Four-transmitter, four-receiver millimeter-wave radar and its detection method

Abstract

This application provides a four-transmit, four-receive millimeter-wave radar and its detection method. The radar includes an antenna group and a main control module. The phase centers of the four receiving antennas in the antenna group are equally spaced along a preset horizontal direction. The phase centers of the first, second, and third transmitting antennas, as well as the fourth and third transmitting antennas, are distributed along the first and second preset directions in a preset coordinate system, respectively. The main control module is used to execute the detection method, which includes: sequentially controlling the second, first, third, and fourth transmitting antennas to transmit radar signals to the target; when each receiving antenna samples the echo signal of the same transmitting antenna, analyzing the echo signal to obtain point cloud data; and performing phase compensation on the instantaneous horizontal angle and instantaneous elevation angle of each point according to each transmitting antenna, its phase center, and each instantaneous velocity to obtain compensated horizontal angle and compensated elevation angle, which are then combined with instantaneous distance and instantaneous velocity as sensing information.

Description

Technical Field

[0001] This application relates to the field of millimeter-wave radar technology, and in particular to a four-transmitter, four-receiver millimeter-wave radar and its detection method. Background Technology

[0002] Existing millimeter-wave radars generally rely on multiple-input multiple-output (MIMO) virtual arrays to improve angular resolution. In order to balance the effective aperture in both horizontal and elevation dimensions, the area occupied by the transmitting and receiving antennas needs to be expanded, which causes the chip area of ​​millimeter-wave radar to increase in tandem with the antenna size, thereby increasing the cost of hardware and algorithms. Summary of the Invention

[0003] This application provides a four-transmit, four-receive millimeter-wave radar and its detection method. By using a four-transmit, four-receive antenna array, a sequential transmission strategy, and phase compensation processing, it can achieve high-precision detection of horizontal and elevation angles while suppressing the increase in area, hardware, and algorithm costs caused by the expansion of antenna size.

[0004] In a first aspect, embodiments of this application provide a four-transmitter, four-receiver millimeter-wave radar. The four-transmitter, four-receiver millimeter-wave radar includes an antenna group and a main control module. The antenna group includes four transmitting antennas and four receiving antennas. The phase centers corresponding to the four receiving antennas are evenly distributed along a predetermined horizontal direction in a predetermined coordinate system. The four transmitting antennas include a first transmitting antenna, a second transmitting antenna, a third transmitting antenna, and a fourth transmitting antenna. The phase centers corresponding to the first, second, and third transmitting antennas are arranged along a first predetermined direction in the predetermined coordinate system, and the phase centers corresponding to the fourth and third transmitting antennas are arranged along a second predetermined direction in the predetermined coordinate system. The first predetermined direction and the second predetermined direction form a predetermined angle in the predetermined coordinate system. The main control module includes a memory and a processor. The memory stores a computer program. The processor executes the computer program to implement a detection method for the four-transmitter, four-receiver millimeter-wave radar. The detection method for the four-transmitter, four-receiver millimeter-wave radar includes: sequentially controlling the second transmitting antenna, the... The first, third, and fourth transmitting antennas transmit radar signals to the target under test. When each receiving antenna samples the echo signal from the same transmitting antenna, signal processing is performed on the corresponding echo signal to obtain a digital signal, wherein the echo signal is the radar signal reflected by the target under test. A multi-dimensional Fourier transform is performed on the digital signal to generate a range-Doppler map, wherein the multi-dimensional dimensions include range and velocity dimensions. Constant false alarm rate (CFAR) detection is performed on the range-Doppler map to obtain point cloud data, wherein the point cloud data includes multiple points and instantaneous sensing information corresponding to each point. Each instantaneous sensing information includes the instantaneous distance, instantaneous velocity, instantaneous horizontal angle, and instantaneous elevation angle of the corresponding point in the range-Doppler map. Based on each transmitting antenna and its corresponding phase center, and each instantaneous velocity, phase compensation is performed on the instantaneous horizontal angle and instantaneous elevation angle corresponding to each point to obtain compensated horizontal angle and compensated elevation angle. The instantaneous distance, instantaneous velocity, compensated horizontal angle, and compensated elevation angle are used as the sensing information.

[0005] Secondly, embodiments of this application provide a detection method for a four-transmitter, four-receiver millimeter-wave radar. The detection method is used to detect a target to obtain corresponding sensing information, including distance, velocity, horizontal angle, and elevation angle. The millimeter-wave radar is equipped with an antenna group, which includes four transmitting antennas and four receiving antennas. The phase centers of the four receiving antennas are evenly distributed along a preset horizontal direction in a preset coordinate system. The four transmitting antennas include a first transmitting antenna, a second transmitting antenna, a third transmitting antenna, and a fourth transmitting antenna. The phase centers of the first, second, and third transmitting antennas are arranged along a first preset direction in the preset coordinate system, and the phase centers of the fourth and third transmitting antennas are arranged along a second preset direction in the preset coordinate system. The first preset direction and the second preset direction form a preset angle in the preset coordinate system. The detection method includes: sequentially controlling the second transmitting antenna, the first transmitting antenna, the third transmitting antenna, and the fourth transmitting antenna. The antenna and the fourth transmitting antenna transmit radar signals to the target under test. When each receiving antenna samples the echo signal from the same transmitting antenna, the corresponding echo signal is processed to obtain a digital signal, which is the radar signal reflected by the target under test. The digital signal is processed by a multi-dimensional Fourier transform to generate a range Doppler map, which includes a range dimension and a velocity dimension. The range Doppler map is subjected to constant false alarm rate (CFAR) detection to obtain point cloud data, which includes multiple points and the instantaneous sensing information corresponding to each point. Each instantaneous sensing information includes the instantaneous distance, instantaneous velocity, instantaneous horizontal angle, and instantaneous elevation angle of the corresponding point in the range Doppler map. Based on each transmitting antenna and the phase center corresponding to each transmitting antenna, as well as each instantaneous velocity, the instantaneous horizontal angle and instantaneous elevation angle corresponding to each point are phase-compensated to obtain compensated horizontal angle and compensated elevation angle. The instantaneous distance, instantaneous velocity, compensated horizontal angle, and compensated elevation angle are used as the sensing information.

[0006] The aforementioned four-transmitter, four-receiver millimeter-wave radar and its detection method utilize an asymmetrical, equidistant array of antennas arranged along different preset directions within a preset coordinate system. The four transmitting antennas are then sequentially activated. By combining instantaneous velocity phase compensation with the output of compensated horizontal and elevation angles, high-precision detection is achieved without expanding the antenna area, thus mitigating the increase in area, hardware, and algorithm costs caused by antenna expansion. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0008] Figure 1 This is a structural block diagram of a four-transmitter, four-receiver millimeter-wave radar provided in an embodiment of this application.

[0009] Figure 2 This is a schematic diagram of the phase center of the antenna group provided in the embodiments of this application in a preset coordinate system.

[0010] Figure 3 A coordinate table of the phase center of the antenna group provided in the embodiments of this application in a preset coordinate system.

[0011] Figure 4 A flowchart illustrating the detection method of a four-transmitter, four-receiver millimeter-wave radar provided in an embodiment of this application.

[0012] Figure 5 A flowchart of step S103 provided in the embodiments of this application.

[0013] Figure 6 A flowchart of step S1031 provided in the embodiments of this application.

[0014] Figure 7 A flowchart of step S1032 provided in the embodiments of this application.

[0015] Figure 8 A flowchart of step S105 provided in the embodiments of this application.

[0016] Figure 9 This is a schematic diagram of the radar signal transmitted by the transmitting antenna provided in an embodiment of this application.

[0017] Figure 10 This is a schematic diagram illustrating the verification of the accuracy of perceived information provided in an embodiment of this application.

[0018] Figure 11 This is a schematic diagram of the internal structure of the main control module provided in the embodiments of this application.

[0019] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0021] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar planned objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data are interchangeable where appropriate; in other words, the described embodiments are implemented according to a sequence other than that illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, may also include other content; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] It should be noted that the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0023] Please refer to Figure 1This is a structural block diagram of a four-transmitter, four-receiver millimeter-wave radar provided in an embodiment of this application. This application provides a four-transmitter, four-receiver millimeter-wave radar 10. The four-transmitter, four-receiver millimeter-wave radar 10 includes an antenna group 200 and a main control module 100. The antenna group 200 includes four transmitting antennas and four receiving antennas Rx1-Rx4. The four transmitting antennas include a first transmitting antenna Tx1, a second transmitting antenna Tx2, a third transmitting antenna Tx3, and a fourth transmitting antenna Tx4. The phase centers corresponding to the four receiving antennas Rx1-Rx4 are evenly distributed along a preset horizontal direction X in a preset coordinate system. The phase centers corresponding to the first transmitting antenna Tx1, the second transmitting antenna Tx2, and the third transmitting antenna Tx3 are arranged in a first preset direction D1 in the preset coordinate system. The third transmitting direction Tx3 and the fourth transmitting direction Tx4 are arranged along a second preset direction D2 in the preset coordinate system. More specifically, along the preset horizontal direction X, the phase centers corresponding to the third transmitting antenna Tx3, the first transmitting antenna Tx1, and the second transmitting antenna Tx2 are arranged sequentially, and the spacing between the phase centers corresponding to adjacent transmitting antennas is equal. Along the preset vertical direction Z, the phase centers corresponding to the third transmitting antenna Tx3, the first transmitting antenna Tx1, and the second transmitting antenna Tx2 are also arranged sequentially, and the spacing between the phase centers corresponding to adjacent transmitting antennas is equal. In this application, the preset coordinate system is the zOx coordinate system. The first preset direction D1 and the second preset direction D2 form a preset angle in the preset coordinate system. The preset horizontal direction X and the preset vertical direction Z are perpendicular to each other in the preset coordinate system. For example, the preset horizontal direction X and the preset vertical direction Z can be the x-axis direction and the z-axis direction, respectively, in the preset coordinate system. The angle value of the preset angle can be customized according to the deployment requirements of the transmitting antennas.

[0024] Furthermore, the spacing between adjacent receiving antennas and the spacing between adjacent transmitting antennas are determined by the operating wavelength of the millimeter-wave radar. The second preset direction D2 and the preset horizontal direction X are parallel to each other in the preset coordinate system. That is to say, the phase centers corresponding to the fourth transmitting antenna Tx4 and the third transmitting antenna Tx3 are aligned in the preset vertical direction Z.

[0025] The main control module 100 is used to execute the detection method of a four-transmit, four-receive millimeter-wave radar. The four-transmit, four-receive millimeter-wave radar 10 provided in this application can execute the corresponding detection method through the main control module 100 to acquire sensing information within a limited virtual channel, forming effective apertures for horizontal and elevation angles for high-precision detection, while suppressing the increase in area, hardware, and algorithm costs caused by antenna expansion. The sensing information in this application includes range, velocity, horizontal angle, and elevation angle. This sensing information can be used to make the four-transmit, four-receive millimeter-wave radar 10 suitable for various application scenarios, such as outlining the contours of the target, distinguishing between the horizon and high-altitude objects, and improving the classification and tracking capabilities of stationary vehicles, roadside guardrails, speed bumps, and overpasses. The features of the main control module 100 will be further described below. The following will describe how to implement the detection method of the four-transmit, four-receive millimeter-wave radar.

[0026] Please refer to Figure 4 This is a flowchart of a detection method for a four-transmitter, four-receiver millimeter-wave radar provided in an embodiment of this application. The detection method for a four-transmitter, four-receiver millimeter-wave radar includes steps S101-S106.

[0027] Step S101: Sequentially control the second transmitting antenna, the first transmitting antenna, the third transmitting antenna, and the fourth transmitting antenna to transmit radar signals to the target under test.

[0028] In step S101, the radar signal can be a CHIRP signal. A CHIRP signal is a linear frequency modulated signal whose carrier frequency can change linearly over its duration. The target to be detected is the target expected to be detected in the application scenario of the four-transmitter, four-receiver millimeter-wave radar 10. For example, when the four-transmitter, four-receiver millimeter-wave radar 10 is applied to a vehicle, the target to be detected can be the horizon, high-altitude objects, other vehicles, roadside guardrails, speed bumps, overpasses, etc. The radar signal corresponding to each transmitting antenna includes multiple pulses. In one embodiment, an example of the waveform parameters of a single pulse is: a starting frequency of 79 GHz, an idle time of 3 μs, linear modulation at 320 MHz within 14 μs, and a total duration of 17 μs. For each sequentially selected transmitting antenna, the same transmitting antenna continuously transmits Q pulses to form a radar signal. The four transmitting antennas use a time-division multiplexing method to transmit in turn. That is, after the second transmitting antenna Tx2 transmits all Q pulses to the target under test, the first transmitting antenna Tx1, the third transmitting antenna Tx3, and the fourth transmitting antenna Tx4 then transmit all Q pulses to the target under test in sequence, just like the second transmitting antenna Tx2.

[0029] Step S102: When each receiving antenna samples the echo signal from the same transmitting antenna, the corresponding echo signal is processed to obtain a digital signal.

[0030] In step S102, the echo signal is the radar signal reflected by the target under test. Signal processing includes radio frequency (RF) processing and digital-to-analog (DAC) processing. RF processing includes, but is not limited to, low-noise amplification, mixing, and filtering. DAC processing can be implemented using a DAC. In this application, the digital signal is represented as s(p,q; m,n), where m represents the m-th transmitting antenna, n represents the n-th receiving antenna, q represents the q-th pulse, and p represents the sampled value corresponding to the q-th pulse. In this application, the sampled value can be a discrete complex voltage value obtained after DAC processing, i.e., a time-domain sampling sequence, which carries the distance, velocity, and angle information of the target under test, and also determines the resolution and angle measurement accuracy of the subsequent point cloud.

[0031] Step S103: Perform multi-dimensional Fourier transform processing on the digital signal to generate a distance Doppler map.

[0032] In step S103, the multi-dimensional aspect includes both range and velocity dimensions. This application uses Fourier transform processing to convert the time-domain sampling sequence of each pulse into a highly visual range-Doppler image, intuitively displaying the target's distribution characteristics at different distances and velocities, providing crucial input for subsequent constant false alarm rate (CFAR) detection and phase compensation.

[0033] Please refer to Figure 5 The flowchart below shows step S103, which is a sub-step provided in the embodiments of this application. The process of generating a range Doppler map by performing multi-dimensional Fourier transform processing on the digital signal includes steps S1031-S1033.

[0034] Step S1031: Perform a Fast Fourier Transform on the digital signal based on the distance dimension to obtain distance transform data.

[0035] In step S1031, the Fourier transform processing is performed as a Fast Fourier Transform (FFT). This application converts the time-domain sampling sequence of each pulse into a spectrum by performing a Fast Fourier Transform on the digital signal in the distance dimension, so that the echoed digital signal is mapped to a discrete distance gate, thereby obtaining distance transform data for subsequent velocity processing and angle estimation.

[0036] Please refer to Figure 5 This is a flowchart of step S103, a sub-step provided in the embodiments of this application. The process of performing a Fast Fourier Transform on the digital signal based on the distance dimension to obtain distance transform data includes steps S10311-S10313.

[0037] Step S10311: Use the first formula to perform distance-average processing on the digital signal.

[0038] In step S10311, the first formula is expressed as follows: Where s1(p,q;m,n) represents the digital signal after distance-average subtraction processing, and P represents the total number of sampled values. This application removes the influence of DC signals in the digital signal on subsequent velocity processing and angle estimation by performing distance-average subtraction processing on the digital signal.

[0039] Step S10312: Apply a distance window to the digital signal after the distance mean subtraction process using the second formula.

[0040] In step S10312, the second formula is expressed as s2(p,q;m,n)=s1(p,q;m,n)ω R (p), where s2(p,q;m,n) represents the digital signal after distance windowing, ω R (p) represents a preset range window function used for range windowing. In this application, the preset range window function can be a Hamming window, Hanning window, or Chebyshev window, etc. By applying a range window to the digital signal after subtracting the mean range using the preset range window function, the sidelobes can be reduced and the confidence of the main lobe can be improved, thereby enhancing the resolution of the target in subsequent processing.

[0041] Step S10313: Perform a fast Fourier transform on the digital signal after distance windowing to obtain distance transform data.

[0042] Step S1032: Perform a Fast Fourier Transform on the distance transformation data based on the velocity dimension to obtain velocity transformation data.

[0043] In step S1032, based on the velocity dimension, an FFT is performed on the distance transformation data obtained in step S1031 along the sequence corresponding to the pulse, converting the time-domain phase change into a Doppler frequency shift, thereby mapping the radial velocity of the target to be measured into a discrete velocity gate, and obtaining velocity transformation data, which provides velocity dimension information for subsequent constant false alarm detection and angle estimation.

[0044] Please refer to Figure 6 This is a flowchart of sub-step S1032 provided in the embodiments of this application. Obtaining velocity transformation data by performing a Fast Fourier Transform on the distance transformation data based on the velocity dimension includes steps S10321-S10322.

[0045] Step S10321: Apply acceleration windowing to the distance transformation data using the third formula.

[0046] In step S10321, the third formula is expressed as s4(p,q;m,n)=s3(p,q;m,n)ω v (q), where s4(p,q;m,n) represents the distance transformation data after acceleration windowing, s3(p,q;m,n) represents the distance transformation data, and ωk (q) represents a preset velocity window function used for acceleration windowing. In this application, the preset velocity window function can be a Hamming window, Hanning window, or Chebyshev window, etc. By performing acceleration windowing on the range transform data using a preset velocity window function, the velocity dimension sidelobes can be reduced, thereby improving the reliability of the Doppler frequency shift of the target and enhancing the system's anti-interference capability in complex environments.

[0047] Step S10322: Perform a fast Fourier transform on the distance transformation data after acceleration window processing to obtain velocity transformation data.

[0048] Step S1033: Calculate the distance Doppler map based on the velocity transformation data.

[0049] In step S1033, calculating the range Doppler map based on the velocity transformation data specifically includes the following steps: calculating the range Doppler map using the fourth formula on the velocity transformation data. In this application, the fourth formula is expressed as follows: Wherein, s6(P,Q) represents the range Doppler image, and s5(p,q; m,n) represents the velocity transformation data. In this application, each pixel in the range Doppler image represents a resolvable "range-velocity" unit. Accordingly, the width of the range unit and the width of the velocity unit in the range Doppler image can be determined by the slope and total number of pulses of each radar signal in step S101. By visualizing the amplitude information in the spectrum corresponding to the velocity dimension through the range Doppler image, the distribution characteristics of the target at different distances and velocities are intuitively displayed, providing key input for subsequent constant false alarm rate detection and point cloud generation.

[0050] Step S104: Perform constant false alarm rate (CFAR) detection on the distance Doppler image to obtain point cloud data.

[0051] In step S104, the point cloud data includes multiple points and the instantaneous sensing information corresponding to each point. Each instantaneous sensing information includes the instantaneous distance, instantaneous velocity, instantaneous horizontal angle, and instantaneous pitch angle of the corresponding point in the distance-Doppler map. The instantaneous distance is used to obtain the distance, and the instantaneous velocity is used to obtain the velocity. Specifically, the point cloud data is represented as follows: Where, r k v represents the instantaneous distance of the k-th point. k Let θ represent the instantaneous velocity at the k-th point. k This represents the instantaneous horizontal angle at the k-th point. Let α represent the instantaneous pitch angle at the k-th point. k This represents the echo intensity at the k-th point, used to measure the reflectivity of the target. It provides a basis for subsequent operations such as confidence scoring, classification, noise filtering, and visualization of the target, improving the purity of the point cloud data and the reliability of subsequent identification. Where r... k Represented as rk =P k δ R v k Represented as v k =Q k δ V P k δ represents the distance dimension index value of the k-th point obtained by constant false alarm rate detection in the Doppler map. R Q represents the preset distance resolution. k δ represents the velocity dimension index value of the k-th point obtained by constant false alarm rate (CFAR) detection in the Doppler map. V This represents the preset velocity resolution. In other words, it represents the velocity resolution corresponding to each point r. k and v k The distance and velocity of the target relative to the millimeter-wave radar within the corresponding time sequence of the sampled values ​​are formed. In this application, constant false alarm rate (CFAR) detection includes, but is not limited to, Cell-Averaging Constant False Alarm Rate (CA-CFAR) and Ordered Statistical Constant False Alarm Rate (OS-CFAR). The preset range resolution and preset velocity resolution can be preset together when transmitting the radar signal in step S101. For example, in this application, the preset range resolution can be set to 1.17m, and the preset velocity resolution can be set to 0.1463m / s. The range Doppler image is analyzed through CFAR detection to extract information such as the instantaneous distance, instantaneous velocity, instantaneous horizontal angle, instantaneous elevation angle, and echo intensity of the target, forming point cloud data. It is understood that each point in the point cloud data contains the above five types of information, comprehensively describing the spatiotemporal position and reflection characteristics of the target, providing a basis for subsequent operations such as confidence scoring, classification and filtering, noise removal, and visualization of the target.

[0052] Step S105: Based on each transmitting antenna and its corresponding phase center, as well as each instantaneous velocity, perform phase compensation on the instantaneous horizontal angle and instantaneous elevation angle corresponding to each point to obtain the compensated horizontal angle and compensated elevation angle.

[0053] Please refer to Figure 7 The flowchart below shows step S105, which is provided in the embodiment of this application. Based on each transmitting antenna and its corresponding phase center, as well as each instantaneous velocity, phase compensation is performed on the instantaneous horizontal angle and instantaneous elevation angle corresponding to each point to obtain the compensated horizontal angle and compensated elevation angle, including steps S1051-S1053.

[0054] Step S1051: Based on the four transmitting antennas and the instantaneous velocity and index value of any point among the plurality of points, the Doppler phase compensation process is performed on any point using the fifth formula to obtain the compensation result.

[0055] In step S1051, the index values ​​include the distance dimension index value and the velocity dimension index value corresponding to any point. The compensation result is used to perform angle compensation on the points corresponding to each pulse and its corresponding sample value in the point cloud data. The expression of the fifth formula in this application is:

[0056] Wherein, λ represents the operating wavelength of the four-transmitter, four-receiver millimeter-wave radar 10, which can be set and adjusted independently according to the application scenarios applicable to the four-transmitter, four-receiver millimeter-wave radar 10.

[0057] Step S1052: Based on the compensation results and the phase center corresponding to each transmitting antenna, calculate the compensated horizontal angle and the compensated elevation angle using the sixth formula.

[0058] In step S1052, the compensated horizontal angle and compensated pitch angle are calculated using the matched filtering principle based on the spatial position relationship. It can be understood that when the target reaches the true horizontal and pitch angles (i.e., the compensated horizontal and pitch angles of this application), the coherent accumulation of the signals will reach its maximum value. The expression for the sixth formula is:

[0059] in, The expression is:

[0060] Since the compensation amount is only related to the phase center corresponding to the transmitting antenna, the angle correction can be completed by pre-calibrating the phase offset of each transmitting antenna, thereby simplifying the calculation steps and reducing the amount of computation.

[0061] Step S1053: Based on the instantaneous velocity and index value of the four transmitting antennas and the remaining points among multiple points, perform Doppler phase compensation processing on the remaining points using the fifth formula to obtain the compensation result, until the compensated horizontal angle and compensated elevation angle of all points are calculated.

[0062] In step S1053, the compensated horizontal angle and compensated pitch angle of all points are obtained by performing steps S1051-S1052 on the remaining points respectively.

[0063] Step S106: The instantaneous distance, instantaneous velocity, compensated horizontal angle, and compensated pitch angle are used as sensing information.

[0064] In step S106, the point cloud data is combined The instantaneous distance and velocity of each point obtained in step S105, as well as the compensated horizontal angle and compensated elevation angle obtained in step S105, are used as the sensing information of the detected target. The accuracy of the data from the four-transmitter, four-receiver millimeter-wave radar 10 provided in this application when executing the corresponding detection method will be verified through a Monte Carlo experiment.

[0065] The experiment was conducted according to Figure 2 and Figure 3 Pre-deploy transmitting antennas Tx1-Tx4 and receiving antennas Rx1-Rx4, and according to... Figure 9 The radar signal control transmitting antennas shown transmit sequentially in the order of Tx2, Tx1, Tx3, and Tx4. The radar signals transmitted by transmitting antennas Tx2, Tx1, Tx3, and Tx4 are identical, but with different pulse waveform parameters: a starting frequency of 80 GHz, an idle time of 5 μs, and modulation of approximately 200 MHz within 20 μs. The preset range resolution is 1.17 m, and the preset velocity resolution is 0.1463 m / s.

[0066] like Figure 10 As shown, Figure 10 The verification results of the sensing information obtained by the detection method of the four-transmitter, four-receiver millimeter-wave radar of this application are shown, specifically including the measurement error distribution in four dimensions: range (RNG), velocity (VEL), horizontal angle (AZI), and pitch angle (ELE). Figure 10 Plotting the corresponding physical quantity on the horizontal axis and the measurement error corresponding to that physical quantity on the vertical axis, the experiment visually displays the deviation between the measured value and the true value. Specifically, the experiment sets up 100 point targets... Figure 10 The results show that the measurement error on the RNG is controlled within ±1.17m, which is less than one time the preset distance resolution, indicating that the method can accurately measure the target distance and meets the preset distance resolution. Meanwhile, in Figure 10 The measurement error of velocity VEL remains within ±0.1463 m / s, which is also less than one times the preset velocity resolution, verifying the method's high-precision detection capability of the radial velocity of the target. Furthermore, Figure 10 The results show that the measurement error of the horizontal angle AZI is less than ±0.25°, and the measurement error of the elevation angle ELE is less than ±0.6°, further demonstrating the high accuracy of this method in angle estimation. These results collectively confirm the accuracy of the sensing information obtained by the detection method of the four-transmitter, four-receiver millimeter-wave radar of this application.

[0067] Please refer to Figure 11 This is a schematic diagram of the internal structure of the main control module provided in the embodiments of this application.

[0068] like Figure 11As shown, the main control module 100 can be a computer device. The main control module 100 includes a memory 901 and a processor 902. The processor 902 is used to run computer program instructions in the memory 901 to implement the detection method of the four-transmitter, four-receiver millimeter-wave radar.

[0069] The memory 901 includes at least one type of readable storage medium, including flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the memory 901 can be an internal storage unit of a computer device, such as a hard disk. In other embodiments, the memory 901 can be an external storage device of a computer device, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, etc., configured in the computer device. Furthermore, the memory 901 can include both internal and external storage units of a computer device. The memory 901 can be used not only to store application software and various types of data installed on the computer device, such as the code for a detection method of a four-transmit, four-receive millimeter-wave radar, but also to temporarily store data that has been output or will be output.

[0070] Furthermore, the main control module 100 also includes a bus 903. The bus 903 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. This bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 11 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0071] Furthermore, the main control module 100 may also include a display component 904. The display component 904 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an organic light-emitting diode (OLED) touch screen, etc. The display component 904 may also be appropriately referred to as a display device or display unit, used to display information processed in the main control module 100 and to display a visual user interface.

[0072] Furthermore, the main control module 100 may also include a communication component 905. The communication component 905 may optionally include a wired communication component and / or a wireless communication component (such as a Wi-Fi communication component, a Bluetooth communication component, etc.), which is typically used to establish a communication connection between the main control module 100 and other computer devices.

[0073] Figure 11 Only the main control module 100, which includes some components and a detection method for a four-transmitter, four-receiver millimeter-wave radar, is shown. Those skilled in the art will understand that... Figure 11 The structure shown does not constitute a limitation on the main control module 100, and may include fewer or more components than shown, or combine certain components, or have different component arrangements.

[0074] In the above embodiments, the antenna array is asymmetrically and equally spaced along different preset directions in a preset coordinate system, and four transmitting antennas are sequentially emitted. Combined with the phase compensation of instantaneous velocity, the compensated horizontal angle and the compensated elevation angle are output. High-precision detection is achieved without expanding the antenna area, and the increase in area, hardware and algorithm costs caused by the expansion of antenna scale is suppressed.

[0075] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

[0076] The above-listed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A millimeter-wave radar with four transmitters and four receivers, characterized in that, The four-transmitter, four-receiver millimeter-wave radar includes: An antenna array includes four transmitting antennas and four receiving antennas; wherein the phase centers of the four receiving antennas are equally spaced along a predetermined horizontal direction in a predetermined coordinate system; the four transmitting antennas include a first transmitting antenna, a second transmitting antenna, a third transmitting antenna, and a fourth transmitting antenna, wherein the phase centers of the first, second, and third transmitting antennas are arranged along a first predetermined direction in the predetermined coordinate system, and the phase centers of the fourth and third transmitting antennas are arranged along a second predetermined direction in the predetermined coordinate system, wherein the first predetermined direction and the second predetermined direction form a predetermined angle in the predetermined coordinate system; and The main control module includes: Memory, used to store computer programs; and A processor is configured to execute the computer program to implement a detection method for a four-transmit, four-receive millimeter-wave radar; the detection method for the four-transmit, four-receive millimeter-wave radar includes: The second transmitting antenna, the first transmitting antenna, the third transmitting antenna, and the fourth transmitting antenna are sequentially controlled to transmit radar signals to the target under test. When each receiving antenna samples the echo signal from the same transmitting antenna, the corresponding echo signal is processed to obtain a digital signal, wherein the echo signal is the radar signal reflected by the target under test; The digital signal is subjected to multi-dimensional Fourier transform processing to generate a range Doppler map, wherein the multi-dimensional processing includes a range dimension and a velocity dimension; Point cloud data is obtained by performing constant false alarm rate detection on the range Doppler image. The point cloud data includes multiple points and instantaneous sensing information corresponding to each point. Each instantaneous sensing information includes the instantaneous distance, instantaneous velocity, instantaneous horizontal angle and instantaneous pitch angle of the corresponding point in the range Doppler image. Based on each transmitting antenna and its corresponding phase center, as well as each instantaneous velocity, phase compensation is performed on the instantaneous horizontal angle and instantaneous pitch angle corresponding to each point to obtain the compensated horizontal angle and compensated pitch angle. The instantaneous distance, the instantaneous velocity, the compensated horizontal angle, and the compensated pitch angle are used as the sensing information.

2. The millimeter-wave radar as described in claim 1, characterized in that, Along the preset horizontal direction, the phase centers corresponding to the third transmitting antenna, the first transmitting antenna, and the second transmitting antenna are arranged sequentially, and the spacing between the phase centers corresponding to adjacent transmitting antennas is equal. Along a predetermined vertical direction, the phase centers corresponding to the third transmitting antenna, the first transmitting antenna, and the second transmitting antenna are arranged sequentially, and the spacing between the phase centers corresponding to adjacent transmitting antennas is equal. The preset horizontal direction and the preset vertical direction are perpendicular to each other in the preset coordinate system.

3. The millimeter-wave radar as described in claim 2, characterized in that, The spacing between adjacent receiving antennas and the spacing between adjacent transmitting antennas are determined by the operating wavelength of the millimeter-wave radar; the second preset direction and the preset horizontal direction are parallel to each other in the preset coordinate system.

4. A detection method for a four-transmitter, four-receiver millimeter-wave radar, characterized in that, The detection method is used to detect the target to obtain corresponding sensing information, including distance, velocity, horizontal angle, and elevation angle. The millimeter-wave radar is equipped with an antenna group, which includes four transmitting antennas and four receiving antennas. The phase centers of the four receiving antennas are evenly distributed along a preset horizontal direction in a preset coordinate system. The four transmitting antennas include a first transmitting antenna, a second transmitting antenna, a third transmitting antenna, and a fourth transmitting antenna. The phase centers of the first, second, and third transmitting antennas are arranged along a first preset direction in the preset coordinate system, and the phase centers of the fourth and third transmitting antennas are arranged along a second preset direction in the preset coordinate system. The first preset direction and the second preset direction form a preset angle in the preset coordinate system. The detection method includes: The second transmitting antenna, the first transmitting antenna, the third transmitting antenna, and the fourth transmitting antenna are sequentially controlled to transmit radar signals to the target under test. When each receiving antenna samples the echo signal from the same transmitting antenna, the corresponding echo signal is processed to obtain a digital signal, wherein the echo signal is the radar signal reflected by the target under test; The digital signal is subjected to multi-dimensional Fourier transform processing to generate a range Doppler map, wherein the multi-dimensional processing includes a range dimension and a velocity dimension; Point cloud data is obtained by performing constant false alarm rate detection on the range Doppler image. The point cloud data includes multiple points and instantaneous sensing information corresponding to each point. Each instantaneous sensing information includes the instantaneous distance, instantaneous velocity, instantaneous horizontal angle and instantaneous pitch angle of the corresponding point in the range Doppler image. Based on each transmitting antenna and its corresponding phase center, as well as each instantaneous velocity, phase compensation is performed on the instantaneous horizontal angle and instantaneous pitch angle corresponding to each point to obtain the compensated horizontal angle and compensated pitch angle. The instantaneous distance, the instantaneous velocity, the compensated horizontal angle, and the compensated pitch angle are used as the sensing information.

5. The detection method as described in claim 4, characterized in that, The signal processing includes radio frequency processing and digital-to-analog conversion processing. Each radar signal includes multiple pulses. The digital signal is represented as s(p,q; m,n), where m represents the m-th transmitting antenna, n represents the n-th receiving antenna, q represents the q-th pulse, and p represents the sampled value corresponding to the q-th pulse. Multi-dimensional Fourier transform processing is performed on the digital signal to generate a range Doppler map, including: The distance transform data is obtained by performing a Fast Fourier Transform on the digital signal based on the distance dimension. Based on the velocity dimension, the distance transformation data is processed by Fast Fourier Transform to obtain velocity transformation data; The distance Doppler map is calculated based on the velocity transformation data.

6. The detection method as described in claim 5, characterized in that, Based on the distance dimension, the digital signal is processed by Fast Fourier Transform to obtain distance transform data, including: The digital signal is subjected to distance-mean subtraction using a first formula, which is expressed as follows: Where s1(p,q;m,n) represents the digital signal after distance mean reduction processing, and P represents the total number of sampled values; The digital signal after the distance-mean subtraction process is processed by adding a distance window using the second formula, which is expressed as s2(p,q;m,n)=s1(p,q;m,n)ω R (p), where s2(p,q;m,n) represents the digital signal after distance windowing, ω R (p) represents a preset distance window function, used to perform the distance windowing process; The distance transform data is obtained by performing a Fast Fourier Transform on the digital signal after the distance windowing process.

7. The detection method as described in claim 6, characterized in that, Based on the velocity dimension, the distance transformation data is processed by Fast Fourier Transform to obtain velocity transformation data, including: The distance transformation data is processed using an acceleration window using a third formula, which is expressed as s4(p,q;m,n)=s3(p,q;m,n)ω v (q), where s4(p,q;m,n) represents the distance transformation data after acceleration window processing, s3(p,q;m,n) represents the distance transformation data, ω v (q) represents a preset velocity window function used for the acceleration window processing; The velocity transformation data is obtained by performing a Fast Fourier Transform on the distance transformation data after the acceleration window processing.

8. The detection method as described in claim 7, characterized in that, The calculation of the range Doppler map based on the velocity transformation data specifically involves: calculating the range Doppler map using a fourth formula on the velocity transformation data, wherein the fourth formula is expressed as follows: Wherein, s6(P,Q) represents the range Doppler image, and s5(p,q;m,n) represents the velocity transformation data.

9. The detection method as described in claim 8, characterized in that, The point cloud data is represented as Where, r k v represents the instantaneous distance of the k-th point. k Let θ represent the instantaneous velocity at the k-th point. k This represents the instantaneous horizontal angle at the k-th point. Let α represent the instantaneous pitch angle at the k-th point. k Let r represent the echo intensity at the k-th point, used to measure the reflection intensity of the target under test; where r k Represented as r k =P k δ R v k Represented as v k =Q k δ V P k δ represents the distance dimension index value of the k-th point in the distance-Doppler map. R Q represents the preset distance resolution. k δ represents the velocity dimension index value of the k-th point in the distance-Doppler map. V This indicates the preset speed resolution.

10. The detection method as described in claim 9, characterized in that, Based on each transmitting antenna and its corresponding phase center, as well as each instantaneous velocity, phase compensation is performed on the instantaneous horizontal angle and instantaneous elevation angle corresponding to each point to obtain the compensated horizontal angle and compensated elevation angle, including: Based on the instantaneous velocity and index value of any one of the four transmitting antennas and the plurality of points, a Doppler phase compensation process is performed on the point using the fifth formula to obtain the compensation result. The index value includes the range dimension index value and the velocity dimension index value corresponding to the point. The fifth formula is expressed as follows: Wherein, λ represents the operating wavelength of the four-transmitter, four-receiver millimeter-wave radar; Based on the compensation result and the phase center corresponding to each transmitting antenna, the compensated horizontal angle and the compensated elevation angle are calculated using the sixth formula, which is: in, The expression is: The process involves using the fifth formula to perform Doppler phase compensation on the remaining points based on the instantaneous velocities and index values ​​of the four transmitting antennas and the remaining points among the plurality of points, until the compensated horizontal angle and compensated elevation angle of all points are calculated.

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