Method and system for searching and positioning signals of mobile phone mounted on unmanned aerial vehicle

Abstract

The invention relates to the technical field of unmanned aerial vehicle application, in particular to a signal searching and positioning method and system for mounting a mobile phone on an unmanned aerial vehicle, and the method comprises the steps: S1, covering geographic information based on an operator network, planning and executing a flight task by the unmanned aerial vehicle, starting mobile phone information collection equipment after arriving at a to-be-searched target area, a mobile phone signal coverage area is formed below the unmanned aerial vehicle; s2, the mobile phone information acquisition device and a mobile phone in a mobile phone signal coverage area obtain IMSI information through signaling interaction, a positioning function is started for a specified IMSI, the unmanned aerial vehicle approaches a target through the change of the field intensity of a mobile phone signal, and finally the position of the mobile phone is locked; and S3, according to the trajectory diagram of the unmanned aerial vehicle and the IMSI trajectory diagram, displaying and confirming the position in real time in a geographic information system of a ground platform, and immediately providing the position to a professional ground search and rescue team. Compared with the prior art, the searching and positioning method and system using the unmanned aerial vehicle to mount the mobile phone signal have the advantages that the searching and positioning efficiency is high, the additional flight time is basically not increased, the effective working time of the unmanned aerial vehicle is prolonged, quick searching is realized, and lost people can be quickly found and rescued.

Description

Technical field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) application technology, and in particular to a method and system for searching and locating mobile phone signals by mounting a UAV on the mobile phone. [Background Technology]

[0002] In mountainous areas with lush trees, tourists, hikers, and farmers often get lost in the forests. Existing technologies are usually based on image acquisition and recognition technology, using drones equipped with visible light, thermal imaging, and other equipment to search. However, due to the terrain and vegetation characteristics of the lost areas, traditional drones' visible light and thermal imaging cannot penetrate the dense foliage and cannot identify lost persons through image acquisition, resulting in low search efficiency and not conducive to quickly finding lost persons. [Summary of the invention]

[0003] In order to overcome the above problems, the present invention proposes a method and system for searching and locating mobile phone signals by mounting a drone, which can effectively solve the above problems.

[0004] The present invention provides a technical solution to solve the above technical problems by providing a method and system for searching and locating mobile phone signals by using a drone, including the following steps:

[0005] Step S1: Based on the operator's network coverage geographic information, the drone plans and executes the flight mission. After arriving at the target area to be searched, the mobile phone information collection device is turned on to form a mobile phone signal coverage area below the drone.

[0006] Step S2: The mobile phone information collection device obtains IMSI information from mobile phones within the mobile phone signal coverage area through signaling interaction. The positioning function is activated for the specified IMSI, and the drone is allowed to approach the target by observing the changes in the mobile phone signal field strength, and finally the location of the mobile phone is locked.

[0007] In step S3, the position of the drone is displayed and confirmed in real time in the geographic information system of the ground station based on the drone's trajectory map and the IMSI trajectory map, and is immediately provided to the professional ground search and rescue team.

[0008] Preferably, in step S1, the mobile phone information collection device establishes available cells for the four major operators, namely, China Mobile, China Unicom, China Telecom and China Broadcasting Corporation; China Mobile and China Broadcasting Corporation share carrier parameters, while China Unicom and China Telecom share carrier parameters.

[0009] Preferably, in step S2, the drone arrives at the search starting point, turns on the radio frequency of the mobile phone information collection device, and the simulated operator carrier works simultaneously. The drone performs the flight mission according to the preset search flight path. During the search flight path, the mobile phone information collection device records the time point when the mobile phone IMSI information is collected, and also records its geographic location information and mobile phone field strength value, and immediately notifies the drone to change to the positioning flight path for flight.

[0010] Preferably, in step S2, when the UAV flies according to the positioning flight path, the mobile phone information collection device performs the positioning task, and the mobile phone information collection device and the positioned mobile phone periodically interact to obtain more mobile phone signal field strength values, which fall on different flight trajectories.

[0011] Preferably, in step S3, after the drone returns, the ground station combines the real-time return data during the flight and more data cached by the mobile phone information collection device to completely restore the drone trajectory map and each reporting point and field strength value trajectory map of each IMSI. The same IMSI is given a target location range according to the trend of field strength value changes; the ground station outputs the trajectory geographic information data and provides it to a professional ground search and rescue team or a further search and rescue flight.

[0012] Preferably, in step S3, a three-point positioning method is used to determine the target position range:

[0013] When detecting point D1, the field strength value of the target IMSI is measured as RSSI-1. Draw a circle with D1 as the center and RSSI-1 as the field strength value as the radius.

[0014] When detecting point D2, the field strength value of the target IMSI is measured as RSSI-2. Draw a circle 2 with D2 as the center and RSSI-2 as the field strength value as the radius;

[0015] When detecting point D3, the field strength value of the target IMSI is measured to be RSSI-3. Draw a circle with D3 as the center and RSSI-3 as the field strength value as the radius.

[0016] The intersection of circles 1, 2, and 3 is the location of the target IMSI;

[0017] D1, D2, and D3 are the locations of the drone when the same IMSI is detected for the first, second, and third time, respectively.

[0018] Preferably, in step S3, the ground station pre-downloads an offline map of the target area, and the acquisition device periodically reads the GPS position information onboard the UAV during the entire flight, and reports it to the ground station in real time. The ground station uses the offline map to mark each position information;

[0019] When the acquisition device detects the IMSI, it reads the onboard GPS location information, records the field strength value RSSI detected at the same time, and reports it to the ground station in the form of a single message;

[0020] The ground station application records the location information in real time on the offline map with another identifier, including the IMSI and field strength value.

[0021] Use a drone to mount a mobile phone signal search and positioning system, including a ground station, a drone, and a mobile phone information collection device that can be mounted on the drone;

[0022] The mobile phone information collection device is mounted on a drone, and the drone and the mobile phone information collection device are respectively connected to a ground station for communication;

[0023] The mobile phone information collection device is configured with a combined carrier of 4G LTE and 5G NR to simulate the cell information of China Mobile and broadcasting operators; the mobile phone information collection device is configured with a combined carrier of 4G LTE and 5G NR to simulate the cell information of China Telecom and China Unicom operators;

[0024] The mobile phone information collection device is equipped with a 2W power amplifier and a directional antenna. At an altitude of 120 meters, it effectively covers a ground radius of 200 meters. The signal strength of the cells in this area meets the needs of mobile phone access.

[0025] The mobile phone information collection device includes a Beidou and GPS dual-mode geographic information collection module and an IMSI collection module. The geographic information collection module shares data with the IMSI collection device in real time and records the real-time data provided by the module while collecting IMSI.

[0026] Preferably, the mobile phone information collection device includes a remote data communication module, which is a pair of point-to-point data communication modules, so as to realize long-distance data sharing and control between the IMSI collection module and the ground station.

[0027] Preferably, the ground station includes an industrial computer with transmission, battery and sound and light alarm functions, installation and updating of local detailed geographic information system, running IMSI collection and positioning control desktop software, and can display flight trajectory and IMSI in real time in the geographic information system.

[0028] Compared with the prior art, the present invention uses a method and system for searching and locating mobile phone signals mounted on drones. In areas where mobile phone signals are lost, drones are used to deploy mobile phone information collection equipment, simulate communication base stations, transmit cell carrier signals, attract mobile phone registrations and interaction information within the coverage area, collect mobile phone IMSI information, and specify the target IMSI in real time for flight positioning. During the positioning process, the entire geographic latitude and longitude information trajectory is recorded to form a trajectory map. In areas where mobile phone signals are lost, the mobile phone information collection equipment can be configured with a small amount of carriers and low-power signals, so that the target mobile phone can be quickly collected at an altitude of about 120 meters. In the case of a small number of carriers and low power, the collection equipment can meet the requirements of small size and light weight that can be supported by commonly used small drones, thereby achieving low search costs. The use of mobile phone signals for search and positioning is highly efficient, basically does not increase additional flight time, increases the effective working time of the drone, achieves rapid search, and is conducive to quickly finding lost people and rescuing them.

Brief Description of the Drawings

[0029] Figure 1 This is a flow chart of the method for searching and locating a mobile phone signal by using a drone mounted on it according to the present invention;

[0030] Figure 2 A reference diagram of the search flight path for the method of searching and locating mobile phone signals using a drone mounted on a mobile phone according to the present invention;

[0031] Figure 3 A reference diagram of the positioning flight path for the method of searching and positioning a mobile phone signal using a drone mounted on the mobile phone according to the present invention;

[0032] Figure 4 This is a schematic diagram of three-point positioning detection using a method for searching and locating a mobile phone signal mounted on a drone according to the present invention;

[0033] Figure 5 This is a framework diagram of the present invention's system for searching and locating mobile phone signals using a drone;

[0034] Figure 6 A three-dimensional diagram of a mobile phone information collection device using a drone mounted on a mobile phone signal search and positioning system according to the present invention;

[0035] Figure 7 This is a diagram showing the internal structure of a mobile phone information collection device that uses a drone to mount a mobile phone signal search and positioning system. [Specific implementation method]

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and implementation examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] It should be noted that in the embodiment of the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are limited to relative positions on the specified view, rather than absolute positions.

[0038] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0039] See also Figure 1 The method for searching and locating a mobile phone signal by using a drone mounted on the mobile phone of the present invention comprises the following steps:

[0040] In step S1, based on the geographical information of the operator's network coverage, the drone plans and executes the flight mission. After arriving at the target area to be searched, the mobile phone information collection device is turned on to form a mobile phone signal coverage area under the drone.

[0041] In step S2, the mobile phone information collection device obtains IMSI information through signaling interaction with mobile phones within the mobile phone signal coverage area, activates the positioning function for the specified IMSI, and uses the changes in the mobile phone signal field strength to allow the drone to approach the target and eventually lock the mobile phone location.

[0042] In step S3, the position of the drone is displayed and confirmed in real time in the geographic information system of the ground station based on the drone's trajectory map and the IMSI trajectory map, and is immediately provided to the professional ground search and rescue team.

[0043] In step S1, the mobile phone information collection device is mounted on the drone, and the mobile phone information collection device is in a standby state when the drone departs.

[0044] In step S1, the mobile phone information collection device establishes available cells for the four major operators, namely China Mobile, China Unicom, China Telecom and China Broadcasting Corporation; China Mobile and China Broadcasting Corporation share carrier parameters, China Unicom and China Telecom share carrier parameters, and preset working frequencies.

[0045] In step S1, by presetting the area in the geographic information system where the operator network has no signal or weak signal but is difficult for mobile phones to access and the approximate range of this flight mission, the specific search area is determined, the drone flight route is planned, the search starting point and end point are searched, and the return time point is determined.

[0046] In step S1, the mobile phone information collection device forms a mobile phone signal coverage area with an angle of 120 degrees downward at a height of 120 meters, and the ground coverage area forms a circular area with a radius of 200 meters.

[0047] In step S2, the drone arrives at the search starting point, turns on the radio frequency of the mobile phone information collection device, and the simulated operator carrier works simultaneously. The drone performs the flight mission according to the preset search flight path. During the search flight path, the mobile phone information collection device records the time point when the mobile phone IMSI information is collected, and also records its geographic location information (via GPS or Beidou) and the mobile phone field strength value, and immediately notifies the drone to change to the positioning flight path for flight.

[0048] Please refer to 2, Efficiency Description:

[0049] The calculation formula for one area search time is:

[0050] t (search time) = a (area length) * b (area width) / d (search diameter) / s (flight speed)

[0051] In this invention: the search diameter is 400 meters, the search speed is maintained at 40 kilometers per hour,

[0052] Reference target area to be searched: within an area of ​​5 kilometers in length and 1.6 kilometers in width, the effective search area is 8 square kilometers.

[0053] By making four round trips, the search can be completed in about 30 minutes.

[0054] Calculation data:

[0055] t = 5000 m * 1600 m / 400 m / (40000 m / 3600 s) = 1800 s = 30 minutes.

[0056] In step S2, when the drone flies according to the positioning flight path, the mobile phone information collection device performs the positioning task, and the mobile phone information collection device periodically interacts with the positioned mobile phone to obtain more mobile phone signal field strength values, falling on different flight trajectories; during the positioning flight process, if a second or more IMSIs are collected, the system will record these IMSI information, but will not initiate a positioning flight for them, and will regard them as being in the same target group as the IMSI being positioned.

[0057] Please refer to 3, main legend:

[0058] D (Detect) is the first detection of the IMSI location;

[0059] T (Target) is the assumed location of the target IMSI; T must fall within the coverage area of ​​a circle with a radius of 200 meters centered at point D.

[0060] The solid line is the search flight path, and the device is in code detection mode;

[0061] Line segment 1, line segment 2, line segment 3, the device changes to positioning mode, periodically detects and records changes in field strength values.

[0062] Segment 1: Fly 100 meters in the direction of the search flight path;

[0063] Line segment 2, along the circumference of a circle with point D as the center and a radius of 100 meters, continues to fly one circle;

[0064] Line segment 3: Keep flying in the search flight path direction for 100 meters. When it flies out of the 200-meter circle coverage area, it stops positioning and resumes the code detection mode.

[0065] When positioning completes a circle, the radius of the effective detection range is expanded to 300 meters.

[0066] The calculation formula for one-time positioning flight time is:

[0067] T = [R1 (positioning flight radius) + C (positioning flight circle circumference) + R (search radius) - R1] / S (positioning flight speed)

[0068] In this case, R1 = 100 meters, R = 200 meters, C = 2π*R1

[0069] Calculation result: T = [100 meters + 2*3.14*100 meters + 200 meters - 100 meters] / (40,000 meters / 3,600 seconds) ~ = 74 seconds

[0070] The period of recording field strength of the position marking is set to 2 seconds, which can sample more than 37 valid field strength value data for position analysis.

[0071] The calculation formula for the flight time when a positioning exceeds the preset trajectory is:

[0072] Td = C (positioning flight circle circumference) / S (positioning flight speed)

[0073] The calculation result of the present invention is: Td=2*3.14*100 / (40000 / 3600)=56.5 seconds.

[0074] In step S2, after completing the IMSI positioning flight, the UAV executes the preset search flight path to continue flying and search for the next possible IMSI; or accepts the control of the ground station, ends the current search mission, and returns to the flight site.

[0075] In step S3, after the drone returns, the ground station combines the real-time return data during the flight and more data cached by the mobile phone information collection device to completely restore the drone trajectory map and each reporting point and field strength value trajectory map of each IMSI. The same IMSI is given the target location range according to the field strength value change trend; the ground station outputs the trajectory geographic information data and provides it to a professional ground search and rescue team or a further search and rescue flight.

[0076] In step S3, the target position range is determined using a three-point positioning method. Please refer to Figure 4 for the main illustrations:

[0077] D1, D2, and D3 are the drone’s locations when the same IMSI is detected for the first, second, and third time, respectively;

[0078] T is the target IMSI assumed location.

[0079] When detecting point D1, the field strength value of the target IMSI is measured as RSSI-1. Draw a circle with D1 as the center and RSSI-1 as the field strength value as the radius.

[0080] When detecting point D2, the field strength value of the target IMSI is measured as RSSI-2. Draw a circle 2 with D2 as the center and RSSI-2 as the field strength value as the radius;

[0081] When detecting point D3, the field strength value of the target IMSI is measured to be RSSI-3. Draw a circle with D3 as the center and RSSI-3 as the field strength value as the radius.

[0082] The intersection of circles 1, 2, and 3 is the location of the target IMSI.

[0083] During a 1-minute positioning flight, the actual number of times the same IMSI can be detected is generally greater than 3 times, which can further compensate for the RSSI measurement error.

[0084] In step S3, the ground station pre-downloads an offline map of the target area, which contains high-precision location information such as longitude and latitude, contour lines, etc. Before the flight mission begins, the ground station loads the offline map of the target area for this mission.

[0085] During the entire flight of the drone, the collection equipment periodically reads the onboard GPS location information and reports it to the ground station in real time. The ground station will mark each location information on the offline map.

[0086] When the acquisition device detects the IMSI, it reads the onboard GPS location information, records the simultaneously detected field strength value RSSI, and reports it to the ground station in the form of a single message. The ground station application records the location information, including the IMSI and field strength value, by marking it with another marker on an offline map in real time.

[0087] See also Figures 5 to 7 The present invention discloses a mobile phone signal search and positioning system using a drone mounted thereon, comprising a ground station, a drone, and a mobile phone information collection device that can be mounted on the drone.

[0088] The mobile phone information collection device is mounted on a drone, and the drone and the mobile phone information collection device are respectively connected to a ground station for communication.

[0089] The mobile phone information collection device is configured with a combined carrier of 4G LTE and 5G NR to simulate the cell information of China Mobile and broadcasting operators; the mobile phone information collection device is configured with a combined carrier of 4G LTE and 5G NR to simulate the cell information of China Telecom and China Unicom operators.

[0090] The mobile phone information collection device is equipped with a 2W power amplifier and a directional antenna, which ensures effective coverage of a 200-meter ground radius at a height of 120 meters. The cell signal strength in this area meets the needs of mobile phone access.

[0091] The mobile phone information collection device includes a special Beidou and GPS dual-mode geographic information collection module and an IMSI collection module. The geographic information collection module shares data with the IMSI collection device in real time and records the real-time data provided by the module while collecting IMSI.

[0092] The mobile phone information collection device includes a remote data communication module, which is a pair of point-to-point data communication modules, so that long-distance (more than 5km) data sharing and control can be achieved between the IMSI collection module and the ground station.

[0093] The ground station is an IMSI search ground control console.

[0094] The ground station includes an industrial computer with transmission, battery, and audio / optical alarm functions. It also has the ability to install and update a detailed local geographic information system (GIS), run IMSI collection and positioning control desktop software, and display flight trajectories and IMSIs in real time within the GIS. The industrial computer also features data export capabilities and an integrated UAV flight control console interface.

[0095] The present invention uses a method and system for searching and locating mobile phone signals mounted on a drone. In an area where mobile phone signals are lost, the drone can be used to deploy mobile phone information collection equipment, simulate a communication base station, transmit a cell carrier signal, attract mobile phone registrations and interaction information within the coverage area, collect mobile phone IMSI information, and specify the target IMSI in real time for flight positioning. During the positioning process, the entire geographic latitude and longitude information trajectory is recorded to form a trajectory map. In the area where mobile phone signals are lost, the mobile phone information collection equipment can be configured with a small amount of carrier and low-power signal, so that the target mobile phone can be quickly collected at an altitude of about 120 meters. In the case of a small amount of carrier and low power, the collection equipment can meet the requirements of small size and light weight that can be supported by commonly used small drones, thereby achieving low search costs. The use of mobile phone signals for search and positioning is highly efficient, basically does not increase additional flight time, increases the effective working time of the drone, achieves rapid search, and is conducive to quickly finding lost people and rescuing them.

[0096] The method and system for searching and locating mobile phone signals by mounting a drone of the present invention are less affected by obstructions from mountains and forests, and have a fast acquisition speed. Mobile phone signal acquisition and search and rescue equipment can be mounted on a drone to search for and locate the mobile phones of lost persons, thereby improving the efficiency of search and rescue work, reducing costs, and saving the lives of lost persons to the greatest extent.

[0097] At the same time, the system can be used to collect, track and capture criminal information such as forest fire prevention, gambling and escape arrest, illegal mining of minerals, and poaching of rare animals and plants in areas without mobile phone signals in the wild; the system can also be used for relief data analysis and emergency search and rescue when the operator's mobile system is damaged due to sudden natural disasters.

[0098] Specifically, the mobile phone information collection device includes a drone connection seat 01, a communication compartment 02, a business compartment 03, and an antenna compartment 11. The drone connection seat 01, the communication compartment 02, the business compartment 03, and the antenna compartment 11 are connected and assembled in sequence from top to bottom. The drone connection seat 01 is suspended at the bottom of the drone, and the antenna of the antenna compartment 11 faces downward to cover the ground.

[0099] The communication warehouse 02 includes a power indicator light 03, a power interface 04, a network port 05, a GPS antenna interface 06, a data transmission module antenna interface 07, a data transmission module 12, a switch module 13, and a power module 14. The power indicator light 03 and the power interface 04 are respectively connected to the power module 14, the data transmission module antenna interface 07 is connected to the data transmission module 12, and the network port 05 and the GPS antenna interface 06 are respectively connected to the switch module 13.

[0100] The data transmission module 12 is connected to the antenna via the data transmission module antenna interface 07 and communicates with the data transmission module of the ground station, thereby transmitting the data of the mobile phone information collection device to the ground station.

[0101] The business warehouse 08 includes a 4G scanning network synchronization antenna interface 09, a 5G scanning network synchronization antenna interface 10, a 4 / 5G base station module 15, a fan 16, and a full-band power amplifier module 17. The 4G scanning network synchronization antenna interface 09 and the 5G scanning network synchronization antenna interface 10 are respectively connected to the full-band power amplifier module 17, and the full-band power amplifier module 17 is connected to the 4 / 5G base station module 15. The 4 / 5G base station module 15 is connected to the switch module 13 via a network cable, and the switch module 13 is connected to the data transmission module 12 via a network cable to realize a complete data communication network.

[0102] The 4 / 5G base station module 15 is connected to the full-band power amplifier module 17 via a radio frequency line to amplify the multi-carrier base station signal before transmitting it. The 4 / 5G base station module 15 realizes the concurrent use of 2 arbitrary 4G carriers and 2 arbitrary 5G carriers. The full-band power amplifier module 17 supports all 11 domestic 4 / 5G frequency bands (B1 / N1, B3, B5, B8, N28, B34, B39, B40, B41 / N41, N78, N79). Its 4-way input signal is connected to the 4 / 5G four-way base station signal one by one, and its 6-way output signal is N28, B5 / B8, B1(N1) / B3, B39 / B34 / B40 / B41(N41), N78, N79, which are connected to the corresponding antenna array in the antenna compartment 11 via radio frequency lines.

[0103] In the business compartment 08, the 4 / 5G base station module 15 and the full-band power amplifier module 17 are installed back to back, and the heat dissipation teeth 18 are distributed on the back of the 4 / 5G base station module 15 and the full-band power amplifier module 17. The fan 16 is embedded in one end of the heat dissipation teeth 18 as an air inlet, and the other end of the heat dissipation teeth 18 is an air outlet.

[0104] The 4 / 5G base station module 15 provides GPS function, connects to the GPS antenna interface 06 located in the communication compartment 02 via a radio frequency line, and then obtains GPS location information in real time through an external GPS / BD antenna.

[0105] The 4 / 5G base station module 15 provides two network scanning synchronization interfaces, which are connected to the 4G network scanning synchronization antenna interface 09 and the 5G network scanning synchronization antenna interface 10 through radio frequency cables, respectively, to complete the signal scanning and analysis of the 4G public network and the 5G public network, respectively, and realize automatic frequency configuration and public network synchronization functions.

[0106] There are 6 antenna arrays in the antenna compartment 11, which are respectively connected to the 6 outputs of the full-band power amplifier module 17. The antenna connection port 19 is the connection window channel between the business compartment 08 and the antenna compartment 11.

[0107] The specific working process of the mobile phone information collection device is as follows:

[0108] The onboard mobile phone information collection device supports carrier frequency and cell scanning in the target environment. For initial operation in the target area, typically at the county or city level, or if the device has not been used for a long time, using network scanning and self-configuration is more effective in configuring the optimal operating frequency and improving detection success rates in signal-deprived areas. If the same device is frequently used in the same location, self-configuration can be disabled, and the last frequency configuration can be used. The option to enable self-configuration can be pre-set.

[0109] When the drone takes off, the acquisition device powers on and, with the self-configuration option enabled, initiates the network scan self-configuration thread, sequentially starting 4G (LTE) and 5G (NR) frequency scans. 4G scans Bands 1, 3, 5, 8, 34, 39, 40, and 41; 5G scans N1, N28, N41, N78, and N79.

[0110] After scanning the cell signal, it will parse its MIB and main SIB to obtain the cell signal strength (RSRP), operator code (PLMN), frequency (ARFCN), physical cell ID (PCI), and the same-frequency and different-frequency cell information of each cell.

[0111] The self-configuration algorithm extracts this key information and, according to a specific algorithm, filters and sorts it to determine the optimal two 4G and two 5G operating frequencies, as well as other cell-related parameters. At the end of the network scan self-configuration thread, the acquired cell configuration is saved, replacing the previously saved values. If the self-configuration option is not enabled, the acquisition device directly reads the saved cell configuration to establish four cells: two 4G and two 5G.

[0112] In parallel, after the data acquisition device is powered on, it starts the GPS thread and the thread for connecting to the ground station (usually a TCP connection). If the connection with the ground station is successful, the cell establishment status will be reported to the ground station in real time, and then the device will wait for the work instructions from the ground station. At the same time, the device's radio frequency is turned off, that is, it is not in operation.

[0113] When the drone flies to the boundary of the target area, it will send a work start command to the collection device through the ground station. The collection device will turn on the radio frequency, enter the search mode, start collecting code detection status, and start periodically reporting the current device location information.

[0114] When the first mobile phone card code (IMSI-1) is detected, the collection device switches to positioning mode, that is, through signaling induction, it continuously collects the IMSI. At the same time, it notifies the drone through the ground station to fly a circle according to the preset positioning flight path. Each time an IMSI is collected, the device records the time, longitude and latitude and other location information, measures the received field strength value RSSI, and packages this information to the ground station. The ground station records and saves this information in real time in its geographic information system. When the preset positioning time is completed, the collection device switches back to search and detection mode and notifies the drone through the ground station to resume flying according to the preset search path.

[0115] Repeatedly, within the effective flight time, the search and positioning of N mobile phone card codes (IMSI-N) can be completed until the flight time ends, or the ground station issues an end-of-work instruction in advance, the collection device turns off the radio frequency, and ends the periodic reporting of the device location information.

[0116] After the collection equipment returns with the drone, ground station staff can use the GIS to more accurately map the location of each IMSI that has passed through the positioning flight using a multi-point positioning method (three points is the minimum). In theory, there is a definite relationship between RSSI measurements and wireless transmission distance. Although RSSI measurements are significantly affected by the environment, since there are few obstructions between the drone and the target phone, and they are mostly fixed objects, the RSSI measurements are repeatable. The average of multiple measurements will significantly improve the final measurement accuracy.

[0117] Actual measurement results show that the positioning accuracy of this solution can reach within 10 meters, which significantly reduces the search and rescue range for subsequent manual search and rescue.

[0118] The drone uses DJI's industrial-grade Matrick 300 / 350RTK model, which supports a 2.7kg payload, a speed of 40 kilometers per hour, and a flight time of 55 minutes.

[0119] The data transmission module 07 adopts the TZ-C33 integrated image and data transmission module with 2W transmission power and a maximum transmission distance of 20 kilometers.

[0120] The 4 / 5G base station module 15 adopts the XP-G578 baseband board, which supports any combination of 2*4G and 2*5G concurrent carriers.

[0121] The full-band power amplifier module 17 adopts the HR-P90101 power amplifier module, which supports amplification of all 11 4 / 5G frequency band signals, and the output power of each frequency band is 1W.

[0122] The information collection equipment including accessories weighs less than 2.2kg and consumes less than 45W. Its structural dimensions are 8cm, 16cm, and 22cm from top to bottom in the width direction of the drone, and its length and height are both 13cm, which meet the drone mounting requirements.

[0123] Compared with the prior art, the present invention uses a method and system for searching and locating mobile phone signals mounted on drones. In areas where mobile phone signals are lost, drones are used to deploy mobile phone information collection equipment, simulate communication base stations, transmit cell carrier signals, attract mobile phone registrations and interaction information within the coverage area, collect mobile phone IMSI information, and specify the target IMSI in real time for flight positioning. During the positioning process, the entire geographic latitude and longitude information trajectory is recorded to form a trajectory map. In areas where mobile phone signals are lost, the mobile phone information collection equipment can be configured with a small amount of carriers and low-power signals, so that the target mobile phone can be quickly collected at an altitude of about 120 meters. In the case of a small number of carriers and low power, the collection equipment can meet the requirements of small size and light weight that can be supported by commonly used small drones, thereby achieving low search costs. The use of mobile phone signals for search and positioning is highly efficient, basically does not increase additional flight time, increases the effective working time of the drone, achieves rapid search, and is conducive to quickly finding lost people and rescuing them.

[0124] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any modifications, equivalent replacements and improvements made within the concept of the present invention should be included in the patent protection scope of the present invention.

Claims

1. A method for searching and locating mobile phone signals by using a drone, characterized in that: The steps include: Step S1: Based on the operator's network coverage geographic information, the drone plans and executes the flight mission. After arriving at the target area to be searched, the mobile phone information collection device is turned on to form a mobile phone signal coverage area below the drone. Step S2: The mobile phone information collection device obtains IMSI information from mobile phones within the mobile phone signal coverage area through signaling interaction. The positioning function is activated for the specified IMSI, and the drone is allowed to approach the target by observing the changes in the mobile phone signal field strength, and finally the location of the mobile phone is locked. In step S3, the position of the drone is displayed and confirmed in real time in the geographic information system of the ground station based on the drone's trajectory map and the IMSI trajectory map, and is immediately provided to the professional ground search and rescue team.

2. The method for searching and locating mobile phone signals by using a drone as claimed in claim 1, wherein: In step S1, the mobile phone information collection device establishes available cells for the four major operators, namely, China Mobile, China Unicom, China Telecom and China Broadcasting Corporation; China Mobile and China Broadcasting Corporation share carrier parameters, while China Unicom and China Telecom share carrier parameters.

3. The method for searching and locating mobile phone signals by using a drone as claimed in claim 1, wherein: In step S2, the drone arrives at the search starting point, turns on the radio frequency of the mobile phone information collection device, and the simulated operator carrier works simultaneously. The drone performs the flight mission according to the preset search flight path. During the search flight path, the mobile phone information collection device records the time point when the mobile phone IMSI information is collected, and also records its geographic location information and mobile phone field strength value, and immediately notifies the drone to change to the positioning flight path for flight.

4. The method for searching and locating a mobile phone signal by using a drone as claimed in claim 3, wherein: In step S2, when the UAV flies according to the positioning flight path, the mobile phone information collection device performs the positioning task, and the mobile phone information collection device periodically interacts with the positioned mobile phone to obtain more mobile phone signal field strength values, which fall on different flight trajectories.

5. The method for searching and locating mobile phone signals by using a drone as claimed in claim 1, wherein: In step S3, after the drone returns, the ground station combines the real-time return data during the flight with more data cached by the mobile phone information collection device to completely restore the drone trajectory map and each reporting point and field strength value trajectory map of each IMSI. For the same IMSI, the target location range is given according to the field strength value change trend; The ground station outputs the trajectory geographic information data and provides it to professional ground search and rescue teams or further search and rescue flights.

6. The method for searching and locating mobile phone signals by using a drone as claimed in claim 1, wherein: In step S3, the target position range is determined using a three-point positioning method: When detecting point D1, the field strength value of the target IMSI is measured as RSSI-1. Draw a circle with D1 as the center and RSSI-1 as the field strength value as the radius. When detecting point D2, the field strength value of the target IMSI is measured as RSSI-2. Draw a circle 2 with D2 as the center and RSSI-2 as the field strength value as the radius; When detecting point D3, the field strength value of the target IMSI is measured to be RSSI-3. Draw a circle with D3 as the center and RSSI-3 as the field strength value as the radius. The intersection of circles 1, 2, and 3 is the location of the target IMSI; D1, D2, and D3 are the drone’s locations when the same IMSI is detected for the first, second, and third time, respectively.

7. The method and system for searching and locating mobile phone signals by using a drone as claimed in claim 1, wherein: In step S3, the ground station pre-downloads an offline map of the target area. The acquisition device periodically reads the GPS location information onboard the drone throughout its flight and reports it to the ground station in real time. The ground station then marks each location information on the offline map. When the acquisition device detects the IMSI, it reads the onboard GPS location information, records the field strength value RSSI detected at the same time, and reports it to the ground station in the form of a single message; The ground station application records the location information in real time on the offline map with another identifier, including the IMSI and field strength value.

8. The mobile phone signal search and positioning system using a drone as claimed in claim 1, wherein: Including ground stations, drones, and mobile phone information collection equipment that can be mounted on drones; The mobile phone information collection device is mounted on a drone, and the drone and the mobile phone information collection device are respectively connected to a ground station for communication; The mobile phone information collection device is configured with a combined carrier of 4G LTE and 5G NR to simulate the cell information of China Mobile and broadcasting operators; the mobile phone information collection device is configured with a combined carrier of 4G LTE and 5G NR to simulate the cell information of China Telecom and China Unicom operators; The mobile phone information collection device is equipped with a 2W power amplifier and a directional antenna. At an altitude of 120 meters, it effectively covers a ground radius of 200 meters. The signal strength of the cells in this area meets the needs of mobile phone access. The mobile phone information collection device includes a Beidou and GPS dual-mode geographic information collection module and an IMSI collection module. The geographic information collection module shares data with the IMSI collection device in real time and records the real-time data provided by the module while collecting IMSI.

9. The mobile phone signal search and positioning system using a drone as claimed in claim 8, characterized in that: The mobile phone information collection device includes a remote data communication module, which is a pair of point-to-point data communication modules, so that long-distance data sharing and control can be achieved between the IMSI collection module and the ground station.

10. The mobile phone signal search and positioning system using a drone as claimed in claim 9, wherein: The ground station includes an industrial computer with transmission, battery and sound and light warning functions, an installation and update of a local detailed geographic information system, and the ability to run IMSI collection and positioning control desktop software, and can display the flight trajectory and IMSI in real time in the geographic information system.

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