Single-station positioning method based on doppler frequency shifts and time difference information, and system and electronic device

Abstract

A single-station positioning method based on Doppler frequency shifts and time difference information, and a system and an electronic device. The method comprises: acquiring an actual period of a pilot signal sent by an unmanned aerial vehicle (S1); on the basis of the actual period of the pilot signal sent by the unmanned aerial vehicle, determining two adjacent target signals sent by the unmanned aerial vehicle in a target area, and acquiring actual center frequencies of target signal information, an actual time difference of arrival between the two target signals at a receiving base station, actual angles of arrival, and actual Doppler frequency shifts of the unmanned aerial vehicle (S2); importing an actual range of the target area, the actual period of the pilot signal, the actual center frequencies of the target signals, the actual time difference and the actual angles of arrival into variables in a preset theoretical Doppler frequency shift model, so as to obtain a theoretical Doppler frequency shift value table, wherein the table comprises different theoretical Doppler frequency shift values corresponding to different distances from the unmanned aerial vehicle to the receiving base station (S3); performing error metric calculation processing on the actual Doppler frequency shifts and each theoretical Doppler frequency shift value, so as to obtain a theoretical Doppler frequency shift value corresponding to the minimum error metric (S4); and on the basis of the theoretical Doppler frequency shift value corresponding to the minimum error metric, determining the positions at which the unmanned aerial vehicle sends the target signals (S5). The method can ensure the accuracy of single-station positioning in a complex scenario.

Description

Single station positioning method, system and electronic device based on Doppler shift and time difference information TECHNICAL FIELD

[0001] The present application relates to the field of single station positioning, in particular to a single station positioning method, system and electronic device based on Doppler shift and time difference information. BACKGROUND

[0002] Single station positioning system is suitable for monitoring specific areas or objects due to its simple deployment, high flexibility, low cost and easy maintenance.

[0003] However, current single station positioning is generally based on measuring the direction strength, angle of arrival and Doppler shift of the signal arriving at the receiving station, but these methods are greatly affected by environmental factors such as multipath effect, and require high signal-to-noise ratio, making it difficult to achieve accurate positioning in practical applications.

[0004] Therefore, how to improve the positioning accuracy of single station and apply it to complex scenarios has become a technical problem that needs to be solved in the industry. SUMMARY

[0005] The present application provides a single station positioning method, system and electronic device based on Doppler shift and time difference information, which solves the technical problem of how to improve the positioning accuracy of single station and apply it to complex scenarios.

[0006] According to a first aspect of the present application, the embodiments of the present application provide a single station positioning method based on Doppler shift and time difference information, applied to a receiving base station, the single station positioning method comprising:

[0007] obtaining the actual period of the pilot signal sent by the unmanned aerial vehicle;

[0008] based on the actual period of the pilot signal sent by the unmanned aerial vehicle, determining adjacent two target signals sent by the unmanned aerial vehicle in the target area, and obtaining the actual center frequency of the target signal, the actual time difference of the receiving base station reached by the two target signals, the actual wave arrival angle, and the actual Doppler shift of the unmanned aerial vehicle;

[0009] introducing the actual range of the target area, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference, and the actual wave arrival angle into a preset theoretical Doppler shift model to obtain a Doppler shift theoretical value table, the Doppler shift theoretical value table including different Doppler shift theoretical values corresponding to different distances from the unmanned aerial vehicle to the receiving base station;

[0010] The actual Doppler shift is subjected to error measurement calculation with each of the Doppler shift theoretical values to obtain the Doppler shift theoretical value corresponding to the minimum error measurement;

[0011] The position of the UAV when sending the target signal is determined based on the Doppler shift theoretical value corresponding to the minimum error measurement.

[0012] Optionally, the receiving base station receives the first target signal and the second target signal in sequence, the first target signal and the second target signal being adjacent two target signals sent by the UAV;

[0013] The method for establishing a theoretical Doppler shift model comprises:

[0014] The direct path of the first target signal is taken as a first coordinate axis, the position of the receiving base station is taken as an origin, and a two-dimensional plane coordinate system is established according to the direction of arrival of the first target signal and the direction of arrival of the second target signal, and a second coordinate axis is perpendicular to the first coordinate axis;

[0015] A first step length and a first number based on the first coordinate axis are obtained;

[0016] A plurality of first preset coordinates corresponding to the UAV when sending the first target signal are obtained based on the first step length and the first number of the first coordinate axis, the first preset coordinates being coordinates on the two-dimensional plane coordinate system;

[0017] A plurality of second preset coordinates corresponding to the UAV when sending the second target signal are determined based on the plurality of first preset coordinates, a time difference variable and a direction of arrival angle variable of the receiving base station receiving the first target signal and the second target signal, the second preset coordinates being coordinates on the two-dimensional plane coordinate system;

[0018] A theoretical Doppler shift model is established based on a time difference variable of adjacent two target signals sent by the UAV, a center frequency variable of the target signal, the plurality of first preset coordinates and the corresponding second preset coordinates, so that the Doppler shift theoretical value corresponding to each of the first preset coordinates can be calculated to obtain a Doppler shift theoretical value table.

[0019] Optionally, the Doppler shift theoretical value corresponding to the first preset coordinate is calculated based on a time difference variable of adjacent two target signals sent by the UAV, the first preset coordinate and the corresponding second preset coordinate, comprising:

[0020] A period variable of a pilot signal sent by the UAV is obtained;

[0021] obtaining a corresponding first speed component of the UAV in a direction of the first coordinate axis and a corresponding second speed component of the UAV in a direction of the second coordinate axis based on the period variable, the first preset coordinate and the corresponding second preset coordinate;

[0022] calculating the speed of the UAV based on the first speed component and the second speed component;

[0023] calculating the Doppler shift theoretical value corresponding to the first preset coordinate based on the speed of the UAV, the center frequency variable and the first speed component.

[0024] Optionally, the range of the target region is [d low ,d high ];

[0025] Then, the first number L is determined based on the first step length and the range of the target region, L=(d high -d low ) / d step +1

[0026] wherein d step is the first step length.

[0027] Optionally, the first coordinate axis is the Y axis and the second coordinate axis is the X axis.

[0028] Then, the actual range of the target region, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference and the actual wave arrival angle are introduced into a preset theoretical Doppler shift model to obtain the Doppler shift theoretical value corresponding to the first preset coordinate, including:

[0029] determining the lth first preset coordinate and

[0030] wherein 1≤l≤L.

[0031] determining the lth second preset coordinate based on the lth first preset coordinate and the actual time difference τ and the actual wave arrival angle θ.

[0032] wherein c is the speed of light.

[0033] calculating the lth first preset coordinate based on the actual period T, the lth first preset coordinate obtaining a corresponding first speed component of the UAV in a direction of the first coordinate axis

[0034] and a corresponding second speed component of the UAV in a direction of the second coordinate axis

[0035] calculating a speed of the UAV corresponding to the first preset coordinate of the lth based on the first speed component and the second speed component

[0036] calculating a Doppler shift theoretical value corresponding to the first preset coordinate of the lth based on an actual center frequency f of the target signal, a speed v of the UAV l and the first speed component

[0037] Optionally, the UAV has a flight speed upper limit.

[0038] calculating the Doppler shift theoretical value corresponding to the first preset coordinate based on the speed of the UAV and the first speed component, comprising:

[0039] when the speed of the UAV is less than or equal to the flight speed upper limit, obtaining the first preset coordinate corresponding to the speed of the UAV;

[0040] calculating the Doppler shift theoretical value corresponding to the first preset coordinate based on the first preset coordinate;

[0041] when the speed of the UAV is greater than the flight speed upper limit, the Doppler shift theoretical value corresponding to the UAV is 0.

[0042] Optionally, obtaining the Doppler shift theoretical value table comprises:

[0043] obtaining the Doppler shift theoretical value corresponding to the first preset coordinate, the first preset coordinate corresponding to the speed of the UAV being less than or equal to the flight speed upper limit;

[0044] arranging the Doppler shift theoretical values of all the first preset coordinates into the Doppler shift theoretical value table based on a first step length of the first coordinate axis and a first quantity.

[0045] Optionally, the error measurement calculation method comprises mean square error calculation and root mean square error.

[0046] According to a second aspect of the present application, an embodiment of the present application provides a single station positioning system applied to a receiving base station, comprising: ​

[0047] an actual period acquisition module, configured to acquire an actual period of a pilot signal sent by a UAV;

[0048] a target signal information acquisition module, configured to determine adjacent two target signals sent by the UAV in a target area based on the actual period of the pilot signal sent by the UAV, and acquire an actual center frequency of the target signals, an actual time difference of arrival of the two target signals at the receiving base station, an actual wave arrival angle, and an actual Doppler shift of the UAV;

[0049] a Doppler shift theoretical value table acquisition module, configured to input the actual range of the target area, the actual period of the pilot signal, the actual center frequency of the target signals, the actual time difference, and the actual wave arrival angle into a preset theoretical Doppler shift model to obtain a Doppler shift theoretical value table, the Doppler shift theoretical value table including different Doppler shift theoretical values corresponding to different distances from the UAV to the receiving base station;

[0050] an error metric calculation module, configured to perform error metric calculation processing on the actual Doppler shift and each Doppler shift theoretical value to obtain the Doppler shift theoretical value corresponding to the minimum error metric;

[0051] a positioning module, configured to determine the position of the UAV when sending the target signals based on the Doppler shift theoretical value corresponding to the minimum error metric.

[0052] Optionally, the receiving base station receives a first target signal and a second target signal in sequence, the first target signal and the second target signal being adjacent two target signals sent by the UAV;

[0053] The Doppler shift theoretical value table acquisition module includes:

[0054] a two-dimensional plane coordinate system establishment unit, configured to take a direct path of the first target signal as a first coordinate axis, take a position of the receiving base station as an origin, and establish a two-dimensional plane coordinate system according to a wave arrival direction of the first target signal and a wave arrival direction of the second target signal, a second coordinate axis being perpendicular to the first coordinate axis;

[0055] a coordinate axis segmentation unit, configured to acquire a first step length and a first number based on the first coordinate axis;

[0056] a first preset coordinate determination unit, configured to acquire a plurality of first preset coordinates corresponding to the UAV sending the first target signal based on the first step length and the first number of the first coordinate axis, the first preset coordinates being coordinates on the two-dimensional plane coordinate system;

[0057] A second preset coordinate determination unit is configured to determine a plurality of second preset coordinates corresponding to the second target signal sent by the UAV based on the plurality of first preset coordinates, a time difference variable and a wave angle variable of the time at which the receiving base station receives the first target signal and the second target signal, the second preset coordinates being coordinates on the two-dimensional plane coordinate system;

[0058] A Doppler shift theoretical value table obtaining unit is configured to establish a theoretical Doppler shift model based on a time difference variable of adjacent two target signals sent by the UAV, the plurality of first preset coordinates and the corresponding second preset coordinates, so that the Doppler shift theoretical value corresponding to each first preset coordinate can be calculated to obtain the Doppler shift theoretical value table.

[0059] Optionally, the Doppler shift theoretical value table obtaining unit comprises:

[0060] A period setting subunit is configured to obtain a period variable of the pilot signal sent by the UAV;

[0061] A velocity component calculation subunit is configured to obtain a corresponding first velocity component of the UAV in the direction of the first coordinate axis and a corresponding second velocity component of the UAV in the direction of the second coordinate axis based on the period variable, the first preset coordinates and the corresponding second preset coordinates.

[0062] A UAV velocity calculation subunit is configured to calculate the velocity of the UAV based on the first velocity component and the second velocity component.

[0063] A Doppler shift theoretical value calculation subunit is configured to calculate the Doppler shift theoretical value corresponding to the first preset coordinate based on the velocity of the UAV, the center frequency variable and the first velocity component.

[0064] According to a third aspect of the present application, an embodiment of the present application provides an electronic device comprising the single station positioning system according to any one of the second aspect of the present application.

[0065] Compared with the prior art, the technical scheme of the embodiment of the present application has the following beneficial effects:

[0066] In the single station positioning method, the system and the electronic device, the actual period of the pilot signal sent by the unmanned aerial vehicle is acquired, two adjacent target signals sent by the unmanned aerial vehicle in the target area are determined, and the target signal information and the actual Doppler shift of the unmanned aerial vehicle are acquired; the target signal information is introduced into a variable in a preset theoretical Doppler shift model, and a Doppler shift theoretical value table is obtained; the actual Doppler shift and each Doppler shift theoretical value are subjected to error measurement calculation processing, and the Doppler shift theoretical value corresponding to the minimum error measurement is obtained; and the position of the unmanned aerial vehicle when sending the target signal is determined based on the Doppler shift theoretical value corresponding to the minimum error measurement, so that the method provided by the application can guarantee the accuracy of single station positioning in a complex scene. BRIEF DESCRIPTION OF DRAWINGS

[0067] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0068] Fig. 1 is a flowchart of a single station positioning method according to an embodiment of the present application;

[0069] Fig. 2 is a system model diagram according to an embodiment of the present application;

[0070] Fig. 3 is a flowchart of a method for establishing a theoretical Doppler shift model according to an embodiment of the present application;

[0071] Fig. 4 is a schematic diagram of a two-dimensional plane coordinate system according to an embodiment of the present application;

[0072] Fig. 5 is a flowchart of calculating the Doppler shift theoretical value according to an embodiment of the present application;

[0073] Fig. 6 is a flowchart of obtaining a Doppler shift theoretical value table according to an embodiment of the present application;

[0074] Fig. 7 is a block diagram of a single station positioning system according to an embodiment of the present application;

[0075] Fig. 8 is a block diagram of a Doppler shift theoretical value table obtaining module according to an embodiment of the present application;

[0076] Fig. 9 is a block diagram of a Doppler shift theoretical value table obtaining unit according to an embodiment of the present application.

[0077] Explanation of reference signs: 10-receiving base station; 61-actual period acquisition module; 62-target signal information acquisition module; 63-Doppler shift theoretical value table acquisition module; 64-error metric calculation module; 65-positioning module; 631-two-dimensional plane coordinate system establishment unit; 632-coordinate axis segmentation unit; 633-first preset coordinate determination unit; 634-second preset coordinate determination unit; 635-Doppler shift theoretical value table acquisition unit; 6351-period setting subunit; 6352-velocity component calculation subunit; 6353-velocity calculation subunit of unmanned aerial vehicle; 6354-Doppler shift theoretical value calculation subunit. DETAILED DESCRIPTION

[0078] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0079] The terms "first", "second", "third", "fourth" and the like (if any) in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0080] The technical solutions of the present application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in some embodiments.

[0081] As described in the background, how to improve the positioning accuracy of a single station and be applicable to complex scenes has become a technical problem that needs to be solved in the industry, which will be described in detail below.

[0082] Single station positioning of unmanned aerial vehicles usually uses specific signal information from the target, combined with pre-known data or specific measurement methods to position the unmanned aerial vehicle. The commonly used single station positioning methods at present mainly include the following:

[0083] 1. Angle measurement:

[0084] By measuring the direction angle of the signal arriving at the receiving station, the bearing of the target can be determined. In practical applications, a device with a directional antenna (such as a direction-finding antenna) is usually used to measure the angle of arrival of the signal for rough positioning.

[0085] 2. Received signal strength measurement:

[0086] Since the strength of the signal will be affected in the propagation path during the transmission of the signal, the positioning of the signal can be based on the strength of the received signal. In the case of known signal propagation model (such as spatial path loss model), the received signal strength can be compared with the theoretical strength under the known model, and the distance to the target can be estimated. However, in practical applications, the method based on received signal strength measurement is greatly affected by environmental factors such as multipath effect, which reduces the positioning effect.

[0087] 3. Doppler shift measurement:

[0088] For a target in motion, the received signal will produce a Doppler shift effect. By measuring the frequency change caused by the relative speed of the target to the receiving station at a certain time, the speed information and movement trend of the target can be obtained, which can be used to track the movement trajectory of the target. However, in practical applications, Doppler effect can only measure the radial velocity of the target (the velocity component along the radar beam direction), and cannot directly obtain the lateral velocity of the target, so the positioning effect cannot be guaranteed.

[0089] 4. Time difference measurement:

[0090] Single station positioning based on time difference information measures the time difference between multiple reflections or multipath signals for positioning. This method requires the signal to propagate on multiple paths, and the change of the path is known.

[0091] It can be seen that the prior art cannot guarantee the accuracy of single station positioning in complex scenarios. Therefore, the present application provides a single station positioning method based on Doppler shift and time difference information. By receiving the adjacent two pilot signals sent by the unmanned aerial vehicle in the target area, the pilot signal information and the actual Doppler shift of the unmanned aerial vehicle are obtained. The pilot signal information is introduced into the variable of the preset theoretical Doppler shift model, and the Doppler shift theoretical value table is obtained. The actual Doppler shift and each Doppler shift theoretical value are calculated and processed by error measurement, and the Doppler shift theoretical value corresponding to the minimum error measurement is obtained. Based on the Doppler shift theoretical value corresponding to the minimum error measurement, the position of the unmanned aerial vehicle when sending the target signal is determined, thereby guaranteeing the accuracy of single station positioning in complex scenarios.

[0092] The embodiment of the present application provides a single station positioning method based on Doppler frequency shift and time difference information, which is applied to a receiving base station, please refer to figure 1, the single station positioning method comprises:

[0093] S1: obtaining the actual period of the pilot signal sent by the unmanned aerial vehicle;

[0094] S2: determining adjacent two target signals sent by the unmanned aerial vehicle in the target area based on the actual period of the pilot signal sent by the unmanned aerial vehicle, and obtaining the actual center frequency of the target signal, the actual time difference of the target signal arriving at the receiving base station, the actual wave arrival angle, and the actual Doppler frequency shift of the unmanned aerial vehicle;

[0095] S3: introducing the actual range of the target area, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference, and the actual wave arrival angle into a preset theoretical Doppler frequency shift model to obtain a Doppler frequency shift theoretical value table, wherein the Doppler frequency shift theoretical value table comprises different Doppler frequency shift theoretical values corresponding to different distances from the unmanned aerial vehicle to the receiving base station;

[0096] S4: performing error measurement calculation processing on the actual Doppler frequency shift and each Doppler frequency shift theoretical value to obtain the Doppler frequency shift theoretical value corresponding to the minimum error measurement;

[0097] S5: determining the position of the unmanned aerial vehicle when sending the target signal based on the Doppler frequency shift theoretical value corresponding to the minimum error measurement.

[0098] It can be seen that the present scheme fully utilizes the Doppler frequency shift and time difference information of the received signal, and searches for the position by establishing a coordinate system and traversing a certain distance. Compared with the existing single station positioning method and system, higher positioning accuracy can be obtained. And because the Doppler frequency shift and time difference information are used at the same time, the performance of the present scheme in various scenarios is more adaptable.

[0099] The method provided by the embodiment of the present application will be further described:

[0100] Because the signal sent by the unmanned aerial vehicle contains repeated pilot information, please refer to figure 1, step S1 is performed:

[0101] S1: obtaining the actual period of the pilot signal sent by the unmanned aerial vehicle.

[0102] In an embodiment, the method of step S1 comprises:

[0103] obtaining the signal sent by the unmanned aerial vehicle;

[0104] obtaining the pilot information and the actual period of the pilot signal from the signal sent by the unmanned aerial vehicle.

[0105] Since the pilot information is generally located at the front end of the target signal, and then based on the actual period T of the pilot signal, the time of the adjacent two target signals sent by the unmanned aerial vehicle can be known, of course, the present application does not limit the position of the pilot information, and those skilled in the art can also select a suitable target signal confirmation mode according to the needs.

[0106] In this case, in one embodiment, referring to FIG. 1 and FIG. 2, step S2 is performed,

[0107] S2: receiving the adjacent two target signals sent by the unmanned aerial vehicle in the target area, and obtaining the actual center frequency of the target signal, the actual time difference of the target signal arriving at the receiving base station, the actual wave arrival angle, and the actual Doppler shift of the unmanned aerial vehicle.

[0108] Specifically, the target signal s p (t) sent by the unmanned aerial vehicle at time t in the target area is received, and the target signal s p (t+T) sent by the unmanned aerial vehicle at time t+T is received, and the actual center frequency f c of the target signal, the actual time difference τ of the target signal arriving at the receiving base station, the actual wave arrival angle θ, and the actual Doppler shift f d ' of the unmanned aerial vehicle are obtained.

[0109] In one embodiment, the time difference of arrival can be obtained by cross-correlation algorithm on the pilot part of the received signal, or can be obtained by actual equipment. Since this technology is prior art, the present application will not be described in detail here.

[0110] As an example, the system model diagram of the receiving base station 10 receiving the two target signals can be as shown in FIG. 2, wherein the first position when the unmanned aerial vehicle sends the first target signal s p (t), the second position when the unmanned aerial vehicle sends the second target signal s p (t+T), the position of the receiving base station 10 and the actual wave arrival angle θ are output.

[0111] It should be understood that the target signal can include a pilot signal and a signal carrying information after the pilot.

[0112] Referring to FIG. 1, FIG. 3 to FIG. 6, step S3 is performed,

[0113] S3: introducing the actual range of the target area, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference, and the actual wave arrival angle into a preset theoretical Doppler shift model to obtain a Doppler shift theoretical value table, the Doppler shift theoretical value table including different Doppler shift theoretical values corresponding to different distances from the UAV to the receiving base station.

[0114] The establishment of the preset theoretical Doppler shift model is described as follows:

[0115] In a specific embodiment, the receiving base station receives a first target signal s p (t) and a second target signal s p (t+T) in sequence, the first target signal s p (t) and the second target signal s p (t+T) being adjacent target signals sent by the UAV; for the convenience of introducing actual values, the symbols of the variables used in the establishment of the theoretical Doppler shift model are the same as the symbols of the actual values.

[0116] In actual application, the receiving base station receives continuous signals, and the first target signal s p (t) and the second target signal s p (t+T) are adjacent target signals in the continuous signals.

[0117] In this case, please refer to FIG. 3, the method for establishing a theoretical Doppler shift model includes:

[0118] S311: taking a direct path of the first target signal as a first coordinate axis, taking a position of the receiving base station as an origin, and establishing a two-dimensional plane coordinate system according to a wave arrival direction of the first target signal and a wave arrival direction of the second target signal, a second coordinate axis being perpendicular to the first coordinate axis;

[0119] For example, the established two-dimensional plane coordinate system can be as shown in FIG. 4, in the example of FIG. 4, the first coordinate axis is the Y axis, the second coordinate axis is the X axis, a first coordinate P p of the UAV when sending the first target signal s t (t) is (0, d1), a second coordinate P p of the UAV when sending the second target signal s t+T (t+T) is (x t+T , y t+T ), a coordinate of the receiving base station is (0, 0), and an actual wave arrival angle is θ.

[0120] S312: obtaining a first step length and a first quantity based on the first coordinate axis;

[0121] Specifically, a first step length and a first number based on a first coordinate axis are obtained according to a range of the target area.

[0122] In a specific embodiment, the range of the target area is [d low ,d high ].

[0123] Then, the first number L is determined based on the first step length and the range of the target area, L=(d high -d low ) / d step +1

[0124] wherein d step is the first step length.

[0125] Taking a range radius of 5km of a base station receiving signal as an example, for a determined distance range [0, 5km], it can be divided into L=51 different distance values with a certain step length d step =100m.

[0126] S313: Obtain a plurality of first preset coordinates corresponding to the first target signal sent by the unmanned aerial vehicle based on the first step length and the first number of the first coordinate axis, wherein the first preset coordinates are coordinates on the two-dimensional plane coordinate system;

[0127] Specifically, the distance of the unmanned aerial vehicle from the base station at time t is wherein l is an integer and l is less than or equal to L.

[0128] S314: Determine a plurality of second preset coordinates corresponding to the second target signal sent by the unmanned aerial vehicle based on the plurality of first preset coordinates, a time difference variable and a wave angle variable of the receiving base station receiving the first target signal and the second target signal, wherein the second preset coordinates are coordinates on the two-dimensional plane coordinate system.

[0129] Specifically, step S314 includes:

[0130] According to the first preset coordinates and the time difference variable τ of the receiving base station receiving the first target signal and the second target signal, the distance difference cτ of the first coordinate and the second coordinate (x t+T , y t+T ) is determined, wherein c represents the speed of light.

[0131] According to the distance difference cτ, the distance of the second coordinate from the receiving base station is determined as

[0132] Based on the first preset coordinates a second preset coordinate corresponding to the second target signal sent by the UAV is determined based on a distance between the second coordinate and the receiving base station, and a wave arrival angle variable θ

[0133] S315: A theoretical Doppler shift model is established based on a time difference variable of adjacent two target signals sent by the UAV, a center frequency variable of the target signal, a plurality of the first preset coordinates, and the corresponding second preset coordinates, so that the theoretical value of the Doppler shift corresponding to each first preset coordinate can be calculated, and a table of theoretical values of the Doppler shift is obtained.

[0134] In a specific embodiment, referring to FIG. 5, the calculation of the theoretical value of the Doppler shift corresponding to the first preset coordinate in step S315 based on the time difference variable of adjacent two target signals sent by the UAV, the first preset coordinate, and the corresponding second preset coordinate includes:

[0135] S3151: Obtain a period variable of a pilot signal sent by the UAV;

[0136] S3152: Obtain a corresponding first speed component of the UAV in the direction of the first coordinate axis and a corresponding second speed component of the UAV in the direction of the second coordinate axis based on the period variable, the first preset coordinate, and the corresponding second preset coordinate, respectively;

[0137] Specifically, based on the period variable T, the first preset coordinate (0, d1l), and the corresponding second preset coordinate obtain a corresponding first speed component of the UAV in the direction of the first coordinate axis:

[0138] and a corresponding second speed component of the UAV in the direction of the second coordinate axis:

[0139] S3153: Calculate the speed of the UAV based on the first speed component and the second speed component;

[0140] Specifically, the speed of the UAV is

[0141] S3154: Calculate the theoretical value of the Doppler shift corresponding to the first preset coordinate based on the speed of the UAV, the center frequency variable, and the first speed component.

[0142] Specifically, the theoretical value of the Doppler shift corresponding to the first preset coordinate is

[0143] It can be seen that the embodiment of the application can obtain higher positioning accuracy by establishing a two-dimensional plane coordinate system and obtaining a Doppler frequency shift theoretical value table by traversing all assumed distances, and performing position search through the theoretical Doppler frequency shift model. Moreover, due to the simultaneous use of Doppler frequency shift and time difference information, the performance of the scheme can be more adaptable in various scenarios.

[0144] The calculation process of importing the actual range of the target area, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference, and the actual wave arrival angle into a preset theoretical Doppler frequency shift model in step S3 will be described below:

[0145] In an embodiment, the first coordinate axis is the Y axis, and the second coordinate axis is the X axis.

[0146] In this case, the actual range of the target area, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference, and the actual wave arrival angle are imported into a preset theoretical Doppler frequency shift model to obtain the Doppler frequency shift theoretical value corresponding to the first preset coordinate, which includes:

[0147] Based on the theoretical Doppler frequency shift model, the lth first preset coordinate is determined and

[0148] wherein, 1≤l≤L;

[0149] Based on the lth first preset coordinate the actual time difference τ and the actual wave arrival angle θ, the lth second preset coordinate is determined and

[0150] wherein, c is the speed of light;

[0151] Based on the actual period T, the lth first preset coordinate and the corresponding second preset coordinate the corresponding first speed component of the UAV in the direction of the first coordinate axis is obtained

[0152] and the corresponding second speed component of the UAV in the direction of the second coordinate axis is obtained

[0153] Based on the first speed component and the second speed component, the speed of the UAV corresponding to the lth first preset coordinate is calculated

[0154] based on an actual center frequency f of the target signal, a speed v of the UAV l and the first speed component calculate the theoretical Doppler shift value corresponding to the first preset coordinate

[0155] In a preferred embodiment, the UAV has a flight speed upper limit;

[0156] In this case, based on the speed of the UAV and the first speed component, the calculation of the theoretical Doppler shift value corresponding to the first preset coordinate comprises:

[0157] When the speed of the UAV is less than or equal to the flight speed upper limit, obtain the first preset coordinate corresponding to the speed of the UAV;

[0158] Based on the first preset coordinate, calculate the theoretical Doppler shift value corresponding to the first preset coordinate;

[0159] When the speed of the UAV is greater than the flight speed upper limit, the theoretical Doppler shift value corresponding to the UAV is 0.

[0160] In this case, according to v y,l The theoretical Doppler shift is calculated as:

[0161] Where c represents the speed of light, f c is the center frequency of the signal, v max is the flight speed upper limit of the UAV.

[0162] In an embodiment, referring to FIG. 6, the method of obtaining the Doppler shift theoretical value table in step S3 comprises:

[0163] S33: Obtain the Doppler shift theoretical value corresponding to the first type of preset coordinate, which is the first preset coordinate corresponding to the speed of the UAV being less than or equal to the flight speed upper limit;

[0164] S34: Based on the first step length and the first number of the first coordinate axis, arrange all the Doppler shift theoretical values of the first type of preset coordinate into the Doppler shift theoretical value table.

[0165] Referring to FIG. 1, step S4 is performed:

[0166] S4: Perform error measurement calculation processing on the actual Doppler shift and each Doppler shift theoretical value to obtain the Doppler shift theoretical value corresponding to the minimum error measurement.

[0167] Specifically, the actual Doppler shift result is used to traverse the Doppler shift theoretical value table, the detection value is compared with the theoretical value, and the Doppler shift theoretical value corresponding to the minimum error metric is obtained.

[0168] In an implementation mode, the error metric is calculated as a mean square error calculation, in which case the obtained Doppler shift detection value f' d The error metric of the first Doppler shift theoretical value The error metric of the first Doppler shift theoretical value

[0169] In other implementation modes, the error metric calculation can also be a root mean square error, and the application is not limited thereto, and other error sensitivity higher calculation modes can also be used.

[0170] In summary, the actual period of the pilot signal sent by the unmanned aerial vehicle is obtained, the adjacent two target signals sent by the unmanned aerial vehicle in the target area are determined, the target signal information and the actual Doppler shift of the unmanned aerial vehicle are obtained, the target signal information is introduced into the variable in the preset theoretical Doppler shift model, and the Doppler shift theoretical value table is obtained. The actual Doppler shift is calculated and processed by error metric for each Doppler shift theoretical value, and the Doppler shift theoretical value corresponding to the minimum error metric is obtained. Based on the Doppler shift theoretical value corresponding to the minimum error metric, the position of the unmanned aerial vehicle when sending the target signal is determined, so that the method provided by the application can guarantee the accuracy of single station positioning in a complex scene.

[0171] In addition, referring to FIG. 7, the embodiment of the application further provides a single station positioning system applied to a receiving base station, comprising:

[0172] The actual period acquisition module 61 is used to obtain the actual period of the pilot signal sent by the unmanned aerial vehicle.

[0173] The target signal information acquisition module 62 is used to determine the adjacent two target signals sent by the unmanned aerial vehicle in the target area based on the actual period of the pilot signal sent by the unmanned aerial vehicle, and obtain the actual center frequency of the target signal, the actual time difference of the arrival of the two target signals at the receiving base station, the actual wave arrival angle, and the actual Doppler shift of the unmanned aerial vehicle.

[0174] The Doppler shift theoretical value table acquisition module 63 is used to introduce the actual range of the target area, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference, and the actual wave arrival angle into a preset theoretical Doppler shift model to obtain a Doppler shift theoretical value table, wherein the Doppler shift theoretical value table comprises different Doppler shift theoretical values corresponding to different distances from the unmanned aerial vehicle to the receiving base station.

[0175] an error metric calculation module 64, configured to perform error metric calculation on the actual Doppler shift and each of the Doppler shift theoretical values, to obtain the Doppler shift theoretical value corresponding to the minimum error metric;

[0176] a positioning module 65, configured to determine the position of the UAV when sending the target signal based on the Doppler shift theoretical value corresponding to the minimum error metric.

[0177] In one embodiment, the receiving base station receives the first target signal and the second target signal in sequence, the first target signal and the second target signal being adjacent target signals sent by the UAV;

[0178] In this case, referring to FIG. 8, the Doppler shift theoretical value table obtaining module 63 comprises:

[0179] a two-dimensional plane coordinate system establishing unit 631, configured to take the direct path of the first target signal as a first coordinate axis, take the position of the receiving base station as an origin, and establish a two-dimensional plane coordinate system according to the direction of arrival of the first target signal and the direction of arrival of the second target signal, a second coordinate axis being perpendicular to the first coordinate axis;

[0180] a coordinate axis dividing unit 632, configured to obtain a first step length and a first number based on the first coordinate axis;

[0181] a first preset coordinate determining unit 633, configured to obtain a plurality of first preset coordinates corresponding to the UAV sending the first target signal based on the first step length and the first number of the first coordinate axis, the first preset coordinates being coordinates on the two-dimensional plane coordinate system;

[0182] a second preset coordinate determining unit 634, configured to determine a plurality of second preset coordinates corresponding to the UAV sending the second target signal based on the plurality of first preset coordinates, a time difference variable and an angle of arrival variable of the receiving base station receiving the first target signal and the second target signal, the second preset coordinates being coordinates on the two-dimensional plane coordinate system;

[0183] a Doppler shift theoretical value table obtaining unit 635, configured to establish a theoretical Doppler shift model based on the time difference variable of adjacent target signals sent by the UAV, the plurality of first preset coordinates and the corresponding second preset coordinates, so that the Doppler shift theoretical value corresponding to each of the first preset coordinates can be calculated, to obtain the Doppler shift theoretical value table.

[0184] It can be seen that the embodiment of the present application can obtain a Doppler frequency shift theoretical value table by establishing a two-dimensional plane coordinate system and traversing all the assumed distances, and can obtain higher positioning accuracy by searching for a position through the theoretical Doppler frequency shift model. Moreover, since the Doppler frequency shift and the time difference information are used simultaneously, the performance of the present application can be more adaptable in various scenarios.

[0185] In an embodiment, referring to FIG. 9, the Doppler frequency shift theoretical value table obtaining unit 635 comprises:

[0186] A period setting sub-unit 6351 is configured to obtain a period variable of a pilot signal sent by the UAV;

[0187] A velocity component calculation sub-unit 6352 is configured to obtain a corresponding first velocity component of the UAV in the direction of the first coordinate axis and a corresponding second velocity component of the UAV in the direction of the second coordinate axis based on the period variable, the first preset coordinate and the corresponding second preset coordinate, respectively;

[0188] A UAV velocity calculation sub-unit 6353 is configured to calculate the velocity of the UAV based on the first velocity component and the second velocity component;

[0189] A Doppler frequency shift theoretical value calculation sub-unit 6354 is configured to calculate the Doppler frequency shift theoretical value corresponding to the first preset coordinate based on the velocity of the UAV, the center frequency variable and the first velocity component.

[0190] In addition, the embodiment of the present application further provides an electronic device comprising the single-station positioning system described above. As an example, the electronic device can be an antenna base station or the like, and the present application is not limited in this regard. Of course, the electronic device can also be other electronic devices that need to be positioned by a single station.

[0191] To sum up, the embodiment of the present application obtains the actual period of the pilot signal sent by the UAV, determines the adjacent two target signals sent by the UAV in the target region, and obtains the target signal information and the actual Doppler frequency shift of the UAV. The target signal information is introduced into the variable in the preset theoretical Doppler frequency shift model, and the Doppler frequency shift theoretical value table is obtained. The actual Doppler frequency shift and each Doppler frequency shift theoretical value are calculated and processed by error measurement, and the Doppler frequency shift theoretical value corresponding to the minimum error measurement is obtained. Based on the Doppler frequency shift theoretical value corresponding to the minimum error measurement, the position of the UAV when sending the target signal is determined, so that the method provided by the present application can guarantee the accuracy of single-station positioning in complex scenarios.

[0192] Although the present application has been disclosed with reference to the above embodiments, the application is not limited to the above embodiments. It will be apparent to those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the application. The scope of the application should be limited only by the appended claims.

Claims

1. A single station positioning method based on Doppler shift and time difference information, characterized in that, The single station positioning method is applied to a receiving base station and comprises the following steps: acquiring an actual period of a pilot signal sent by a UAV; based on the actual period of the pilot signal sent by the UAV, determining adjacent two target signals sent by the UAV in a target area, and acquiring an actual center frequency of the target signals, an actual time difference of arrival of the target signals at the receiving base station, an actual wave arrival angle, and an actual Doppler shift of the UAV; introducing the actual range of the target area, the actual period of the pilot signal, the actual center frequency of the target signals, the actual time difference, and the actual wave arrival angle into a preset theoretical Doppler shift model to obtain a Doppler shift theoretical value table, wherein the Doppler shift theoretical value table comprises different Doppler shift theoretical values corresponding to different distances from the UAV to the receiving base station; performing error measurement calculation processing on the actual Doppler shift and each Doppler shift theoretical value to obtain the Doppler shift theoretical value corresponding to the minimum error measurement; based on the Doppler shift theoretical value corresponding to the minimum error measurement, determining the position of the UAV when sending the target signals.

2. The mono-stationary positioning method of claim 1, characterized in that, The receiving base station sequentially receives a first target signal and a second target signal, and the first target signal and the second target signal are adjacent two target signals sent by the UAV; The method for establishing a theoretical Doppler shift model comprises the following steps: taking a direct path of the first target signal as a first coordinate axis, taking a position of the receiving base station as an origin, and establishing a two-dimensional plane coordinate system according to a wave arrival direction of the first target signal and a wave arrival direction of the second target signal, wherein a second coordinate axis is perpendicular to the first coordinate axis; acquiring a first step length and a first number based on the first coordinate axis; based on the first step length and the first number based on the first coordinate axis, obtaining a plurality of first preset coordinates corresponding to the UAV when sending the first target signal, wherein the first preset coordinates are coordinates on the two-dimensional plane coordinate system; based on the plurality of first preset coordinates, a time difference variable of the receiving base station receiving the first target signal and the second target signal, and a wave arrival angle variable, determining a plurality of second preset coordinates corresponding to the UAV when sending the second target signal, wherein the second preset coordinates are coordinates on the two-dimensional plane coordinate system; based on the time difference variable of the adjacent two target signals sent by the UAV, the center frequency variable of the target signals, the plurality of first preset coordinates, and the corresponding second preset coordinates, establishing a theoretical Doppler shift model, so that the Doppler shift theoretical value corresponding to each first preset coordinate can be calculated to obtain the Doppler shift theoretical value table.

3. The mono-pit positioning method of claim 2, wherein, based on the time difference variable of the adjacent two target signals sent by the UAV, the first preset coordinates, and the corresponding second preset coordinates, calculating the Doppler shift theoretical value corresponding to the first preset coordinates, comprising: acquiring a period variable of a pilot signal sent by a UAV; obtaining a corresponding first speed component of the unmanned aerial vehicle in a direction of the first coordinate axis and a corresponding second speed component of the unmanned aerial vehicle in a direction of the second coordinate axis based on the period variable, the first preset coordinate, and the corresponding second preset coordinate; calculating the speed of the unmanned aerial vehicle based on the first speed component and the second speed component; calculating the Doppler shift theoretical value corresponding to the first preset coordinate based on the speed of the unmanned aerial vehicle, the center frequency variable, and the first speed component.

4. The mono-stationary positioning method of claim 3, wherein The target region ranges from [d low ,d high ]; determining the first number based on the first step and the range of the target region L = (d high - d low ) / d step + 1 wherein d step is the first step size.

5. The mono-pit positioning method of claim 4, wherein, the first coordinate axis is the Y axis, and the second coordinate system is the X axis; then the actual range of the target region, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference, and the actual wave arrival angle are introduced into a preset theoretical Doppler shift model to obtain the Doppler shift theoretical value corresponding to the first preset coordinate, including: determining the lth first preset coordinate based on the theoretical Doppler shift model and wherein 1≤l≤L; based on the first preset coordinate The actual time difference τ, the actual wave arrival angle θ, determine the lth second preset coordinate and wherein c is the speed of light; based on the actual period T, the first preset coordinate of the lth first preset coordinate and the corresponding second preset coordinate obtaining a corresponding first speed component of the drone in a direction of the first coordinate axis and a corresponding second speed component of the drone in the direction of the second coordinate axis calculating a speed of the unmanned aerial vehicle corresponding to the first preset coordinate pair based on the first speed component and the second speed component based on an actual center frequency f of the target signal, a speed v of the drone l and the first speed component calculating the Doppler frequency shift theoretical value corresponding to the lth first preset coordinate 6. The mono-stationary positioning method of claim 3, wherein the unmanned aerial vehicle has a flight speed upper limit; calculating the Doppler shift theoretical value corresponding to the first preset coordinate based on the speed of the unmanned aerial vehicle and the first speed component, including: when the speed of the unmanned aerial vehicle is less than or equal to the flight speed upper limit, obtaining the first preset coordinate corresponding to the speed of the unmanned aerial vehicle; calculating the Doppler shift theoretical value corresponding to the first preset coordinate based on the first preset coordinate; when the speed of the unmanned aerial vehicle is greater than the flight speed upper limit, the Doppler shift theoretical value corresponding to the unmanned aerial vehicle is 0.

7. The mono-stationary positioning method of claim 6, characterized in that, obtaining the Doppler shift theoretical value table, including: obtaining the Doppler shift theoretical value corresponding to the first preset coordinate, which is the first preset coordinate corresponding to the speed of the unmanned aerial vehicle being less than or equal to the flight speed upper limit; arranging the Doppler shift theoretical values of all the first preset coordinates into the Doppler shift theoretical value table based on the first step and the first number of the first coordinate axis.

8. The mono-stationary positioning method of claim 1, wherein, The error metric calculation method includes mean square error calculation and root mean square error.

9. A single station positioning system, characterized by applied to a receiving base station, including: an actual period acquisition module configured to acquire an actual period of a pilot signal transmitted by an unmanned aerial vehicle; a target signal information acquisition module configured to determine adjacent two target signals transmitted by the unmanned aerial vehicle in a target region based on the actual period of the pilot signal transmitted by the unmanned aerial vehicle, and acquire an actual center frequency of the target signal, an actual time difference between the arrival of the two target signals at the receiving base station, an actual wave arrival angle, and an actual Doppler shift of the unmanned aerial vehicle; a Doppler shift theoretical value table acquisition module configured to introduce the actual range of the target region, the actual period of the pilot signal, the actual center frequency of the target signal, the actual time difference, and the actual wave arrival angle into a preset theoretical Doppler shift model to obtain a Doppler shift theoretical value table, the Doppler shift theoretical value table including different Doppler shift theoretical values corresponding to different distances from the unmanned aerial vehicle to the receiving base station. an error metric calculation module, configured to perform error metric calculation on the actual Doppler shift and each of the Doppler shift theoretical values, and obtain the Doppler shift theoretical value corresponding to the minimum error metric; a positioning module, configured to determine the position of the UAV when sending the target signal based on the Doppler shift theoretical value corresponding to the minimum error metric.

10. A monostatic positioning system as claimed in claim 9, characterized in that The receiving base station sequentially receives the first target signal and the second target signal, and the first target signal and the second target signal are adjacent target signals sent by the UAV. The Doppler shift theoretical value table obtaining module comprises: a two-dimensional plane coordinate system establishing unit, configured to take the direct path of the first target signal as a first coordinate axis, take the position of the receiving base station as an origin, and establish a two-dimensional plane coordinate system according to the direction of arrival of the first target signal and the direction of arrival of the second target signal, and a second coordinate axis is perpendicular to the first coordinate axis; a coordinate axis segmentation unit, configured to obtain a first step length and a first number based on the first coordinate axis; a first preset coordinate determining unit, configured to obtain a plurality of first preset coordinates corresponding to the UAV when sending the first target signal based on the first step length and the first number of the first coordinate axis, and the first preset coordinates are coordinates on the two-dimensional plane coordinate system; a second preset coordinate determining unit, configured to determine a plurality of second preset coordinates corresponding to the UAV when sending the second target signal based on the plurality of first preset coordinates, a time difference variable of the receiving base station receiving the first target signal and the second target signal, and an angle of arrival variable, and the second preset coordinates are coordinates on the two-dimensional plane coordinate system; a Doppler shift theoretical value table obtaining unit, configured to establish a theoretical Doppler shift model based on the time difference variable of the adjacent target signals sent by the UAV, the plurality of first preset coordinates, and the corresponding second preset coordinates, so that the Doppler shift theoretical value corresponding to each first preset coordinate can be calculated, and the Doppler shift theoretical value table is obtained.

11. The monostatic positioning system of claim 10, wherein, The Doppler shift theoretical value table obtaining unit comprises: a period setting subunit, configured to obtain a period variable of the pilot signal sent by the UAV; a velocity component calculation subunit, configured to obtain a corresponding first velocity component of the UAV in the direction of the first coordinate axis and a corresponding second velocity component of the UAV in the direction of the second coordinate axis based on the period variable, the first preset coordinates, and the corresponding second preset coordinates; a UAV velocity calculation subunit, configured to calculate the velocity of the UAV based on the first velocity component and the second velocity component; a Doppler shift theoretical value calculation subunit, configured to calculate the Doppler shift theoretical value corresponding to the first preset coordinates based on the velocity of the UAV, the center frequency variable, and the first velocity component.

12. An electronic device, comprising: The single-station positioning system comprises any one of claims 9-11.

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