Single-station positioning method, system and electronic equipment based on Doppler frequency shift and time difference information

Abstract

The present invention provides a single-station positioning method, system and electronic equipment based on Doppler frequency shift and time difference information. By acquiring the actual period of a pilot signal sent by a drone, two adjacent target signals sent by a drone in a target area are determined, and target signal information and the actual Doppler frequency shift of the drone are obtained; the target signal information is introduced into a variable in a preset theoretical Doppler frequency shift model to obtain a Doppler frequency shift theoretical value table; the actual Doppler frequency shift and each Doppler frequency shift theoretical value are subjected to error metric calculation processing to obtain a Doppler frequency shift theoretical value corresponding to a minimum error metric; based on the Doppler frequency shift theoretical value corresponding to the minimum error metric, the position of the drone when sending the target signal is determined, so that the method provided by the present invention can ensure the accuracy of single-station positioning in complex scenes.

Description

Technical Field

[0001] The present invention relates to the field of single-station positioning, and in particular to a single-station positioning method, system and electronic equipment based on Doppler frequency shift and time difference information. Background Art

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

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

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

[0005] The present invention provides a single-station positioning method, system and electronic equipment based on Doppler frequency shift and time difference information, which solves the technical problem of how to improve the positioning accuracy of a single station and can be applied to complex scenes.

[0006] According to a first aspect of the present invention, an embodiment of the present invention provides a single-station positioning method based on Doppler frequency shift and time difference information, which is applied to a receiving base station. The single-station positioning method includes:

[0007] Get the actual period of the pilot signal sent by the drone;

[0008] Based on the actual period of the pilot signal sent by the drone, determine two adjacent target signals sent by the drone in the target area, and obtain the actual center frequency of the target signal, the actual time difference between the two target signals arriving at the receiving base station, the actual incoming wave angle, and the actual Doppler frequency shift of the drone;

[0009] 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 incoming wave angle are introduced 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 includes different Doppler frequency shift theoretical values ​​corresponding to different distances from the UAV to the receiving base station;

[0010] Performing error metric calculation processing on the actual Doppler frequency shift and each of the Doppler frequency shift theoretical values ​​to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric;

[0011] Based on the Doppler frequency shift theoretical value corresponding to the minimum error metric, the position of the UAV when sending the target signal is determined.

[0012] Optionally, the receiving base station receives a first target signal and a second target signal in sequence, where the first target signal and the second target signal are two adjacent target signals sent by the drone;

[0013] The method of establishing a theoretical Doppler frequency shift model includes:

[0014] Taking the direct path of the first target signal as the first coordinate axis, taking the position of the receiving base station as the origin, and establishing a two-dimensional plane coordinate system according to the wave direction of the first target signal and the wave direction of the second target signal, the second coordinate axis is perpendicular to the first coordinate axis;

[0015] Get the first step length and the first quantity based on the first coordinate axis;

[0016] Based on the first step length and the first quantity of the first coordinate axis, a plurality of first preset coordinates corresponding to when the drone sends the first target signal are obtained, where the first preset coordinates are coordinates on the two-dimensional plane coordinate system;

[0017] Based on the plurality of first preset coordinates, the time difference variable of the receiving base station receiving the first target signal and the second target signal, and the wave angle variable, determine a plurality of second preset coordinates corresponding to when the drone sends the second target signal, where the second preset coordinates are coordinates on the two-dimensional plane coordinate system;

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

[0019] Optionally, calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinate based on the time difference variable of two adjacent target signals sent by the drone, the first preset coordinate and the corresponding second preset coordinate includes:

[0020] Get the periodic variable of the pilot signal sent by the drone;

[0021] Based on the periodic variable, the first preset coordinate and the corresponding second preset coordinate, respectively obtain a corresponding first velocity component of the drone in the direction of the first coordinate axis and a corresponding second velocity component of the drone in the direction of the second coordinate axis;

[0022] Calculating the speed of the drone based on the first speed component and the second speed component;

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

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

[0025] Based on the first step length and the range of the target area, the first quantity is determined

[0026] L=(d high -d low ) / d step +1

[0027] Among them, d step is the first step length.

[0028] Optionally, the first coordinate axis is the Y axis, and the second coordinate axis is the X axis;

[0029] Then, 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 incoming wave angle are introduced into a preset theoretical Doppler shift model to obtain the Doppler shift theoretical value corresponding to the first preset coordinate, including:

[0030] Based on the theoretical Doppler frequency shift model, determine the lth first preset coordinate and

[0031]

[0032] Among them, 1≤l≤L;

[0033] Based on the lth first preset coordinate The actual time difference τ and the actual incoming wave angle θ determine the lth second preset coordinate and

[0034]

[0035] Where c is the speed of light;

[0036] Based on the actual period T, the lth first preset coordinate and the corresponding second preset coordinates Obtain the first velocity component corresponding to the UAV in the direction of the first coordinate axis respectively

[0037]

[0038] and the corresponding second velocity component of the drone in the direction of the second coordinate axis

[0039]

[0040] Based on the first velocity component and the second velocity component, the velocity of the drone corresponding to the first preset coordinate is calculated.

[0041]

[0042] Based on the actual center frequency f of the target signal and the speed v of the UAV l and the first velocity component Calculate the theoretical value of the Doppler frequency shift corresponding to the first preset coordinate

[0043]

[0044] Optionally, the drone has an upper limit on flight speed;

[0045] Calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinate based on the speed of the drone and the first speed component includes:

[0046] 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;

[0047] Based on the first preset coordinates, calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinates;

[0048] When the speed of the UAV is greater than the flight speed upper limit, the Doppler frequency shift theoretical value corresponding to the UAV is 0.

[0049] Optionally, obtaining the Doppler frequency shift theoretical value table includes:

[0050] Obtaining the Doppler frequency shift theoretical value corresponding to the first type of preset coordinates, where the first type of preset coordinates are the first preset coordinates corresponding to the speed of the UAV being less than or equal to the upper limit of the flight speed;

[0051] Based on the first step length and the first number of the first coordinate axis, the Doppler frequency shift theoretical values ​​of all the first-type preset coordinates are arranged into the Doppler frequency shift theoretical value table.

[0052] Optionally, the error metric calculation method includes mean square error calculation and root mean square error.

[0053] According to a second aspect of the present invention, an embodiment of the present invention provides a single-station positioning system, applied to a receiving base station, including:

[0054] The actual period acquisition module is used to obtain the actual period of the pilot signal sent by the UAV;

[0055] The target signal information acquisition module determines two adjacent target signals sent by the drone in the target area based on the actual period of the pilot signal sent by the drone, and obtains the actual center frequency of the target signal, the actual time difference between the two target signals arriving at the receiving base station, the actual wave angle, and the actual Doppler frequency shift of the drone;

[0056] A Doppler frequency shift theoretical value table acquisition module is used to import 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 incoming wave 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 includes different Doppler frequency shift theoretical values ​​corresponding to different distances from the UAV to the receiving base station;

[0057] An error metric calculation module is used to perform error metric calculation processing on the actual Doppler frequency shift and each of the Doppler frequency shift theoretical values ​​to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric;

[0058] The positioning module is used to determine the position of the UAV when sending the target signal based on the Doppler frequency shift theoretical value corresponding to the minimum error metric.

[0059] Optionally, the receiving base station receives a first target signal and a second target signal in sequence, where the first target signal and the second target signal are two adjacent target signals sent by the drone;

[0060] The Doppler frequency shift theoretical value table acquisition module includes:

[0061] a two-dimensional plane coordinate system establishing unit, configured to establish a two-dimensional plane coordinate system with the direct path of the first target signal as the first coordinate axis, the position of the receiving base station as the origin, and according to the wave direction of the first target signal and the wave direction of the second target signal, wherein the second coordinate axis is perpendicular to the first coordinate axis;

[0062] A coordinate axis segmentation unit, used for obtaining a first step length and a first quantity based on a first coordinate axis;

[0063] A first preset coordinate determining unit, configured to obtain, based on the first step length and the first quantity of the first coordinate axis, a plurality of first preset coordinates corresponding to when the drone sends the first target signal, wherein the first preset coordinates are coordinates on the two-dimensional plane coordinate system;

[0064] A second preset coordinate determination unit, configured to determine a plurality of second preset coordinates corresponding to when the drone sends the second target signal based on the plurality of first preset coordinates, a time difference variable for receiving the first target signal and the second target signal by the receiving base station, and an incoming wave angle variable, wherein the second preset coordinates are coordinates on the two-dimensional plane coordinate system;

[0065] The Doppler frequency shift theoretical value table obtaining unit is used to establish a theoretical Doppler frequency shift model based on the time difference variable of two adjacent target signals sent by the UAV, multiple first preset coordinates and corresponding second preset coordinates, so that it can calculate the Doppler frequency shift theoretical value corresponding to each of the first preset coordinates to obtain the Doppler frequency shift theoretical value table.

[0066] Optionally, the Doppler frequency shift theoretical value table obtaining unit includes:

[0067] The period setting subunit is used to obtain the period variable of the pilot signal sent by the UAV;

[0068] a velocity component calculation subunit, configured to obtain, based on the periodic variable, the first preset coordinate, and the corresponding second preset coordinate, 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;

[0069] a speed calculation subunit of the drone, configured to calculate the speed of the drone based on the first speed component and the second speed component;

[0070] The Doppler frequency shift theoretical value calculation subunit is used to calculate the Doppler frequency shift theoretical value corresponding to the first preset coordinate based on the speed of the drone, the center frequency variable and the first speed component.

[0071] According to a third aspect of the present invention, an embodiment of the present invention provides an electronic device, comprising a single-station positioning system as described in any one of the second aspects of the present invention.

[0072] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0073] In the single-station positioning method, system and electronic device of the technical solution of the present invention, by obtaining the actual period of the pilot signal sent by the drone, two adjacent target signals sent by the drone in the target area are determined, and the target signal information and the actual Doppler frequency shift of the drone are obtained; the target signal information is imported into the variables in the preset theoretical Doppler frequency shift model to obtain a Doppler frequency shift theoretical value table; the actual Doppler frequency shift and each Doppler frequency shift theoretical value are subjected to error metric calculation processing to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric; based on the Doppler frequency shift theoretical value corresponding to the minimum error metric, the position of the drone when sending the target signal is determined, so that the method provided by the present invention can ensure the accuracy of single-station positioning in complex scenes. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In order to more clearly illustrate the embodiments of the present invention 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0075] Figure 1 It is a flowchart of a single-station positioning method provided by an embodiment of the present invention;

[0076] Figure 2 is a system model diagram provided by an embodiment of the present invention;

[0077] Figure 3 It is a flow chart of a method for establishing a theoretical Doppler frequency shift model provided by an embodiment of the present invention;

[0078] Figure 4 is a schematic diagram of a two-dimensional plane coordinate system provided by an embodiment of the present invention;

[0079] Figure 5 is a schematic diagram of a flow chart of calculating the theoretical value of Doppler frequency shift provided by an embodiment of the present invention;

[0080] Figure 6 It is a schematic diagram of a flow chart of obtaining a Doppler frequency shift theoretical value table provided by an embodiment of the present invention;

[0081] Figure 7 is a block diagram of a single-station positioning system provided by an embodiment of the present invention;

[0082] Figure 8 It is a block diagram of a module for obtaining a Doppler frequency shift theoretical value table provided by an embodiment of the present invention;

[0083] Fig. 9It is a block diagram of a Doppler frequency shift theoretical value table obtaining unit provided in one embodiment of the present invention.

[0084] Description of reference numerals:

[0085] 10-receiving base station;

[0086] 61-actual cycle acquisition module;

[0087] 62-target signal information acquisition module;

[0088] 63-Doppler frequency shift theoretical value table acquisition module;

[0089] 64- Error metric calculation module;

[0090] 65- positioning module;

[0091] 631-two-dimensional plane coordinate system establishment unit;

[0092] 632-coordinate axis division unit;

[0093] 633-first preset coordinate determining unit;

[0094] 634-second preset coordinate determining unit;

[0095] 635-Doppler frequency shift theoretical value table obtaining unit;

[0096] 6351-cycle setting subunit;

[0097] 6352-Velocity component calculation subunit;

[0098] 6353-UAV speed calculation subunit;

[0099] 6354-Doppler frequency shift theoretical value calculation subunit. DETAILED DESCRIPTION

[0100] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0101] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. 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 necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0102] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0103] As described in the background technology, how to improve the positioning accuracy of a single station and apply it to complex scenarios has become a technical problem that urgently needs to be solved in the industry, which will be described in detail below.

[0104] Single-station positioning of drones usually uses specific signal information from the target, combined with pre-known data or specific measurement methods to locate the drone. Currently, the common single-station positioning methods are mainly the following:

[0105] 1. Angle measurement:

[0106] By measuring the direction angle of the signal arriving at the receiving station, the direction of the target can be determined. In practical applications, devices with directional antennas (such as direction-finding antennas) are usually used to measure the angle of arrival of the signal for rough positioning.

[0107] 2. Received signal strength measurement:

[0108] Since the signal strength will be affected in the propagation path during the signal transmission process, the signal can be located based on the strength of the received signal. In the case of a known signal propagation model (such as a spatial path loss model), the received signal strength can be compared with the theoretical strength under the known model to estimate the distance to the target. However, in practical applications, the method based on the received signal strength measurement is greatly affected by environmental factors such as the multipath effect, which reduces the positioning effect.

[0109] 3. Doppler shift measurement:

[0110] For moving targets, the received signal will produce a Doppler frequency shift effect. The target's speed information and movement trend can be obtained through the frequency change caused by the change in the relative speed of the target to the receiving station in a certain period of time, which can be used to track the target's movement trajectory. However, in practical applications, the Doppler effect can only measure the radial velocity of the target (the velocity component along the direction of the radar beam), but cannot directly obtain the target's lateral velocity, and its positioning effect cannot be guaranteed.

[0111] 4. Time difference measurement:

[0112] Single-station positioning based on time difference information performs positioning by measuring the time difference between multiple reflected or multipath signals. This method requires that the signal propagates on multiple paths and the changes in the paths are known.

[0113] It can be seen that the existing technology is difficult to ensure the accuracy of single-station positioning in complex scenarios. In view of this, the present invention provides a single-station positioning method based on Doppler frequency shift and time difference information, which receives two adjacent pilot signals sent by a drone in the target area, and obtains the pilot signal information and the actual Doppler frequency shift of the drone; the pilot signal information is imported into the variables in the preset theoretical Doppler frequency shift model to obtain a Doppler frequency shift theoretical value table; the actual Doppler frequency shift and each Doppler frequency shift theoretical value are subjected to error metric calculation processing to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric; based on the Doppler frequency shift theoretical value corresponding to the minimum error metric, the position of the drone when sending the target signal is determined, thereby ensuring the accuracy of single-station positioning in complex scenarios.

[0114] The embodiment of the present invention provides a single-station positioning method based on Doppler frequency shift and time difference information, which is applied to a receiving base station. Figure 1 , the single-station positioning method includes:

[0115] S1: Get the actual period of the pilot signal sent by the drone;

[0116] S2: Based on the actual period of the pilot signal sent by the drone, determine two adjacent target signals sent by the drone in the target area, and obtain the actual center frequency of the target signal, the actual time difference between the two target signals arriving at the receiving base station, the actual wave angle, and the actual Doppler frequency shift of the drone;

[0117] S3: 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 incoming wave 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 includes different Doppler frequency shift theoretical values ​​corresponding to different distances from the UAV to the receiving base station;

[0118] S4: performing error metric calculation processing on the actual Doppler frequency shift and each of the Doppler frequency shift theoretical values ​​to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric;

[0119] S5: Based on the Doppler frequency shift theoretical value corresponding to the minimum error metric, determine the position of the UAV when it sends the target signal.

[0120] It can be seen that this solution makes full use of the Doppler frequency shift and time difference information of the received signal, and performs location search by establishing a coordinate system and traversing a certain distance. Compared with the existing single-station positioning methods and systems, 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 this solution in various scenarios can be more adaptable.

[0121] The method provided by the embodiment of the present invention is now further described:

[0122] Since the signal sent by the drone will contain repeated pilot information, please refer to Figure 1 , execute step S1:

[0123] S1: Get the actual period of the pilot signal sent by the drone.

[0124] In one embodiment, the method of step S1 includes:

[0125] Get the signal sent by the drone;

[0126] Obtain pilot information and the actual period of the pilot signal from the signal sent by the drone.

[0127] Since the pilot information is generally located at the front end of the target signal, based on the actual period T of the pilot signal, the time between two adjacent target signals sent by the UAV can be known. Of course, the present invention does not limit the location of the pilot information, and technicians in this field can also choose a suitable target signal confirmation method as needed.

[0128] In this case, one implementation method is to refer to Figure 1 as well as Figure 2 , execute step S2,

[0129] S2: Receive two adjacent target signals sent by the UAV in the target area, and obtain the actual center frequency of the target signal, the actual time difference between the two target signals arriving at the receiving base station, the actual incoming wave angle, and the actual Doppler frequency shift of the UAV.

[0130] Specifically, the target signal s sent by the drone in the target area at time t is received p(t), and the target signal s sent by the UAV at time t+T p (t+T), and obtain the actual center frequency f of the target signal c , the actual time difference τ between the two target signals arriving at the receiving base station, the actual wave angle θ, and the actual Doppler frequency shift f of the UAV d '.

[0131] In one implementation, the arrival time difference can be obtained by performing cross-correlation algorithms on the pilot part of the received signal corresponding to the received signal, or can be obtained by actual equipment. Since this technology is prior art, the present invention will not be described in detail herein.

[0132] As an example, the system model diagram of the receiving base station 10 receiving the target signal twice can be as follows: Figure 2 As shown, the output of the UAV sending the first target signal s p (t) at the first position, sending the second target signal s p The second position at (t+T), the position of the receiving base station 10 and the actual incoming wave angle θ.

[0133] It should be understood that the target signal may include a pilot signal and a signal carrying information after the pilot signal.

[0134] Please refer to Figure 1 , Figure 3 to Figure 6 , execute step S3,

[0135] S3: Import 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 incoming wave angle into a preset theoretical Doppler shift model to obtain a Doppler shift theoretical value table, wherein the Doppler shift theoretical value table includes different Doppler shift theoretical values ​​corresponding to different distances from the drone to the receiving base station.

[0136] The establishment of the preset theoretical Doppler frequency shift model is now explained:

[0137] In a specific implementation manner, the receiving base station sequentially receives the first target signal s p (t) and the second target signal s p (t+T), the first target signal s p (t) and the second target signal s p (t+T) is the two adjacent target signals sent by the UAV; in order to facilitate the introduction of actual values, the sign of the variable used in establishing the theoretical Doppler frequency shift model is the same as the sign of the actual value.

[0138] In practical applications, the receiving base station receives a continuous signal. The first target signal s p (t) and the second target signal s p (t+T) is the adjacent target signal in the continuous signal.

[0139] In this case, please refer to Figure 3 , a method for establishing a theoretical Doppler frequency shift model, including:

[0140] S311: Taking the direct path of the first target signal as the first coordinate axis, taking the position of the receiving base station as the origin, and establishing a two-dimensional plane coordinate system according to the wave direction of the first target signal and the wave direction of the second target signal, wherein the second coordinate axis is perpendicular to the first coordinate axis;

[0141] As an example, the two-dimensional plane coordinate system can be established as follows Figure 4 As shown, in Figure 4 In the example, the first coordinate axis is the Y axis, the second coordinate axis is the X axis, and the UAV sends a first target signal s p The first coordinate P at (t) t is (0, d1), and sends the second target signal s p The second coordinate P at (t+T) t+T is (x t+T ,y t+T ), the coordinates of the receiving base station are (0, 0), and the actual incoming wave angle is θ.

[0142] S312: Obtaining the first step length and the first quantity based on the first coordinate axis;

[0143] Specifically, a first step length and a first quantity based on the first coordinate axis are acquired according to the range of the target area.

[0144] In a specific implementation manner, the range of the target area is [d low ,d high ];

[0145] Based on the first step length and the range of the target area, the first quantity is determined

[0146] L=(d high -d low ) / d step +1

[0147] Among them, d step is the first step length.

[0148] Taking the base station receiving signal range radius as 5km as an example, for a certain distance range [0,5km], it can be increased by a certain step size d step=100m divides it into L = 51 different distance values.

[0149] S313: Based on the first step length and the first number of the first coordinate axis, obtaining a plurality of first preset coordinates corresponding to when the drone sends the first target signal, where the first preset coordinates are coordinates on the two-dimensional plane coordinate system;

[0150] Specifically, the distance of the drone relative to the base station at time t is Wherein l is an integer, and l is less than or equal to L.

[0151] S314: Based on the plurality of first preset coordinates, the time difference variable of the receiving base station receiving the first target signal and the second target signal, and the wave angle variable, determine a plurality of second preset coordinates corresponding to when the drone sends the second target signal, where the second preset coordinates are coordinates on the two-dimensional plane coordinate system;

[0152] Specifically, step S314 includes:

[0153] According to the first preset coordinates The receiving base station receives a time difference variable τ between the first target signal and the second target signal, and determines the first coordinate And the second coordinate (x t+T ,y t+T ), where c represents the speed of light;

[0154] According to the distance difference cτ, the distance between the second coordinate and the receiving base station is determined as

[0155] Based on the first preset coordinates The distance of the second coordinate from the receiving base station and the variable θ of the incoming wave angle determine the second preset coordinate corresponding to when the UAV sends the second target signal

[0156] S315: Based on the time difference variable of two adjacent target signals sent by the drone, the center frequency variable of the target signal, multiple first preset coordinates and the corresponding second preset coordinates, a theoretical Doppler frequency shift model is established so that the theoretical Doppler frequency shift value corresponding to each of the first preset coordinates can be calculated to obtain the theoretical Doppler frequency shift value table.

[0157] For a specific implementation, please refer to Figure 5 , in step S315, based on the time difference variable of two adjacent target signals sent by the drone, the first preset coordinate and the corresponding second preset coordinate, calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinate includes:

[0158] S3151: Obtain the periodic variable of the pilot signal sent by the UAV;

[0159] S3152: Based on the periodic variable, the first preset coordinate, and the corresponding second preset coordinate, respectively obtain a corresponding first velocity component of the drone in the direction of the first coordinate axis, and a corresponding second velocity component of the drone in the direction of the second coordinate axis;

[0160] Specifically, based on the periodic variable T, the first preset coordinate and the corresponding second preset coordinates The corresponding first velocity components of the UAV in the direction of the first coordinate axis are obtained respectively:

[0161]

[0162] And the corresponding second velocity component of the UAV in the direction of the second coordinate axis:

[0163]

[0164] S3153: Calculating the speed of the UAV based on the first speed component and the second speed component;

[0165] Specifically, the speed of the drone is

[0166] S3154: Calculate the Doppler frequency 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.

[0167] Specifically, the theoretical value of the Doppler frequency shift corresponding to the first preset coordinate is

[0168] It can be seen that the embodiment of the present invention establishes a two-dimensional plane coordinate system and traverses all the assumed distances to obtain a Doppler frequency shift theoretical value table. By performing a position search through the theoretical Doppler frequency shift model, a 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 this solution in various scenarios can be more adaptable.

[0169] 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 incoming wave angle into the preset theoretical Doppler frequency shift model in step S3 is now described:

[0170] In one implementation, the first coordinate axis is the Y axis, and the second coordinate system is the X axis;

[0171] 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 incoming wave angle are introduced into a preset theoretical Doppler shift model to obtain the Doppler shift theoretical value corresponding to the first preset coordinate, including:

[0172] Based on the theoretical Doppler frequency shift model, determine the lth first preset coordinate and

[0173]

[0174] Among them, 1≤l≤L;

[0175] Based on the lth first preset coordinate The actual time difference τ and the actual incoming wave angle θ determine the lth second preset coordinate and

[0176]

[0177] Where c is the speed of light;

[0178] Based on the actual period T, the lth first preset coordinate and the corresponding second preset coordinates Obtain the first velocity component corresponding to the UAV in the direction of the first coordinate axis respectively

[0179]

[0180] and the corresponding second velocity component of the drone in the direction of the second coordinate axis

[0181]

[0182] Based on the first velocity component and the second velocity component, the velocity of the drone corresponding to the first preset coordinate is calculated.

[0183]

[0184] Based on the actual center frequency f of the target signal and the speed v of the UAV l and the first velocity component Calculate the theoretical value of the Doppler frequency shift corresponding to the first preset coordinate

[0185]

[0186] In a preferred embodiment, the drone has an upper limit on flight speed;

[0187] In this case, calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinate based on the speed of the drone and the first speed component includes:

[0188] 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;

[0189] Based on the first preset coordinates, calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinates;

[0190] When the speed of the UAV is greater than the flight speed upper limit, the Doppler frequency shift theoretical value corresponding to the UAV is 0.

[0191] In this case, according to v y, l Calculate the theoretical Doppler shift:

[0192]

[0193] Where c is the speed of light, f c is the center frequency of the signal, v max The upper limit of the drone's flight speed.

[0194] In one implementation, please refer to Figure 6 The method for obtaining the Doppler frequency shift theoretical value table in step S3 includes:

[0195] S33: Obtain the Doppler frequency shift theoretical value corresponding to the first type of preset coordinates, where the first type of preset coordinates are the first preset coordinates corresponding to the speed of the UAV being less than or equal to the upper limit of the flight speed;

[0196] S34: Based on the first step length and the first quantity of the first coordinate axis, the Doppler frequency shift theoretical values ​​of all the first-type preset coordinates are arranged into the Doppler frequency shift theoretical value table.

[0197] Please refer to Figure 1 , execute step S4:

[0198] S4: performing error metric calculation processing on the actual Doppler frequency shift and each of the Doppler frequency shift theoretical values ​​to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric.

[0199] Specifically, the Doppler frequency shift theoretical value table is traversed using the actual Doppler frequency shift result, and the detected value is compared with the theoretical value to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric.

[0200] In one implementation, the error metric is calculated as a mean square error. In this case, the obtained Doppler frequency shift detection value f d ′ and the theoretical value of the lth Doppler frequency shift The error metric

[0201]

[0202] In other implementations, the error metric calculation may also be a root mean square error, which is not limited in the present invention, and may also be other calculation methods with higher error sensitivity.

[0203] In summary, the present invention obtains the actual period of the pilot signal sent by the drone, determines two adjacent target signals sent by the drone in the target area, and obtains the target signal information and the actual Doppler frequency shift of the drone; imports the target signal information into the variables in the preset theoretical Doppler frequency shift model to obtain a Doppler frequency shift theoretical value table; performs error metric 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 metric; based on the Doppler frequency shift theoretical value corresponding to the minimum error metric, determines the position of the drone when sending the target signal, so that the method provided by the present invention can ensure the accuracy of single-station positioning in complex scenes.

[0204] In addition, please refer to Figure 7 The embodiment of the present invention further provides a single-station positioning system, which is applied to a receiving base station, including:

[0205] The actual period acquisition module 61 is used to acquire the actual period of the pilot signal sent by the UAV;

[0206] The target signal information acquisition module 62 is used to determine two adjacent target signals sent by the drone in the target area based on the actual period of the pilot signal sent by the drone, and obtain the actual center frequency of the target signal, the actual time difference between the two target signals arriving at the receiving base station, the actual wave angle, and the actual Doppler shift of the drone;

[0207] The Doppler frequency shift theoretical value table acquisition module 63 is used to import 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 incoming wave 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 includes different Doppler frequency shift theoretical values ​​corresponding to different distances from the UAV to the receiving base station;

[0208] An error metric calculation module 64 is used to perform error metric calculation processing on the actual Doppler frequency shift and each of the Doppler frequency shift theoretical values ​​to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric;

[0209] The positioning module 65 is used to determine the position of the UAV when sending the target signal based on the Doppler frequency shift theoretical value corresponding to the minimum error metric.

[0210] In a specific implementation manner, the receiving base station receives a first target signal and a second target signal in sequence, where the first target signal and the second target signal are two adjacent target signals sent by the drone;

[0211] In this case, please refer to Figure 8 The Doppler frequency shift theoretical value table obtaining module 63 comprises:

[0212] A two-dimensional plane coordinate system establishing unit 631 is used to establish a two-dimensional plane coordinate system with the direct path of the first target signal as the first coordinate axis and the position of the receiving base station as the origin, and according to the wave direction of the first target signal and the wave direction of the second target signal, wherein the second coordinate axis is perpendicular to the first coordinate axis;

[0213] A coordinate axis segmentation unit 632, used to obtain a first step length and a first quantity based on a first coordinate axis;

[0214] A first preset coordinate determining unit 633 is used to obtain a plurality of first preset coordinates corresponding to when the UAV sends the first target signal based on the first step length and the first number of the first coordinate axis, where the first preset coordinates are coordinates on the two-dimensional plane coordinate system;

[0215] A second preset coordinate determining unit 634 is used to determine a plurality of second preset coordinates corresponding to when the drone sends 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 incoming wave angle variable, wherein the second preset coordinates are coordinates on the two-dimensional plane coordinate system;

[0216] The Doppler frequency shift theoretical value table obtaining unit 635 is used to establish a theoretical Doppler frequency shift model based on the time difference variable between two adjacent target signals sent by the drone, multiple first preset coordinates and corresponding second preset coordinates, so that it can calculate the Doppler frequency shift theoretical value corresponding to each of the first preset coordinates to obtain the Doppler frequency shift theoretical value table.

[0217] It can be seen that the embodiment of the present invention establishes a two-dimensional plane coordinate system and traverses all the assumed distances to obtain a Doppler frequency shift theoretical value table. By performing a position search through the theoretical Doppler frequency shift model, a 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 this solution in various scenarios can be more adaptable.

[0218] In one implementation, please refer to Fig. 9 , the Doppler frequency shift theoretical value table obtaining unit 635 includes:

[0219] The period setting subunit 6351 is used to obtain the period variable of the pilot signal sent by the UAV;

[0220] a velocity component calculation subunit 6352, configured to obtain, based on the periodic variable, the first preset coordinate, and the corresponding second preset coordinate, 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;

[0221] The UAV speed calculation subunit 6353 is used to calculate the speed of the UAV based on the first speed component and the second speed component;

[0222] The Doppler frequency shift theoretical value calculation subunit 6354 is used to calculate the Doppler frequency 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.

[0223] In addition, an embodiment of the present invention further provides an electronic device, including the above-mentioned single-station positioning system. As an example, the electronic device can be an antenna base station, etc., and the present invention is not limited to this. Of course, it can also be other electronic devices that require single-station positioning.

[0224] In summary, the embodiment of the present invention obtains the actual period of the pilot signal sent by the drone, determines two adjacent target signals sent by the drone in the target area, and obtains the target signal information and the actual Doppler frequency shift of the drone; the target signal information is imported into the variables in the preset theoretical Doppler frequency shift model to obtain a Doppler frequency shift theoretical value table; the actual Doppler frequency shift and each Doppler frequency shift theoretical value are subjected to error metric calculation processing to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric; based on the Doppler frequency shift theoretical value corresponding to the minimum error metric, the position of the drone when sending the target signal is determined, so that the method provided by the present invention can ensure the accuracy of single-station positioning in complex scenarios.

[0225] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A single-station positioning method based on Doppler frequency shift and time difference information, characterized in that: Applied to a receiving base station, the single-station positioning method includes: Get the actual period of the pilot signal sent by the drone; Based on the actual period of the pilot signal sent by the drone, determine two adjacent target signals sent by the drone in the target area, and obtain the actual center frequency of the target signal, the actual time difference between the two target signals arriving at the receiving base station, the actual incoming wave angle, and the actual Doppler frequency shift of the drone; 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 incoming wave angle are introduced 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 includes different Doppler frequency shift theoretical values ​​corresponding to different distances from the UAV to the receiving base station; Performing error metric calculation processing on the actual Doppler frequency shift and each of the Doppler frequency shift theoretical values ​​to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric; Based on the Doppler frequency shift theoretical value corresponding to the minimum error metric, the position of the UAV when sending the target signal is determined.

2. The single-station positioning method according to claim 1, characterized in that: The receiving base station receives a first target signal and a second target signal in sequence, where the first target signal and the second target signal are two adjacent target signals sent by the drone; The method of establishing a theoretical Doppler frequency shift model includes: Taking the direct path of the first target signal as the first coordinate axis, taking the position of the receiving base station as the origin, and establishing a two-dimensional plane coordinate system according to the wave direction of the first target signal and the wave direction of the second target signal, the second coordinate axis is perpendicular to the first coordinate axis; Get the first step length and the first quantity based on the first coordinate axis; Based on the first step length and the first quantity of the first coordinate axis, a plurality of first preset coordinates corresponding to when the drone sends the first target signal are obtained, where the first preset coordinates are coordinates on the two-dimensional plane coordinate system; Based on the plurality of first preset coordinates, the time difference variable of the receiving base station receiving the first target signal and the second target signal, and the wave angle variable, determine a plurality of second preset coordinates corresponding to when the drone sends the second target signal, where the second preset coordinates are coordinates on the two-dimensional plane coordinate system; Based on the time difference variable of two adjacent target signals sent by the drone, the center frequency variable of the target signal, multiple first preset coordinates and the corresponding second preset coordinates, a theoretical Doppler frequency shift model is established so that the theoretical Doppler frequency shift value corresponding to each of the first preset coordinates can be calculated to obtain the theoretical Doppler frequency shift value table.

3. The single-station positioning method according to claim 2, characterized in that: Calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinate based on the time difference variable of two adjacent target signals sent by the drone, the first preset coordinate, and the corresponding second preset coordinate, including: Get the periodic variable of the pilot signal sent by the drone; Based on the periodic variable, the first preset coordinate and the corresponding second preset coordinate, respectively obtain a corresponding first velocity component of the drone in the direction of the first coordinate axis and a corresponding second velocity component of the drone in the direction of the second coordinate axis; Calculating the speed of the drone based on the first speed component and the second speed component; The Doppler frequency shift theoretical value corresponding to the first preset coordinate is calculated based on the speed of the drone, the center frequency variable and the first speed component.

4. The single-station positioning method according to claim 3, characterized in that: The range of the target area is [d low ,d high ]; Based on the first step length and the range of the target area, the first quantity is determined L=(d high -d low ) / d step +1 Among them, d step is the first step length.

5. The single-station positioning method according to claim 4, characterized in that: The first coordinate axis is the Y axis, and the second coordinate axis is the X axis; Then, 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 incoming wave angle are introduced into a preset theoretical Doppler shift model to obtain the Doppler shift theoretical value corresponding to the first preset coordinate, including: Based on the theoretical Doppler frequency shift model, determine the lth first preset coordinate and Among them, 1≤l≤L; Based on the lth first preset coordinate The actual time difference τ and the actual incoming wave angle θ determine the lth second preset coordinate and Where c is the speed of light; Based on the actual period T, the lth first preset coordinate and the corresponding second preset coordinates Obtain the first velocity component corresponding to the UAV in the direction of the first coordinate axis respectively and the corresponding second velocity component of the drone in the direction of the second coordinate axis Based on the first velocity component and the second velocity component, the velocity of the drone corresponding to the first preset coordinate is calculated. Based on the actual center frequency f of the target signal and the speed v of the UAV l and the first velocity component Calculate the theoretical value of the Doppler frequency shift corresponding to the first preset coordinate 6. The single-station positioning method according to claim 3, characterized in that: The drone has an upper limit on its flight speed; Calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinate based on the speed of the drone and the first speed component includes: 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; Based on the first preset coordinates, calculating the Doppler frequency shift theoretical value corresponding to the first preset coordinates; When the speed of the UAV is greater than the flight speed upper limit, the Doppler frequency shift theoretical value corresponding to the UAV is 0.

7. The single-station positioning method according to claim 6, characterized in that: Obtaining the Doppler frequency shift theoretical value table includes: Obtaining the Doppler frequency shift theoretical value corresponding to the first type of preset coordinates, where the first type of preset coordinates are the first preset coordinates corresponding to the speed of the UAV being less than or equal to the upper limit of the flight speed; Based on the first step length and the first number of the first coordinate axis, the Doppler frequency shift theoretical values ​​of all the first-type preset coordinates are arranged into the Doppler frequency shift theoretical value table.

8. The single-station positioning method according to claim 1, characterized in that: The error metric calculation methods include mean square error calculation and root mean square error.

9. A single-station positioning system, characterized in that: Applicable to receiving base stations, including: The actual period acquisition module is used to obtain the actual period of the pilot signal sent by the UAV; A target signal information acquisition module is used to determine two adjacent target signals sent by the drone in the target area based on the actual period of the pilot signal sent by the drone, and obtain the actual center frequency of the target signal, the actual time difference between the two target signals arriving at the receiving base station, the actual incoming wave angle, and the actual Doppler frequency shift of the drone; A Doppler frequency shift theoretical value table acquisition module is used to import 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 incoming wave 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 includes different Doppler frequency shift theoretical values ​​corresponding to different distances from the UAV to the receiving base station; An error metric calculation module is used to perform error metric calculation processing on the actual Doppler frequency shift and each of the Doppler frequency shift theoretical values ​​to obtain the Doppler frequency shift theoretical value corresponding to the minimum error metric; The positioning module is used to determine the position of the UAV when sending the target signal based on the Doppler frequency shift theoretical value corresponding to the minimum error metric.

10. The single-station positioning system according to claim 9, characterized in that: The receiving base station receives a first target signal and a second target signal in sequence, where the first target signal and the second target signal are two adjacent target signals sent by the drone; The Doppler frequency shift theoretical value table acquisition module includes: a two-dimensional plane coordinate system establishing unit, configured to establish a two-dimensional plane coordinate system with the direct path of the first target signal as the first coordinate axis, the position of the receiving base station as the origin, and according to the wave direction of the first target signal and the wave direction of the second target signal, wherein the second coordinate axis is perpendicular to the first coordinate axis; A coordinate axis segmentation unit, used for obtaining a first step length and a first quantity based on a first coordinate axis; A first preset coordinate determining unit, configured to obtain, based on the first step length and the first quantity of the first coordinate axis, a plurality of first preset coordinates corresponding to when the drone sends the first target signal, wherein the first preset coordinates are coordinates on the two-dimensional plane coordinate system; A second preset coordinate determination unit, configured to determine a plurality of second preset coordinates corresponding to when the drone sends the second target signal based on the plurality of first preset coordinates, a time difference variable for receiving the first target signal and the second target signal by the receiving base station, and an incoming wave angle variable, wherein the second preset coordinates are coordinates on the two-dimensional plane coordinate system; The Doppler frequency shift theoretical value table obtaining unit is used to establish a theoretical Doppler frequency shift model based on the time difference variable of two adjacent target signals sent by the UAV, multiple first preset coordinates and corresponding second preset coordinates, so that it can calculate the Doppler frequency shift theoretical value corresponding to each of the first preset coordinates to obtain the Doppler frequency shift theoretical value table.

11. The single-station positioning system according to claim 10, characterized in that: The Doppler frequency shift theoretical value table obtaining unit comprises: The period setting subunit is used to obtain the period variable of the pilot signal sent by the UAV; a velocity component calculation subunit, configured to obtain, based on the periodic variable, the first preset coordinate, and the corresponding second preset coordinate, 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; a speed calculation subunit of the drone, configured to calculate the speed of the drone based on the first speed component and the second speed component; The Doppler frequency shift theoretical value calculation subunit is used to calculate the Doppler frequency shift theoretical value corresponding to the first preset coordinate based on the speed of the drone, the center frequency variable and the first speed component.

12. An electronic device, characterized in that: It comprises a single-station positioning system as described in any one of claims 9 to 11.

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