post-earthquake ruin electromagnetic scene and performing grid division on a post-earthquake experimental area; constructing a position matrix of the signal collection nodes, and obtaining a received data column vector based on signals synchronously collected by the plurality of signal collection nodes; constructing a path loss matrix according to a current post-earthquake electromagnetic environment and the post-earthquake ruin electromagnetic scene model; based on the path loss matrix, calculating a sensing matrix and initializing search and rescue positioning parameters.

[0009] In some example embodiments, the simultaneously obtaining position information of the mobile terminals of the plurality of rescue targets, selecting a support set, and calculating signal strength values corresponding to the position information support set comprises: based on the sensing matrix and a residual error, calculating a possible rescue target position index set and updating a rescue position support set; obtaining a sensing matrix according to the updated rescue position support set; and calculating a rescue target original signal estimation vector according to the sensing matrix.

[0010] In some example embodiments, based on the sensing matrix and the residual, a possible rescue target position index set is calculated, comprising: based on the sensing matrix, a normalized vector is obtained; according to the sparse optimization principle, the most relevant rescue target position index set is calculated; based on the sensing matrix and the residual, the projection of the sample is obtained; based on the normalized vector, the projection of the sample is normalized to obtain a normalized projection; the normalized projection is sorted, and based on the rescue target position information support set, a target position first support set is obtained; wherein the sensing matrix is obtained by formula (1) from the position matrix of the signal acquisition node and the path loss matrix:

[0011] (1)

[0012] Wherein S represents the sensing matrix, G represents the position matrix of the signal acquisition node, and PL is the path loss matrix;

[0013] Based on the sensing matrix and the transpose matrix of the sensing matrix, the normalized vector is calculated by formula (2):

[0014] (2)

[0015] Wherein Nor represents the normalized vector, S T is the transpose matrix of the sensing matrix S;

[0016] Based on the residual and the sensing matrix, the projection of the sample is calculated by formula (3):

[0017] (3)

[0018] Wherein Q is the projection, is the residual.

[0019] In some example embodiments, based on the position information first support set and the signal strength value, the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target are calculated by iteration, comprising: obtaining the rescue target position information support set and updating the iteration upper limit number; based on the rescue target position support set, the sensing matrix corresponding to the rescue target position support set is obtained, and the original rescue signal estimate value is calculated; based on the original rescue signal estimate value and the sensing matrix, the residual of the next iteration is calculated; the iteration number is compared with the iteration upper limit number, if the iteration number is less than the iteration upper limit, the iteration continues, and the rescue target position index is calculated and obtained; if the iteration number is greater than or equal to the iteration upper limit number, the iteration process is ended, and the rescue target position information support set is obtained; and based on the rescue target position information support set, the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target are obtained.

[0020] In some example embodiments, the acquiring the position information support set and updating the iteration upper limit number comprises: calculating a decision threshold based on the inverse original rescue signal column vector; acquiring a rescue position information support set based on the decision threshold; calculating the iteration upper limit number based on the rescue position information support set; wherein the decision threshold is calculated by formula (4):

[0021] (4)

[0022] wherein, is the decision threshold, is the inverse original rescue signal column vector;

[0023] The iteration upper limit number is calculated by formula (5):

[0024] (5)

[0025] wherein, PIS represents the rescue position information support set, and the rescue position information support set is a collection of positions of mobile terminals of multiple rescue targets in a post-earthquake search and rescue scene.

[0026] In a second aspect, the embodiments of the present application further provide a post-earthquake search and rescue positioning system, comprising: an induction signal generation module, a synchronous signal acquisition module and a multi-target positioning analysis module connected in sequence; the induction signal generation module is configured to generate an induction signal according to a mobile communication network protocol, and induce a mobile terminal of a rescue target to send a signal to access a network; the synchronous signal acquisition module is configured to synchronously acquire electromagnetic signals in a post-earthquake environment through multiple signal acquisition nodes; and the multi-target positioning analysis module is configured to simultaneously perform positioning analysis on multiple rescue targets to obtain position information of the rescue targets and signal strengths of mobile terminals corresponding to the rescue targets.

[0027] In addition, the present application further provides an electronic device, comprising: at least one processor; and a memory in communication connection with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the post-earthquake search and rescue positioning method.

[0028] In addition, the present application further provides a computer readable storage medium storing a computer program, and the computer program is executed by a processor to implement the post-earthquake search and rescue positioning method.

[0029] The technical scheme provided by the embodiments of the present application has at least the following advantages:

[0030] The embodiment of the present application provides a post-earthquake search and rescue positioning method, system, device and storage medium, and the method comprises the following steps: first, generating an induction signal according to a mobile communication network protocol, and inducing a mobile terminal of a rescue target to send a signal to access the network; next, a plurality of signal collection nodes synchronously collect electromagnetic signals in a post-earthquake environment; finally, simultaneously positioning and analyzing a plurality of rescue targets to obtain position information of the rescue targets and signal strengths of the mobile terminals corresponding to the rescue targets.

[0031] The post-earthquake search and rescue positioning method provided by the present application is a post-earthquake search and rescue positioning method which can realize simultaneous positioning and analysis of multiple targets after an earthquake. In a post-earthquake environment where a base station is destroyed, the network mode of a mobile phone carried by a trapped person may gradually fall back from 4G / 5G to 2G GSM network mode in order to search for signals. The present application can make a signal collection node send an induction signal to realize active induction and reception of electromagnetic signals of a mobile terminal carried by a trapped person, and indirectly search and position the mobile terminal of a post-earthquake rescue target. The post-earthquake search and rescue positioning method for multiple targets simultaneously proposed by the present application selects a large number of possible rescue target positions for judgment and screening, and sets an upper limit of iteration times, so that the accurate position of a rescue target can be obtained in a small number of iteration processes without prior information such as signal strength, the calculation time is short, and the method can be used for real-time search and positioning of multiple trapped persons simultaneously, widely and efficiently. BRIEF DESCRIPTION OF DRAWINGS

[0032] One or more embodiments are exemplified by pictures in the drawings corresponding thereto, and the exemplifications do not constitute limitations on the embodiments, unless specifically stated otherwise, and the drawings do not constitute proportional limitations.

[0033] Figure 1 A flowchart of a post-earthquake search and rescue positioning method provided by an embodiment of the present application.

[0034] Figure 2 A structural diagram of a post-earthquake search and rescue positioning system provided by an embodiment of the present application.

[0035] Figure 3 A post-earthquake search and rescue system design diagram based on under-sampling multi-radiation source simultaneous positioning and analysis provided by an embodiment of the present application taking GSM network as an example.

[0036] Figure 4 A burst pulse forming process diagram provided by an embodiment of the present application.

[0037] Figure 5 A burst pulse train forming structure provided by an embodiment of the present application.

[0038] Figure 6A GSM K modulation flowchart based on FPGA provided by an embodiment of the present application.

[0039] Figure 7 A GSM signal formation result provided by an embodiment of the present application.

[0040] Figure 8 A multi-node time synchronization scheme structure diagram provided by an embodiment of the present application.

[0041] Figure 9 A time synchronization calibration scheme state transition diagram provided by an embodiment of the present application.

[0042] Figure 10 A spatial electromagnetic signal synchronous acquisition result provided by an embodiment of the present application.

[0043] Figure 11 An after-earthquake multi-target simultaneous search and rescue positioning and analysis flowchart based on undersampling provided by an embodiment of the present application.

[0044] Figure 12 A multi-radiation source simultaneous positioning simulation diagram of a traditional undersampling algorithm and a positioning accuracy comparison simulation diagram of the present application.

[0045] Figure 13 An after-earthquake multi-target simultaneous search and rescue positioning and analysis positioning accuracy comparison simulation diagram under different numbers of receivers provided by an embodiment of the present application.

[0046] Figure 14 A structural schematic diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0047] As known from the background, at present, there is a problem that when disaster scenes, base stations and other infrastructures are destroyed, the positioning of mobile phones is extremely difficult, leading to difficult search and rescue.

[0048] Based on the practice of post-disaster rescue after historical earthquakes, it is known that in the emergency rescue stage, efficient rescue of survivors buried in ruins is the key to reducing casualties, the more manpower and material resources invested in rescue, the more advanced the rescue facilities, and the higher the rescue efficiency. The premise of implementing rescue is "search", that is, the identification and positioning ability of life information. At present, the life search and positioning method of trapped personnel can be divided into two categories: positioning based on human life characteristics and positioning based on carried beacons.

[0049] With the rapid development of mobile communication technology, mobile phones have become an indispensable product in people's daily life. People are used to carrying mobile phones with them, so detecting buried mobile phone signals in post-earthquake search and rescue operations largely represents detecting the buried. Mobile phone detection can be divided into passive and active types according to whether the equipment passively detects signals or actively detects signals. The principle of passive mobile phone detection is that the detection equipment passively receives the signals transmitted by the mobile phone receiver to achieve the purpose of detection, that is, only when the mobile phone has a signal, the detection equipment can detect the mobile phone.

[0050] In the post-earthquake environment, the base station is likely to be damaged and destroyed. In order to search for signals, the network mode of the multi-mode mobile phone carried by the trapped personnel may gradually fall back from 4G / 5G to 2G Global System for Mobile Communications (GSM). Although the Long Term Evolution (LTE) network of 4G and the Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) network of 3G use a two-way authentication mechanism on the network side and the mobile end, the authentication process occurs after the random access process. In the random access process, the base station and the mobile terminal also exchange information, and by generating and sending part of the information such as broadcast messages, the mobile terminal can be induced to feedback signals, which provides support for subsequent multi-radiation source simultaneous positioning and analysis. The GSM network is relatively complete in system theory, and the protocol, technology, etc. are very mature and the signal form is determined, and a one-way authentication mechanism is used to facilitate the connection between the detection equipment and the mobile terminal and to induce the mobile phone to actively send signals. In addition, compared with other network modes, the overall deployment of GSM has a lower frequency band, and the uplink frequency band of GSM900 is 890 to 915 MHz. The lower the frequency of electromagnetic signals, the farther the propagation distance and the stronger the penetration. In the post-earthquake search and rescue scenario, the attenuation caused by the ruins and concrete is lower, and it has better propagation characteristics.

[0051] Multi-radiation source simultaneous positioning and analysis is to use receivers and other equipment to obtain data by simultaneously sensing the electromagnetic environment, and to calculate the position and signal strength of multiple terminal weak signals in the ruins environment through data processing, so as to quickly obtain overall electromagnetic environment information and provide information basis for searching and rescuing trapped personnel. The positioning of the radiation source in the electromagnetic environment is to obtain the electromagnetic information of the current space through the receiver, and to obtain the transmitter position through calculation.

[0052] At present, the search and rescue positioning method based on human life characteristics mainly includes acoustic positioning method, infrared positioning method and life radar positioning method. The acoustic positioning method is based on the sound source positioning technology of microphone array. Its positioning principle is based on the time delay estimation (TDE) of the time delay of the target sound signal arriving at all microphones of the microphone array. The life radar positioning method detects the weak human vital sign signals such as heartbeat and respiration to obtain the number of survivors trapped in obstacles such as ruins and collapsed buildings. The infrared thermal imaging method detects the infrared imaging of trapped personnel through the detection cable penetrating into the ruins to find and locate the trapped personnel. The current mobile phone positioning technology includes satellite positioning, radio frequency identification (RFID) positioning, etc. Satellite positioning uses the network formed by artificial satellites to triangulate the position of the receiver and provides latitude and longitude coordinates. RFID technology uses radio frequency to realize non-contact two-way communication and data exchange to achieve identification and positioning.

[0053] The current radiation source positioning technology includes non-rangefinding-based positioning technology, TOA-based positioning technology, TDOA-based positioning technology, AOA-based positioning technology and compressed sensing-based RSS positioning technology. The non-rangefinding-based positioning technology uses part of the known positions as the input of the algorithm to determine the remaining positions through various topological relationships of the known positions; the TOA-based positioning technology positions the radiation source by detecting the signal arrival time at the receiver; the TDOA-based positioning technology positions the radiation source by detecting the signal arrival time difference at the receiver; the AOA-based positioning technology positions the radiation source by detecting the signal arrival angle at the receiver; and the compressed sensing-based RSS positioning technology positions the radiation source by detecting the signal strength at the receiver.

[0054] At present, the trapped personnel life search positioning method can be divided into two categories: human life characteristic positioning and carried beacon positioning. Among them, the human life characteristic positioning refers to directly searching for human characteristics or certain signals emitted by human body by using various instruments and equipment, mainly including acoustic positioning method, optical positioning method, infrared positioning method and life radar positioning method. Although these search technologies have universality, in the ruins environment of disasters such as earthquakes, due to the complex terrain environment and the small signal strength emitted by the human body itself, the positioning difficulty is large, and it is difficult to meet the demand of large-scale rapid search and positioning. The beacon positioning method can search and locate the position of trapped personnel indirectly according to the beacon carried by the trapped personnel, and has the advantages of high efficiency and large range. Since everyone carries a mobile phone in today's society, the beacon positioning based on mobile phone has great advantages.

[0055] Currently, there are many mobile phone positioning technologies, but most of the mobile positioning technologies are developed for location-based service (LBS) applications, and few of them are designed for disaster scenarios. In disaster scenarios, the infrastructure such as base stations is destroyed, and the mobile phone users cannot operate the mobile phones, which makes it extremely difficult to position the mobile phones. The passive mobile phone detection method is limited to the condition that there is a network, and the owner of the mobile phone has the ability to operate the mobile phone to communicate. This cannot fully meet the needs of mobile phone detection, and active detection methods must be added to detect, that is, to activate the mobile phone to actively transmit signals, and then detect the signals to obtain useful information to help the search and rescue team to search and rescue efficiently.

[0056] However, the current radiation source positioning technology also has some problems in obtaining the position of the radiation source. The non-ranged-based positioning technology uses part of the known positions as the input of the algorithm, and judges the remaining positions through various topological relationships of the known positions. The hardware requirement is small, the model is simple, but the positioning accuracy of the radiation source is poor. The TOA-based positioning technology positions the radiation source by detecting the time of arrival of the signal by the receiver. The TOA technology has high positioning accuracy, but the hardware requirement is high, the hardware time synchronization is needed, the signal needs to be monitored for a certain time, the time overhead is large, and the positioning speed is slow. The TDOA-based positioning technology positions the radiation source by detecting the time difference of arrival of the signal by the receiver. The TDOA technology has a little higher positioning accuracy than the TOA technology, but the time synchronization requirement of the receiver is higher, the hardware deployment cost is high, and it cannot be applied to the simultaneous and same frequency signal. The AOA-based positioning technology positions the radiation source by detecting the angle of arrival of the signal by the receiver. The AOA positioning technology does not need time synchronization, but needs an antenna array, and the deployment cost is high, and the small-scale positioning accuracy is low.

[0057] The positioning technology based on compressed sensing and received signal strength (RSS) detects signal strength by a receiver to position a radiation source. The RSS positioning technology does not need time synchronization, can support simultaneous signals at the same frequency, has low deployment cost and small time overhead. In a solving process of a traditional sparse optimization RSS positioning technology, a known number of radiation sources, that is, sparsity, is usually used as an iteration stop condition, otherwise, incomplete position information or excessive position information is obtained, resulting in inaccurate radiation source position acquisition. When multiple radiation sources exist in a scene, the sparse optimization RSS positioning technology obtains position information by querying a maximum value index of an inner product, and the multiple radiation sources interfere with each other, so that the position information is not accurately obtained and the accuracy is reduced.

[0058] To solve the above technical problems, the embodiments of the present application provide a post-earthquake search and rescue positioning method, system, device and storage medium. The method comprises the following steps: first, generating an induced signal according to a mobile communication network protocol, and inducing a mobile terminal of a rescue target to send a signal to access a network; next, synchronously collecting electromagnetic signals in a post-earthquake environment by multiple signal collection nodes; finally, positioning and analyzing multiple rescue targets at the same time to obtain position information of the rescue targets and signal strengths of mobile terminals corresponding to the rescue targets. The present application provides a post-earthquake search and rescue positioning method, which can simultaneously, widely and efficiently search and position multiple trapped personnel in real time.

[0059] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art can understand that in the embodiments of the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, the technical solutions claimed by the present application can be realized even without these technical details and various changes and modifications based on the following embodiments.

[0060] Figure 1 A flowchart of a post-earthquake search and rescue positioning method is provided for the embodiments of the present application. Figure 2 A structure diagram of a post-earthquake search and rescue positioning system is provided for the embodiments of the present application. Figure 3 A post-earthquake search and rescue system scheme design diagram based on under-sampling and simultaneous positioning and analysis of multiple radiation sources is provided for the case of a GSM network. Figure 4 A burst pulse formation process diagram is provided. Figure 5 A burst pulse string formation structure is provided. Figure 6 A GSMK modulation flowchart based on FPGA is provided. Figure 7 A GSM signal formation result diagram is provided. Figure 8 A multi-node time synchronization scheme structure diagram is provided. Figure 9 A time synchronization calibration scheme state transition diagram is provided. Figure 10 A synchronous collection result of electromagnetic signals in space is provided.Figure 11 A flow chart of a post-earthquake multi-target simultaneous search and rescue positioning and analysis based on undersampling. Figure 12 A simulation diagram of a multi-radiation source simultaneous positioning of a traditional undersampling algorithm and a positioning accuracy comparison of the present application. Figure 13 A simulation diagram of a positioning accuracy comparison of a post-earthquake multi-target simultaneous search and rescue positioning and analysis based on undersampling in different numbers of receivers. Figure 14 A structural schematic diagram of an electronic device provided by an embodiment of the present application.

[0061] Referring to Figure 1 The embodiment of the present application provides a post-earthquake search and rescue positioning method, which comprises the following steps.

[0062] Step S1, generating an induction signal according to a mobile communication network protocol, and inducing a mobile terminal of a rescue target to send a signal to access a network.

[0063] Step S2, synchronously collecting electromagnetic signals in a post-earthquake environment by a plurality of signal collection nodes.

[0064] Step S3, simultaneously positioning and analyzing a plurality of rescue targets to obtain position information of the rescue targets and signal strengths of mobile terminals corresponding to the rescue targets.

[0065] Specifically, the step S1 is a process of causing the signal collection node to send an induced signal. The induced signal can be generated according to a mobile communication network protocol such as LTE / TD-SCDMA / GSM. In view of the post-earthquake debris environment in which the base station is destroyed and the multi-mode mobile phone that can gradually fall back to a network mode for searching for a signal, the induced signal is generated by using the characteristic that the two-way authentication process of the 3G / 4G network occurs after the random access process and the one-way authentication characteristic of the GSM network. The mobile terminal (mobile phone) of the buried person sends a signal. The under-sampling multi-radiation source positioning only needs to receive the mobile phone signal and does not require the information contained in the signal. Therefore, in the LTE network, only the primary synchronization signal PSS, the secondary synchronization signal SSS, and the necessary MIB main information block and SIB system information block messages are sent to enable the mobile phone to initiate the random access process. At this time, the mobile phone actively sends MSG1 to the base station. MSG1 contains a preamble sequence and is sent by the mobile terminal on the PRACH. The preamble consists of a cyclic prefix CP, a preamble ZC sequence, and a guard time slot GP. The preambles of different lengths have different time domain lengths and occupy 1-3 complete 1ms subframes. After the mobile terminal sends MSG1 and does not receive MSG2, it waits for a timeout and then retransmits according to the PRACH transmission period. By using the sending of MSG1, the mobile phone electromagnetic signal can be received for positioning. In the TD-CDMA 3G network, the mobile phone electromagnetic signal induction process is similar. Only the PLMN selection and cell selection of the mobile terminal are required to complete the cell camping and trigger the RRC connection, and the mobile phone electromagnetic signal can be received. In the GSM network, the authentication of the system is a one-way authentication of the network side to the mobile terminal, which is more convenient for forming the induced signal. Only the frequency correction channel FCCH, the synchronization channel SCH, and the broadcast control channel BCCH information need to be sent to receive the random access channel RACH signal feedback by the mobile terminal. At the same time, if the search for a specific search target is performed, the paging information can be sent through the paging channel PCH to induce the mobile phone signal.

[0066] Because the GSM has the characteristic of one-way authentication and the GSM 900 frequency is low, the attenuation caused by the debris and concrete in the post-earthquake search and rescue scene is low, and the propagation characteristic is better. Therefore, the GSM is taken as an example to illustrate the induced signal generation scheme. The original bit information is subjected to different encoding, interleaving, and encryption methods to form a burst pulse of 156.25 bits. Referring to Figure 3 , the burst pulse train is formed in the FPGA at a symbol transmission rate of 270797 bits / s. Finally, the burst pulse train is modulated by GMSK and emitted by an antenna.

[0067] Referring to Figure 4 , the specific steps of forming the burst pulse train are shown as follows.

[0068] (1) BCCH, PCH burst type is the conventional burst NB, by 184 bit original padding information generated. For 184 bit information, PCH type message is unique, BCCH has 8 message types, select GSM900 network, according to the protocol padding BCCH Type1, Type 2, Type 3, Type 4.

[0069] 184 bit original padding information, according to the generating polynomial Cyclic redundancy coding and adding 4 bit all 0 tail bits, form 228 bit information.

[0070] 228 bit information through the convolutional coding with coding rate of 1 / 2, form 456 bit information, the specific process is as follows:

[0071]

[0072] Wherein, when k < 0, .

[0073] Then through interleaving, reordering and grouping form 4 groups of 114 bit encryption bits, the specific process is as follows: , wherein,

[0074]

[0075] Every 1 group again join the training sequence, tail bits, borrow marks and guard time form 156.25 bit burst, that is, a time slot of information.

[0076] (2) FCCH burst type is frequency correction burst FB, since the content is 156.25 bit fixed information, no need to encode process directly form;

[0077] (3) SCH burst type is synchronization burst SB, 25 bit original padding information, contains TDMA frame number generated dynamic information, therefore the encoding process is realized in FPGA. 25 bit information according to the generating polynomial Cyclic redundancy coding and adding 4 bit all 0 tail bits, form 39 bit information, information through the convolutional coding with coding rate of 1 / 2, form 78 bit information, the specific process is as follows:

[0078]

[0079] Wherein, when k < 0, .

[0080] Formed 78 bit information is divided into two groups, and then join the training sequence, tail bits and guard time form 156.25 bit burst.

[0081] (4) such as Figure 5 As shown in the diagram, F represents FCCH; S represents SCH; B represents BCCH; C represents CCCH, which includes AGCH and PCH messages. Since our system does not require the AGCH phase, a blank message is sent during the AGCH phase; I represents an idle frame, containing no information and serving only as the end marker for a multiframe. The GSM system has 8 time slots. 51 frames make up one frame, and 51 frames make up a multiframe. If... Indicates the primary carrier frequency. of Used for broadcast channels and common control channels; of For use in dedicated control channels; of All are used for service channels. In each frame The time slots transmit FCCH, SCH, BCCH and PCH information in a certain order. Each time slot has a width of 0.577ms and forms a burst pulse train in the FPGA at a symbol transmission rate of 270797bit / s.

[0082] See Figure 6 The GMSK modulation process is as follows.

[0083] (1) The generated burst pulse train is differentially encoded in the FPGA to obtain a differential sequence, which is used as the input of a Gaussian low-pass filter. GMSK modulation uses a Gaussian low-pass filter with BT=0.3, a truncated length of 5T, and two sampling points per symbol. The filter response function is:

[0084]

[0085] The filter coefficients generated by MATLAB are stored in the FPGA's ROM. The difference sequence is then convolved after passing through a Gaussian low-pass filter to obtain the impulse response sequence. .

[0086] (2) Impulse response sequence The data has a bit width of 12. The data is accumulated and then normalized, as follows:

[0087]

[0088] Accumulation yields a phase sequence ranging from -1 to 1. Set as a fixed-point number with 3 integer digits and 11 decimal digits, the in-phase component can be calculated using the CORDIC algorithm in an FPGA. and orthogonal components The value of .

[0089] (3) The data is sent to AD9361 in I and Q two ways, AD9361 receives the data with a sampling frequency of 0.541667MSPS, sets the bandwidth to 0.4MHz, and transmits it to the DAC via four digital interpolation filters, and then converts it again through two low-pass filters, mixes it to the 935MHz frequency band through the antenna, and emits it. The results of GSM induction signal generation are shown in Figure 5

[0090] Specifically, step S2 is the process of synchronously collecting electromagnetic information in the post-earthquake environment by multiple signal collection nodes. The Beidou timing module carried by the signal collection node receives the latitude, altitude, time information, and PPS second pulse signal transmitted by the satellite. In the FPGA, the received time information is calibrated using the PPS signal, and the time of multiple signal collection nodes is synchronized. At the required time, the electromagnetic signal in space is collected by AD9361 and uploaded.

[0091] Referring to Figure 8 , the specific steps of synchronous collection are as follows:

[0092] (1) The AD9361 receiving end works in the 890MHz frequency band, and collects electromagnetic information in space at all times, but does not store it, in preparation for subsequent synchronous collection work; the Beidou timing module receives the latitude, altitude, time information, and PPS second pulse signal transmitted by the satellite.

[0093] (2) The received signal is parsed according to the UART serial port protocol of 1 bit start bit, 1 bit stop bit, and 8 bit information bit, and the information in ASCII code form is converted into corresponding numbers. A signal time_flag is generated, which changes from 0 to 1 after receiving each time information packet; the positioning information is directly stored in RAM for subsequent processing.

[0094] (3) As shown in Figure 9 ​As shown, the time information and PPS signal verification calibration is implemented by using a state machine. In the idle state, the FPGA enters state S1 upon detecting the PPS rising edge. At this time, the FPGA starts timing by using a counter, and if the time_flag rising edge is detected within 1S, the state machine enters state F0. The FPGA counter starts timing again from 0, and if the PPS rising edge is detected within 1S, the state machine enters state F1. In state F1, if the time_flag rising edge is received within 1S, and compared with the previous time information, if the second difference is 1, it is considered that the verification is completed once, and it is proved that the received Beidou satellite time information is valid and correct. In this way, a total of three verifications are performed, and at the end of the last verification, the state machine is in S2, the last year is used as a sample to verify the validity of the date, the state machine jumps to S3, and the counter timing information of the FPGA is recorded as more accurate time information. The time information synchronization calibration is completed, and from this moment, the Beidou time information is no longer read at all times, and the clock signal is provided by the external crystal oscillator of the FPGA, and the timing is performed by using the FPGA clock.

[0095] In order to reduce the cumulative error generated by the clock timing of the signal acquisition node itself, the timing re-calibration is controlled by the upper computer sending a command, or the FPGA automatically performs synchronization calibration every 40 minutes by receiving the Beidou signal again. The state machine jumps from state S3 to S4, and starts a round of synchronization calibration again.

[0096] (4) Store the time information and positioning information into the RAM. In order to save resources for the arm part, we use time_flag as a flag, and combine the date and time information formed at the same time into two 32-bit information stored in the RAM, waiting for the ARM to read.

[0097] (5) The upper computer sends a request to collect time, and multiple acquisition nodes synchronously collect electromagnetic signals. The time comparison module compares the time sent by the upper computer with the FPGA timer timing at all times, and when the time difference is less than 1 / 3 seconds, waits for the PPS rising edge to come, and the acquisition trigger signal smp_trig changes from 0 to 1, indicating that the acquisition starts, and the I and Q signals collected by the AD9361 are written into the RAM. After the writing is completed, an interrupt is uploaded to inform the ARM that the acquisition is completed and can be read.

[0098] Referring to Figure 2The embodiment of the application provides a post-earthquake search and rescue positioning system, comprising: an induction signal generation module 101, a synchronous signal collection module 102 and a multi-target positioning analysis module 103 connected in sequence; the induction signal generation module 101 is used for generating an induction signal according to a mobile communication network protocol, and inducing a mobile terminal of a rescue target to send a signal to access a network; the synchronous signal collection module 102 is used for synchronously collecting electromagnetic signals in a post-earthquake environment through a plurality of signal collection nodes; and the multi-target positioning analysis module 103 is used for simultaneously positioning and analyzing a plurality of rescue targets to obtain position information of the rescue targets and signal strengths of mobile terminals corresponding to the rescue targets.

[0099] The application provides a post-earthquake search and rescue system based on under-sampling multi-radiation source simultaneous positioning and analysis. First, a mobile terminal electromagnetic signal active induction and receiving technology for post-earthquake search and rescue is used. Due to the development of communication, everyone carries a mobile phone. In a post-earthquake debris environment where a base station is destroyed, a multi-mode mobile phone may gradually return to a GSM network for signal search, and a network standard may gradually return from 4G / 5G. An electromagnetic signal sensing node carried by an unmanned aerial vehicle sends an induction signal to induce a mobile phone to send a signal to access a network. A plurality of electromagnetic sensing nodes use a PPS synchronous collection technology to obtain electromagnetic signals of a target frequency band to help perform radiation source positioning.

[0100] In the post-earthquake search and rescue positioning method provided by the application, step S3 is mainly to provide a method for simultaneously positioning and analyzing a plurality of rescue targets. Specifically, the method for simultaneously positioning and analyzing a plurality of rescue targets provided by the application is based on an under-sampling post-earthquake multi-target simultaneous search and rescue positioning and analysis method. The application provides an under-sampling multi-rescue target radiation source simultaneous positioning and analysis method without prior information, which can detect simultaneous signals at the same frequency and has high accuracy. Compared with a traditional method, the under-sampling post-earthquake multi-target simultaneous search and rescue positioning and analysis method does not require prior information and has fewer iterations. The plurality of signal collection nodes are placed at different geographic positions in a search and rescue area, electromagnetic monitoring signal data at the time is obtained at the same time at the positions, and then the under-sampling sparse inversion technology is used to obtain geographic position information of a plurality of rescue targets in a search and rescue scene.

[0101] In one aspect, the application can make the signal acquisition node emit an induction signal, realize the active induction and reception of the mobile terminal electromagnetic signal carried by the trapped personnel, and indirectly search and locate the mobile terminal of the post-earthquake target to be rescued. In another aspect, the application proposes a simultaneous positioning and analysis method based on under-sampling multi-radiation sources, a large number of possible target positions to be rescued are selected for judgment and screening, and the upper limit of the iteration number is set. In the absence of prior information such as signal strength, the accurate position of the target to be rescued can also be obtained in a few iterations, the calculation time is short, and the method can be used for real-time search and positioning of multiple trapped personnel in a large range and efficiently after a disaster.

[0102] In some embodiments, the positioning analysis of the plurality of rescue targets in step S3 obtains the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target, including.

[0103] Step S301, constructing a post-earthquake debris electromagnetic scene model, calculating a sensing matrix and initializing search and rescue positioning parameters.

[0104] Step S302, simultaneously obtaining the position information of the mobile terminal of the plurality of rescue targets, selecting a support set, and calculating the signal strength value corresponding to the position information support set.

[0105] Step S303, based on the position information support set and the signal strength value, obtaining the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target through iterative calculation.

[0106] In some embodiments, step S301 of constructing a post-earthquake debris electromagnetic scene model, calculating a sensing matrix and initializing search and rescue positioning parameters, includes:

[0107] Step S3011, constructing a post-earthquake debris electromagnetic scene model: assuming a complex post-earthquake debris electromagnetic scene, and dividing the post-earthquake experimental area into M grid nodes and X grid centers; in the post-earthquake experimental area, X rescue targets are randomly distributed at I signal acquisition nodes are uniformly distributed on the M grid nodes.

[0108] Step S3012, constructing a position matrix of the signal acquisition node and obtaining a received data column vector: constructing a matrix G for representing the positions of the I signal acquisition nodes on the M grid nodes in the search and rescue area; according to the signals synchronously collected by the plurality of signal acquisition nodes, an I-dimensional received data column vector Zr is obtained, Zr representing the collected energy intensity.

[0109] Step S3013, constructing a path loss matrix according to the current post-earthquake electromagnetic environment and the post-earthquake debris electromagnetic scene model: in the current electromagnetic environment, the energy loss adopts a free propagation path loss model, and the path loss values of M grid vertexes and grid center points in the current electromagnetic environment form a path loss matrix PL, obtaining a search and rescue area path loss matrix.

[0110] Step S3014, calculating a sensing matrix: the sensing matrix is a matrix, which represents the path loss values of I signal collection nodes to the corresponding search and rescue area grid center points.

[0111] Step S3015, initializing search and rescue positioning parameters: defining a support set PIS for storing the position information of the rescue target signal source in the post-earthquake scene; initializing the set of position information as an empty set, initializing the residual R as the received data column vector Zr, initializing the upper limit number of iterations , initializing the iteration number as 1, initializing the pre-stored possible rescue target position information as the selected support set , and initializing the size of .

[0112] Specifically, in step S3012, first, a matrix G is constructed, which is composed of 1 and 0, and each element G ij in the matrix can be represented by the following formula:

[0113]

[0114] wherein represents the set of signal collection node positions in the post-earthquake search and rescue scene, i represents the position of the i-th signal collection node, represents M grid nodes in the search and rescue area, j represents the j-th grid node in the search and rescue area, represents that the i-th signal collection node is located on the j-th grid node, and a matrix G is constructed in turn, the element of the i-th row and the j-th column of the matrix G is 1, and the remaining elements of the row are 0, indicating that the i-th signal collection node in the search and rescue area is located on the j-th grid node.

[0115] In the post-earthquake experimental scene, I signal collection nodes collect signals from the debris electromagnetic scene at the same time, and the collected energy intensity is combined into an R-dimensional received sample column vector . is represented as follows:

[0116]

[0117] Based on the current post-earthquake electromagnetic environment and the established mathematical model, a corresponding path loss matrix is ​​constructed. In the current electromagnetic environment, energy loss adopts a free propagation path loss model:

[0118]

[0119] Combine M grid vertices and The path loss values ​​of the center points of each grid cell are used to form the path loss matrix PL, resulting in a... The path loss matrix for the search and rescue area.

[0120] After obtaining the path loss matrix PL, the sensing matrix S is calculated using the following formula:

[0121]

[0122] From the above equation, the sensing matrix S is a... A matrix representing the search and rescue area corresponding to I signal acquisition nodes. The path loss value of the center point of each grid cell.

[0123] Define a support set PIS to store the location information of the signal sources corresponding to rescue targets in the post-earthquake scene. Initialize this location information set as an empty set, and initialize the residual R as a column vector of received data. Initialize the upper limit of iterations Initialize the number of iterations Set the initial support set (BPIS) to 1, pre-store the location information of possible rescue targets, and initialize its size to 1. .

[0124] In some embodiments, step S302, which involves simultaneously acquiring a selected support set of location information for mobile terminals of multiple rescue targets and calculating the signal strength value corresponding to the selected support set of location information, includes:

[0125] Step S3021: Based on the sensing matrix and residuals, calculate and obtain the set of possible rescue target location indices, and update the preliminary support set of rescue locations.

[0126] Step S3022: Select the support set based on the updated rescue location and obtain the sensor matrix.

[0127] Step S3023: Calculate the original signal estimation vector of the rescue target based on the sensing matrix.

[0128] Specifically, in step S3021, the set of possible rescue target location indices is obtained by calculating the sensing matrix S and the residual. In the first In the next iteration, the transpose of each column of the sensing matrix array vector The two-norm of the product of the current residual multiplied by the inverse of the transpose of the sensing matrix array vector A set of dimension column vectors, the index of the first maximum value of the vector is the set of target position column indices most relevant to the current residual , and the rescue position pre-selection support set is updated accordingly .

[0129] It should be noted that after obtaining the dimension column vector, the index of the first maximum value of the vector is the set of target position column indices most relevant to the current residual , and the target rescue position pre-selection support set is obtained by combining the position information support set PIS . In each iteration process of the present application, the position accuracy is improved by the normalization process, and multiple positions are selected into the target rescue position pre-selection support set , which improves the calculation speed of the algorithm, reduces the positioning error caused by mutual interference of multiple radiation sources, and improves the accuracy of the algorithm.

[0130] Specifically, step S3022 is mainly to obtain the corresponding sensing matrix from the target rescue position pre-selection support set.

[0131] In step S3023, the rescue target original signal estimation vector is calculated according to the sensing matrix: the corresponding inverse original rescue target signal column vector is calculated by least square method from the sensing matrix and the data column vector Zr.

[0132] In some embodiments, the possible target rescue position index set is obtained by calculating the sensing matrix S and the residual in step S3021, including:

[0133] In step S3021a, the normalization vector Nor is calculated based on the sensing matrix S.

[0134] Wherein, the sensing matrix S is obtained by calculating the signal acquisition node position matrix G and the path loss matrix PL through formula (1):

[0135] (1)

[0136] The normalization vector Nor is 1 / 2 of the diagonal element of the matrix obtained by multiplying the sensing matrix S and its transpose matrix S T , as shown in formula (2):​

[0137] (2)

[0138] Step S3021b, according to the sparse optimization principle, calculate the most relevant rescue target position index set .

[0139] Step S3021c, based on the sensing matrix and the residual, obtain the projection of the sample.

[0140] The sample, i.e. the residual, is multiplied by the inner product of the dictionary sensing matrix S to obtain its projection Q, as shown in formula (3):

[0141] (3)

[0142] Step S3021d, based on the normalization vector, normalize the projection of the sample to obtain the normalized projection. Specifically, the projection Q is normalized using the normalization vector Nor to obtain the normalized projection .

[0143] Step S3021e, sort the normalized projection, and based on the rescue target position information support set, obtain the target position pre-selected support set. The normalized projection is sorted, and the indexes of the largest maximal values in the first are selected as the current residual most relevant column index set .

[0144] In some embodiments, in step S303, based on the position information pre-selected support set and the signal strength value, the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target are obtained through iterative calculation, including:

[0145] Step S3031, obtain the rescue target position information support set PIS and update the iteration upper limit number . Specifically, according to the inversion of the rescue original signal value, determine the position index that meets the inversion of the rescue original signal column vector , and after combination, obtain the rescue target position information support set PIS of the current iteration, update the iteration upper limit number to the size of the rescue target position information support set PIS.

[0146] Step S3032, obtain the residual of the next iteration. Specifically, according to the rescue target position support set PIS, obtain the corresponding sensing matrix and calculate its original rescue signal estimate , and the original rescue signal estimate With sensing matrix Calculate and invert rescue target signals The residual from the next iteration is the inverted rescue target signal. .

[0147] Step S3033: Calculate the number of iterations. With the upper limit of iterations Comparison: If the number of iterations is less than the upper limit of iterations, the iteration continues and returns to continue the calculation to obtain the location index of the target to be rescued; if the number of iterations is greater than or equal to the upper limit of iterations, the iteration process ends and the current location information support set (PIS) of the target to be rescued is obtained.

[0148] It should be noted that the iteration stopping condition in the algorithm steps of this invention can also be determined by comparing the residual size of different iterations. That is, the residual obtained in each iteration is compared with the previous one, and a threshold is set for this value. If the threshold is exceeded, the iteration stops.

[0149] Specifically, steps S3031 to S3033 mainly involve determining the matching position indices in the column vector of the original rescue target signal based on the retrieved original rescue signal values, combining them to obtain the support set PIS of the target location information for the current iteration, and updating the upper limit of iterations. The size of the target location information support set PIS.

[0150] This invention estimates the number of possible radiation sources of the target to be rescued by judging the rationality of possible signal positions in the inverted original signal column vector, and sets an upper limit for the number of iterations accordingly. Due to the reasonable control of the iteration process, this invention does not require known information such as the number of radiation sources as a priori conditions to stop the iteration of multi-radiation source localization. Moreover, the number of iterations is stable and small, and the calculation time is short, which meets the real-time requirements of simultaneous search and rescue and localization of multiple targets after an earthquake.

[0151] Based on the search and rescue target support set The position index is used to select the corresponding column in the sensing matrix S to form... Size of the sensing matrix And calculate its corresponding original signal estimate. From the original signal estimate With sensing matrix Calculate and retrieve the received signal The residual from the next iteration will be used to retrieve the rescue target signal. The iteration count will be... With the upper limit of iterations If the iteration number is less than the iteration upper limit number, the iteration continues, the iteration number is incremented by 1, and the step of obtaining the index of the target position to be rescued is returned to continue the calculation of obtaining the index of the target position to be rescued. If the iteration number is greater than or equal to the iteration upper limit number, the iteration process is ended, and the current position information support set PIS is obtained.

[0152] In some embodiments, the position information support set PIS is obtained in step S3031 and the iteration upper limit number is updated , comprising the following steps.

[0153] According to the value of the inverse original rescue signal column vector , the decision threshold is calculated, as shown in formula (4).

[0154] (4)

[0155] The setting of the decision threshold is a reasonable assumption in an experimental scenario that the energy difference of the rescue target mobile terminal in the post-earthquake region will not exceed a certain order of magnitude, and the decision threshold is set; by obtaining the maximum value of the inverse original rescue signal column vector , and determining the signal position that is more than ten times smaller than the maximum value of the inverse original rescue signal column vector as an unreasonable rescue position, the decision threshold is calculated.

[0156] According to the decision threshold , the rescue position information support set PIS is obtained:

[0157] The positions in the inverse original rescue signal column vector with values smaller than the decision threshold are determined as unreasonable rescue positions, and the remaining position index combinations are the target position information support set PIS;

[0158] According to the target position information support set PIS, the iteration upper limit number is calculated, as shown in formula (5):

[0159] (5)

[0160] Wherein, the current target position information set PIS is the position of the mobile terminal of the plurality of trapped personnel in the post-earthquake search and rescue scene.

[0161] In summary, the post-earthquake search and rescue positioning method and system provided by the application provides a mobile terminal electromagnetic signal active induction technical solution for post-earthquake search and rescue, specifically: in the case of destroyed base stations after an earthquake, multi-mode mobile phones carried by trapped personnel may gradually fall back to GSM network mode for signal search, and the network standard may gradually fall back from 4G / 5G to GSM network mode. The present solution can generate induction signals according to 2G / 3G / 4G network protocols, and at the same time induce multiple trapped personnel to carry mobile terminals to send signals to access the network, thereby indirectly searching for trapped personnel after an earthquake. On the other hand, the present solution provides a scheme for synchronous electromagnetic data acquisition of multiple nodes in a post-earthquake environment, specifically: multiple acquisition nodes equipped with Beidou timing modules collect signals in the ruins environment, and in the FPGA, the PPS signal is used to calibrate the time information sent by the Beidou satellite and perform synchronous acquisition of electromagnetic signals, thereby preparing for subsequent multi-target simultaneous positioning.

[0162] The post-earthquake multi-target simultaneous search and rescue positioning and analysis method based on undersampling provided by the application can be used for positioning without prior conditions and can simultaneously search and rescue multiple targets. Specifically, the current PIS position information set is the position of the mobile terminal of the multiple trapped personnel in the post-earthquake search and rescue scene, and the multiple rescue signal strengths are calculated, the position of the trapped personnel is constrained to a very small range, and strong support is provided for subsequent post-earthquake rescue work.

[0163] Compared with the prior art, the present application has the following advantages:

[0164] (1) The present application provides a high-efficiency large-range fast and accurate search and positioning scheme for multiple trapped personnel after an earthquake: the unmanned aerial vehicle carries an electromagnetic signal acquisition node, which can move fast in a large range, and the node carries a Beidou timing module, which can receive Beidou satellite signals in the case of destroyed communication base stations. As everyone carries a mobile phone in today's society, in the case of destroyed base stations after an earthquake, multi-mode mobile phones may fall back for signal search, and the network standard may gradually fall back from 4G / 5G to GSM network mode. The present solution can generate induction signals according to 2G / 3G / 4G network protocols, and the wireless radio frequency transceiver integrated processing unit of the present solution can work at different frequencies, which can simultaneously induce multiple trapped personnel mobile phones to send signals and synchronously collect electromagnetic signals of the required frequency band.

[0165] (2) The application provides a new search and rescue technical scheme for simultaneously locating multiple targets after an earthquake without prior information based on undersampling: the application equates the undersampling multi-radiation source positioning to a sparse optimization solving problem, finds the maximum value position index by normalizing the inner product of the received signal sample and the path loss matrix dictionary, and solves the radiation source position, indirectly searches for the trapped personnel after the earthquake, and intelligently judges and iteratively stops the possible to-be-rescued positions, so that good positioning performance can be obtained without the number of trapped personnel and the signal strength of the mobile terminal carried by the trapped personnel, and the multi-target simultaneous search and rescue positioning based on undersampling is more practical.

[0166] (3) The search and rescue target positioning does not need prior information: in the process of stopping the judgment of the to-be-searched target positioning, the application does not need to use the information such as the number of trapped personnel and the signal strength of the mobile terminal carried by the trapped personnel as known information for judgment, but selects a large number of possible to-be-rescued target positions at one time, and screens and calculates the number of to-be-rescued targets through reasonable judgment, and sets an upper limit of the number of iterations, so that the stopping judgment condition of the iteration process can be reasonably calculated without the information such as the number of trapped personnel and the signal strength of the mobile terminal carried by the trapped personnel.

[0167] (4) The node signal collection synchronization error is small: the Beidou time service module of the distributed collection node receives the PPS second pulse signal, which can indicate the time interval of an integer second, and the rising edge of the PPS indicates the specific time corresponding to the UTC time given by the Beidou satellite. The accuracy of the integer second time indicated by it can reach nanoseconds, and in the case of a sampling rate of 61.44MHz, the error is only a few nanoseconds, and there is no cumulative error in the time synchronization using PPS.

[0168] (5) The positioning optimizes the redundant calculation process: after obtaining a large number of possible to-be-rescued target positions, the application inverses the original rescue signal estimate value through the least square method, and screens and selects through reasonable judgment, so that the accurate to-be-rescued target position can be obtained in a few iteration processes, the useless calculation process is reduced, and the calculation process is relatively simple.

[0169] (6) Low computational complexity: in the to-be-rescued target positioning, radiation source position judgment and iteration stop condition calculation of each iteration, only basic multiplication and division operations and size comparison are used, so the computational complexity is low, the target positioning time is short during search and rescue, and the target search and rescue positioning can be performed in real time in the scene after the earthquake.

[0170] The present application can realize active induction and reception of mobile terminal electromagnetic signals of trapped personnel in a disaster environment such as earthquake ruins, and indirect positioning through a mobile terminal carried by the trapped personnel. Experiments show that the present application uses under-sampling to obtain signals in a scene, and can obtain accurate positions of targets to be rescued after a small number of iteration times, and increasing the number of signal collection nodes can obviously improve the search and rescue positioning performance, and can effectively enhance the search and rescue positioning performance under the influence of Gaussian white noise.

[0171] Reference Figure 14 Another embodiment of the present application provides an electronic device, comprising: at least one processor 110; and a memory 111 in communication connection with the at least one processor; wherein the memory 111 stores instructions executable by the at least one processor 110, and the instructions are executed by the at least one processor 110 to enable the at least one processor 110 to perform any of the above method embodiments.

[0172] The memory 111 and the processor 110 are connected in a bus manner, the bus can include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors 110 and the memory 111 together. The bus can also connect various other circuits such as peripheral devices, voltage stabilizers and power management circuits together, which are well known in the art, and therefore, they will not be further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements such as multiple receivers and transmitters, which provide units for communicating with various other devices on the transmission medium. The data processed by the processor 110 is transmitted on the wireless medium through the antenna, and further, the antenna also receives data and transmits the data to the processor 110.

[0173] The processor 110 is responsible for managing the bus and general processing, and can also provide various functions including timing, peripheral interface, voltage regulation, power management and other control functions. And the memory 111 can be used to store data used by the processor 110 in performing operations.

[0174] Another embodiment of the present application relates to a computer readable storage medium storing a computer program. The computer program is executed by the processor to implement the above method embodiments.

[0175] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a program stored in a storage medium, including a plurality of instructions for causing a device (which can be a single-chip microcomputer, a chip, etc.) or a processor to execute all or part of the steps of the above-mentioned methods of various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0176] From the above technical solutions, the embodiment of the present application provides a post-earthquake search and rescue positioning method, system, device and storage medium, which comprises the following steps: first, generating an induction signal according to a mobile communication network protocol, and inducing a mobile terminal of a rescue target to send a signal to access the network; next, synchronously collecting electromagnetic signals in a post-earthquake environment by a plurality of signal collection nodes; finally, simultaneously positioning and analyzing a plurality of rescue targets to obtain position information of the rescue targets and signal strengths of the mobile terminals corresponding to the rescue targets.

[0177] The post-earthquake search and rescue positioning method provided by the present application is a post-earthquake search and rescue positioning method that can realize simultaneous positioning and analysis of multiple targets after an earthquake. In the ruins environment where the base station is destroyed after an earthquake, the mobile phone carried by the trapped personnel may gradually fall back to the 2G GSM network mode from 4G / 5G for signal searching. The present application can make the signal collection nodes send induction signals to realize active induction and reception of the electromagnetic signals of the mobile terminals carried by the trapped personnel, and indirectly search and position the mobile terminals of the post-earthquake rescue targets. The post-earthquake search and rescue positioning method for multiple targets simultaneously proposed by the present application selects a large number of possible rescue target positions for judgment and screening, and sets an upper limit on the number of iterations. In the case of no prior information such as signal strength, the accurate rescue target position can also be obtained in a small number of iterations, the calculation time is short, and the method can be used for real-time search and positioning of multiple trapped personnel simultaneously, widely and efficiently.

[0178] Those skilled in the art can understand that the above-mentioned embodiments are specific embodiments for implementing the present application, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. A method for post-earthquake search and rescue positioning, characterized in that, The method comprises the steps of: According to the mobile communication network protocol, an induction signal is generated, and the mobile terminal of the rescue target is induced to access the network; A plurality of signal collection nodes synchronously collect electromagnetic signals in the post-earthquake environment; A plurality of rescue targets are simultaneously positioned and analyzed to obtain the position information of the rescue targets and the signal strength of the mobile terminal corresponding to the rescue targets; The plurality of rescue targets are simultaneously positioned and analyzed to obtain the position information of the rescue targets and the signal strength of the mobile terminal corresponding to the rescue targets, comprising: A post-earthquake ruin electromagnetic scene model is constructed, a sensing matrix is calculated, and search and rescue positioning parameters are initialized; The position information of the mobile terminal of a plurality of rescue targets is simultaneously obtained, a support set is selected, and the signal strength value corresponding to the position information support set is calculated; Based on the position information support set and the signal strength value, the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target are obtained through iterative calculation; The position information of the mobile terminal of a plurality of rescue targets is simultaneously obtained, a support set is selected, and the signal strength value corresponding to the position information support set is calculated, comprising: Based on the sensing matrix and the residual error, a possible rescue target position index set is calculated and obtained, and a rescue position support set is updated; According to the updated rescue position support set, the sensing matrix is obtained; According to the sensing matrix, the original signal estimation vector of the rescue target is calculated; Based on the sensing matrix and the residual error, a possible rescue target position index set is calculated and obtained, comprising: Based on the sensing matrix, a normalized vector is obtained; According to the principle of sparse optimization, the most relevant rescue target position index set is calculated; Based on the sensing matrix and the residual error, the projection of the sample is obtained; Based on the normalized vector, the projection of the sample is normalized to obtain a normalized projection; The normalized projection is sorted, and the target position support set is obtained based on the rescue target position information support set; Wherein, the sensing matrix is obtained by formula (1) through the position matrix of the signal collection node and the path loss matrix: （1） Wherein, S represents the sensing matrix, G represents the position matrix of the signal collection node, and PL is the path loss matrix; Based on the sensing matrix and the transpose matrix of the sensing matrix, the normalized vector is calculated through formula (2): （2） where Nor represents a normalized vector, S T is the transpose matrix of the sensing matrix S; Based on the residual error and the sensing matrix, the projection of the sample is calculated through formula (3): （3） wherein Q is a projection, is the residual.

2. The post-earthquake search and rescue positioning method according to claim 1, characterized in that, The method comprises the steps of: By assuming the post-earthquake ruin electromagnetic scene and dividing the post-earthquake experimental area into grids, a post-earthquake ruin electromagnetic scene model is constructed; The position matrix of the signal collection node is constructed, and the received data column vector is obtained based on the signals synchronously collected by a plurality of signal collection nodes; According to the current post-earthquake electromagnetic environment and the post-earthquake ruin electromagnetic scene model, a path loss matrix is constructed; Based on the path loss matrix, the sensing matrix is calculated, and the search and rescue positioning parameters are initialized.

3. The post-earthquake search and rescue positioning method according to claim 1, characterized in that, Based on the position information, a support set of the rescue target is selected and the signal strength value is calculated by iterative calculation to obtain the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target, comprising: Obtaining a support set of the position information of the rescue target and updating the upper limit number of iterations; Based on the rescue target position support set, a sensing matrix corresponding to the rescue target position support set is acquired, and an original rescue signal estimation value is calculated; based on the original rescue signal estimation value and the sensing matrix, a residual error for next iteration is calculated ​ Comparing the number of iterations with the upper limit number of iterations, if the number of iterations is less than the upper limit number of iterations, the iteration continues, and the calculation of obtaining the position index of the rescue target is returned; if the number of iterations is greater than or equal to the upper limit number of iterations, the iteration process is ended, and the support set of the position information of the rescue target is obtained; and based on the support set of the position information of the rescue target, the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target are obtained.

4. The post-earthquake search and rescue positioning method according to claim 3, characterized in that, Obtaining a support set of the position information and updating the upper limit number of iterations, comprising: Based on the inversion of the original rescue signal column vector, the decision threshold is calculated; Based on the decision threshold, a support set of the rescue position information is obtained; Based on the support set of the rescue position information, the upper limit number of iterations is calculated; Wherein, the decision threshold is calculated by formula (4): （4） wherein is a decision threshold, is an inverse original rescue signal column vector; The upper limit number of iterations is calculated by formula (5): （5） Wherein, PIS represents the support set of the rescue position information, and the support set of the rescue position information is the union of the positions of the mobile terminals of multiple rescue targets in the post-earthquake search and rescue scene.

5. A post-earthquake search and rescue positioning system for implementing the post-earthquake search and rescue positioning method according to any one of claims 1 to 4, characterized in that, Comprising: The inducement signal generation module, the synchronous signal acquisition module and the multi-target positioning analysis module are connected in turn; The inducement signal generation module is used to generate inducement signals according to the mobile communication network protocol, and to induce the mobile terminal of the rescue target to send signals to access the network; The synchronous signal acquisition module is used to synchronously acquire electromagnetic signals in the post-earthquake environment through multiple signal acquisition nodes; The multi-target positioning analysis module is used to simultaneously position and analyze multiple rescue targets to obtain the position information of the rescue target and the signal strength of the mobile terminal corresponding to the rescue target.

6. An electronic device, comprising: Comprising: At least one processor; And The memory is in communication connection with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the post-earthquake search and rescue positioning method of any one of claims 1 to 4.

7. A computer readable storage medium storing a computer program, characterized in that, The computer program is executed by the processor to realize the post-earthquake search and rescue positioning method of any one of claims 1 to 4.

Images