Six-dimensional sensing radar system based on multi-beam detection and sensing method

Abstract

A six-dimensional perception radar based on multi-beam detection can measure the three-dimensional position and the three-dimensional speed of an object at the same time. The radar comprises a transmitting module, a multi-beam scanning module, a detection receiving module and a demodulation module. According to the specific measurement scheme, a plurality of detection beams in different directions are used for detecting a target object, and relative distances and velocity components of the target object in different detection beam directions are obtained; the three-dimensional position of the target object is determined according to the angle relation of the multiple detection beams of the radar and the relative distance obtained through measurement; and determining the three-dimensional speed of the target object according to the angle relation of the plurality of detection beams of the radar and the measured relative distance and speed component. On the basis of the three-dimensional position and the three-dimensional speed of the target object, six-dimensional parameters of the target object in the space can be determined, and then efficient target tracking, motion trail prediction and the like are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radar detection, and particularly relates to a six-dimensional perception radar system and a perception method based on multi-beam detection, which can simultaneously measure the three-dimensional position and three-dimensional velocity of a target object. BACKGROUND

[0002] Radar has practical application requirements in the fields of multi-target object detection and tracking, automatic driving, etc., and its role is to perform real-time three-dimensional perception on the surrounding environment, detect the motion of the object, so as to realize the functions of tracking the target object or responding to emergency situations, etc. In 2016, Ayush Dewan et al. reported in International Conference on Robotics and Automation (ICRA) that a model-free method was used to detect and track dynamic objects in 3D lidar scans obtained by a motion sensor (see Dewan A, Caselitz T, Tipaldi G D, et al. Motion-based detection and tracking in 3D lidar scans [C] / / 2016 IEEE international conference on robotics and automation (ICRA). IEEE, 2016: 4508-4513.), which realized the estimation of the motion model and the tracking of the moving object, but the accuracy of the velocity measurement using the traditional time of flight lidar was low, and the maximum velocity measurement error could reach the order of m / s.

[0003] At present, the detection and tracking of multi-target objects are mostly performed by using pictures or video information combined with deep learning, and there are few radar used for the detection and tracking of multi-target objects, which has the defects of high computational complexity, etc. The characteristics of simultaneously measuring the range and velocity of radar can realize the measurement of the Doppler velocity of the object, and further obtain the three-dimensional position and three-dimensional velocity of the object, so as to realize the functions of tracking the target object or responding to emergency situations, etc.

[0004] Therefore, it is of great significance to design a six-dimensional perception radar based on multi-beam detection, which can simultaneously measure the three-dimensional position and three-dimensional velocity of the object, and is expected to promote the practical application of radar in the fields of multi-target object detection and tracking, emergency escape, automatic driving, etc. SUMMARY

[0005] The present application aims at the deficiencies of the prior art, and provides a six-dimensional perception radar system and a perception method based on multi-beam detection, which realizes high-precision synchronous acquisition of three-dimensional position (X, Y, Z) and three-dimensional velocity (Vx, Vy, Vz) of a target object through multi-beam cooperative measurement and spatial geometry solution. The radar comprises a transmitting module, a multi-beam scanning module, a detection receiving module and a demodulation module. The specific measurement scheme uses multiple detection beams to detect the target object in different directions to obtain the relative distance and velocity component of the target object in different detection beam directions; the three-dimensional position of the target object is determined according to the angle relationship of the multiple detection beams of the radar and the measured relative distance; and the three-dimensional velocity of the target object is determined according to the angle relationship of the multiple detection beams of the radar and the measured relative distance and velocity component. According to the characteristics of the object itself, the motion can be divided into two-dimensional translation, three-dimensional translation and two-dimensional rotation for solution. The technical solution of the present application is as follows:

[0006] First, multiple detection beams are used to detect the target object in different directions to measure the relative distance and velocity component of the target object in different detection beam directions. The characteristics are that,

[0007] The radar can be a laser radar or a millimeter wave radar. The radar comprises four parts of a transmitting module, a multi-beam scanning module, a detection receiving module and a demodulation module. The transmitting module generates the required detection beams, and multiple beams can be transmitted in parallel, and the included angle between the beams is known; the multi-beam scanning module transmits each beam from the same point and scans at a fixed angle interval to facilitate the construction of the geometric relationship between the detection beams; the detection receiving module detects and converts the signals of the beams reflected by the target object; and the demodulation module obtains the distance and radial velocity of the target object along the beam.

[0008] According to the angle relationship of the multiple detection beams of the radar and the measured relative distance, the three-dimensional position of the target object can be determined; and according to the angle relationship of the multiple detection beams of the radar and the measured relative distance and velocity component, the three-dimensional velocity of the target object can be determined. According to the characteristics of the object itself, the motion can be divided into two-dimensional translation, three-dimensional translation and two-dimensional rotation for solution.

[0009] In the two-dimensional translation case, the radar uses at least two detection beams to detect the target object in different directions to obtain the distance measurement values L1, L2, …, L N and the velocity measurement values V1, V2, …, V N , wherein L1 and V1 are the distance value and velocity value measured by the first detection beam, L2 and V2 are the distance value and velocity value measured by the second detection beam, L N and V NThe distance and speed values ​​measured by the Nth detection beam.

[0010] According to the spatial geometric relationship of the multiple detection beams emitted by the radar and the principle of vector synthesis and decomposition, the following equations are obtained:

[0011]

[0012] Among them, θ i (i=1, 2, …, N) is the angle between the i-th detection beam and the first detection beam, and its sign corresponds to the positive or negative sign of the Doppler frequency shift measured by each detection beam. V is the absolute motion velocity of the target object to be determined, and α is the angle between the absolute motion velocity of the target object to be determined and the first detection beam.

[0013] When all the detection beams are in the same plane as the target object's motion direction, the absolute motion velocity V and direction α of the target object can be obtained by solving the equation group (1), that is, the three-dimensional velocity can be obtained.

[0014] When all the detection beams are in the same plane, but not in the same plane as the target object's motion direction, the velocity magnitude V and direction α obtained by solving equation (1) are the components of the target object's absolute motion velocity magnitude and direction on the detection beam plane.

[0015] In the case of three-dimensional translation, the radar uses at least three detection beams to detect the target object in different directions, and obtains the distance measurement values ​​L1, L2, ..., L N and speed measurement values ​​V1, V2, ..., V N , where L1 and V1 are the distance and speed values ​​measured by the first detection beam, L2 and V2 are the distance and speed values ​​measured by the second detection beam, L N and V N The distance and speed values ​​measured by the Nth detection beam.

[0016] According to the spatial geometric relationship of the multiple detection beams emitted by the radar and the principle of vector synthesis and decomposition, the following equations are obtained:

[0017]

[0018] Wherein, A is a transformation matrix composed of the position coordinates of the reflection points of each detection beam. x ,V y ,V z ] is the component of the actual motion velocity of the target object in the direction of each coordinate axis of the Cartesian coordinate system, V is the actual motion velocity of the target object to be determined, α i(i=x,y,z) is the angle between the actual velocity of the target object and each coordinate axis. By solving the above equations, the absolute velocity V and the direction of the velocity α of the target object can be obtained. i (i=x,y,z), that is, the three-dimensional velocity is obtained.

[0019] In the case of two-dimensional rotation, the radar uses at least three detection beams to detect the target object in different directions, and obtains velocity measurement values ​​V1, V2, ..., V of each detection beam. N and distance measurements L1, L2, ..., L N , where V1 and L1 are the speed and distance values ​​measured by the first detection beam, V2 and L2 are the speed and distance values ​​measured by the second detection beam, V N and L N The speed and distance values ​​measured by the Nth detection beam.

[0020] According to the spatial geometric relationship of the multiple detection beams emitted by the radar and the principle of vector synthesis and decomposition, the following equations are obtained:

[0021]

[0022] Where ω is the angular velocity of the object, [R1, R2, …, R N ] is the distance from the point where each detection beam is emitted to the target object to the rotation axis, [α1,α2,…,α N ] is the angle between the velocity of each detection beam at the point where it is emitted to the target object and the direction of the corresponding beam, is the angle between the two corresponding outgoing beams, is the distance between two points on the target object. [R1,R2,…,R N ] can be measured based on the distance values ​​L1, L2, ..., L of each detection beam N as well as Please solve.

[0023] When all the detection beams are in the same plane as the target object's motion direction, the target object's rotational angular velocity ω and the actual motion velocity V of each point can be obtained by solving the equation group shown in formula (3): i (i=1,2,…,N) and direction, that is, the three-dimensional velocity is obtained.

[0024] According to the spatial geometric relationship of the multiple detection beams emitted by the radar and the distance measurement values ​​L1, L2, ..., L N , obtain the point cloud image of the target object about the position, and then obtain the distance components of the target object on the x, y, and z coordinate axes in the coordinate system, and then determine the three-dimensional position.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] (1) The object motion speed error obtained by using pictures, video information and computer vision demodulation is large, and the present application can realize high-precision measurement of the three-dimensional position and three-dimensional speed of the object by using the ranging and speed measurement characteristics of the radar.

[0027] (2) The object motion information obtained by using pictures, video information and computer vision demodulation needs multiple frames of data, and the demodulation has a time delay. The present application can realize high-precision measurement of the three-dimensional position and three-dimensional speed of the object by using the ranging and speed measurement characteristics of the radar, only one frame of data is needed, the demodulation has instantaneity, and it is helpful for predicting the motion of the target object and responding to sudden situations.

[0028] (3) The calculation process of the object motion information obtained by using pictures, video information and computer vision demodulation is complex, and the calculation amount is large. The present application obtains the relative distance and radial speed component of the target object in the direction of the detection beam by using the radar measurement. According to the angle relationship of the multiple detection beams of the radar and the measured relative distance, the three-dimensional position of the target object is determined; according to the angle relationship of the multiple detection beams of the radar and the measured relative distance and speed component, the three-dimensional speed of the target object is determined, and the calculation complexity is low and the speed is fast.

[0029] (4) The present application has high universality, and the radar module can be a laser radar or a millimeter wave radar. The radar includes a transmitting module, a multi-beam scanning module, a detection receiving module and a demodulation module. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structural composition schematic diagram of the six-dimensional perception radar of the present application based on multi-beam detection.

[0031] Figure 2 is a schematic diagram of the spatial geometric relationship between the multiple detection beams emitted by the present application in the case of two-dimensional translation and the three-dimensional position and three-dimensional motion speed of the object.

[0032] Figure 3 is a schematic diagram of the spatial geometric relationship between the multiple detection beams emitted by the present application in the case of three-dimensional translation and the three-dimensional position and three-dimensional motion speed of the object.

[0033] Figure 4 is a schematic diagram of the spatial geometric relationship between the multiple detection beams emitted by the present application in the case of two-dimensional rotation and the three-dimensional position and three-dimensional motion speed of the object. DETAILED DESCRIPTION

[0034] The application will be further described below in conjunction with the embodiments and drawings. The embodiments are implemented on the premise of the technical solutions of the application, and detailed implementation manners and specific work flows are given, but the protection scope of the application is not limited to the following embodiments.

[0035] The target object is detected in different directions using multiple detection beams, and the relative distance and velocity component of the target object in the direction of the detection beam are measured. The radar can be a laser radar or a millimeter wave radar.

[0036] Figure 1 A structural diagram of the six-dimensional perception radar based on multi-beam detection is shown in the figure, and the radar system includes four parts of a transmitting module (1-2), a multi-beam scanning module (1-3), a detection receiving module (1-4), and a demodulation module (1-5). The transmitting module (1-2) generates the required detection beams, and multiple beams can be transmitted in parallel, and the included angle between the beams is known. The multi-beam scanning module (1-3) transmits each beam from the same point and scans at a fixed angular interval to facilitate the construction of the geometric relationship between each detection beam. The receiving module (1-4) detects and converts the signals of the beams reflected by the target object. The demodulation module (1-5) obtains the distance and radial velocity of the target object along the beam. According to the angle relationship of the multiple detection beams of the radar and the measured relative distance, the three-dimensional position of the target object can be determined; according to the angle relationship of the multiple detection beams of the radar and the measured relative distance and velocity component, the three-dimensional velocity of the target object can be determined.

[0037] Figure 2 is a schematic diagram of the spatial geometric relationship between the multiple detection beams emitted by the application in the case of two-dimensional translation and the three-dimensional position and three-dimensional motion velocity of the target object. The radar module involved here can be a laser radar or a millimeter wave radar, and its structure includes four parts of a transmitting module, a multi-beam scanning module, a detection receiving module, and a demodulation module. Multiple detection beams are transmitted in different directions to detect the target object, and the relative distance and velocity component of the target object in the direction of the detection beam are measured. According to the angle relationship of the multiple detection beams of the radar and the measured relative distance, the three-dimensional position of the target object can be determined; according to the angle relationship of the multiple detection beams of the radar and the measured relative distance and velocity component, the three-dimensional velocity of the target object can be determined.

[0038] In the case of two-dimensional translation, the radar (2-1) uses at least two detection beams to detect the target object in different directions, and obtains the distance measurement values L1, L2, …, L N and the velocity measurement values V1, V2, …, V Nwherein L1 and V1 are the distance value and velocity value measured by the first probe beam (2-2), L2 and V2 are the distance value and velocity value measured by the second probe beam (2-3), L v and V v are the distance value and velocity value measured by the Nth probe beam (2-4).

[0039] According to the spatial geometric relationship of the multiple probe beams emitted by the radar (2-1) and the vector synthesis decomposition principle, the following equation group is obtained:

[0040]

[0041] wherein θ i (i = 1, 2, …, N) is the included angle between the ith probe beam and the first probe beam, the positive or negative sign corresponds to the positive or negative of the Doppler shift measured by each probe beam, V is the absolute motion velocity of the target object to be solved, and a is the included angle between the absolute motion velocity of the target object to be solved and the first probe beam.

[0042] When all the probe beams are in the same plane as the direction of motion of the target object, the absolute motion velocity V and the direction a of the target object can be obtained by solving the equation group of formula (1), that is, the three-dimensional velocity is obtained.

[0043] When all the probe beams are in the same plane but not in the same plane as the direction of motion of the target object, the velocity V and the direction a obtained by solving formula (1) are the components of the absolute motion velocity size and direction of the target object in the plane of the probe beam.

[0044] According to the spatial geometric relationship of the multiple probe beams emitted by the radar and the distance measurement values L1, L2, …, L N of each probe beam, the point cloud image of the target object with respect to the position is obtained, and then the distance components of the target object on the x, y, and z coordinate axes in the coordinate system are obtained, and then the three-dimensional position is determined.

[0045] Figure 3 is a schematic diagram of the spatial geometric relationship between the multiple probe beams emitted by the radar in the three-dimensional translational case and the three-dimensional position and three-dimensional motion velocity of the target object. The radar module emits multiple probe beams to detect the target object in different directions, and measures the relative distance and velocity components of the target object in the direction of the probe beam. According to the angle relationship of the multiple probe beams of the radar and the measured relative distance, the three-dimensional position of the target object can be determined; according to the angle relationship of the multiple probe beams of the radar and the measured relative distance and velocity components, the three-dimensional velocity of the target object can be determined.

[0046] In the case of three-dimensional translation, the radar (3-1) uses at least three detection beams to detect the target object in different directions, and obtains distance measurement values L1, L2, …, L N and velocity measurement values V1, V2, …, V N , wherein L1 and V1 are the distance value and velocity value measured by the first detection beam (3-2), L2 and V2 are the distance value and velocity value measured by the second detection beam (3-3), L N and V N are the distance value and velocity value measured by the Nth detection beam (3-4).

[0047] According to the spatial geometric relationship of the multiple detection beams emitted by the radar and the vector synthesis decomposition principle, the following equation group is obtained:

[0048]

[0049] , wherein A is a conversion matrix composed of the position coordinates of the reflection points of the detection beams.[V x ,V y ,V z ] are the components of the actual motion velocity of the target object in the direction of each coordinate axis in the Cartesian coordinate system, V is the target object actual motion velocity to be solved, and α i (i=x, y, z) is the angle between the actual motion velocity of the target object and each coordinate axis. By solving the above equation group, the absolute velocity V and the motion velocity direction α i (i=x, y, z) of the target object can be obtained, that is, the three-dimensional velocity is obtained.

[0050] According to the spatial geometric relationship of the multiple detection beams emitted by the radar and the distance measurement values L1, L2, …, L N of the detection beams, the point cloud image of the target object with respect to the position is obtained, and then the distance components of the target object on the x, y, and z coordinate axes in the coordinate system are obtained, and then the three-dimensional position is determined.

[0051] Figure 4 is a schematic diagram of an embodiment of the spatial geometric relationship between the multiple detection beams emitted by the radar in the case of two-dimensional rotation and the three-dimensional position and three-dimensional motion velocity of the target object. The radar module emits multiple detection beams to detect the target object in different directions, and measures the relative distance and velocity component of the target object in the direction of the detection beam. According to the spatial geometric relationship of the multiple detection beams emitted by the radar and based on the vector synthesis decomposition principle, the motion velocity size and direction of the target object can be demodulated.

[0052] In the case of two-dimensional rotation, the radar (4-1) uses at least three detection beams to detect the target object in different directions, and obtains velocity measurement values ​​V1, V2, ..., V N and distance measurements L1, L2, ..., L N , where V1 and L1 are the speed and distance values ​​measured by the first detection beam (4-2), V2 and L2 are the speed and distance values ​​measured by the second detection beam (4-3), V N and L N The speed and distance values ​​measured by the Nth detection beam (4-4) are:

[0053] According to the spatial geometric relationship of the multiple detection beams emitted by the radar (4-1) and the principle of vector synthesis and decomposition, the following equations are obtained:

[0054]

[0055] Where ω is the angular velocity of the object, [R1, R2, …, R N ] is the distance from the point where each detection beam is emitted to the target object to the rotation axis, [α1,α2,…,α N ] is the angle between the velocity of each detection beam at the point where it is emitted to the target object and the direction of the corresponding beam, is the angle between the two corresponding outgoing beams, is the distance between two points on the target object. [R1,R2,…,R N ] can be measured based on the distance values ​​L1, L2, ..., L of each detection beam N as well as Please help.

[0056] When all the detection beams are in the same plane as the target object's motion direction, the target object's rotational angular velocity ω and the actual motion velocity V of each point can be obtained by solving the equation group shown in formula (3): i (i=1,2,…,N) and direction, that is, the three-dimensional velocity is obtained.

[0057] According to the spatial geometric relationship of the multiple detection beams emitted by the radar and the distance measurement values ​​L1, L2, ..., L N , obtain the point cloud image of the target object about the position, and then obtain the distance components of the target object on the x, y, and z coordinate axes in the coordinate system, and then determine the three-dimensional position.

Claims

1. A six-dimensional perception radar system based on multi-beam detection, characterized in that: include: a transmitting module configured to simultaneously transmit at least two probing beams having a fixed spatial angle; The multi-beam scanning module is used to control the emission of each detection beam from the same point and scan at fixed angle intervals to establish the spatial geometric relationship between the detection beams; A receiving module is used to receive the beam signal reflected by the target object and perform signal conversion; The demodulation module is used to demodulate the echo signals of each detection beam, obtain the distance information and radial velocity information of the target object in the direction of each beam, and calculate the three-dimensional position and three-dimensional velocity of the target object based on the spatial geometric relationship between the beams.

2. The six-dimensional perception radar system based on multi-beam detection according to claim 1 is characterized in that: The transmitting module adopts a laser transmitter or a millimeter wave transmitter, and the angle between each detection beam is adjustable in the range of 0.1° to 30°.

3. The six-dimensional perception radar system based on multi-beam detection according to claim 1 is characterized in that: The demodulation module determines the three-dimensional position of the target object by: According to the spatial geometric relationship of each detection beam and the distance measurement values ​​L1, L2, ..., L N , obtain the point cloud image of the target object about the position; Based on the point cloud image, the x, y, and z coordinate components of the target object in the Cartesian coordinate system are calculated to determine the three-dimensional position.

4. The six-dimensional perception radar system based on multi-beam detection according to claim 1 is characterized in that: The demodulation module calculates the three-dimensional velocity in different ways according to the motion type of the target object: (1) In the case of two-dimensional translation: use at least two detection beams to detect the target object in different directions, and obtain the distance measurement values ​​L1, L2, ..., L N and speed measurement values ​​V1, V2, ..., V N , where L1 and V1 are the distance and speed values ​​measured by the first detection beam (2-2), L2 and V2 are the distance and speed values ​​measured by the second detection beam (2-3), L N and V N The distance and velocity values ​​measured by the Nth detection beam (2-4); According to the spatial geometric relationship of the multiple detection beams emitted by the radar (2-1) and the principle of vector synthesis and decomposition, the following equations are obtained: Among them, θ i (i=1, 2, …, N) is the angle between the i-th detection beam and the first detection beam, and its sign corresponds to the sign of the Doppler shift measured by each detection beam. V is the absolute velocity of the target object to be determined, and α is the angle between the absolute velocity of the target object to be determined and the first detection beam. When all the detection beams are in the same plane as the target object's motion direction, by solving the equation group (1), the absolute motion velocity V and direction α of the target object can be obtained, that is, the three-dimensional velocity can be obtained; When all the detection beams are in the same plane, but not in the same plane as the target object's motion direction, the velocity magnitude V and direction α obtained by solving equation (1) are the components of the target object's absolute motion velocity magnitude and direction on the detection beam plane. (2) In the case of three-dimensional translation: use at least three detection beams to detect the target object in different directions, and obtain the distance measurement values ​​L1, L2, ..., L N and speed measurement values ​​V1, V2, ..., V N , where L1 and V1 are the distance and speed values ​​measured by the first detection beam (3-2), L2 and V2 are the distance and speed values ​​measured by the second detection beam (3-3), L N and V N The distance and velocity values ​​measured by the Nth detection beam (3-4); According to the spatial geometric relationship of the multiple detection beams emitted by the radar (3-1) and the principle of vector synthesis and decomposition, the following equations are obtained: Wherein, A is a transformation matrix composed of the position coordinates of the reflection points of each detection beam. x ,V y ,V z ] is the component of the actual motion velocity of the target object in the direction of each coordinate axis of the Cartesian coordinate system, V is the actual motion velocity of the target object to be determined, α i (i=x,y,z) is the angle between the actual velocity of the target object and each coordinate axis. By solving the above equations, the absolute velocity V and the direction of the velocity α of the target object can be obtained. i (i=x,y,z), that is, the three-dimensional velocity is obtained; (3) In the case of two-dimensional rotation: use at least three detection beams to detect the target object in different directions, and obtain velocity measurement values ​​V1, V2, ..., V N and distance measurements L1, L2, ..., L N , where V1 and L1 are the speed and distance values ​​measured by the first detection beam (4-2), V2 and L2 are the speed and distance values ​​measured by the second detection beam (4-3), V N and L N The speed and distance values ​​measured by the Nth detection beam (4-4); According to the spatial geometric relationship of the multiple detection beams emitted by the radar (4-1) and the principle of vector synthesis and decomposition, the following equations are obtained: Where ω is the angular velocity of the object, [R1, R2, …, R N ] is the distance from the point where each detection beam is emitted to the target object to the rotation axis, [α1,α2,…,α N ] is the angle between the velocity of each detection beam at the point where it is emitted to the target object and the direction of the corresponding beam, is the angle between the two corresponding outgoing beams, is the distance between two points on the target object. [R1,R2,…,R N ] can be measured based on the distance values ​​L1, L2, ..., L of each detection beam N as well as Solve; When all the detection beams are in the same plane as the target object's motion direction, the target object's rotational angular velocity ω and the actual motion velocity V of each point can be obtained by solving the equation group shown in formula (3): i (i=1,2,…,N) and direction, that is, the three-dimensional velocity is obtained.

5. A six-dimensional sensing method based on multi-beam detection, characterized in that: The steps include: Simultaneously emitting at least two probe beams having a fixed spatial angle; receiving each detection beam signal reflected by the target object; The relative distance (L) and radial velocity (V) in each beam direction are demodulated, and the three-dimensional position (X, Y, Z) of the target object is calculated based on the spatial geometric relationship between the beams. The three-dimensional velocity (Vx, Vy, Vz) is solved using vector decomposition or rotational motion models based on the target motion type (translational or rotational).

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