A method and system for finding and positioning an unmanned aerial vehicle

Abstract

The present invention discloses a method and system for searching and locating a drone. The method for searching and locating includes: obtaining local position information and target position information sent by a drone end, wherein the target position information is the position information of the drone; calculating the azimuth angle between the local end and the drone according to the local position information and the target position information; when the distance between the drone and the local end is less than a preset distance, obtaining the ranging information between the local end and the drone, and confirming the search radius according to the ranging information; determining the position of the drone according to the azimuth angle and the search radius. The technical solution of the embodiment of the present invention can further confirm the search radius of the drone by obtaining the position coordinates of the local end and the drone end, calculating the azimuth angle, and obtaining accurate ranging data between the two ends, so that the crashed drone can be accurately searched according to the azimuth angle and the search radius, achieving decimeter-level positioning accuracy.

Description

Technical Field

[0001] The embodiments of the present invention relate to precise positioning technology, and more particularly to a method and system for searching and positioning an unmanned aerial vehicle. Background Art

[0002] In recent years, with the rapid development of drone technology, drones have been applied in many fields. The inspection function of drones is mainly to replace the staff to complete the dirty and tiring information collection work, to replace the staff to go to the required place to collect the required information, and then quickly and accurately convey it to the ground staff for analysis, judgment, and solution formulation, so as to reduce the labor intensity of the staff and improve the efficiency and safety of power inspection work.

[0003] However, when a drone loses control and crashes, searching for it is difficult due to the large search range and high risk factor. The existing technology uses carrier phase differential (Real Time Kinematic, RTK) positioning to search for drones, which can achieve accurate positioning, but its operation is easily affected by the environment or communication quality. Summary of the invention

[0004] The present invention provides a method and system for searching and locating a UAV, so as to realize a quick and safe search for a UAV that crashed out of control without using an RTK differential positioning method, and can achieve a positioning accuracy of decimeter level.

[0005] In a first aspect, an embodiment of the present invention provides a method for finding and locating a drone, comprising:

[0006] Get the local location information and the target location information sent by the drone. The target location information is the location information of the drone.

[0007] Calculate the azimuth angle between the local and the UAV based on the local position information and the target position information;

[0008] When the distance between the drone and the local area is less than the preset distance, the distance measurement information between the local area and the drone is obtained, and the search radius is confirmed according to the distance measurement information;

[0009] Determine the position of the drone based on the azimuth angle and search radius.

[0010] Optionally, the target location information includes target longitude and target latitude, and the local location information includes local longitude and local latitude;

[0011] Calculate the azimuth angle based on the local position information and the target position information, including:

[0012] Subtract the local latitude from the target latitude to obtain the first distance;

[0013] Subtract the local longitude from the target longitude to obtain the second distance;

[0014] The azimuth angle θ is calculated according to the trigonometric function tan θ=first distance / second distance.

[0015] Optionally, obtain the distance information between the drone and the local area, including:

[0016] After receiving the pulse signal from the drone, the signal arrival angle AOA and time difference TDOA are used to calculate the distance information between the local and the target.

[0017] Optionally, after determining the position of the drone according to the azimuth angle and the search radius, the following steps are further included:

[0018] Load the offline map to display the local location and the location of the drone.

[0019] Optionally, the preset distance is less than or equal to 1000 meters.

[0020] In a second aspect, an embodiment of the present invention further provides a drone search and positioning system, the search and positioning system comprising:

[0021] The front-end device is arranged on the UAV and is used to locate the position of the UAV and obtain the target position information;

[0022] The back-end device is used to locate the local position to obtain the local position information and receive the target position information; calculate the azimuth angle according to the local position information and the target position information; when the distance between the UAV and the local is less than the preset distance, obtain the distance measurement information between the UAV and the local, and confirm the search radius according to the distance measurement information; determine the position of the UAV according to the azimuth angle and the search radius.

[0023] Optionally, the front-end device includes a first Beidou module, a first wireless communication module, a UWB pulse wireless communication tag, a first dual-mode antenna, a first UWB pulse wireless communication antenna and a Raspberry Pi;

[0024] The Raspberry Pi is used to collect the drone coordinate data output by the first Beidou module, store the drone coordinate data in real time, and transmit the drone coordinate data to the back-end device through the first wireless communication module; the UWB pulse wireless communication tag is used to send a pulse signal to the back-end device to instruct the back-end device to communicate and measure distance in real time according to the pulse signal.

[0025] Optionally, the front-end device further includes a battery, an indicator light and a shell; the indicator light is connected to the Raspberry Pi; the battery is used to supply power to the Raspberry Pi; the shell encapsulates the first Beidou module, the first wireless communication module, the Raspberry Pi, the battery, the indicator light and the UWB pulse wireless communication tag; and the shell is fixed to the drone body;

[0026] The first dual-mode antenna and the first UWB pulse wireless communication antenna are fixed on the upper side of the shell, the first dual-mode antenna is connected to the first Beidou module and the first wireless communication module, the first UWB pulse wireless communication antenna is connected to the UWB pulse wireless communication tag; the first Beidou module is connected to the Raspberry Pi via the UART to USB port; the first wireless communication module is connected to the Raspberry Pi via the UART to USB port; the UWB pulse wireless communication tag is connected to the Raspberry Pi via the UART to USB port.

[0027] Optionally, the backend device includes a second Beidou module, a second wireless communication module, a UWB pulse wireless communication micro base station, a second dual-mode antenna, a second UWB pulse wireless communication antenna and a processing module;

[0028] The second Beidou module is used to locate the local position and transmit the local coordinate data to the processing module;

[0029] The processing module is used to receive the drone coordinate data transmitted by the first wireless communication module through the second wireless communication module; calculate the azimuth angle according to the drone coordinate data and the local coordinate data; the UWB pulse wireless communication micro base station is used to receive the pulse signal emitted by the UWB pulse wireless communication tag, and use the signal arrival angle measurement and time difference to calculate the local and target high-precision measurement distance information.

[0030] Optionally, the processing module includes a tablet computer;

[0031] The second Beidou module is connected to the tablet computer via the UART to USB port; the second wireless communication module is connected to the tablet computer via the UART to USB port; the UWB pulse wireless communication micro base station is connected to the tablet computer via the UART to USB port; the second dual-mode antenna is connected to the second Beidou module and the second wireless communication module, and the second UWB pulse wireless communication antenna is connected to the UWB pulse wireless communication micro base station.

[0032] The drone search and positioning method provided in the embodiment of the present invention obtains the local position information and the target position information of the drone end respectively, calculates the azimuth angle between the local end and the drone end, then receives the ranging distance between the local end and the drone end, and further calculates the search radius of the search range positioning accuracy circle, so that the position of the crashed drone can be determined according to the azimuth angle and the search radius, and the crashed drone can be accurately positioned without using the RTK differential positioning method, and the positioning accuracy can reach the decimeter level, so that the search personnel can quickly and accurately locate and search the drone after the drone loses control and crashes, thereby recovering economic losses to the greatest extent and ensuring the personal safety of the search personnel when performing operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1This is a flow chart of a method for finding and locating a drone provided by an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of a method for searching and locating a drone provided by an embodiment of the present invention;

[0035] Figure 3 This is a flow chart of another method for finding and locating a drone provided by an embodiment of the present invention;

[0036] Figure 4 This is a flow chart of another method for finding and locating a drone provided by an embodiment of the present invention;

[0037] Figure 5 This is a flow chart of another method for finding and locating a drone provided by an embodiment of the present invention;

[0038] Figure 6 It is a structural diagram of a drone search and positioning system provided by an embodiment of the present invention;

[0039] Figure 7 It is a structural diagram of another drone search and positioning system provided by an embodiment of the present invention;

[0040] Figure 8 It is a structural diagram of another drone search and positioning system provided by an embodiment of the present invention;

[0041] Fig. 9 It is a structural diagram of another drone search and positioning system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0043] As introduced in the background technology, the application of drones in power work can improve the efficiency and safety of power inspection work. However, due to the product quality of the drones themselves, the control level of the operators and the control of some air areas, drones are prone to lose control and crash.

[0044] At present, there are two main methods for searching after a drone crash: the first is to conduct a large-scale search based on the last location information of the drone before it lost control. This method is extremely labor-intensive, and searching in the wilderness also poses a threat to the personal safety of the staff, and the probability of finding the drone is not high; the second is to load the RTK differential positioning component on the drone. This method is costly and does not ensure safe communication with third-party networks. In addition, the RTK differential positioning component is heavy, which affects the flight efficiency of the drone.

[0045] Therefore, inventing a scientific, accurate and practical method for accurately finding and locating drones in the event of a loss, which can quickly and safely search for drones has become an urgent problem to be solved in the industry.

[0046] The embodiment of the present invention provides a method for searching and locating a UAV, which can be performed by a UAV searching and locating device, which can be implemented by software and / or hardware. The method is performed by a first Beidou module and a UWB pulse wireless communication tag in a front-end device and a second Beidou module, a tablet computer and a UWB pulse wireless communication micro base station in a back-end device. Figure 1 is a flow chart of a method for finding and locating a drone provided by an embodiment of the present invention. Figure 2 is a schematic diagram of a method for finding and locating a drone provided by an embodiment of the present invention. This embodiment can be applied to accurately locate the position of a crashed drone that has lost control, such as Figure 1 As shown, the search and positioning method includes:

[0047] S110, obtaining local location information and target location information sent by the drone end, where the target location information is the location information of the drone.

[0048] Specifically, the local location information can be obtained by a local positioning device, and then the local location is obtained according to the local location information. The local location can be obtained by the positioning software through the positioning device, for example, the positioning software uses a ground control system, and the ground control system is pre-installed in the staff's handheld tablet computer. The target position is the positioning position of the drone end, for example, it can be the position coordinate information of the drone end sent to the ground control system after the positioning device on the drone locates the position of the drone. By pre-installing the positioning software in the tablet computer, the coordinate data collected by the local positioning device such as the Beidou positioning system is obtained in real time to determine the local position. The target position is determined according to the position coordinate information of the drone end obtained by the drone end positioning device. It should be noted that the positioning software pre-installed in the staff's handheld tablet computer can be written in C++ and run on a Windows system. The software may include the following contents: offline map, location calculation and display program.

[0049] For example, see Figure 2The schematic diagram of the method for searching and locating the unmanned aerial vehicle shown in the figure, the positioning software in the tablet receives the real position of the local end collected by the Beidou positioning system and records it as O10, and the real position of the unmanned aerial vehicle end is recorded as O20. However, there may be certain errors when the Beidou positioning system is running. In order to improve the accuracy, the error needs to be taken into account during calculation. In an embodiment of the present invention, the maximum error range of the Beidou positioning system is included in the calculation, and the maximum error range radius can be 30 meters. Therefore, considering the error, the maximum error position of the local end is recorded as O11 and O12 respectively, the distance between O10 and O11 is equal to the distance between O10 and O12, both of which are 30 meters, and O10, O11 and O12 are located on a straight line parallel to the true north; the maximum error position of the unmanned aerial vehicle end is recorded as O21 and O22 respectively, the distance between O20 and O21 is equal to the distance between O20 and O22, and O20, O21 and O22 are located on the same straight line.

[0050] S120: Calculate the azimuth angle between the local location and the UAV according to the local location information and the target location information.

[0051] Specifically, to search for a crashed drone, it is necessary to determine the search range. By determining the azimuth angle between the crashed drone and the local position, the approximate direction of the drone can be roughly determined, which facilitates further determination of the drone's position. Based on the position coordinates of the local end and the drone end, a right triangle can be formed with the line between the local end and the drone end as the hypotenuse. The azimuth angle of the drone relative to the local end is the acute angle of the local end.

[0052] For example, see Figure 2, with the local end real position O10 as the center and the line between O10 and O20 as the radius, a circle is drawn to obtain the first preset range; with the local end maximum error position O11 as the center and the line between O11 and O21 as the radius, a circle is drawn to obtain the second preset range; with the local end maximum error position O12 as the center and the line between O12 and O22 as the radius, a circle is drawn to obtain the third preset range, and the three preset ranges are equal in size. With O10 and O20 points, horizontal and vertical perpendicular lines are drawn, intersecting at point M, to obtain the first right triangle formed by O10, O20 and M; with O11 and O21 points, horizontal and vertical perpendicular lines are drawn, intersecting at point N, to obtain the second right triangle formed by O11, O21 and N; with O12 and O22 points, horizontal and vertical perpendicular lines are drawn, intersecting at point P, to obtain the third right triangle formed by O12, O22 and P. Among them, within the first preset range, the first azimuth angle of the real position O20 of the drone end relative to the real position O10 of the local end is ∠O20O10M, that is, ∠B0; within the second preset range, the second azimuth angle of the maximum error position O21 of the drone end relative to the maximum error position O11 of the local end is ∠O21O11N, that is, ∠B1; within the third preset range, the third azimuth angle of the maximum error position O22 of the drone end relative to the maximum error position O12 of the local end is ∠O22O12P, that is, ∠B2. In the first right triangle, the distance between points O10 and M is recorded as a0, and the distance between points O20 and M is recorded as b0; in the second right triangle, the distance between points O11 and N is recorded as a1, and the distance between points O21 and N is recorded as b1; in the third right triangle, the distance between points O12 and P is recorded as a2, and the distance between points O22 and P is recorded as b2. According to the trigonometric function formula, the degree of the first azimuth angle can be calculated in the first right triangle, the degree of the second azimuth angle can be calculated in the second right triangle; and the degree of the third azimuth angle can be calculated in the third right triangle.

[0053] S130: When the distance between the UAV and the local device is less than a preset distance, obtain the distance measurement information between the local device and the UAV, and confirm the search radius according to the distance measurement information.

[0054] Specifically, the preset distance is applicable to the drone search and positioning method provided in the embodiment of the present invention, and the maximum distance that the local end and the drone end can be apart. Because the Beidou positioning system can guarantee a high degree of accuracy within a certain range when collecting real-time position coordinates. If the local end and the drone end are too far apart and exceed the preset distance, the Beidou positioning system cannot collect relatively accurate position coordinate data. The search radius is the radius length of the positioning accuracy circle with the drone end as the center. The distance data between the local and the drone is measured by the drone end, and the distance information measured between the local and the drone is received by the local UWB pulse wireless communication micro base station, and the search radius for searching the crashed drone is determined through a series of calculations.

[0055] For example, in the first right triangle, the distance between O10 and O20 is recorded as c0; in the second right triangle, the distance between O11 and O21 is recorded as c1; in the third right triangle, the distance between O12 and O22 is recorded as c2. Among them, the lengths of c0, c1 and c2 can be calculated after the local UWB pulse wireless communication micro base station receives the measurement data of the drone end. The position coordinates of the local end and the drone end collected by the Beidou positioning system are calculated according to the trigonometric function to calculate the first azimuth ∠B0, the second azimuth ∠B1 and the third azimuth ∠B2. According to the sine trigonometric function of the right triangle, sin∠B0=b0 / c0, sin∠B1=b1 / c1 and sin∠B2=b2 / c2. Therefore, the lengths of b0, b1 and b2 can be calculated by the sine trigonometric function.

[0056] Furthermore, according to the Pythagorean theorem, in the first right triangle we have c0 2 =b0 2 +a0 2 , in the second right triangle we have c1 2 =b1 2 +a1 2 , in the third right triangle we have c2 2 =b2 2 +a2 2 , from which the lengths of a0, a1, and a2 can be calculated. Then, according to the Pythagorean theorem, the distance L1 between the local end's true position O10 and the drone end's maximum error position O22 can be calculated by L1 2 =a2 2 +(b2-30) 2 Calculate and obtain the distance L2 between the local real position O10 and the maximum error position O21 of the drone, which can be obtained by L2 2 =a1 2 +(b1+30) 2 Calculated.

[0057] Furthermore, according to the sine trigonometric function, the angle ∠B5 between L1 and a0 can be calculated by sin∠B5=(b2-30) / L1, and the angle ∠B6 between L2 and a0 can be calculated by sin∠B6=(b1+30) / L2. Thus, the first positioning angle ∠B4 can be obtained by subtracting ∠B5 and ∠B6, that is, ∠B4=∠B5-∠B6, and no matter how the ranging distance between the drone end and the local end changes within the preset distance, the first positioning angle ∠B4 is always a constant.

[0058] Therefore, in the triangle formed by the three points O10, O21 and O22, if L1, L2, and the first positioning angle ∠B4 between L1 and L2 are known, the distance between the two points O21 and O22 can be calculated according to the trigonometric function formula, and the search radius is half of the distance between O21 and O22.

[0059] S140: Determine the position of the UAV according to the azimuth angle and the search radius.

[0060] Specifically, after determining the approximate direction of the drone by the obtained azimuth angle, the crashed drone can be accurately located near the approximate position of the drone at a certain ranging distance from the local end, within the positioning accuracy circle determined by the search radius, achieving high-precision positioning at the decimeter level.

[0061] For example, after determining that the crashed drone is located within the range of the first positioning angle ∠B4 fixed by the drone's actual position relative to the actual position of the local end, the search range can be greatly narrowed based on the search radius of the calculated positioning accuracy circle range, and the positioning accuracy can reach the decimeter level.

[0062] The drone search and positioning method provided in the embodiment of the present invention obtains the local position information and the target position information of the drone end respectively, calculates the azimuth angle between the local end and the drone end, then receives the ranging distance between the local end and the drone end, and further calculates the search radius of the search range positioning accuracy circle, so that the position of the crashed drone can be determined according to the azimuth angle and the search radius, and the crashed drone can be accurately positioned without using the RTK differential positioning method, and the positioning accuracy can reach the decimeter level, so that the search personnel can quickly and accurately locate and search the drone after the drone loses control and crashes, thereby recovering economic losses to the greatest extent and ensuring the personal safety of the search personnel when performing operations.

[0063] Optional, Figure 3 FIG. 1 is a flowchart of another method for finding and locating a drone provided by an embodiment of the present invention. Figure 3 The drone search and positioning method provided by the embodiment of the present invention also includes:

[0064] The target location information includes target longitude and target latitude, and the local location information includes local longitude and local latitude.

[0065] The target position information may include the real position information and the maximum error position information of the UAV end, the target longitude and target latitude may include the real longitude and latitude of the UAV end, and the longitude and latitude of the maximum error position, which may be acquired in real time by the first Beidou module. The local position information may include the real position information and the maximum error position information of the ground control system, the local longitude and local latitude may include the real longitude and latitude of the local end, and the longitude and latitude of the maximum error position, which may be acquired in real time by the second Beidou module.

[0066] S210, obtaining local location information and target location information sent by the drone end, where the target location information is the location information of the drone.

[0067] S220: Subtract the local latitude from the target latitude to obtain a first distance.

[0068] Specifically, in the geographic coordinate system, if the latitude differs by 1°, the distance differs by 111 kilometers. Therefore, according to the latitude coordinates collected in real time by the Beidou positioning system, the real position latitude of the drone end is subtracted from the real local latitude of the local end, and the difference is multiplied by 111 to calculate the first distance data of the real position, that is, the distance b0 between O20 and point M. The maximum error position latitude of the drone end is subtracted from the maximum error local latitude of the local end, and the difference is multiplied by 111 to calculate the first distance data of the maximum error position, that is, the distance b1 between O21 and point N and the distance b2 between O22 and point P.

[0069] S230: Subtract the local longitude from the target longitude to obtain a second distance.

[0070] Specifically, in the geographic coordinate system, after calculating the north-south distance between the two locations, the two points need to be translated to the latitude of one of the locations so that they are on the same latitude plane. Then, the longitude difference is obtained by subtracting the real local longitude of the local end from the real location longitude of the drone end, and then multiplied by 111, and then multiplied by the cosine value of the latitude of the latitude plane at this time, and the second distance data of the real location can be obtained, that is, the distance a0 between O10 and point M. The difference between the maximum error location longitude of the drone end and the maximum error local longitude of the local end is multiplied by 111, and then multiplied by the cosine value of the latitude of the latitude plane, and the second distance data of the maximum error location is calculated, that is, the distance a1 between O11 and point N and the distance a2 between O12 and point P.

[0071] S240, calculating the azimuth angle θ according to the trigonometric function tanθ=first distance / second distance.

[0072] Specifically, a right triangle can be formed by taking the line connecting the drone and the local end as the hypotenuse, and the first distance and the second distance as the two right-angled sides, and the acute angle between the line connecting the drone and the local end and the second distance is the azimuth angle θ of the drone relative to the local end. In the right triangle, the value of the azimuth angle θ can be calculated by the tangent trigonometric function tanθ=first distance / second distance.

[0073] Exemplarily, in the first right triangle, the first distance is b0, the second distance is a0, θ is the first azimuth angle ∠B0, and the angle of ∠B0 can be calculated by tan∠B0=b0 / a0; in the second right triangle, the first distance is b1, the second distance is a1, θ is the second azimuth angle ∠B1, and ∠B1 can be calculated by tan∠B1=b1 / a1; in the third right triangle, the first distance is b2, the second distance is a2, θ is the third azimuth angle ∠B2, and the angle of ∠B2 can be calculated by tan∠B2=b2 / a2.

[0074] S250: When the distance between the UAV and the local device is less than a preset distance, obtain the distance measurement information between the local device and the UAV, and confirm the search radius according to the distance measurement information.

[0075] S260: Determine the position of the UAV according to the azimuth angle and the search radius.

[0076] Optional, Figure 4 FIG. 1 is a flowchart of another method for finding and locating a drone provided by an embodiment of the present invention. Figure 4 The drone search and positioning method provided by the embodiment of the present invention also includes:

[0077] S310, obtaining local location information and target location information sent by the drone end, where the target location information is the location information of the drone.

[0078] S320: Calculate the azimuth angle between the local location and the UAV based on the local location information and the target location information.

[0079] S330: When the distance between the UAV and the local is less than a preset distance, a pulse signal is received from the UAV end, and the ranging information between the local and the target is calculated using the signal arrival angle measurement AOA and the time difference TDOA, and the search radius is confirmed based on the ranging information.

[0080] Specifically, the preset distance can be the maximum distance allowed between the drone end and the local end. Angle-of-Arrival (AOA) is a typical ranging-based positioning algorithm that uses hardware devices to sense the arrival direction of the transmitting node signal, calculates the relative orientation or angle between the receiving node and the anchor node, and then uses triangulation or other methods to calculate the position of the unknown node. This common wireless sensor network node self-positioning algorithm has low algorithm communication overhead and high positioning accuracy.

[0081] Time Difference of Arrival (TDOA) is a method of positioning using time difference. By measuring the time it takes for a signal to arrive at a monitoring station, the distance of the signal source can be determined. The distance from the signal source to each monitoring station can be used to determine the location of the signal.

[0082] The pulse signal sent by the drone is received through a specific communication device at the local end. It can be a pulse signal with a sound frequency lower than 41dB and a time interval less than 1ns. The two algorithms of signal arrival angle measurement AOA and time difference TDOA are used to calculate the ranging distance between the local end and the drone target end with an error less than ±10 cm. The search radius of the drone can be further calculated and confirmed based on the ranging distance of the two locations.

[0083] S340: Determine the position of the UAV according to the azimuth angle and the search radius.

[0084] Optional, Figure 5 FIG. 1 is a flowchart of another method for finding and locating a drone provided by an embodiment of the present invention. Figure 5 The drone search and positioning method provided by the embodiment of the present invention also includes:

[0085] S410, obtaining local location information and target location information sent by the drone end, where the target location information is the location information of the drone.

[0086] S420: Calculate the azimuth angle between the local location and the UAV based on the local location information and the target location information.

[0087] S430: When the distance between the UAV and the local device is less than a preset distance, obtain the distance measurement information between the local device and the UAV, and confirm the search radius according to the distance measurement information.

[0088] S440: Determine the position of the UAV according to the azimuth angle and the search radius.

[0089] S450: Load the local location and the location of the drone displayed on the offline map.

[0090] Specifically, the pre-installed positioning software package in the staff's handheld tablet computer contains offline maps. The terminal is based on the Windows system and has the MapDownloader map server installed. The 18-level offline map is downloaded through the map server. Each time the terminal is turned on and enters the Windows system, it automatically runs the map server program and retrieves the offline map at the same time. Through the high-precision positioning algorithm, based on the target position information of the drone end and the local position information of the local end collected by the Beidou positioning system, the positions of the local end and the drone end can be displayed on the offline map in real time, thereby guiding ground search personnel to accurately find the drone according to the map.

[0091] Optionally, the preset distance is less than or equal to 1000 meters.

[0092] Specifically, since the position coordinates collected in real time by the Beidou positioning system have a certain error range, the maximum error range can be 30 meters. According to any of the above-mentioned drone search and positioning methods, when the drone target end is 1000 meters away from the local end, the radius of the positioning accuracy circle is calculated, that is, the search radius is 30 meters, which has reached the maximum error range of the Beidou positioning system. Therefore, if the drone end is more than 1000 meters away from the local end, the drone search and positioning method provided by the embodiment of the present invention cannot be executed to accurately locate the crashed drone.

[0093] For example, when the distance between the drone end and the local end is less than the preset distance, if the two ends are 500 meters apart, the radius of the positioning accuracy circle is calculated, that is, the search radius is 26.8 meters; if the two ends are 200 meters apart, the search radius is calculated to be 10.75 meters; if the two ends are 200 meters apart, the search radius is 10.75 meters; if the two ends are 100 meters apart, the search radius is calculated to be 5.37 meters; if the two ends are 50 meters apart, the search radius is 2.63 meters; if the two ends are 20 meters apart, the search radius is calculated to be 1.075 meters;

[0094] It should be noted that since the real-time ranging accuracy of the drone has an error of ±0.1 meters, the positioning accuracy range also has an error of less than ±0.1 meters.

[0095] For example, see Figure 2In the drone search and positioning method provided in any of the above embodiments, taking the drone target end and the local end as an example, a circle is drawn with the local end's real position O10 as the center and the line connecting O10 and O20 as the radius to obtain a first preset range; a circle is drawn with the local end's maximum error position O11 as the center and the line connecting O11 and O21 as the radius to obtain a second preset range; a circle is drawn with the local end's maximum error position O12 as the center and the line connecting O12 and O22 as the radius to obtain a third preset range. Draw horizontal and vertical perpendiculars through points O10 and O20, intersecting at point M, to obtain the first right triangle formed by points O10, O20 and M; draw horizontal and vertical perpendiculars through points O11 and O21, intersecting at point N, to obtain the second right triangle formed by points O11, O21 and N; draw horizontal and vertical perpendiculars through points O12 and O22, intersecting at point P, to obtain the third right triangle formed by points O12, O22 and P. Within the three preset ranges, the first azimuth of the real position O20 of the drone end relative to the real position O10 of the local end is ∠O20O10M, that is, ∠B0, the second azimuth of the maximum error position O21 of the drone end relative to the maximum error position O11 of the local end is ∠O21O11N, that is, ∠B1, and the third azimuth of the maximum error position O22 of the drone end relative to the maximum error position O12 of the local end is ∠O22O12P, that is, ∠B2. The distance between points O10 and M is recorded as a0, the distance between points O11 and N is a1, the distance between points O12 and P is a2, the distance between points O20 and M is recorded as b0, the distance between points O21 and N is b1, and the distance between points O22 and P is b2. The distance between O10 and O20 is recorded as c0, the distance between O11 and O21 is recorded as c1, and the distance between O12 and O22 is recorded as c2.

[0096] According to the position coordinates of the local end and the drone end, after calculating the first azimuth ∠B0, the second azimuth ∠B1 and the third azimuth ∠B2, the local end communication device receives the measurement data of the drone end to obtain the lengths of c0, c1 and c2. According to the trigonometric functions sin∠B0=b0 / c0, sin∠B1=b1 / c1 and sin∠B2=b2 / c2, the lengths of b0, b1 and b2 can be calculated. Furthermore, according to the Pythagorean theorem, in the first right triangle, c0 2 =b0 2 +a0 2 , in the second right triangle there is c1 2 =b1 2 +a1 2 , in the third right triangle there is c2 2 =b2 2 +a2 2, from which the lengths of a0, a1, and a2 can be calculated. The distance L1 between the local end's true position O10 and the drone end's maximum error position O22, and the distance L2 between the local end's true position O10 and the drone end's maximum error position O21, can be calculated by the Pythagorean theorem L1 2 =a2 2 +(b2-30) 2 and L2 2 =a1 2 +(b1+30) 2 Calculated.

[0097] Furthermore, ∠B5 between the hypotenuse L1 and a0 and ∠B6 between the hypotenuse L2 and a0 can be solved by the trigonometric functions sin∠B5=(b2-30) / L1 and sin∠B6=(b1+30) / L2. Therefore, the first positioning angle ∠B4 can be obtained by ∠B4=∠B5-∠B6, and no matter how the ranging distance between the drone end and the local end changes within the preset distance, the first positioning angle ∠B4 is always a constant. Therefore, in the triangle formed by the three points O10, O21 and O22, according to the trigonometric formula, L1, L2 and the first positioning angle ∠B4, the distance between the two points O21 and O22 can be calculated, and the search radius is half of the distance between O21 and O22, which is calculated to be 30 meters. And as the distance between the UAV end and the local end changes, the corresponding search radius can be calculated by similar triangles and combined with the azimuth angle to achieve accurate positioning of the UAV.

[0098] Figure 6 FIG. 1 is a structural diagram of a drone search and positioning system provided by an embodiment of the present invention. Figure 6 The drone search and positioning system provided in the embodiment of the present invention can be used to execute the drone search and positioning method described in any of the above embodiments. The drone search and positioning system 30 includes:

[0099] The front-end device 10 is arranged on the drone, and is used to locate the position of the drone and obtain target position information;

[0100] The back-end device 20 is used to locate the local position to obtain the local position information and receive the target position information. The azimuth angle is calculated according to the local position information and the target position information. When the distance between the drone and the local is less than the preset distance, the distance measurement information between the drone and the local is obtained, and the search radius is confirmed according to the distance measurement information. The position of the drone is determined according to the azimuth angle and the search radius.

[0101] The drone search and positioning system provided in this embodiment obtains the local position information and the target position information of the drone end, calculates the azimuth angle between the local end and the drone end, receives the ranging distance between the local end and the drone, and calculates the search radius of the search drone, thereby determining the position of the crashed drone based on the azimuth angle and the search radius, and achieves accurate positioning of the crashed drone without using the RTK differential positioning method, achieving decimeter-level positioning accuracy, so that search personnel can quickly and accurately locate and search the drone after the drone loses control and crashes, thereby minimizing economic losses and ensuring the personal safety of search personnel during operations.

[0102] Optional, Figure 7 FIG. 1 is a structural diagram of another drone search and positioning system provided by an embodiment of the present invention. Figure 7 The drone search and positioning system 30 provided in an embodiment of the present invention also includes: the front-end device 10 includes a first Beidou module 11, a first wireless communication module 12, a UWB pulse wireless communication tag 13, a first dual-mode antenna 14, a first UWB pulse wireless communication antenna 15 and a Raspberry Pi 16.

[0103] The Raspberry Pi 16 is used to collect the drone coordinate data output by the first Beidou module 11 , store the drone coordinate data in real time, and transmit the drone coordinate data to the backend device 20 through the first wireless communication module 12 .

[0104] Specifically, the Raspberry Pi 16 is pre-installed with the LIUNX system, and collects the real-time coordinate data measured by the first Beidou module 11 through the USB to UART port data receiving end, and stores and forwards the data in real time through the data processing software deployed in the Raspberry Pi 16, and outputs the data to the first wireless communication module 12 in a unified format.

[0105] The UWB pulse wireless communication tag 13 is used to send a pulse signal to the backend device 20 to instruct the backend device 20 to communicate and measure distance in real time according to the pulse signal.

[0106] Specifically, the UWB pulse wireless communication tag 13 enters the working mode when it is turned on, and performs real-time communication and distance measurement with the back-end communication device, and the distance measurement accuracy can reach ±10 cm.

[0107] The first dual-mode antenna 14 adopts a 4G, 1561M frequency band packaged circular antenna, and the first UWB pulse wireless communication antenna 15 adopts a 3600M frequency band packaged circular antenna.

[0108] Optional, Figure 8 FIG. 1 is a structural diagram of another drone search and positioning system provided by an embodiment of the present invention. Figure 8The drone search and positioning system 30 provided in the embodiment of the present invention further includes: the front-end device 10 further includes a battery 17, an indicator light 18 and a housing 19.

[0109] The battery 17 is used to power the Raspberry Pi 16. It uses a 3.7V 2000mA lithium battery to provide a boosted 5V DC power supply. The Raspberry Pi 16 supplies power to the first Beidou module 11, the first wireless communication module 12, the UWB pulse wireless communication tag 13 and the indicator light 18 through the USB to UART port DC power supply terminal.

[0110] The indicator light 18 is connected to the Raspberry Pi 16 and can use an LED light source to flash in poor light conditions or at night to facilitate quick search at night.

[0111] The outer shell 19 is fixed on the drone body and can be made of light aluminum, and is used to encapsulate the first Beidou module 11, the first wireless communication module 12, the Raspberry Pi 16, the battery 17, the indicator light 18 and the UWB pulse wireless communication tag 13.

[0112] The first dual-mode antenna 14 and the first UWB pulse wireless communication antenna 15 are fixed on the upper side of the housing 19, the first dual-mode antenna 14 is connected to the first Beidou module 11 and the first wireless communication module 12, the first UWB pulse wireless communication antenna 15 is connected to the UWB pulse wireless communication tag 13; the first Beidou module 11 is connected to the Raspberry Pi 16 via the UART to USB port; the first wireless communication module 12 is connected to the Raspberry Pi 16 via the UART to USB port; the UWB pulse wireless communication tag 13 is connected to the Raspberry Pi 16 via the UART to USB port.

[0113] Optional, Fig. 9 FIG. 1 is a structural diagram of another drone search and positioning system provided by an embodiment of the present invention. Fig. 9 The drone search and positioning system 30 provided in an embodiment of the present invention also includes: the back-end device 20 includes a second Beidou module 21, a second wireless communication module 22, a UWB pulse wireless communication micro base station 23, a second dual-mode antenna 24, a second UWB pulse wireless communication antenna 25 and a processing module 26.

[0114] The second Beidou module 21 is used to locate the local position and transmit the local coordinate data to the processing module 26 .

[0115] The processing module 26 is used to receive the drone coordinate data transmitted by the first wireless communication module 12 through the second wireless communication module 22, and calculate the azimuth angle according to the drone coordinate data and the local coordinate data.

[0116] The UWB pulse wireless communication micro base station 23 is used to receive the pulse signal sent by the UWB pulse wireless communication tag 13, and calculate the local and target high-precision measurement distance information by using the signal arrival angle measurement and time difference.

[0117] Specifically, the UWB pulse wireless communication micro base station 23 performs real-time communication and distance measurement with the front-end UWB pulse wireless communication tag 13, and the distance measurement data is pushed to the processing module 26 via the UART port of the UWB pulse wireless communication micro base station 23, and the positioning software pre-installed in the processing module 26 is used to determine the search radius based on the measured distance.

[0118] Optionally, based on the above embodiment, continue to refer to Fig. 9 The drone search and positioning system 30 provided in the embodiment of the present invention further includes: the processing module 26 includes a tablet computer.

[0119] Specifically, the tablet computer is pre-installed with positioning software, which uses offline maps and high-precision positioning algorithms loaded by the positioning software to display the local location and target location in real time, and can guide search personnel to accurately find the crashed drone according to the map.

[0120] The second Beidou module 21 is connected to the tablet computer via the UART to USB port, the second wireless communication module 22 is connected to the tablet computer via the UART to USB port, the UWB pulse wireless communication micro base station 23 is connected to the tablet computer via the UART to USB port, the second dual-mode antenna 24 is connected to the second Beidou module 21 and the second wireless communication module 22, and the second UWB pulse wireless communication antenna 25 is connected to the UWB pulse wireless communication micro base station 23.

[0121] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for finding and locating a drone, characterized in that: include: Obtaining local location information and target location information sent by the drone, where the target location information is the location information of the drone; Calculate the azimuth angle between the local location and the UAV according to the local location information and the target location information; When the distance between the UAV and the local area is less than a preset distance, obtaining distance measurement information between the local area and the UAV, and determining the search radius according to the distance measurement information; Determine the position of the drone according to the azimuth angle and the search radius; Among them, the real position of the local end is recorded as O10, the real position of the drone end is recorded as O20, the positions with the maximum error of the local end are recorded as O11 and O12, and the positions with the maximum error of the drone end are recorded as O21 and O22; the distance between O10 and O11 is equal to the distance between O10 and O12, both of which are 30 meters, and O10, O11 and O12 are located on a straight line parallel to the true north; the distance between O20 and O21 is equal to the distance between O20 and O22, and O20, O21 and O22 are located on the same straight line; a circle is drawn with the real position O10 of the local end as the center and the line between O10 and O20 as the radius to obtain the first preset range; the maximum error of the local end is recorded as O11 and O12, respectively. A circle is drawn with the difference position O11 as the center and the line between O11 and O21 as the radius to obtain the second preset range; a circle is drawn with the local end maximum error position O12 as the center and the line between O12 and O22 as the radius to obtain the third preset range; horizontal and vertical perpendiculars are drawn with points O10 and O20, intersecting at point M, to obtain the first right triangle formed by points O10, O20 and M; horizontal and vertical perpendiculars are drawn with points O11 and O21, intersecting at point N, to obtain the second right triangle formed by points O11, O21 and N; horizontal and vertical perpendiculars are drawn with points O12 and O22, intersecting at point P, to obtain the third right triangle formed by points O12, O22 and P; The step of confirming the search radius according to the ranging information includes: According to the sine trigonometric function of the right triangle, according to sin∠B0=b0 / c0, sin∠B1=b1 / c1 and sin∠B2=b2 / c2, the lengths of b0, b1 and b2 are calculated respectively; wherein ∠B0 is the first azimuth angle of the real position O20 of the drone end relative to the real position O10 of the local end, c0 is the distance between O10 and O20, and b0 is the distance between O20 and M; ∠B1 is the second azimuth angle of the maximum error position O21 of the drone end relative to the maximum error position O11 of the local end, c1 is the distance between O11 and O21, and b1 is the distance between O21 and N; ∠B2 is the third azimuth angle of the maximum error position O22 of the drone end relative to the maximum error position O12 of the local end, c2 is the distance between O12 and O22, and b2 is the distance between O22 and P; According to the Pythagorean theorem, according to c0 2 =b0 2 +a0 2 , c1 2 =b1 2 +a1 2 and c2 2 =b2 2 +a2 2 , calculate the lengths of a0, a1 and a2 respectively; where a0 is the distance between O10 and M, a1 is the distance between O11 and N, and a2 is the distance between O12 and P; According to the Pythagorean theorem, according to L1 2 =a2 2 +(b2-30) 2 and L2 2 =a1 2 +(b1+30) 2 , calculate the lengths of L1 and L2 respectively; where L1 is the distance between the local real position O10 and the drone's maximum error position O22, and L2 is the distance between the local real position O10 and the drone's maximum error position O21; According to the sine trigonometric function, ∠B5 is calculated according to sin∠B5=(b2-30) / L1, and ∠B6 is calculated according to sin∠B6=(b1+30) / L2; where ∠B5 is the angle between L1 and a0, and ∠B6 is the angle between L2 and a0; The first positioning angle ∠B4 is calculated according to ∠B4=∠B5-∠B6; wherein the first positioning angle ∠B4 is the angle between L1 and L2; The search radius is calculated according to L1, L2 and the first positioning angle ∠B4 according to the trigonometric formula.

2. The method according to claim 1, characterized in that The target location information includes target longitude and target latitude, and the local location information includes local longitude and local latitude; Calculating the azimuth angle according to the local position information and the target position information includes: Subtract the local latitude from the target latitude to obtain the first distance; Subtract the local longitude from the target longitude to obtain the second distance; The azimuth angle θ is calculated according to the trigonometric function tan θ=first distance / second distance.

3. The method according to claim 1, characterized in that Get the distance information between the drone and the local area, including: After receiving the pulse signal from the drone, the signal arrival angle AOA and time difference TDOA are used to calculate the distance information between the local and the drone.

4. The method according to claim 1, characterized in that: After determining the position of the drone according to the azimuth angle and the search radius, the method further includes: Load offline maps to display the local location and the location of the drone.

5. The method according to claim 1, characterized in that The preset distance is less than or equal to 1000 meters.

6. A drone search and positioning system, characterized in that: include: A front-end device is provided on the drone, and is used to locate the position of the drone and obtain target position information; The back-end device is used to locate the local position to obtain the local position information and receive the target position information; calculate the azimuth angle according to the local position information and the target position information; when the distance between the drone and the local is less than a preset distance, obtain the distance measurement information between the drone and the local, and confirm the search radius according to the distance measurement information; determine the position of the drone according to the azimuth angle and the search radius; Among them, the real position of the local end is recorded as O10, the real position of the drone end is recorded as O20, the positions with the maximum error of the local end are recorded as O11 and O12, and the positions with the maximum error of the drone end are recorded as O21 and O22; the distance between O10 and O11 is equal to the distance between O10 and O12, both of which are 30 meters, and O10, O11 and O12 are located on a straight line parallel to the true north; the distance between O20 and O21 is equal to the distance between O20 and O22, and O20, O21 and O22 are located on the same straight line; a circle is drawn with the real position O10 of the local end as the center and the line between O10 and O20 as the radius to obtain the first preset range; the maximum error of the local end is recorded as O11 and O12, respectively. A circle is drawn with the difference position O11 as the center and the line between O11 and O21 as the radius to obtain the second preset range; a circle is drawn with the local end maximum error position O12 as the center and the line between O12 and O22 as the radius to obtain the third preset range; horizontal and vertical perpendiculars are drawn with points O10 and O20, intersecting at point M, to obtain the first right triangle formed by points O10, O20 and M; horizontal and vertical perpendiculars are drawn with points O11 and O21, intersecting at point N, to obtain the second right triangle formed by points O11, O21 and N; horizontal and vertical perpendiculars are drawn with points O12 and O22, intersecting at point P, to obtain the third right triangle formed by points O12, O22 and P; The back-end device is also used to calculate the lengths of b0, b1 and b2 according to the sine trigonometric function of the right triangle, according to sin∠B0=b0 / c0, sin∠B1=b1 / c1 and sin∠B2=b2 / c2; wherein ∠B0 is the first azimuth angle of the real position O20 of the drone end relative to the real position O10 of the local end, c0 is the distance between O10 and O20, and b0 is the distance between O20 and M; ∠B1 is the second azimuth angle of the maximum error position O21 of the drone end relative to the maximum error position O11 of the local end, c1 is the distance between O11 and O21, and b1 is the distance between O21 and N; ∠B2 is the third azimuth angle of the maximum error position O22 of the drone end relative to the maximum error position O12 of the local end, c2 is the distance between O12 and O22, and b2 is the distance between O22 and P; The back-end device is also used to calculate the value of c0 according to the Pythagorean theorem. 2 =b0 2 +a0 2 , c1 2 =b1 2 +a1 2 and c2 2 =b2 2 +a2 2 , calculate the lengths of a0, a1 and a2 respectively; where a0 is the distance between O10 and M, a1 is the distance between O11 and N, and a2 is the distance between O12 and P; The back-end device is also used to calculate the L1 2 =a2 2 +(b2-30) 2 and L2 2 =a1 2 +(b1+30) 2 , calculate the lengths of L1 and L2 respectively; where L1 is the distance between the local real position O10 and the drone's maximum error position O22, and L2 is the distance between the local real position O10 and the drone's maximum error position O21; The back-end device is further used to calculate ∠B5 according to sin∠B5=(b2-30) / L1 and ∠B6 according to sin∠B6=(b1+30) / L2 based on the sine trigonometric function; wherein ∠B5 is the angle between L1 and a0, and ∠B6 is the angle between L2 and a0; The rear end device is further used to calculate a first positioning angle ∠B4 according to ∠B4=∠B5-∠B6; wherein the first positioning angle ∠B4 is the angle between L1 and L2; The back-end device is also used to calculate the search radius according to L1, L2 and the first positioning angle ∠B4 based on a trigonometric function formula.

7. The drone search and positioning system according to claim 6, characterized in that: The front-end device includes a first Beidou module, a first wireless communication module, a UWB pulse wireless communication tag, a first dual-mode antenna, a first UWB pulse wireless communication antenna and a Raspberry Pi; The Raspberry Pi is used to collect the drone coordinate data output by the first Beidou module, store the drone coordinate data in real time, and transmit the drone coordinate data to the back-end device through the first wireless communication module; the UWB pulse wireless communication tag is used to send a pulse signal to the back-end device to instruct the back-end device to communicate and measure distance in real time according to the pulse signal.

8. The drone search and positioning system according to claim 7, characterized in that: The front-end device further includes a battery, an indicator light and a shell; the indicator light is connected to the Raspberry Pi; the battery is used to supply power to the Raspberry Pi; the shell encapsulates the first Beidou module, the first wireless communication module, the Raspberry Pi, the battery, the indicator light and the UWB pulse wireless communication tag; the shell is fixed to the drone body; The first dual-mode antenna and the first UWB pulse wireless communication antenna are fixed on the upper side of the shell, the first dual-mode antenna is connected to the first Beidou module and the first wireless communication module, the first UWB pulse wireless communication antenna is connected to the UWB pulse wireless communication tag; the first Beidou module is connected to the Raspberry Pi via a UART to USB port; the first wireless communication module is connected to the Raspberry Pi via a UART to USB port; the UWB pulse wireless communication tag is connected to the Raspberry Pi via a UART to USB port.

9. The drone search and positioning system according to claim 7, characterized in that: The backend device includes a second Beidou module, a second wireless communication module, a UWB pulse wireless communication micro base station, a second dual-mode antenna, a second UWB pulse wireless communication antenna and a processing module; The second Beidou module is used to locate the local position and transmit the local coordinate data to the processing module; The processing module is used to receive the drone coordinate data transmitted by the first wireless communication module through the second wireless communication module; and calculate the azimuth angle according to the drone coordinate data and the local coordinate data; The UWB pulse wireless communication micro base station is used to receive the pulse signal sent by the UWB pulse wireless communication tag, and uses signal arrival angle measurement and time difference to calculate high-precision measurement distance information between the local area and the drone.

10. The drone search and positioning system according to claim 9, characterized in that: The processing module includes a tablet computer; The second Beidou module is connected to the tablet computer via the UART to USB port; the second wireless communication module is connected to the tablet computer via the UART to USB port; the UWB pulse wireless communication micro base station is connected to the tablet computer via the UART to USB port; the second dual-mode antenna is connected to the second Beidou module and the second wireless communication module, and the second UWB pulse wireless communication antenna is connected to the UWB pulse wireless communication micro base station.

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