Outdoor positioning method and device

Abstract

The present application provides an outdoor positioning method and device, which is applied to a ground positioning server in a positioning system, and the method includes: obtaining signal reception information collected by each drone and corresponding receiving station location information; determining multiple distance differences based on the signal reception information, wherein there is a measurement error between the distance difference and the true value due to noise; estimating the position of the target object based on the multiple receiving station location information and the multiple distance differences to determine the target position. In this way, the ground positioning server in the present application obtains the signal reception information about the target object collected by each drone to obtain multiple distance differences, and then obtains the target position through the distance differences and the receiving station location information, thereby improving the accuracy and efficiency of the ground positioning server in measuring the position of the target object, effectively reducing the measurement error of the drone, and thus improving the accuracy of radio navigation.

Description

Technical Field

[0001] The present application belongs to the field of radio navigation technology in the high-end equipment manufacturing industry, and specifically relates to an outdoor positioning method and device. Background Art

[0002] At present, drones participating in collaborative positioning have been widely used in many common fields and have become one of the most commonly used positioning methods. They have diverse mission execution capabilities, such as monitoring, searching, and rescuing specific targets.

[0003] However, in actual applications, the traditional time difference of arrival (TDOA) positioning measurement method used by drones in collaborative positioning will result in a large deviation between the final positioning position and the actual position due to signal interference and other reasons.

[0004] Therefore, there is an urgent need for an outdoor positioning method and device that can solve the above problems. Summary of the invention

[0005] The embodiments of the present application provide an outdoor positioning method and device. The ground positioning server in the positioning system estimates the position of the target object by acquiring the signal reception information collected by the drone and the position information of each receiving station, and uses a preset algorithm to improve the accuracy of the position positioning of the target object, thereby improving the accuracy of radio navigation.

[0006] In a first aspect, an embodiment of the present application provides an outdoor positioning method, which is applied to a ground positioning server in a positioning system, wherein the positioning system includes a plurality of drones, each of which carries a linear frequency modulation signal receiving station, and the linear frequency modulation signal receiving station is used to receive a linear frequency modulation signal sent by a target object, and the ground positioning server establishes a communication connection with the plurality of drones; the method includes:

[0007] Acquire signal reception information collected by each of the drones and location information of a receiving station corresponding to each of the drones;

[0008] Determine any one of the drones as a master drone, and determine the remaining drones other than the master drone as auxiliary drones;

[0009] Determine a plurality of distance differences according to the signal reception information, each of the auxiliary drones corresponds to a distance difference, the distance difference is used to describe a first distance between each of the auxiliary drones and the target object, and a difference between a second distance between the main drone and the target object, and there is a measurement error between the distance difference and the true value due to noise;

[0010] The position of the target object is estimated according to the plurality of receiving station position information and the plurality of distance difference values ​​to determine the target position.

[0011] In a second aspect, an embodiment of the present application provides an outdoor positioning device, which is applied to a ground positioning server in a positioning system, wherein the positioning system includes a plurality of drones, each of which is equipped with a linear frequency modulation signal receiving station, wherein the linear frequency modulation signal receiving station is used to receive a linear frequency modulation signal sent by a target object, and the ground positioning server establishes a communication connection with the plurality of drones; the device includes:

[0012] An acquisition unit, used to acquire signal reception information collected by each of the drones and location information of a receiving station corresponding to each of the drones;

[0013] A first determining unit, configured to determine any one of the drones as a master drone, and to determine the remaining drones other than the master drone as auxiliary drones;

[0014] a second determining unit, configured to determine a plurality of distance differences according to the signal reception information, wherein each auxiliary drone corresponds to a distance difference, and the distance difference is used to describe a first distance between each auxiliary drone and the target object, and a difference between a second distance between the main drone and the target object, and there is a measurement error between the distance difference and the true value due to noise;

[0015] The third determining unit is used to estimate the position of the target object according to the plurality of receiving station position information and the plurality of distance differences to determine the target position.

[0016] In a third aspect, an embodiment of the present application provides a ground positioning server, comprising a processor, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, and the program includes instructions for executing the steps in the first aspect of the embodiment of the present application.

[0017] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implement the steps in the first aspect of the embodiment of the present application.

[0018] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program / instructions, which, when executed by a processor, implement some or all of the steps described in the first aspect of the embodiment of the present application.

[0019] It can be seen that in the embodiment of the present application, the ground positioning server obtains the signal reception information about the target object collected by each drone to obtain multiple distance differences, and then obtains the target position through the distance differences and the receiving station location information, thereby improving the accuracy and efficiency of the ground positioning server in measuring the target object position, and effectively reducing the measurement error of the drone, thereby improving the accuracy and precision of the drone's positioning and navigation based on radio technology, and improving the practicality and stability of the drone's navigation and positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a structural block diagram of a positioning system provided in an embodiment of the present application;

[0022] Figure 2 It is a flowchart of an outdoor positioning method provided in an embodiment of the present application;

[0023] Figure 3 It is a hardware block diagram of a linear frequency modulation signal receiving station provided in an embodiment of the present application;

[0024] Figure 4 This is a schematic diagram of a scenario of receiving signals under different weather conditions provided by an embodiment of the present application;

[0025] Figure 5 This is a schematic diagram of a scenario for outdoor positioning of a drone provided in an embodiment of the present application;

[0026] Figure 6 This is a block diagram of the functional units of an outdoor positioning device provided in an embodiment of the present application;

[0027] Figure 7 It is a block diagram of the functional units of another outdoor positioning device provided in an embodiment of the present application;

[0028] Figure 8 It is a structural block diagram of a ground positioning server provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] See also Figure 1 , Figure 1 is a structural block diagram of a positioning system provided in an embodiment of the present application. Figure 1 As shown, the positioning system 100 includes a ground positioning server 110, a drone 120 and a target object 130. Each drone 120 is equipped with a linear frequency modulation signal receiving station, and the linear frequency modulation signal receiving station is used to receive the linear frequency modulation signal sent by the target object 130. The ground positioning server 110 establishes a communication connection with the multiple drones 120. Among them, the ground positioning server 110 can be a server, or a server cluster composed of several servers, or a cloud computing service center, and the drone 120 can be any model of drone available on the market. One ground positioning server 110 can correspond to multiple drones 120 and one or more target objects 130 at the same time.

[0033] Based on this, an embodiment of the present application provides an outdoor positioning method, and the embodiment of the present application is described in detail below in conjunction with the accompanying drawings.

[0034] See also Figure 2 , Figure 2: is a flow chart of an outdoor positioning method provided by an embodiment of the present application, the method is applied to a ground positioning server in a positioning system, the positioning system includes a plurality of drones, each of the drones carries a linear frequency modulation signal receiving station, the linear frequency modulation signal receiving station is used to receive a linear frequency modulation signal sent by a target object, the ground positioning server establishes a communication connection with the plurality of drones; the method includes:

[0035] Step S201, obtaining the signal reception information collected by each drone and the receiving station location information corresponding to each drone.

[0036] Among them, the location information of the receiving station can be equivalent to the location information of the drone carrying it.

[0037] Among them, Linear Frequency Modulation (LFM) is a spread spectrum modulation technology that does not require a pseudo-random coding sequence. Because the bandwidth occupied by the linear frequency modulation signal is much larger than the information bandwidth, a large system processing gain can also be obtained. The linear frequency modulation signal is also called a chirp signal. Because its spectrum bandwidth falls within the audible range and sounds like a bird, it is also called a chirp spread spectrum technology. LFM technology is widely used in radar and sonar technology. For example, in radar positioning technology, it can be used to increase the RF pulse width, increase the communication distance, and increase the average transmission power, while maintaining sufficient signal spectrum width and not reducing the radar's distance resolution. Therefore, the drone in the outdoor positioning method of the present application uses radio signal transmission, and receives the signal sent by the transmitter through its own antenna, thereby maintaining contact with the ground station, and combined with the chirp signal, effectively improving the stability and accuracy of radio positioning and navigation.

[0038] Among them, see Figure 3 , Figure 3 is a hardware block diagram of a linear frequency modulation signal receiving station provided in an embodiment of the present application. Figure 3As shown, the receiving station includes a debugging interface, a UAV data transmission interface, an antenna and a signal receiver. Among them, the signal receiver is implemented by a radio transceiver chip combined with a field programmable gate array architecture. The receiver structure has the characteristics of miniaturization and low power consumption, and improves the stability of radio transmission. Among them, the signal receiver also includes a flash memory based on the serial communication protocol (Serial Peripheral Interface, SPI), a standard interface (Joint Test Action Group, JTAG) for testing and debugging, an asynchronous receiver and transmitter (Universal Asynchronous Receiver, UART), a low noise amplifier, a filter and a microcontroller (Microcontroller Unit, MCU). The receiving station receives the Chirp signal sent by the target object through the antenna, and the Chirp signal is processed by a filter, a low noise amplifier, etc. The signal receiver obtains the second pulse through the UART. The second pulse here refers to the Global Positioning System (GPS) second pulse. At the same time, the timing information and signal strength are output to the UAV data transmission interface through the UART. The MCU is responsible for data protocol processing and configuration, and encrypts the wirelessly transmitted positioning information to improve system security.

[0039] Step S202: determine any one of the drones as a master drone, and determine the remaining drones other than the master drone as auxiliary drones.

[0040] Step S203: determining a plurality of distance differences according to the signal reception information.

[0041] Each of the auxiliary drones corresponds to a distance difference value, and the distance difference value is used to describe the difference between the first distance between each of the auxiliary drones and the target object, and the second distance between the main drone and the target object. There is a measurement error between the distance difference value and the true value due to noise.

[0042] In a possible embodiment, if the signal reception information includes a signal arrival time; determining multiple distance difference values ​​based on the signal reception information includes: determining the arrival time difference of each auxiliary drone based on the signal arrival time corresponding to the main drone and the signal arrival time corresponding to each auxiliary drone; obtaining a signal propagation speed set and a target weather type corresponding to the linear frequency modulation signal; determining a target propagation speed corresponding to the target weather type from the multiple reference propagation speeds; and determining the distance difference value corresponding to each auxiliary drone based on the arrival time difference of each auxiliary drone and the target propagation speed.

[0043] The signal propagation speed set includes a plurality of reference propagation speeds and a plurality of reference weather types, and each reference weather type corresponds to a reference propagation speed.

[0044] Among them, under the premise of time synchronization before positioning on the drone side, when the target object sends a Chirp signal, each drone receives the Chirp signal at different times due to its different positions, so the signal arrival time corresponding to each drone is different. The signal arrival time corresponding to each auxiliary drone is subtracted from the signal arrival time of the main drone to determine multiple arrival time differences, and then according to the target propagation speed, multiple distance differences can be determined, so that the ground positioning server can locate the target object according to these multiple distance differences.

[0045] Among them, under normal circumstances, the signal propagation speed of the Chirp signal in the air is approximately equal to the speed of light. However, different weather types may indeed affect the signal propagation speed. Different meteorological conditions can change the characteristics of the atmosphere, thereby affecting the propagation of signals such as electromagnetic waves or sound waves in the air. The following are some situations where weather factors may affect the signal propagation speed: Rain: Water droplets in rain may absorb and scatter signal propagation, causing the signal propagation speed to slow down. In addition, heavy rainfall may cause multipath effects in the signal propagation path, affecting the propagation stability of the signal. Snow: Similar to rain, snow flakes may also affect the propagation speed and propagation path of the signal. The presence of snow may cause the signal to be scattered and absorbed, thereby affecting the distance and quality of signal propagation. Fog and dew: Water droplets in fog and dew can scatter signals and affect the propagation speed of the signal. In addition, fog and dew may also cause signal absorption, resulting in signal attenuation. Atmospheric humidity: High humidity may cause an increase in the water vapor content in the atmosphere, thereby affecting the signal propagation speed. Changes in humidity may cause changes in the refractive index of the signal, affecting the propagation path of the signal in the atmosphere. Temperature: Changes in temperature affect the density of the atmosphere, thereby affecting the propagation speed of the signal. Generally, as the temperature increases, the atmospheric density decreases, and the signal propagation speed may increase. Obviously, different weather types may lead to different signal propagation speeds, so determining the target signal propagation speed according to the corresponding weather type when performing positioning operations can improve the accuracy of the signal arrival time measured by the drone, thereby improving the accuracy of the distance difference.

[0046] For example, see Figure 4 , Figure 4 Schematic diagram of a scenario of receiving signals under different weather conditions provided by an embodiment of the present application. Figure 4 As shown, after the target object sends the signal, Figure 4 The drone corresponding to 01 received a signal sent in moderate snow weather. Figure 4The drone corresponding to 02 in the figure received a signal sent in heavy snow weather. Figure 4 The drone corresponding to 03 received the signal sent in moderate rain weather. Figure 4 The 04 in the figure corresponds to the drone receiving the signal sent in the haze weather. Figure 4 The degree to which the arrival time of signals received by drones 01-04 is affected by weather is 03, 01, 04, and 02, from small to large.

[0047] It can be seen that in this example, multiple distance differences can be determined through the signal arrival time of the signals received by each drone and the target propagation speed. Determining the target signal propagation speed according to the corresponding weather type when performing the positioning operation can improve the accuracy of the signal arrival time measured by the drone, thereby improving the accuracy of the distance difference.

[0048] In a possible embodiment, the signal receiving signal also includes signal strength; after determining the multiple distance difference values ​​according to the multiple arrival time differences and the target propagation speed, the method also includes: if each of the signal strengths is greater than the preset received signal strength, then determining the signal strength difference value according to the signal strength corresponding to the main UAV and the signal strength corresponding to each of the auxiliary UAVs in turn; obtaining the current environment type and a set of environment attenuation factors; determining one or more target environment attenuation factors corresponding to the current environment type from the multiple reference environment attenuation factors; determining the signal transmission distance difference according to the signal strength difference and the one or more target environment attenuation factors; and updating the distance difference value according to the signal transmission distance difference.

[0049] The environmental attenuation factor set includes a plurality of reference environment types and a plurality of reference environment attenuation factors, and each of the reference environment types corresponds to one or more reference environment attenuation factors.

[0050] Among them, the actual received signal strength of different drones is different due to the influence of distance and environment. During the radio transmission process, the signal strength will be affected by path loss during air propagation. The reason for setting the preset received signal strength is that, assuming that the frequency of the Chirp signal sent by the target object is the same, when the distance between the drone and the target object exceeds a certain value, the signal strength change will suddenly increase, so the reference significance of subsequent calculations by signal strength is not great. Therefore, when the received signal strength is greater than the preset received signal strength, the distance difference is updated through subsequent calculations. Specifically, one or more target environmental attenuation factors are determined by obtaining the current environment type and the set of environmental attenuation factors, and then the signal transmission distance between different drones is determined by the signal strength difference between them, and then the distance difference is updated to improve the accuracy of the distance difference. The types of specific environmental attenuation factors may include the number of buildings, terrain, air medium, noise, etc., which are not limited here.

[0051] It can be seen that in this example, the strength of the received signal is used to improve the accuracy of the distance difference, thereby assisting the positioning system and improving the accuracy of drone positioning and navigation.

[0052] In a possible embodiment, updating the distance difference value according to the signal transmission distance difference includes: if the signal transmission distance difference is greater than or equal to the distance difference value, keeping the distance difference value unchanged; if the signal transmission distance difference is less than the distance difference value, determining a measurement difference value according to the signal transmission distance difference and the distance difference value; determining a compensation coefficient associated with the signal transmission distance difference, the compensation coefficient being negatively correlated with the signal transmission distance difference; determining a distance compensation value according to the compensation coefficient and the measurement difference value; and determining an updated distance difference value according to the distance difference value and the distance compensation value.

[0053] Among them, due to the different properties of different signals, based on the test, it can be obtained that the attenuation degree of the signal caused by the distance is different, so the compensation coefficient is negatively correlated. The greater the distance difference, the lower the reliability. Generally, the error caused by the environment type will make the calculated arrival time value too large, which will lead to a larger distance. Therefore, reducing the error means reducing the compensation value.

[0054] The formula for determining the updated distance difference value according to the distance difference value and the distance compensation value is: distance difference value before updating - distance compensation value = distance difference value after updating.

[0055] It can be seen that in this example, based on the principle of signal propagation, by comparing the signal transmission distance difference and the distance difference, it is determined whether to compensate for the calculated distance difference, thereby improving the accuracy and precision of the target position calculation performed by the ground positioning server.

[0056] Step S204: estimate the position of the target object according to the position information of the multiple receiving stations and the multiple distance differences to determine the target position.

[0057] The positioning system of the present application is based on outdoor target positioning using Chirp signals. The ground positioning server uses an improved traditional TDOA positioning method to obtain the target position of the target object. First, the traditional Time Difference Of Arrival (TDOA) positioning method is introduced. Figure 5 , Figure 5 Schematic diagram of a scenario of outdoor positioning of a drone provided in an embodiment of the present application. Figure 5 As shown in the figure, the basic principle of the traditional TDOA positioning method is: assuming that the first drone is the main drone and the remaining drones are auxiliary drones, with the main drone and any auxiliary drone as the focus, the distance difference between the chirp signal generated by the target object and the two drones as the major axis can be used to obtain a hyperbola, and the target object to be found is on this hyperbola. At least three drones are required to uniquely confirm the position of the target object in a two-dimensional plane, and at least four drones are required in a three-dimensional space. Through the time difference measurement values ​​of these drones, two or more hyperbolas (surfaces) can be obtained, and the intersection of these hyperbolas (surfaces) is the position of the target object to be found.

[0058] Based on this, the improved positioning algorithm in the present application is described in detail below in conjunction with the embodiments.

[0059] Among them, suppose there are M drones u in the two-dimensional space i =[x i ,y i ] T , i=1,2,…,M, the coordinates of the target position of the target object to be found are s=[x,y] T , the target position can be estimated using the known position coordinates of each UAV and the measured TDOA observation values.

[0060] Among them, the arrival time difference t of the Chirp signal sent by the target object to the i-th auxiliary UAV and the main UAV is i1 and the distance difference r i1 It is expressed as:

[0061] t i1 =(r i -r1) / c,i=2,3,…,M.

[0062] r i1 =r i -r1=ct i1,i=2,3,…,M。

[0063] in, r i Represents the first distance or the second distance between the i-th UAV and the target object.

[0064] Furthermore, due to the presence of measurement noise, i.e., measurement error, in the observation process, the distance difference can be expressed as:

[0065] r i1 =r i -r1+n i1 ,i=2,3,…,M,n i1 is the measurement error.

[0066] If the above equation is written in vector form, the observation equation for TDOA positioning is:

[0067]

[0068] Where r = [r 21 ,r 31 ,…,r M1 ] T is the TDOA measurement value with noise error, that is, the distance difference vector, which is known; is the true TDOA value, is unknown; n = [n 21 ,n 31 ,…,n M1 ] T It represents the measurement error vector of the Mth UAV based on TDOA positioning. Assuming that n is a Gaussian distribution with a mean of 0, the corresponding covariance matrix is ​​R, and the covariance matrix expression is: R = E[n T n].

[0069] Rearrange the observation equation into r i1 +r1=r i +n i1 Squaring the last two sides yields:

[0070]

[0071] In the above formula, the second-order term of the error is ignored.

[0072] Furthermore, when three drones (M=3) participate in positioning, based on the above TDOA positioning algorithm, we can obtain two distance differences, namely r 21 and r 31 , the position of the target object can be estimated as:

[0073]

[0074] Furthermore, when four or more drones (M≥4) participate in positioning, the specific algorithm is described in detail through the following embodiments.

[0075] In a possible embodiment, the position of the target object is estimated according to the multiple receiving station position information and the multiple distance differences to determine the target position, including: obtaining a coefficient value corresponding to each auxiliary drone; performing a matrix operation according to the coefficient value and the distance difference corresponding to each auxiliary drone to obtain a first distance matrix; determining a first position matrix according to the receiving station position information of each auxiliary drone and the receiving station position information corresponding to the main drone; determining a first error vector according to the measurement error; and determining the target position corresponding to the target object according to the first error vector, the first distance matrix, the second distance and the first position matrix.

[0076] The specific calculation process is as follows:

[0077] Taking four drones as an example, let the unknown variable to be determined be z1=[s T ,r1] T , can be obtained

[0078] Among them, z1 is the first position information, s is the coordinate of the target object, r1 is the second distance, h1 is the first distance matrix, is the first error vector, k is the coefficient value corresponding to each auxiliary drone, and G1 is the first position matrix.

[0079] Furthermore, according to the coefficient value corresponding to each auxiliary UAV, the receiving station location information of each UAV, the distance difference and the second distance, z1, h1 and G1 are calculated respectively by the following formulas:

[0080]

[0081] In a possible embodiment, determining the first error vector based on the measurement error includes: vectorizing the measurement error to obtain a measurement error vector; constructing a parameter diagonal matrix based on the true value of the first distance corresponding to each auxiliary drone; and determining the first error vector based on the parameter diagonal matrix and the measurement error vector.

[0082] Among them, the true value of the first distance is r 0 , which is the zeroth power of the first distance, and the parameter diagonal matrix is ​​B1.

[0083] The specific calculation process is as follows:

[0084] Among them, when the time difference measurement error is small, the first error vector It can be expressed as:

[0085]

[0086] in, diag is a commonly used function or operator used to extract the diagonal elements of a matrix or construct a diagonal matrix. B1 is the parameter diagonal matrix and n is the measurement error vector.

[0087] In a possible embodiment, the target position corresponding to the target object according to the first error vector, the first distance matrix, the second distance and the first position matrix includes: determining the first position information corresponding to the target object according to the first error vector, the first distance matrix, the first position matrix and the second distance; determining the second distance matrix according to the receiving station position information corresponding to the master drone and the first position information; acquiring the second position matrix and constraint conditions corresponding to the master drone; constructing a second error vector according to the constraint conditions; determining the second position information corresponding to the target object according to the second error vector, the second distance matrix and the second position matrix; determining the target position according to the first position information and the second position information.

[0088] According to the first error vector The specific calculation process of determining the first position information Z1 corresponding to the target object by using the first distance matrix h1, the first position matrix G1 and the second distance r1 is as follows:

[0089] The above-mentioned Calculations can be made to obtain:

[0090]

[0091] Among them, the first error vector The covariance matrix of is:

[0092]

[0093] Among them, the initial moment B1 contains unknown target position parameter information, and z1 cannot be calculated. Usually, W1 = R -1 To obtain an initial estimate of the target position, use it to calculate B1, and use WLS again to get the result of the first weighted least squares method.

[0094] Solving the covariance matrix of z1, we get

[0095] Furthermore, the second distance matrix h1′ is determined by the first position information Z1 and the receiving station position (x1, y1) corresponding to the master UAV.

[0096] According to the constraints, the specific calculation process of constructing the second error vector is as follows:

[0097] According to the second distance matrix h1′, the obtained second position matrix G1′ and the constraint condition r1 2 =(s-u1) T (s-u1), construct a new second error vector And the second position information z2:

[0098]

[0099] in,

[0100]

[0101] Using WLS to solve the above formula, we can get:

[0102]

[0103] After solving for z2, the target position can be calculated by the following formula:

[0104]

[0105] Among them, U=diag(sgn(z1(1:2)-u1)), sgn is the sign discrimination function.

[0106] In a possible embodiment, a drone used in a positioning system, prior to the method: obtains a synchronization pulse output by a synchronization clock at a preset time interval; performs a time synchronization operation based on the synchronization pulse; after the time synchronization operation is completed, starts a local clock timer; when the linear frequency modulation signal sent by the target object is received, determines signal reception information based on the local clock timer and the linear frequency modulation signal; and sends the signal reception information and the receiving station location information corresponding to the linear frequency modulation signal receiving station to the ground positioning server through the drone data link.

[0107] Among them, since the positioning of the drone in this application is to calculate the arrival time difference through the arrival time of the signal received by each drone, and then calculate the distance difference between the linear frequency modulation signal sent by the target object to different drones. Therefore, in order to ensure the accuracy of the arrival time difference, multiple drones in the positioning system need to be time synchronized before the positioning operation. The specific time synchronization method is to perform the timing operation through synchronization pulses. After the positioning operation is started, the local clock of the drone is used to count within seconds, and the Chirp physical layer high-precision timing algorithm is used to obtain the precise Chirp signal arrival time, and the signal reception information and the current position information of the drone are sent to the ground positioning server through the drone data link so that the server can calculate the target position.

[0108] It can be seen that in this example, the drone side of the positioning system uses prior time synchronization to improve the accuracy of the arrival time, and uses local clock counting to determine the exact signal arrival time, thereby avoiding time errors caused by inaccurate timing, and improving the precision and accuracy of the positioning system's radio positioning and navigation through drones.

[0109] visible, Figure 2 This is a flow chart of an outdoor positioning method provided in an embodiment of the present application. The ground positioning server obtains the signal reception information about the target object collected by each drone to obtain multiple distance differences, and then obtains the target position through the distance differences and the receiving station position information, thereby improving the accuracy and efficiency of the ground positioning server in measuring the target object position, effectively reducing the measurement error of the drone, and thus improving the accuracy and precision of the drone navigation.

[0110] The following is an embodiment of the device of the present application. The embodiment of the device of the present application and the embodiment of the method of the present application are of the same concept and are used to execute the method described in the embodiment of the present application. For the convenience of explanation, the embodiment of the device of the present application only shows the part related to the embodiment of the device of the present application. For the specific technical details not disclosed, please refer to the description of the embodiment of the method of the present application, which will not be repeated here one by one.

[0111] An outdoor positioning device provided in an embodiment of the present application is applied to Figure 1 The ground positioning server 110 in the positioning system 100 shown, the positioning system 100 includes the ground positioning server 110 and the drone 120, and the ground positioning server 110 and the drone 120 establish a communication connection. Specifically, the outdoor positioning device is used to execute the steps performed by the ground positioning server in the above outdoor positioning method. The outdoor positioning device provided in the embodiment of the present application may include modules corresponding to the corresponding steps.

[0112] The embodiment of the present application can divide the functional modules of the outdoor positioning device according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of software functional modules. The division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation.

[0113] In the case of dividing each functional module into corresponding functional modules, Figure 6 : This is a functional unit composition block diagram of an outdoor positioning device provided by an embodiment of the present application; the outdoor positioning device 60 is applied to a ground positioning server in a positioning system, the positioning system includes multiple drones, each of which is equipped with a linear frequency modulation signal receiving station, the linear frequency modulation signal receiving station is used to receive the linear frequency modulation signal sent by the target object, and the ground positioning server establishes a communication connection with the multiple drones; the device includes: an acquisition unit 601, used to acquire signal reception information collected by each drone and the receiving station position information corresponding to each drone; a first determination unit 602, used to determine any one of the drones as a main drone, and determine the remaining drones other than the main drone as auxiliary drones; a second determination unit 603, used to determine multiple distance differences according to the signal reception information, each auxiliary drone corresponds to a distance difference, the distance difference is used to describe the difference between the first distance between each auxiliary drone and the target object, and the second distance between the main drone and the target object, and there is a measurement error between the distance difference and the true value due to noise; a third determination unit 604, used to estimate the position of the target object according to the multiple receiving station position information and the multiple distance differences to determine the target position.

[0114] In a possible embodiment, in terms of estimating the position of the target object according to the multiple receiving station position information and the multiple distance differences to determine the target position, the third determination unit 604 is specifically used to: obtain the coefficient value corresponding to each auxiliary drone; perform matrix operations according to the coefficient value and distance difference corresponding to each auxiliary drone to obtain a first distance matrix; determine the first position matrix according to the receiving station position information of each auxiliary drone and the receiving station position information corresponding to the main drone; determine the first error vector according to the measurement error; and determine the target position corresponding to the target object according to the first error vector, the first distance matrix, the second distance and the first position matrix.

[0115] In a possible embodiment, in terms of determining the first error vector based on the measurement error, the third determination unit 604 is specifically used to: vectorize the measurement error to obtain a measurement error vector; construct a parameter diagonal matrix based on the true value of the first distance corresponding to each auxiliary drone; and determine the first error vector based on the parameter diagonal matrix and the measurement error vector.

[0116] In a possible embodiment, in terms of the target position corresponding to the target object according to the first error vector, the first distance matrix, the second distance and the first position matrix, the third determination unit 604 is specifically used to: determine the first position information corresponding to the target object according to the first error vector, the first distance matrix, the first position matrix and the second distance; determine the second distance matrix according to the receiving station position information corresponding to the main UAV and the first position information; obtain the second position matrix and constraints corresponding to the main UAV; construct a second error vector according to the constraints; determine the second position information corresponding to the target object according to the second error vector, the second distance matrix and the second position matrix; determine the target position according to the first position information and the second position information.

[0117] In a possible embodiment, if the signal reception information includes the signal arrival time; in terms of determining multiple distance differences based on the signal reception information, the second determination unit 603 is specifically used to: determine the arrival time difference of each auxiliary drone based on the signal arrival time corresponding to the main drone and the signal arrival time corresponding to each of the auxiliary drones; obtain a signal propagation speed set and a target weather type corresponding to the linear frequency modulation signal, the signal propagation speed set including multiple reference propagation speeds and multiple reference weather types, each reference weather type corresponding to a reference propagation speed; determine the target propagation speed corresponding to the target weather type from the multiple reference propagation speeds; determine the distance difference corresponding to each auxiliary drone based on the arrival time difference of each auxiliary drone and the target propagation speed.

[0118] In a possible embodiment, the signal receiving signal also includes signal strength; after determining the multiple distance difference values ​​according to the multiple arrival time differences and the target propagation speed, the second determination unit 603 is specifically further used to: if each of the signal strengths is greater than a preset received signal strength, determine the signal strength difference value according to the signal strength corresponding to the main UAV and the signal strength corresponding to each of the auxiliary UAVs in turn, and the preset received signal strength is associated with the transmission power of the target object; obtain the current environment type and an environment attenuation factor set, the environment attenuation factor set includes a plurality of reference environment types and a plurality of reference environment attenuation factors, and each reference environment type corresponds to one or more reference environment attenuation factors; determine one or more target environment attenuation factors corresponding to the current environment type from the multiple reference environment attenuation factors; determine the signal transmission distance difference according to the signal strength difference and the one or more target environment attenuation factors; and update the distance difference value according to the signal transmission distance difference.

[0119] In a possible embodiment, in terms of updating the distance difference value according to the signal transmission distance difference, the second determination unit 603 is specifically used to: if the signal transmission distance difference is greater than or equal to the distance difference value, keep the distance difference value unchanged; if the signal transmission distance difference is less than the distance difference value, determine a measurement difference value according to the signal transmission distance difference and the distance difference value; determine a compensation coefficient associated with the signal transmission distance difference, the compensation coefficient is negatively correlated with the signal transmission distance difference; determine a distance compensation value according to the compensation coefficient and the measurement difference value; determine the updated distance difference value according to the distance difference value and the distance compensation value.

[0120] In the case of an integrated unit, such as Figure 7 As shown, Figure 7 This is a block diagram of the functional units of another outdoor positioning device provided by an embodiment of the present application. Figure 7 In the embodiment, the outdoor positioning device 60 includes: a processing module 712 and a communication module 711. The processing module 712 is used to control and manage the actions of the outdoor positioning device, for example, the steps of the acquisition unit 601, the first determination unit 602, the second determination unit 603 and the third determination unit 604, and / or other processes for executing the technology described herein. The communication module 711 is used to support the interaction between the outdoor positioning device and other devices. Figure 7 As shown, the outdoor positioning device may include a storage module 713, and the storage module 713 is used to store program codes and data of the outdoor positioning device.

[0121] Among them, the processing module 712 can be a processor or a controller, for example, a central processing unit (CPU), a general processor, a digital signal processor (DSP), an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It can implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements a computing function, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like. The communication module 711 can be a transceiver, an RF circuit or a communication interface, and the like. The storage module 713 can be a memory.

[0122] All relevant contents of each scenario involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here. Figure 2 The outdoor positioning method shown.

[0123] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state hard disk.

[0124] Figure 8 is a structural block diagram of a ground positioning server provided in an embodiment of the present application. Figure 8As shown, the ground positioning server 110 may include one or more of the following components: a processor 810, and a memory 820 coupled to the processor 810, wherein the memory 820 may store one or more programs 821 (i.e., computer programs), and the one or more computer programs may be configured to implement the methods described in the above embodiments when executed by one or more processors 810.

[0125] The processor 810 may include one or more processing cores. The processor 810 uses various interfaces and lines to connect the various parts of the entire ground positioning server 110, and executes various functions and processes data of the ground positioning server 110 by running or executing instructions, programs, code sets or instruction sets stored in the memory 820, and calling data stored in the memory 820. Optionally, the processor 810 can be implemented in at least one hardware form of digital signal processing (Digital Signal Processing, DSP), field programmable gate array (Field-Programmable Gate Array, FPGA), and programmable logic array (Programmable Logic Array, PLA). The processor 810 can integrate one or a combination of a central processing unit (Central Processing Unit, CPU), a graphics processing unit (Graphics Processing Unit, GPU) and a modem. Among them, the CPU mainly processes the operating system, user interface and application programs; the GPU is responsible for rendering and drawing display content; and the modem is used to process wireless communications. It can be understood that the above-mentioned modem may not be integrated into the processor 810, but may be implemented separately through a communication chip.

[0126] The memory 820 may include a random access memory (RAM) or a read-only memory (ROM). The memory 820 may be used to store instructions, programs, codes, code sets or instruction sets. The memory 820 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc. The data storage area may also store data created by the ground positioning server 110 during use, etc.

[0127] It is understandable that the ground positioning server 110 may include more or fewer structural elements than those in the above structural block diagram, which is not limited here.

[0128] An embodiment of the present application also provides a computer storage medium, on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, part or all of the steps of any method recorded in the above method embodiments are implemented.

[0129] An embodiment of the present application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute part or all of the steps of any method recorded in the above method embodiments.

[0130] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0131] In the several embodiments provided in the present application, it should be understood that the disclosed methods, devices and systems can be implemented in other ways. For example, the device embodiments described above are merely schematic; for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation; for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0132] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0133] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may be physically included separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0134] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform some steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a volatile memory or a non-volatile memory. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM) and direct RAM bus random access memory (DR RAM), among other media that can store program code.

[0135] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions without departing from the spirit and scope of the present invention, and can make various changes and modifications, including the combination of the above-mentioned different functions and implementation steps, including software and hardware implementation methods, all of which are within the scope of protection of the present invention.

Claims

1. An outdoor positioning method, characterized in that: A ground positioning server used in a positioning system, wherein the positioning system includes a plurality of drones, each of which carries a linear frequency modulation signal receiving station, wherein the linear frequency modulation signal receiving station is used to receive a linear frequency modulation signal sent by a target object, and the ground positioning server establishes a communication connection with the plurality of drones; the method includes: Acquire signal reception information collected by each of the drones and location information of a receiving station corresponding to each of the drones; Determine any one of the drones as a master drone, and determine the remaining drones other than the master drone as auxiliary drones; Determine a plurality of distance differences according to the signal reception information, each of the auxiliary drones corresponds to a distance difference, the distance difference is used to describe a first distance between each of the auxiliary drones and the target object, and a difference between a second distance between the main drone and the target object, and there is a measurement error between the distance difference and the true value due to noise; Obtain a coefficient value corresponding to each auxiliary drone, where the coefficient value is a constant value determined according to the receiving station location information corresponding to the auxiliary drone; Performing matrix operations according to the coefficient values ​​and distance differences corresponding to each auxiliary drone to obtain a first distance matrix; Determine a first position matrix according to the receiving station position information of each auxiliary UAV and the receiving station position information corresponding to the master UAV; Determining a first error vector according to the measurement error; Determine first position information corresponding to the target object according to the first error vector, the first distance matrix, the first position matrix and the second distance; Determine a second distance matrix according to the receiving station location information corresponding to the master drone and the first location information; Obtaining a second position matrix and constraint conditions corresponding to the master drone; constructing a second error vector according to the constraint condition; Determine second position information corresponding to the target object according to the second error vector, the second distance matrix and the second position matrix; The target location is determined according to the first location information and the second location information.

2. The method according to claim 1, characterized in that The step of determining a first error vector according to the measurement error comprises: Vectorizing the measurement error to obtain a measurement error vector; Constructing a parameter diagonal matrix according to the true value of the first distance corresponding to each auxiliary drone; The first error vector is determined according to the parameter diagonal matrix and the measurement error vector.

3. The method according to claim 1 or 2, characterized in that: If the signal reception information includes a signal arrival time; determining a plurality of distance differences according to the signal reception information includes: Determine the arrival time difference of each auxiliary drone according to the signal arrival time corresponding to the master drone and the signal arrival time corresponding to each auxiliary drone; Acquire a signal propagation speed set and a target weather type corresponding to the linear frequency modulation signal, wherein the signal propagation speed set includes a plurality of reference propagation speeds and a plurality of reference weather types, and each reference weather type corresponds to a reference propagation speed; determining a target propagation speed corresponding to the target weather type from the plurality of reference propagation speeds; According to the arrival time difference of each auxiliary drone and the target propagation speed, a distance difference corresponding to each auxiliary drone is determined.

4. The method according to claim 3, characterized in that The signal receiving signal also includes signal strength; after determining the multiple distance difference values ​​according to the multiple arrival time differences and the target propagation speed, the method also includes: If each of the signal strengths is greater than a preset received signal strength, a signal strength difference is determined according to the signal strength corresponding to the master drone and the signal strength corresponding to each of the auxiliary drones, wherein the preset received signal strength is associated with the transmission power of the target object; Acquire a current environment type and an environment attenuation factor set, wherein the environment attenuation factor set includes a plurality of reference environment types and a plurality of reference environment attenuation factors, and each reference environment type corresponds to one or more reference environment attenuation factors; Determine one or more target environment attenuation factors corresponding to the current environment type from the multiple reference environment attenuation factors; Determining a signal transmission distance difference according to the signal strength difference and the one or more target environment attenuation factors; The distance difference value is updated according to the signal transmission distance difference.

5. The method according to claim 4, characterized in that The updating of the distance difference value according to the signal transmission distance difference comprises: If the signal transmission distance difference is greater than or equal to the distance difference value, keeping the distance difference value unchanged; If the signal transmission distance difference is less than the distance difference value, determining a measurement difference value according to the signal transmission distance difference and the distance difference value; Determining a compensation coefficient associated with the signal transmission distance difference, wherein the compensation coefficient is negatively correlated with the signal transmission distance difference; Determining a distance compensation value according to the compensation coefficient and the measurement difference; An updated distance difference value is determined according to the distance difference value and the distance compensation value.

6. An outdoor positioning device, characterized in that: A ground positioning server used in a positioning system, wherein the positioning system includes a plurality of drones, each of which is equipped with a linear frequency modulation signal receiving station, wherein the linear frequency modulation signal receiving station is used to receive a linear frequency modulation signal sent by a target object, and the ground positioning server establishes a communication connection with the plurality of drones; the device includes: An acquisition unit, used to acquire signal reception information collected by each of the drones and location information of a receiving station corresponding to each of the drones; A first determining unit, configured to determine any one of the drones as a master drone, and to determine the remaining drones other than the master drone as auxiliary drones; a second determining unit, configured to determine a plurality of distance differences according to the signal reception information, wherein each auxiliary drone corresponds to a distance difference, and the distance difference is used to describe a first distance between each auxiliary drone and the target object, and a difference between a second distance between the main drone and the target object, and there is a measurement error between the distance difference and the true value due to noise; The third determination unit is used to obtain the coefficient value corresponding to each auxiliary drone, wherein the coefficient value is a constant value determined according to the receiving station position information corresponding to the corresponding auxiliary drone; perform matrix operation according to the coefficient value and distance difference corresponding to each auxiliary drone to obtain a first distance matrix; determine the first position matrix according to the receiving station position information of each auxiliary drone and the receiving station position information corresponding to the main drone; determine the first error vector according to the measurement error; determine the first position information corresponding to the target object according to the first error vector, the first distance matrix, the first position matrix and the second distance; determine the second distance matrix according to the receiving station position information corresponding to the main drone and the first position information; obtain the second position matrix and constraint conditions corresponding to the main drone; construct a second error vector according to the constraint conditions; determine the second position information corresponding to the target object according to the second error vector, the second distance matrix and the second position matrix; determine the target position according to the first position information and the second position information.

7. A ground positioning server, characterized in that: The method comprises a processor, a memory, a communication interface, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, and the programs include instructions for executing the steps in the method as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that: A computer program for electronic data exchange is stored, wherein the computer program enables a computer to execute the method according to any one of claims 1 to 5.

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