Positioning method and multi-radar positioning system

Abstract

The invention provides a positioning method and a multi-radar positioning system. In the positioning method, a first radar detects a first object and a second object to respectively obtain a first coordinate and a second coordinate on a first coordinate system. The second radar detects the first object and the second object to respectively obtain a third coordinate and a fourth coordinate on the second coordinate system. And estimating a first candidate coordinate and a second candidate coordinate of the second radar on the first coordinate system according to the third coordinate and the fourth coordinate. And selecting a first candidate coordinate from the first candidate coordinate and the second candidate coordinate as a first radar coordinate of the second radar according to the first coordinate and the second coordinate. And outputting the first radar coordinate.

Description

Technical Field

[0001] The present invention relates to a positioning technology, and in particular to a positioning method and a multi-radar positioning system. Background Art

[0002] Radar systems can be used for high-precision positioning. If millimeter-wave radar is used, the positioning error can be reduced to centimeters. Compared with positioning systems based on communication protocols such as Bluetooth, WiFi, RFID or ZigBee, radar systems can complete positioning in a privacy-friendly manner without collecting data from the user's mobile device. Therefore, radar systems have gradually replaced photography systems as indoor positioning systems.

[0003] Radar systems have many disadvantages. For example, radar detection is limited by the detection distance, and the detection results will be interfered by the barrier effect. In order to solve the above problems, radar systems often use multiple radar fusion technology. When multiple radars of a radar system are installed in a field, the user must first obtain the global map of the field and the installation location of the radar. In this way, after obtaining the detection results, the radar system can be positioned according to the global map and the location of the radar. However, obtaining the global map and the radar position requires manpower and time. Summary of the invention

[0004] The invention provides a positioning method and a multi-radar positioning system, which can automatically convert the detection results of multiple radars into the same coordinate system.

[0005] A multi-radar positioning system according to an embodiment of the present invention comprises a first radar, a second radar and a controller. The first radar detects a first object and a second object to obtain a first coordinate and a second coordinate on a first coordinate system, respectively. The second radar detects the first object and the second object to obtain a third coordinate and a fourth coordinate on a second coordinate system, respectively. The controller is communicatively connected to the first radar and the second radar, and is configured to: estimate a first candidate coordinate and a second candidate coordinate of the second radar on the first coordinate system according to the third coordinate and the fourth coordinate; select a first candidate coordinate from the first candidate coordinate and the second candidate coordinate according to the first coordinate and the second coordinate as a first radar coordinate of the second radar; and output the first radar coordinate.

[0006] A positioning method according to an embodiment of the present invention is used in a multi-radar positioning system including a first radar and a second radar, comprising: detecting a first object and a second object by the first radar to obtain a first coordinate and a second coordinate in a first coordinate system, respectively; detecting the first object and the second object by the second radar to obtain a third coordinate and a fourth coordinate in the second coordinate system, respectively; estimating a first candidate coordinate and a second candidate coordinate of the second radar in the first coordinate system according to the third coordinate and the fourth coordinate; selecting a first candidate coordinate from the first candidate coordinate and the second candidate coordinate according to the first coordinate and the second coordinate as a first radar coordinate of the second radar; and outputting the first radar coordinate.

[0007] Based on the above, the multi-radar positioning system of the present invention can automatically obtain the relative positions between the radars, and then convert the detection results of multiple radars into the same coordinate system. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of a multi-radar system is shown according to an embodiment of the present invention.

[0009] Figure 2 A flowchart of a positioning method is shown according to an embodiment of the present invention.

[0010] Figure 3 A schematic diagram of a radar and an object in a space is shown according to an embodiment of the present invention.

[0011] Figure 4 A schematic diagram of obtaining two candidate coordinates is shown according to an embodiment of the present invention.

[0012] Figure 5 A schematic diagram of obtaining a single candidate coordinate is shown according to an embodiment of the present invention.

[0013] Figure 6 A schematic diagram of obtaining radar coordinates of a radar using detection results of two objects according to an embodiment of the present invention is shown.

[0014] Figure 7 A schematic diagram of obtaining radar coordinates of a radar using detection results of three objects according to an embodiment of the present invention is shown.

[0015] Figure 8 A schematic diagram of mapping radar coordinates of a radar to a reference coordinate system is shown according to an embodiment of the present invention.

[0016] Fig. 9 A flow chart of obtaining the angle θ0 is shown according to an embodiment of the present invention.

[0017] Fig.10 According to an embodiment of the present invention, a schematic diagram of obtaining the angle θ0 when the angle θ1 is greater than 90 degrees is shown.

[0018] Fig.11 According to an embodiment of the present invention, a schematic diagram of obtaining the angle θ0 is shown when the angle θ1 is less than or equal to 90 degrees.

[0019] Fig.12 A schematic diagram of a radar and an object in a three-dimensional space is shown according to an embodiment of the present invention.

[0020] Fig.13 A schematic diagram of mapping the coordinates of a radar and an object to an XY plane is shown according to an embodiment of the present invention.

[0021] Fig.14 A flowchart of a positioning method is shown according to an embodiment of the present invention.

[0022] The reference numerals are described as follows:

[0023] 10: Multi-radar positioning system

[0024] 100: Controller

[0025] 21, 22, 23: Radar

[0026] 31, 32, 33, 34, 71, 72, 73, 74, 75: Object

[0027] 41, 42: Location

[0028] 51, 52, 53: Circle

[0029] 61: Intersection

[0030] A, B, C, D, M, N: vector

[0031] S201, S202, S203, S204, S205, S206, S207, S208, S209, S901,

[0032] S902, S903, S904, S141, S142, S143, S144, S145: Steps

[0033] α, β, θ0, θ 12 ,θ 23 , θ3: Angle

[0034] θ1, θ2, θ A ,θ B ,θ C ,θ D : Angle of arrival DETAILED DESCRIPTION

[0035] In order to make the content of the present invention more understandable, the following embodiments are given as examples that the present invention can be implemented. In addition, wherever possible, the elements / components / steps with the same reference numerals in the drawings and embodiments represent the same or similar parts.

[0036] Figure 1 According to an embodiment of the present invention, a schematic diagram of a multi-radar system 10 is shown. The multi-radar system 10 may include a controller 100 and a plurality of radars, wherein the plurality of radars may include, for example, a radar 21, a radar 22, and a radar 23. The controller 100 may be directly electrically connected, indirectly electrically connected, or communicatively connected to the plurality of radars.

[0037] The controller 100 may include a central processing unit (CPU), or other programmable general-purpose or special-purpose micro control unit (MCU), microprocessor, digital signal processor (DSP), programmable controller, application specific integrated circuit (ASIC), graphics processing unit (GPU), image signal processor (ISP), image processing unit (IPU), arithmetic logic unit (ALU), complex programmable logic device (CPLD), field programmable gate array (FPGA) or other similar components or combinations of the above components. The controller 100 may further include a communication unit (e.g., various communication chips, mobile communication chips, Bluetooth chips or WiFi chips) and a storage unit (e.g., removable random access memory, flash memory or hard disk) and other necessary components for running the controller 100.

[0038] The controller 100 may detect objects in the field through a radar (e.g., radar 21, 22, or 23) to generate a detection result. The detection result may include the coordinates of the object in a coordinate system corresponding to the radar, wherein the coordinates may include information such as the distance between the object and the radar and the direction of the object relative to the radar (or angle of arrival (AoA)). In one embodiment, the controller 100 may obtain the coordinates of the object according to the detection result of the radar (e.g., the point cloud of the object detected by the radar) based on an object detection algorithm or a machine learning (ML) algorithm.

[0039] Figure 2 According to an embodiment of the present invention, a flow chart of a positioning method is shown, wherein the method may be performed as follows: Figure 1 The multi-radar positioning system 10 implementation is shown.

[0040] In step S201, the controller 100 may detect the first object and the second object through the first radar to obtain the first coordinate and the second coordinate in the first coordinate system corresponding to the first radar, respectively. On the other hand, the controller 100 may detect the first object and the second object through the second radar to obtain the third coordinate and the fourth coordinate in the second coordinate system corresponding to the second radar, respectively.

[0041] Figure 3 A schematic diagram of radars and objects in a space is shown according to an embodiment of the present invention. Assume that a plurality of radars including radar 21, radar 22 and radar 23 are set in a space, and objects 31, object 32 and object 33 exist in the space. The coordinates of each object are represented by C(i, j), where i represents the index of the object and j represents the index of the coordinate system (or radar) corresponding to the coordinates of the object. The above coordinates are, for example, two-dimensional coordinates or three-dimensional coordinates.

[0042] The controller 100 can detect the object 31 through the radar 21 to obtain the coordinates C(31,21)=(3.54,7.07) on the coordinate system (or referred to as the reference coordinate system) corresponding to the radar 21, and can detect the object 32 through the radar 21 to obtain the coordinates C(32,21)=(0,7.07) on the coordinate system corresponding to the radar 21. The object 31 and the object 32 can be different objects, or can be the same object. For example, if the object 31 and the object 32 are the same object, the coordinates with different displacements are generated because the objects move. On the other hand, the controller 100 can detect the object 31 through the radar 22 to obtain the coordinates C(31,22)=(-2.5,2.5) on the coordinate system of the radar 22, can detect the object 32 through the radar 22 to obtain the coordinates C(32,22)=(0,5) on the coordinate system corresponding to the radar 22, and can detect the object 33 through the radar 22 to obtain the coordinates C(33,22)=(2.5,2.5) on the coordinate system corresponding to the radar 22. Furthermore, the controller 100 can detect the object 32 through the radar 23 to obtain the coordinates C(32,23)=(0,5) on the coordinate system corresponding to the radar 23, and can detect the object 33 through the radar 23 to obtain the coordinates C(33,23)=(-2.5,2.5) on the coordinate system corresponding to the radar 23.

[0043] Reference Figure 2 and Figure 3 , it will be assumed below that radar 21 corresponds to the first radar, radar 22 corresponds to the second radar, coordinate C(31,21) corresponds to the first coordinate on the first coordinate system, coordinate C(32,21) corresponds to the second coordinate on the first coordinate system, coordinate C(31,22) corresponds to the third coordinate on the second coordinate system, and coordinate C(32,22) corresponds to the fourth coordinate on the second coordinate system. It should be noted that the detection range of radar 21 partially overlaps with the detection range of radar 22, and objects 31 and 32 are both located within the partially overlapping range. Radar 21 detects objects 31 and 32, and obtains the point clouds of objects 31 and 32. Radar 21 obtains the coordinates of the point cloud centroid point, i.e., coordinate C, by calculating the point cloud centroid point of objects 31 and 32. In contrast, radar 22 detects objects 31 and 32, and through an object detection algorithm or a machine learning algorithm, determines the object shape, skeleton, height, width or moving speed and other features of objects 31 and 32 according to the point cloud distribution points, and further determines that objects 31 and 32 detected by radar 22 are objects 31 and 32 detected by radar 21, respectively.

[0044] In step S202, the controller 100 may estimate the first candidate coordinates and the second candidate coordinates of the second radar on the first coordinate system according to the third coordinates and the fourth coordinates. Specifically, the controller 100 may obtain the third coordinates from the detection result of the second radar, and determine the first distance between the first object and the second radar according to the third coordinates. In addition, the controller 100 may obtain the fourth coordinates from the detection result of the second radar, and determine the second distance between the second object and the second radar according to the fourth coordinates. Then, the controller 100 may search for the fifth coordinate on the first coordinate system. If the third distance between the fifth coordinate and the first coordinate is equal to the first distance between the third coordinate and the second radar, and the fourth distance between the fifth coordinate and the second coordinate is equal to the fourth distance between the fourth coordinate and the second radar, the controller 100 may determine that the fifth coordinate is a candidate coordinate. The controller 100 may obtain one or two candidate coordinates (i.e., the first candidate coordinate and / or the second candidate coordinate) according to the above steps.

[0045] Figure 4 According to an embodiment of the present invention, a schematic diagram of obtaining two candidate coordinates is shown. The controller 100 can estimate the candidate coordinates C(41,21) of the candidate position 41 of the radar 22 in the coordinate system corresponding to the radar 21 (i.e., the reference coordinate system) and the candidate coordinates C(42,21) of the candidate position 42 of the radar 22 in the coordinate system corresponding to the radar 21 based on the coordinates C(31,22) and the coordinates C(32,22). Specifically, the controller 100 can determine the distance between the object 31 and the radar 22 based on the coordinates C(31,22) as A circle 51 is drawn with the object 31 as the center and the distance 3.54 as the radius, wherein the circle equation of the circle 51 may be (x-3.54) 2 +(y-7.07) 2 =(-2.5) 2 +(2.5) 2 The controller 100 can also determine the distance between the object 32 and the radar 22 according to the coordinate C(32,22). A circle 52 is drawn with the object 32 as the center and the distance 5 as the radius, wherein the circle equation of the circle 52 may be (x-0) 2 +(y-7.07) 2 =(0) 2 +(5) 2. The controller 100 can calculate the coordinates of the two intersection points of circle 51 and circle 52 according to the circle equation of circle 51 and the circle equation of circle 52, which are coordinate C(41,21)=(3.54,10.60) of position 41 and coordinate C(42,21)=(3.54,3.54) of position 42. Since the distance between coordinate C(41,21) of position 41 and coordinate C(31,21) is equal to the distance between object 31 and radar 22, the controller 100 can determine that position 41 is a candidate position and coordinate C(41,21) is a candidate coordinate. On the other hand, since the distance between coordinate C(42,21) of position 42 and coordinate C(32,21) is equal to the distance between object 32 and radar 22, the controller 100 can determine that position 42 is a candidate position and coordinate C(42,21) is a candidate coordinate. It will be assumed below that the coordinate C (41, 21) is the first candidate coordinate, and the coordinate C (42, 21) is the second candidate coordinate.

[0046] Figure 5 According to an embodiment of the present invention, a schematic diagram of obtaining a single candidate coordinate is shown. The controller 1000 can estimate the candidate coordinate C(41,21) of the candidate position 41 of the radar 22 in the coordinate system corresponding to the radar 21 (i.e., the reference coordinate system) according to the coordinate C(31,22) and the coordinate C(32,22). Specifically, the controller 100 can determine the distance between the object 31 and the radar 22 according to the coordinate C(31,22), and draw a circle 51 with the object 31 as the center and the distance as the radius. The controller 100 can also determine the distance between the object 32 and the radar 22 according to the coordinate C(32,22), and draw a circle 52 with the object 32 as the center and the distance as the radius. Since the circle 51 is tangent to the circle 52, the intersection of the circle 51 and the circle 52 only includes the position 41. Since the distance between the coordinate C(41,21) of the position 41 and the coordinate C(31,21) is equal to the distance between the object 31 and the radar 22, the controller 100 can determine that the position 41 is a candidate position and the coordinate C(41,21) is a candidate coordinate. If the controller 100 obtains only a single candidate coordinate in step S202, the controller 100 can skip steps S203 to S205 and directly determine that the candidate coordinate is the radar coordinate of the second radar in the first coordinate system corresponding to the first radar (or referred to as the first radar coordinate). It will be assumed that the coordinate C(41,21) is the first candidate coordinate.

[0047] Back to Figure 2 In step S203, the controller 100 may determine whether the first radar and the second radar have detected the third object. If both the first radar and the second radar have detected the third object, the process proceeds to step S205. If at least one of the first radar and the second radar has not detected the third object, the process proceeds to step S204.

[0048] In step S204, the controller 100 may select the radar coordinates of the second radar from the first candidate coordinates and the second candidate target according to the coordinates of the first object and the second object. Specifically, the controller 100 may obtain a first vector from the first candidate coordinates to the first coordinates, and may obtain a second vector from the first candidate coordinates to the second coordinates. In addition, the controller 100 may obtain a first angle of arrival according to the third coordinates, and obtain a second angle of arrival according to the fourth coordinates. Then, the controller 100 may rotate the first vector according to the first angle of arrival to obtain a third vector, and rotate the second vector according to the second angle of arrival to obtain a fourth vector. The controller 100 may calculate a first angle between the third vector and the fourth vector, wherein the first angle corresponds to the first candidate coordinates. Based on similar steps, the controller 100 may calculate a second angle corresponding to the second candidate coordinates. If the absolute value of the first angle is less than the absolute value of the second angle, the controller 100 may select the first candidate coordinates from the first candidate coordinates and the second candidate coordinates as the radar coordinates of the second radar.

[0049] Figure 6 According to an embodiment of the present invention, a schematic diagram of obtaining the radar coordinates of the radar 22 using the detection results of two objects is shown. The controller 100 can obtain the vector A=(0,-3.54) from the candidate coordinate C(41,21) to the coordinate C(31,21), and can obtain the vector B=(-3.54,-3.54) from the candidate coordinate C(41,21) to the coordinate C(32,21). In addition, the controller 100 can obtain the arrival angle θ according to the coordinate C(31,22). A =135°, and the arrival angle θ is obtained according to the coordinates C(32,22) B =90°. Then, the controller 100 may rotate the vector A clockwise to an angle θ A To obtain vector A'=(-2.5, 2.5) (not shown in the figure), and rotate vector B clockwise to reach angle θ B The vector B'=(-3.54, 3.54) (not shown in the figure) is obtained. The controller 100 can calculate the angle ∠A'B'=0° between the vector A' and the vector B'. Since the candidate coordinate C (41, 21) is the real coordinate of the radar 22, the absolute value of the angle ∠A'B' should be zero.

[0050] On the other hand, the controller 100 can obtain the vector C=(0,3.54) from the candidate coordinates C(42,21) to the coordinates C(31,21), and can obtain the vector D=(-3.54,3.54) from the candidate coordinates C(42,21) to the coordinates C(32,21). Then, the controller 100 can rotate the vector C clockwise to the angle θ A To obtain vector C'=(2.5, -2.5) (not shown in the figure), and rotate vector D clockwise to reach angle θ BThe controller 100 can calculate the angle between the vector C' and the vector D' = 90° or 270°. The angle of arrival corresponding to the vector C should be θ C Rather than θ A , and the arrival angle corresponding to vector D should be θ D Rather than θ B , so the absolute value of the angle ∠C'D' should be greater than zero. Accordingly, the controller 100 can select the candidate coordinate C(41,21) corresponding to ∠A'B' from the candidate coordinates C(41,21) and the candidate coordinates C(41,21) as the radar coordinates of the radar 22 in response to the absolute value of the angle ∠A'B' being less than the absolute value of the angle ∠C'D'.

[0051] Back to Figure 2 In step S205, the controller 100 may select the radar coordinates of the second radar from the first candidate coordinates and the second candidate target according to the coordinates of the first object, the second object, and the third object. Specifically, the controller 100 may detect the third object through the first radar to obtain the fifth coordinate in the first coordinate system, and may detect the third object through the second radar to obtain the sixth coordinate in the second coordinate system. Then, the controller 100 may calculate the first distance between the first candidate coordinate and the fifth coordinate, and obtain the second distance between the sixth coordinate and the second radar. If the first distance is equal to the second distance, the controller 100 may select the first candidate coordinate as the radar coordinate of the radar 22.

[0052] Figure 7 According to an embodiment of the present invention, a schematic diagram of obtaining the radar coordinates of the radar 22 using the detection results of three objects is shown. The controller 100 can detect the object 34 through the radar 21 to obtain the coordinates C(34,21)=(1.77,7.07) on the coordinate system of the radar 21, and can detect the object 34 through the radar 22 to obtain the coordinates C(34,22)=(-1.25,3.75) on the coordinate system of the radar 22. The controller 100 can also obtain the distance between the coordinates C(34,22) and the radar 22, and draw a circle 53 with the object 34 as the center and the distance as the radius, wherein the circle equation of the circle 53 can be (x-1.77) 2 +(y-7.07) 2 =(-1.25) 2 +(3.75) 2. The controller 100 may also calculate the distance between the candidate coordinates C(41,21) and the coordinates C(34,21). The distance between the candidate coordinates C(41,21) and the coordinates C(34,21) is equal to the distance between the coordinates C(34,22) and the radar 22, which means that the position 41 is located on the circle 53. Accordingly, the controller 100 may determine that the candidate coordinates C(41,21) are the radar coordinates of the radar 22. The controller 100 may also calculate the distance between the candidate coordinates C(42,21) and the coordinates C(34,21). The distance between the candidate coordinates C(42,21) and the coordinates C(34,21) is not equal to the distance between the coordinates C(34,22) and the radar 22, which means that the position 42 is not on the circle 53. Accordingly, the controller 100 may determine that the candidate coordinates C(42,21) are not the radar coordinates of the radar 22.

[0053] Back to Figure 2 In step S206, the controller 100 may determine whether the count value is greater than zero. The controller 100 may pre-store a count value with an initial value of zero, wherein the count value is a natural number. If the controller determines that the count value is greater than zero, the process proceeds to step S207. If the controller 100 determines that the count value is equal to zero, the process proceeds to step S208.

[0054] The count value represents the number of coordinate rotations required to map the radar coordinates obtained in step S204 or S205 to the reference coordinate system. In step S207, the controller 100 may rotate the radar coordinates of the second radar according to the count value to obtain the radar coordinates of the second radar in the reference coordinate system. For the coordinates in the two-dimensional space, the controller 100 may perform the coordinate rotation according to formula (1), where x represents the x coordinate before rotation, y represents the y coordinate before rotation, x' represents the x coordinate after rotation, y' represents the y coordinate after rotation, and θ represents the rotation angle.

[0055]

[0056] Figure 8 According to an embodiment of the present invention, a schematic diagram of mapping the radar coordinates of a radar to a reference coordinate system is shown, wherein the angle θ 12 may represent the angle between the radar 21 and the radar 22 (for example, or the angle between the lateral direction of the radar 21 and the lateral direction of the radar 22, wherein the lateral direction represents the direction perpendicular to the beam emitted by the radar), and the angle θ 23 It can represent the angle between radar 22 and radar 23. Assuming that the coordinate system corresponding to radar 21 is the reference coordinate system, the radar coordinates of radar 22 in the reference coordinate system are known to the controller 100, and the angle θ 12The controller 100 is known, and the count value is 1. The controller 100 may execute a process similar to step S201 to step S205 to obtain the radar coordinates of the radar 23 in the coordinate system corresponding to the radar 22. In order to further obtain the radar coordinates of the radar 23 in the reference coordinate system corresponding to the radar 21, the controller 100 may calculate the radar coordinates of the radar 23 in the reference coordinate system corresponding to the radar 21 based on the count value according to the angle θ. 12 The radar coordinates of the radar 23 in the coordinate system corresponding to the radar 22 are rotated once, thereby obtaining the radar coordinates of the radar 23 in the reference coordinate system corresponding to the radar 23. The controller 100 may rotate the radar coordinates of the radar 23 according to formula (2) to map the radar coordinates of the radar 23 to the reference coordinate system, wherein x(23,22) represents the x coordinate of the radar 23 in the coordinate system corresponding to the radar 22, y(23,22) represents the y coordinate of the radar 23 in the coordinate system corresponding to the radar 22, x(23,21) represents the x coordinate of the radar 23 in the reference coordinate system corresponding to the radar 21, y(23,21) represents the y coordinate of the radar 23 in the reference coordinate system corresponding to the radar 21, and θ 12 Represents the angle between radar 21 and radar 22.

[0057]

[0058] Back to Figure 2 In step S208, the controller 100 may calculate the angle θ0 between the first radar and the second radar (or the angle between the first lateral direction of the first radar and the lateral direction of the second radar, wherein the first lateral direction is a direction perpendicular to the beam emitted by the first radar, and the second lateral direction is a direction perpendicular to the beam emitted by the second radar). In addition, the controller 100 may add one to the count value to update the count value.

[0059] Fig. 9 According to an embodiment of the present invention, a flow chart for obtaining the angle θ0 is shown. In step S901, the controller 100 may obtain a first arrival angle θ1 according to the first coordinate, obtain a second arrival angle θ2 according to the third coordinate, and obtain an angle θ3 formed by the radar coordinates of the first radar (or referred to as the second radar coordinates), the first coordinates, and the radar coordinates of the second radar. In one embodiment, if the coordinate system corresponding to the first radar is a reference coordinate system, the radar coordinates of the first radar may be the origin of the reference coordinate system.

[0060] In step S902, the controller 110 may determine whether the first arrival angle θ1 is greater than ninety degrees. If the first arrival angle θ1 is greater than ninety degrees, the process proceeds to step S903. If the first arrival angle θ1 is less than or equal to ninety degrees, the process proceeds to step S904.

[0061] In step S903, the controller 110 may calculate the angle θ0 according to formula (3), where θ1 is the first arrival angle, θ2 is the second arrival angle, and θ3 is the angle formed by the radar coordinates of the first radar, the first coordinates, and the radar coordinates of the second radar.

[0062] θ0=θ1+θ3-θ2…(3)

[0063] Fig.10 According to an embodiment of the present invention, a schematic diagram of obtaining the angle θ0 when the angle θ1 is greater than ninety degrees is shown. The controller 110 can obtain the first arrival angle θ1 according to the coordinate C(31,21), can obtain the second arrival angle θ2=135° according to the coordinate C(31,22), and can obtain the angle θ3=153.43° formed by the radar coordinates of the radar 21, the first coordinates C(31,21) and the radar coordinates of the second radar. If the first arrival angle θ1 is greater than ninety degrees, the controller 110 can deduce (180°-θ0)+θ1+(180°-θ2)+θ3=360° based on the sum of the interior angles of the quadrilateral formed by the radar coordinates of the radar 21, the coordinates C(31,21) of the object 31, the radar coordinates of the radar 22, and the intersection 61 of the lateral direction of the radar 21 and the lateral direction of the radar 22 being 360°, thereby obtaining formula (3).

[0064] Back to Fig. 9 In step S904, the controller 110 may calculate the angle θ0 according to formula (4), where θ1 is the first arrival angle, θ2 is the second arrival angle, and θ3 is the angle formed by the radar coordinates of the first radar, the first coordinates, and the radar coordinates of the second radar.

[0065] θ0=360°+(θ1-θ3)-θ2…(4)

[0066] Fig.11According to an embodiment of the present invention, a schematic diagram of obtaining the angle θ0 when the angle θ1 is less than or equal to 90 degrees is shown. The controller 110 can obtain the first arrival angle θ1=63.43° according to the coordinate C(31,21), can obtain the second arrival angle θ2=135° according to the coordinate C(31,22), and can obtain the angle θ3=153.43° formed by the radar coordinates of the radar 21, the first coordinates C(31,21) and the radar coordinates of the second radar. If the first arrival angle θ1 is less than or equal to ninety degrees, the controller 110 can deduce (180°-θ0)+(θ1+β)+(180°-θ2+α)=180° and α+β=180°-θ3 based on the sum of the interior angles of the triangle formed by the radar coordinates of the radar 21, the coordinates C(31,21) of the object 31, and the radar coordinates of the radar 22 being 180°, and then obtain formula (4), where α is the angle formed by the coordinates C(31,21) of the object 31, the radar coordinates of the radar 21, and the radar coordinates of the radar 22, and β is the angle formed by the coordinates C(31,21) of the object 31, the radar coordinates of the radar 22, and the radar coordinates of the radar 21. The controller 100 can calculate the angle θ0=135° according to formula (4).

[0067] Back to Figure 2 In step S209, the controller 100 may output the radar coordinates and the angle θ0 of the second radar (eg, radar 22) in the coordinate system (eg, reference coordinate system) corresponding to the first radar.

[0068] Fig.12A schematic diagram of radars and objects in a three-dimensional space is shown according to an embodiment of the present invention. Assume that a plurality of radars including radar 21, radar 22, and radar 23 are set in a three-dimensional space, and objects 71, object 72, object 73, object 74, and object 75 exist in the three-dimensional space. The controller 100 can detect objects 71, object 72, object 73, and object 74 through radar 21 to obtain coordinates C(71,21)=(2,0,0), coordinates C(72,21)=(-2,0,4), coordinates C(73,21)=(-2,4,0), and coordinates C(74,21)=(-2,4,4) on the coordinate system (or referred to as the reference coordinate system) corresponding to radar 21, respectively. The controller 100 can detect the objects 71, 72, 73 and 74 through the radar 22 to obtain the coordinates C(71, 22) = (2, 0, -4), C(72, 22) = (-2, 0, 0), C(73, 22) = (-2, 4, -4) and C(74, 22) = (-2, 4, 0) on the coordinate system corresponding to the radar 22. The controller 100 can detect the objects 72, 73, 74 and 75 through the radar 23 to obtain the coordinates C(72, 23) = (2, 4, 0), C(73, 23) = (2, 0, -4), C(74, 23) = (2, 0, 0) and C(75, 23) = (-2, 0, -4) on the coordinate system corresponding to the radar 23.

[0069] The controller 100 can use the radar coordinates of the radar 21 as the origin (0,0,0) of the reference coordinate system. The controller 100 can calculate the distance between the object 71 and the radar 22 as 4.47 according to the coordinates C (71,22) of the object 71, calculate the distance between the object 72 and the radar 22 as 2 according to the coordinates C (72,22) of the object 72, and calculate the distance between the object 73 and the radar 22 as 6 according to the coordinates C (73,22) of the object 73. The controller 110 can obtain the equation (a) of the sphere with the object 71 as the center and the distance 4.47 as the radius as (x-2) 2 +(y) 2 +(z) 2 =4.47 2 , the equation of the sphere with object 72 as the center and distance 2 as the radius can be obtained as (x+2) 2 +(y) 2 +(z-4) 2 =2 2 , and the equation of the sphere with object 73 as the center and distance 6 as the radius can be obtained as (x+2) 2 +(y-4) 2 +(z) 2 =6 2 .

[0070] The controller 100 can obtain two intersection points of the three circles according to the spherical equations (a), (b) and (c), wherein the coordinates of the two intersection points are the two candidate coordinates of the radar 22. Then the controller 100 can select the real radar coordinates of the radar 22 from the two candidate coordinates according to the object 74. The controller 100 can calculate the distance between the object 74 and the radar 22 as 4.47 according to the coordinates C(74,22) of the object 74. Then, the controller 100 can obtain the spherical equation (d) with the object 74 as the center and the distance 4.47 as the radius: (x+2) 2 +(y-4) 2 +(z-4) 2 =4.47 2 The controller 100 can obtain the unique solution of the radar coordinates of the radar 22 as (0, 0, 4) according to the spherical equations (a), (b), (c), and (d).

[0071] When installing radars, all radars may point to different directions (i.e., the direction of the beam emitted by the radar). In practical applications, the multi-radar positioning system 10 may assume that the Z-axis directions of each radar are consistent. Accordingly, the controller 100 may project the coordinates of each radar onto the XY plane, thereby simplifying the calculation of the radar coordinates of each radar and the angle between the radars. Fig.13 For example, the controller 100 may project the coordinates C(74,21)=(-2,4,4) of the object 74 relative to the radar 21 onto the XY plane to obtain the coordinates (-2,4), and may project the coordinates C(74,23)=(2,0,0) of the object 74 relative to the radar 23 onto the XY plane to obtain the coordinates (2,0). Fig.13 As shown, θ1=116.57° is the arrival angle corresponding to the object 74 and the radar 21, θ2=0° is the arrival angle corresponding to the object 74 and the radar 23, and θ3=63.43° is the angle between the vector M=(-2,4) from the radar 21 to the object 74 and the vector N=(2,0) from the radar 23 to the object 74. The controller 100 can calculate the angle θ0=θ1+θ3-θ2=180° between the radar 21 and the radar 23 according to formula (3) in response to the arrival angle θ1 being greater than ninety degrees.

[0072] Fig.14 According to an embodiment of the present invention, a flow chart of a positioning method is shown, wherein the positioning method may be performed as follows: Figure 1The multi-radar positioning system 10 shown in FIG. 1 is implemented. In step S141, the first radar detects the first object and the second object to obtain the first coordinate and the second coordinate on the first coordinate system, respectively. In step S142, the second radar detects the first object and the second object to obtain the third coordinate and the fourth coordinate on the second coordinate system, respectively. In step S143, the first candidate coordinate and the second candidate coordinate of the second radar on the first coordinate system are estimated according to the third coordinate and the fourth coordinate. In step S144, the first candidate coordinate is selected from the first candidate coordinate and the second candidate coordinate according to the first coordinate and the second coordinate as the first radar coordinate of the second radar. In step S145, the first radar coordinate is output.

[0073] In summary, the multi-radar positioning system of the present invention can automatically calculate the relative positions of each radar without obtaining a global map, and then convert the detection results of each radar into the same coordinate system. Therefore, the present invention can save the time required to measure the global map, thereby speeding up the configuration of the multi-radar positioning system.

Claims

1. A multi-radar positioning system, comprising: a first radar, detecting a first object and a second object to obtain a first coordinate and a second coordinate on a first coordinate system respectively; a second radar, detecting the first object and the second object to obtain a third coordinate and a fourth coordinate on a second coordinate system respectively; as well as a controller, communicatively connected to the first radar and the second radar, and configured to: Estimate a first candidate coordinate and a second candidate coordinate of the second radar in the first coordinate system according to the third coordinate and the fourth coordinate; selecting the first candidate coordinate from the first candidate coordinate and the second candidate coordinate according to the first coordinate and the second coordinate as a first radar coordinate of the second radar; as well as The first radar coordinates are output.

2. The multi-radar positioning system of claim 1, wherein the controller is further configured to: Detecting a third object by the first radar to obtain a fifth coordinate on the first coordinate system, and detecting the third object by the second radar to obtain a sixth coordinate on the second coordinate system; and The first candidate coordinate is selected as the first radar coordinate according to the fifth coordinate and the sixth coordinate.

3. The multi-radar positioning system of claim 2, wherein the controller is further configured to: Calculating a first distance between the first candidate coordinate and the fifth coordinate, and obtaining a second distance between the sixth coordinate and the second radar; and In response to the first distance being equal to the second distance, the first candidate coordinate is selected as the first radar coordinate.

4. The multi-radar positioning system of claim 1, wherein the controller is further configured to: Obtain a first vector from the first candidate coordinate to the first coordinate, and obtain a second vector from the first candidate coordinate to the second coordinate; Obtaining a first arrival angle according to the third coordinate, and obtaining a second arrival angle according to the fourth coordinate; and The first candidate coordinate is selected as the first radar coordinate according to the first vector, the second vector, the first angle of arrival, and the second angle of arrival.

5. The multi-radar positioning system of claim 4, wherein the controller is further configured to: Rotating the first vector according to the first arrival angle to obtain a third vector, and rotating the second vector according to the second arrival angle to obtain a fourth vector; calculating a first angle between the third vector and the fourth vector; and In response to an absolute value of the first angle corresponding to the first candidate coordinate being smaller than an absolute value of a second angle corresponding to the second candidate coordinate, the first candidate coordinate is selected as the first radar coordinate.

6. The multi-radar positioning system of claim 1, wherein the controller is further configured to: Obtaining a first arrival angle according to the first coordinate, and obtaining a second arrival angle according to the third coordinate; Obtaining a first angle formed by a second radar coordinate of the first radar, the first coordinate, and the first radar coordinate; Calculating a second angle according to the first arrival angle, the second arrival angle, and the first angle, wherein the second angle indicates an angle between a first lateral direction of the first radar and a second lateral direction of the second radar; and The second angle is output.

7. The multi-radar positioning system of claim 6, wherein the controller is further configured to: In response to the first arrival angle being greater than ninety degrees, the second included angle is calculated according to a difference between a sum of the first arrival angle and the first included angle and the second arrival angle.

8. The multi-radar positioning system of claim 6, wherein the controller is further configured to: In response to the first arrival angle being less than or equal to ninety degrees, a first difference between the first arrival angle and the first included angle is calculated, and the second included angle is calculated based on a second difference between the first difference and the second arrival angle.

9. The multi-radar positioning system of claim 6, wherein the controller is further configured to: The count value stored in the controller is updated according to the second angle.

10. The multi-radar positioning system as claimed in claim 9, further comprising: a third radar communicatively coupled to the controller, wherein the controller is further configured to: Obtaining a second radar coordinate of the third radar in the second coordinate system; Rotate the second radar coordinate according to the count value to obtain a third radar coordinate of the third radar in the first coordinate system; as well as The third radar coordinates are output.

11. The multi-radar positioning system of claim 1 , wherein the controller is further configured to: determining a first distance between the first object and the second radar according to the third coordinate, and determining a second distance between the second object and the second radar according to the fourth coordinate; and In response to a third distance between a fifth coordinate on the first coordinate system and the first coordinate being equal to the first distance and a fourth distance between the fifth coordinate and the second coordinate being equal to the second distance, the fifth coordinate is determined to be one of the first candidate coordinate and the second candidate coordinate.

12. A positioning method for a multi-radar positioning system including a first radar and a second radar, comprising: Detecting a first object and a second object by the first radar to obtain a first coordinate and a second coordinate on a first coordinate system respectively; The second radar detects the first object and the second object to obtain a third coordinate and a fourth coordinate on a second coordinate system respectively; Estimate a first candidate coordinate and a second candidate coordinate of the second radar in the first coordinate system according to the third coordinate and the fourth coordinate; selecting the first candidate coordinate from the first candidate coordinate and the second candidate coordinate according to the first coordinate and the second coordinate as a first radar coordinate of the second radar; as well as The first radar coordinates are output.

13. The positioning method according to claim 12, wherein the step of selecting the first candidate coordinates from the first candidate coordinates and the second candidate coordinates as the first radar coordinates of the second radar according to the first coordinates and the second coordinates comprises: The first radar detects a third object to obtain a fifth coordinate on the first coordinate system, and the second radar detects the third object to obtain a sixth coordinate on the second coordinate system; as well as The first candidate coordinate is selected as the first radar coordinate according to the fifth coordinate and the sixth coordinate.

14. The positioning method according to claim 13, wherein the step of selecting the first candidate coordinate as the first radar coordinate according to the fifth coordinate and the sixth coordinate comprises: Calculating a first distance between the first candidate coordinate and the fifth coordinate, and obtaining a second distance between the sixth coordinate and the second radar; as well as In response to the first distance being equal to the second distance, the first candidate coordinate is selected as the first radar coordinate.

15. The positioning method according to claim 12, wherein the step of selecting the first candidate coordinates from the first candidate coordinates and the second candidate coordinates as the first radar coordinates of the second radar according to the first coordinates and the second coordinates comprises: Obtain a first vector from the first candidate coordinate to the first coordinate, and obtain a second vector from the first candidate coordinate to the second coordinate; Obtaining a first arrival angle according to the third coordinate, and obtaining a second arrival angle according to the fourth coordinate; as well as The first candidate coordinate is selected as the first radar coordinate according to the first vector, the second vector, the first angle of arrival, and the second angle of arrival.

16. The positioning method according to claim 15, wherein the step of selecting the first candidate coordinate as the first radar coordinate according to the first vector, the second vector, the first arrival angle, and the second arrival angle comprises: Rotating the first vector according to the first arrival angle to obtain a third vector, and rotating the second vector according to the second arrival angle to obtain a fourth vector; calculating a first angle between the third vector and the fourth vector; and In response to an absolute value of the first angle corresponding to the first candidate coordinate being smaller than an absolute value of a second angle corresponding to the second candidate coordinate, the first candidate coordinate is selected as the first radar coordinate.

17. The positioning method according to claim 12, further comprising: Obtaining a first arrival angle according to the first coordinate, and obtaining a second arrival angle according to the third coordinate; Obtaining a first angle formed by a second radar coordinate of the first radar, the first coordinate, and the first radar coordinate; Calculating a second angle according to the first arrival angle, the second arrival angle, and the first angle, wherein the second angle indicates an angle between a first lateral direction of the first radar and a second lateral direction of the second radar; and The second angle is output.

18. The positioning method according to claim 17, wherein the step of calculating the second angle according to the first arrival angle, the second arrival angle and the first angle comprises: In response to the first arrival angle being greater than ninety degrees, the second included angle is calculated according to a difference between a sum of the first arrival angle and the first included angle and the second arrival angle.

19. The positioning method according to claim 17, wherein the step of calculating the second angle according to the first arrival angle, the second arrival angle and the first angle comprises: In response to the first arrival angle being less than or equal to ninety degrees, a first difference between the first arrival angle and the first included angle is calculated, and the second included angle is calculated based on a second difference between the first difference and the second arrival angle.

20. The positioning method of claim 17, further comprising: The count value is updated according to the second angle.

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