Target detection method, device, storage medium and terminal device

Abstract

The present application proposes a target detection method, device, storage medium and terminal device. First, the target point is determined based on the echo data received by the receiving antenna group; the corresponding two-dimensional angle spectrum is constructed according to the target point; the coordinate value of the target point is determined according to the two-dimensional angle spectrum, wherein the coordinate value includes the vertical coordinate of the target point in the vertical direction; the vertical azimuth of the target point is determined according to the vertical coordinate, the vertical array antenna spacing and the carrier wavelength. By obtaining the vertical coordinate and the vertical azimuth, the problem that the existing radar system does not have vertical resolution is overcome.

Description

Technical Field

[0001] The present application relates to the field of radar, and more specifically, to a target detection method, device, storage medium and terminal equipment. Background Art

[0002] With the development of industry and the popularization of intelligence, measurement radars are widely used in vehicles, ships and flying equipment. For example, drones for agricultural operations, irrigation vehicles for automatic irrigation, and other equipment for transportation.

[0003] Most of the current measurement radars are 24Ghz millimeter wave radars, including corner radars, ranging radars, and speed radars. However, corner radars, ranging radars, and speed radars all measure the horizontal plane and do not have vertical resolution capabilities. When information such as the target angle, distance, and speed in the vertical direction is required, the target in the vertical direction needs to be equated with the target in the horizontal direction, resulting in mismeasurement of target angle, distance, and speed information. Summary of the invention

[0004] The purpose of the present application is to provide a target detection method, apparatus, storage medium and terminal device to at least partially improve the above-mentioned problems.

[0005] In order to achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0006] In a first aspect, an embodiment of the present application provides a target detection method, which is applied to a radar device, wherein the radar device includes a receiving antenna group and a transmitting antenna group, wherein the receiving antenna group includes at least two groups of receiving antennas, and the transmitting antenna group includes at least two groups of transmitting antennas, wherein the at least two groups of receiving antennas are arranged horizontally with a fixed spacing, and the at least two groups of transmitting antennas are arranged in sequence with the fixed spacing in both the horizontal direction and the vertical direction, and the method includes:

[0007] Determine a target point based on the echo data received by the receiving antenna group;

[0008] Constructing a corresponding two-dimensional angle spectrum according to the target point;

[0009] Determine the coordinate value of the target point according to the two-dimensional angle spectrum, wherein the coordinate value includes the vertical coordinate of the target point in the vertical direction;

[0010] The vertical azimuth of the target point is determined according to the vertical coordinate, the vertical array antenna spacing and the carrier wavelength.

[0011] In a second aspect, an embodiment of the present application provides a target detection device, which is applied to a radar device, wherein the radar device includes a receiving antenna group and a transmitting antenna group, wherein the receiving antenna group includes at least two groups of receiving antennas, and the transmitting antenna group includes at least two groups of transmitting antennas, wherein the at least two groups of receiving antennas are arranged horizontally with a fixed spacing, and the at least two groups of transmitting antennas are arranged in sequence with the fixed spacing in both the horizontal direction and the vertical direction, and the device includes:

[0012] A preprocessing unit, configured to determine a target point based on the echo data received by the receiving antenna group; and construct a corresponding two-dimensional angle spectrum according to the target point;

[0013] A calculation unit is used to determine the coordinate value of the target point based on the two-dimensional angle spectrum, wherein the coordinate value includes the vertical coordinate of the target point in the vertical direction; and determine the vertical azimuth angle of the target point based on the vertical coordinate, the vertical array antenna spacing and the carrier wavelength.

[0014] In a third aspect, an embodiment of the present application provides a radar device, which includes a receiving antenna group, a transmitting antenna group and a signal processing module; the receiving antenna group includes at least two groups of receiving antennas, the transmitting antenna group includes at least two groups of transmitting antennas, the at least two groups of receiving antennas are arranged horizontally with a fixed spacing, and the at least two groups of transmitting antennas are arranged in sequence with the fixed spacing in both the horizontal and vertical directions; the signal processing module is respectively connected to the receiving antenna group and the transmitting antenna group, and is used to determine the vertical azimuth of the target through the above-mentioned target detection method.

[0015] In a fourth aspect, an embodiment of the present application provides a movable platform, which includes the above-mentioned radar device.

[0016] In a fifth aspect, an embodiment of the present application provides a storage medium on which a computer program is stored, and the computer program implements the above method when executed by a processor.

[0017] In a sixth aspect, an embodiment of the present application provides a terminal device, comprising: a processor and a memory, wherein the memory is used to store one or more programs; when the one or more programs are executed by the processor, the above method is implemented.

[0018] Compared with the prior art, the target detection method, device, storage medium and terminal device provided in the embodiments of the present application first determine the target point based on the echo data received by the receiving antenna group; construct a corresponding two-dimensional angle spectrum according to the target point; determine the coordinate value of the target point according to the two-dimensional angle spectrum, wherein the coordinate value includes the vertical coordinate of the target point in the vertical direction; determine the vertical azimuth of the target point according to the vertical coordinate, the vertical array antenna spacing and the carrier wavelength. By obtaining the vertical coordinate and the vertical azimuth, the problem that the existing radar system does not have vertical resolution is overcome.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of the structure of a terminal device provided in an embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of a radar system provided in an embodiment of the present application;

[0023] Figure 3 A schematic diagram of the antenna array arrangement provided in an embodiment of the present application;

[0024] Figure 4a One of the antenna array arrangement schematic diagrams provided in an embodiment of the present application;

[0025] Figure 4b One of the antenna array arrangement schematic diagrams provided in an embodiment of the present application;

[0026] Figure 5 A schematic diagram of the arrangement of a virtual aperture array provided in an embodiment of the present application;

[0027] Figure 6 A schematic diagram of a target detection method provided in an embodiment of the present application;

[0028] Figure 7 A schematic diagram of the sub-steps of S101 provided in an embodiment of the present application;

[0029] Figure 8 A schematic diagram of sub-steps of S103 provided in an embodiment of the present application;

[0030] Fig. 9 A schematic diagram of sub-steps of S102 provided in an embodiment of the present application;

[0031] Fig.10 One of the flowcharts of the target detection method provided in the embodiment of the present application;

[0032] Fig.11 A unit schematic diagram of a target detection device provided in an embodiment of the present application.

[0033] In the figure: 10 - processor; 11 - memory; 12 - bus; 13 - communication interface; 201 - pre-processing unit; 202 - computing unit. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0036] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0037] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0038] In the description of the present application, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0039] In the description of this application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0041] As mentioned above, when the radar does not have vertical resolution, when the target angle, distance, speed and other information in the vertical direction are needed, the target in the vertical direction needs to be equated with the target in the horizontal direction, resulting in mismeasurement of target angle, distance, speed and other information. At the same time, because of the lack of vertical resolution, the radar imaging technology cannot form a two-dimensional plane picture.

[0042] An embodiment of the present application provides a radar device, which can be applied to a movable platform, and the movable platform can be a drone or an unmanned vehicle or other surveying equipment.

[0043] Please refer to Figure 2In a possible implementation, the radar device may be a millimeter wave imaging radar system, such as a 24 GHz millimeter wave imaging radar. Figure 2 As shown, the 24Ghz millimeter wave imaging radar includes a receiving antenna group, a transmitting antenna group, a 24Ghz signal transmitting and receiving module, and an MCU signal processing module.

[0044] The transmitting antenna group includes at least two groups of transmitting antennas (TX). Figure 3 In the example, four transmitting antennas are used as an example, and the receiving antenna group includes at least two groups of receiving antennas (RX). Figure 3 12 receiving antennas are used as an example. Optionally, the antenna is a 24Ghz transceiver antenna. The 4 transmitting antennas are used to radiate the 24Ghz signal into the air, and the 12 receiving antennas are used to receive the 24Ghz±X signal reflected by obstacles from the air. Figure 3 As shown, at least two groups of receiving antennas are arranged horizontally with a fixed spacing, and at least two groups of transmitting antennas are arranged in sequence with the fixed spacing both horizontally and vertically. In a possible implementation, at least two groups of transmitting antennas are time-division multiplexed according to a preset frequency.

[0045] like Figure 3 Every 8 array elements form a 24Ghz millimeter wave antenna, with a total of 12 receiving antennas (RX1~12) and 4 transmitting antennas (TX1~TX4). The spacing between each receiving antenna is D1=6.2mm (half wavelength of 24Ghz), the horizontal spacing between each transmitting antenna is D2=6.2mm, and the vertical spacing between each transmitting antenna is H=6.2mm. Due to the limitation of the board size, for example, the size is 73.13mmX98.02mm, the transmitting and receiving antennas are placed diagonally. If there is enough space, the transmitting and receiving antennas can be placed horizontally or vertically, such as Figure 4a and Figure 4b Regardless of how the transmitting and receiving antennas are placed, for millimeter-wave radars under the MIMO (multiple-transmitter-multiple-receiver) system, they can be equivalent to the following: Figure 5 The 4X12 parallelogram array (virtual aperture array) shown in the figure. Under this transceiver array, the 24Ghz millimeter wave radar has not only 12 horizontal receiving antennas, but also 4 vertical receiving antennas.

[0046] The 24Ghz signal transmission and receiving module includes frequency detection / control circuit, FMCW Transmitter (FMCW modulated signal transmitter), VCO (24Ghz voltage-controlled oscillator), directional coupler, Power AMP (power amplifier), RF SWITCH (radio frequency switch), LNA (lower noise amplifier), mixer, power divider and BPF (bandpass filter).

[0047] The frequency detection / control circuit is used to detect the frequency of the modulation signal and feed it back to the MCU signal processing module to control the modulation signal frequency in a timely manner, thereby forming a frequency-controllable closed loop.

[0048] The FMCW Transmitter (FMCW modulation signal transmitter) is used to modulate the digital signal sent by the MCU into an analog FMCW modulation signal.

[0049] VCO (24Ghz voltage controlled oscillator) is used to multiply and mix the FMCW modulated signal into a 24Ghz millimeter wave signal and has a certain power amplification.

[0050] The directional coupler is used to generate another 24 GHz millimeter wave signal through energy coupling from a 24 GHz millimeter wave signal, which is the so-called LO (local oscillator signal).

[0051] POWER AMP (power amplifier) ​​is used to amplify the power of 24Ghz millimeter wave signals.

[0052] The three power dividers are used to transmit the LO (local oscillator signal) to the mixer in an equal power manner without changing the frequency.

[0053] LNA (low noise amplifier) ​​is used to amplify the ultra-low power useful signal in the air and pass it to the mixer.

[0054] The mixer is used to mix the useful signal amplified by the LNA with the LO to convert the frequency into an IF (low frequency signal).

[0055] The BPF (Band Pass Filter) is used to filter out the unnecessary low-frequency and high-frequency components in the IF and amplify the IF signal within the band of the BPF.

[0056] The MCU signal processing module includes two MCUs (microcontrollers), one master and one slave. Each of the master and slave MCUs can perform independent FFT (Fast Fourier Transform) operations. Both have several A / D converters (analog-to-digital converters), and the two can exchange data through SPI (high-speed data exchange bus). The main function of FFT (Fast Fourier Transform) is to convert time domain signals into frequency domain signals. A / D converters (analog-to-digital converters) are used to collect analog signals and convert them into digital signals.

[0057] The target detection method provided in the embodiment of the present application can be applied to radar equipment but is not limited to it. For the specific process, please refer to Figure 6 , the target detection method includes: S101, S102, S103 and S104.

[0058] S101, determining a target point based on echo data received by a receiving antenna group.

[0059] In a possible implementation, the echo signal received by the receiving antenna group is Figure 2 The A / D converter shown is used to acquire the echo data.

[0060] Regarding the content in S101, how to determine the target point, the present application embodiment also provides a possible implementation method, please refer to Figure 7 , S101 includes: S101-1, S101-2, S101-3, S101-4, S101-5.

[0061] S101-1, remove low-frequency components in the echo data.

[0062] Optionally, the echo data is fitted by polynomial fitting to obtain a fitting curve, which is approximately equal to the low-frequency component in the signal. The low-frequency component in the echo signal is removed by subtracting the fitting curve from the echo data.

[0063] Optionally, in the echo signal preprocessing part, a curve is fitted according to the echo signal by using an N-order polynomial fitting method, and the fitted polynomial curve is subtracted from the original echo signal to achieve the goal of removing low-frequency components, wherein N is generally not greater than 5.

[0064] S101 - 2 , performing range Fourier transform and Doppler fast Fourier transform on the echo data after the low-frequency components are removed to obtain an RD domain signal spectrum.

[0065] It should be noted that the radar system in the embodiment of the present application adopts an alternating transmission system, TX1 to TX4 transmit in turn, each transmitting antenna corresponds to 12 receiving channels, each receiving channel samples Nr points, and transmits Na rounds alternately to obtain Nr*Na*48 echo data. Perform Na*48 N-point windowed Fourier transforms along the Nr direction, and then perform N*48 Na-point windowed Fourier transforms along the Na direction to obtain an RD signal domain signal spectrum of size N*Na*48.

[0066] S101 - 3 , performing modulus calculation on the RD domain signal spectrum to obtain a modulus value of the RD domain signal spectrum.

[0067] S101 - 4 , performing incoherent superposition on the modulus values ​​of the RD domain signal spectrum to obtain the amplitude of the RD domain signal spectrum.

[0068] Optionally, the RD domain signal spectrum amplitude can be obtained by the following formula:

[0069] D(i, j) = ∑ k |RD(i,j,k)|

[0070] Among them, |RD(i,j,k)| represents the modulus value of the RD domain signal spectrum of the kth receiving channel of the jth Doppler unit of the i-th range unit, and D(i,j) represents the result of the incoherent superposition of the jth Doppler unit of the i-th range unit along the receiving channel. The first dimension of the RD domain signal spectrum amplitude represents the distance, and the second dimension represents the Doppler (speed).

[0071] S101-5, obtaining a one-dimensional distance spectrum according to the RD domain signal spectrum amplitude.

[0072] Optionally, after obtaining the incoherent superposition result D of the RD domain signal spectrum amplitude, the maximum value of the Doppler dimension (second dimension) is searched in D along the distance dimension (first dimension), and the maximum value and its coordinates of the Doppler direction corresponding to each distance unit are recorded. The sequence obtained from the maximum value is a one-dimensional range spectrum sequence, that is, a one-dimensional range spectrum. Its index is used for target velocity estimation and target motion compensation.

[0073] S101-6, determining points in the one-dimensional distance spectrum that are higher than the one-dimensional distance threshold as target points.

[0074] Optionally, the one-dimensional distance threshold consists of three parts: curve model, signal-to-noise ratio threshold, and background noise. The curve model is fitted according to the principle of signal attenuation with distance described by the radar equation, and the formula has been given; the signal-to-noise ratio threshold is a preset value, which is given according to actual needs; the background noise is the average value of the one-dimensional distance signal. All points in the one-dimensional distance spectrum that are higher than the corresponding threshold are determined as target points.

[0075] Optionally, the expression of the one-dimensional distance threshold is as follows:

[0076]

[0077] Wherein, Th(i) represents the threshold value of the i-th distance unit, N is the number of FFT points in the distance dimension, and a is a model parameter obtained by analyzing the actual echo pattern.

[0078] S102, constructing a corresponding two-dimensional angle spectrum according to the target point.

[0079] In one possible implementation, the elements in the two-dimensional angular spectrum are arranged in the same Figure 5 The virtual aperture arrays shown are identical, the virtual aperture arrays being the arrangement of the receiving antenna groups relative to the different transmitting antennas.

[0080] Optionally, the two-dimensional angular spectrum is a two-dimensional matrix formed by two-dimensional angular input values ​​(virtual aperture array) after windowed FFT in horizontal and vertical dimensions, and the amplitude in the RD domain signal spectrum is the modulus value of the corresponding two-dimensional angular spectrum element.

[0081] S103, determining the coordinate value of the target point according to the two-dimensional angle spectrum.

[0082] The coordinate value includes the vertical coordinate of the target point in the vertical direction.

[0083] It can be understood that the coordinate value of the target point can be the coordinate value of the target point in the coordinate system of the radar system, and the vertical direction can be the direction vertical to the ground. By obtaining the vertical coordinate of the target point in the vertical direction, it is provided with vertical resolution.

[0084] S104, determining the vertical azimuth of the target point according to the vertical coordinate, the vertical array antenna spacing and the carrier wavelength.

[0085] In one embodiment, the step S104 may include the following steps: determining the ratio of the vertical array antenna spacing to the carrier wavelength and the number of FFT points in the vertical direction; determining the vertical azimuth angle of the target point based on the vertical coordinate, the ratio and the number of FFT points.

[0086] Optionally, the vertical array antennas are spaced at a fixed interval as described above. The vertical azimuth angle is expressed as:

[0087]

[0088] in, represents the vertical azimuth, in radians; Represents the vertical coordinate; N2 represents the number of FFT points in the vertical direction; d int Characterizes the ratio of the vertical array antenna spacing to the carrier wavelength.

[0089] In summary, the embodiment of the present application provides a target detection method, which is applied to a radar device. The radar device includes a receiving antenna group and a transmitting antenna group. The receiving antenna group includes at least two groups of receiving antennas, and the transmitting antenna group includes at least two groups of transmitting antennas. The at least two groups of receiving antennas are arranged horizontally with a fixed spacing, and the at least two groups of transmitting antennas are arranged in sequence with a fixed spacing in both the horizontal and vertical directions. The target point is determined based on the echo data received by the receiving antenna group; a corresponding two-dimensional angle spectrum is constructed based on the target point; the coordinate value of the target point is determined based on the two-dimensional angle spectrum, wherein the coordinate value includes the vertical coordinate of the target point in the vertical direction; the vertical azimuth of the target point is determined based on the vertical coordinate, the vertical array antenna spacing, and the carrier wavelength. By obtaining the vertical coordinate and the vertical azimuth, the problem that the existing radar system does not have vertical resolution is overcome.

[0090] exist Figure 6 Based on the content in S103, the present application embodiment also provides a possible implementation method, please refer to Figure 8 , S103 includes: S103-1 to S103-5.

[0091] S103-1, performing modulus calculation on the two-dimensional angle spectrum.

[0092] Optionally, Figure 3 Taking the array shown as an example, the expression of the two-dimensional angle spectrum is as follows:

[0093]

[0094] Where A is the two-dimensional angle spectrum, a t，k Indicates the value of the target corresponding to the kth receiving channel of the tth transmitting antenna in the RD signal spectrum. S103-2, search the two-dimensional angle spectrum after the modulo calculation along the horizontal direction to obtain the vertical maximum value, and perform dimensionality reduction processing according to the index of the vertical maximum value to obtain the horizontal angle spectrum.

[0095] Optionally, only the angle corresponding to the vertical maximum value is detected in the vertical direction, and dimensionality reduction is performed according to the index of the vertical maximum value. The vertical maximum value is selected as the angle spectrum value corresponding to the horizontal direction to obtain a one-dimensional angle spectrum in the horizontal direction, i.e., the horizontal angle spectrum.

[0096] S103-3, determining an angle spectrum threshold according to the mean value and maximum value of the horizontal angle spectrum and a preset angle spectrum threshold parameter.

[0097] Optionally, the expression of the angle spectrum threshold is:

[0098] A th =(A max -A ref )F th

[0099] Among them, A th Characterizing the angle spectrum threshold, A max Characterizes the maximum value of the horizontal angle spectrum, A ref Characterizes the mean of the horizontal angle spectrum, F th Characterizes the angle spectrum threshold parameters.

[0100] S103-4, screening out a maximum value greater than an angle spectrum threshold from the horizontal angle spectrum.

[0101] It should be noted that the number of maximum values ​​is not limited in the embodiments of the present application.

[0102] S103-5, performing quadratic curve interpolation processing on the maximum value to obtain the coordinate value of the target point.

[0103] Optionally, the coordinates of the target in the horizontal and vertical directions are obtained through quadratic curve interpolation, that is,

[0104] exist Figure 6Based on the content in S102, the present application embodiment also provides a possible implementation method, please refer to Fig. 9 , S102 includes: S102-1 and S102-2.

[0105] S102-1, arranging the amplitudes of the target points in the RD domain signal spectrum to obtain a corresponding virtual aperture array.

[0106] Optionally, the distance and speed of the target are detected on the amplitude of the RD domain signal spectrum to obtain the coordinates of the target in the RD domain signal spectrum, and the value of the target point in the RD domain signal spectrum is obtained according to the coordinates, and the amplitudes of the target point in the RD domain signal spectrum are arranged to obtain the corresponding virtual aperture array. The virtual aperture array is the arrangement of the receiving antenna group relative to different transmitting antennas, such as Figure 5 shown.

[0107] Specifically, each target point corresponds to 4*12 values, and these values ​​are divided into Figure 5 The positions of the "virtual aperture array" shown in the figure are filled in one by one, and the unfilled values ​​are set to 0 to obtain the virtual aperture array of the target point DOA.

[0108] Optionally, a t，k =RD(i, j, (t-1) × 12 + k); where i represents the distance dimension index of the target point in the RD domain signal spectrum, j represents the Doppler dimension index of the target point in the RD domain signal spectrum, and a t，k Indicates the value of the target in the RD signal spectrum corresponding to the kth receiving channel of the tth transmitting antenna.

[0109] S102-2, adding a Hanning window to the virtual aperture array in the horizontal direction, performing a horizontal Fourier transform, and then performing spectrum shifting; adding a Hanning window to the virtual aperture array in the vertical direction, performing a vertical Fourier transform, and then performing spectrum shifting, thereby obtaining a two-dimensional angular spectrum.

[0110] Optionally, horizontal FFT: add a Hanning window along the horizontal receiving antenna direction, perform N1-point FFT and perform spectrum shifting; vertical FFT: add a Hanning window along the vertical receiving antenna direction, perform N2-point FFT and perform spectrum shifting, thereby obtaining a two-dimensional angular spectrum.

[0111] It can be understood that FFT is a mathematical operation, and the horizontal direction of the virtual aperture array is Figure 5 The horizontal direction is shown, and the vertical direction is Figure 5 The horizontal windowed FFT includes first multiplying each of the 12 horizontal points by the value of the window function (the length of the window is the same as the real signal in that direction [ Figure 5The number of "1" in a single row is the same]); then fill the front and back zeros according to the virtual aperture position [the first row does not need to be filled with zeros, but N1-12 zeros are filled in the back, the second row is filled with 1 zero in the front, and N1-12-1 zeros are filled in the back... and so on]; finally, perform N1-point FFT on each row. The vertical windowed FFT includes first multiplying each of the 4 vertical points by the value of the window function (the length of the window is the same as the real signal in that direction [ Figure 5 The number of "1"s in a single column is the same]); then, zeros are added according to the virtual aperture position [the first column is added with N2-4 zeros, the second column is added with N2-4 zeros... and so on]; finally, N2-point FFT is performed on each column to complete the conversion of the virtual aperture array to a two-dimensional angular spectrum.

[0112] The two-dimensional angle spectrum is determined after obtaining the coordinates of the target point in the one-dimensional signal spectrum amplitude. The target point above the threshold has a one-dimensional distance coordinate and a corresponding Doppler direction coordinate. The two-dimensional coordinates composed of the coordinates are obtained by the formula.

[0113] In a possible implementation, the coordinate value also includes the horizontal coordinate of the target point in the horizontal direction. Figure 6 Based on how to obtain the horizontal azimuth angle, the present application embodiment also provides a possible implementation method, please refer to Fig.10 , the target detection method also includes S105.

[0114] S110, determining the horizontal azimuth of the target point according to the horizontal coordinate, the horizontal array antenna spacing, and the carrier wavelength.

[0115] Optionally, the expression for the horizontal azimuth angle is:

[0116]

[0117] Among them, θ represents the horizontal azimuth, the unit is radian; θ index Represents the horizontal coordinate; N1 represents the number of FFT points in the horizontal direction; d int Characterizes the ratio of the horizontal array antenna spacing to the carrier wavelength.

[0118] The target detection method provided in the embodiment of the present application is applicable to Figure 3 The 4T12R antenna array and the imaging radar array with low angular resolution in the vertical direction are shown. The 3dB beamwidth of the array antenna in the vertical direction is ±15°, which is very close to the angular resolution of 28.65° in the vertical direction. As a result, the ability to distinguish multiple targets at the same distance and speed in the vertical direction is poor. At the same time, the beamwidth in the horizontal direction is ±60°, which is much larger than the angular resolution of 9.55° in the horizontal direction. Therefore, the method of single angle estimation in the vertical direction and multi-angle estimation in the horizontal direction is adopted. This array is suitable for scenes with fewer vertical targets, such as open farmland, over forest areas, and other areas.

[0119] In a possible implementation, the horizontal array spacing is the same as the vertical array spacing, so the same symbol is used to represent the ratio of the horizontal array antenna spacing to the carrier wavelength and the ratio of the vertical array antenna spacing to the carrier wavelength.

[0120] In the target detection method provided in the embodiment of the present application, the 24Ghz millimeter wave radar has not only horizontal dimension angle resolution, but also vertical dimension angle resolution. It can help drones, unmanned vehicles and other equipment to distinguish obstacles on the ground and in the sky, so that the system can better plan obstacle avoidance paths. In addition, because the radar has three-dimensional resolutions of vertical dimension, horizontal dimension and distance dimension, it can help software equipment to build a three-dimensional point cloud map.

[0121] See also Fig.11 , Fig.11 An object detection device is provided in an embodiment of the present application. Optionally, the object detection device is applied to the radar device described above.

[0122] The target detection device includes: a preprocessing unit 201 and a computing unit 202 .

[0123] The preprocessing unit 201 is used to determine the target point based on the echo data received by the receiving antenna group; and construct a corresponding two-dimensional angle spectrum according to the target point.

[0124] The calculation unit 202 is used to determine the coordinate value of the target point according to the two-dimensional angle spectrum, wherein the coordinate value includes the vertical coordinate of the target point in the vertical direction; and determine the vertical azimuth of the target point according to the vertical coordinate, the vertical array antenna spacing and the carrier wavelength.

[0125] Optionally, the preprocessing unit 201 may execute the above S101 and S102, and the computing unit 202 may execute the above S103-S105.

[0126] It should be noted that the target detection device provided in this embodiment can execute the method flow shown in the above method flow embodiment to achieve the corresponding technical effect. For the sake of brief description, for parts not mentioned in this embodiment, reference can be made to the corresponding contents in the above embodiment.

[0127] The present application also provides a storage medium that stores computer instructions and programs, which, when read and executed, execute the target detection method of the above embodiment. The storage medium may include a memory, a flash memory, a register, or a combination thereof.

[0128] The following provides a terminal device, which can be a remote control or other handheld device. The terminal device can communicate with the radar system, and the communication method can be wired communication or wireless communication. Figure 1 As shown, the radar system Figure 2 As shown, the two can cooperate to realize the above-mentioned target detection method. In some embodiments, the radar system can be incorporated into the terminal device so that the terminal device directly has the radar system; in other embodiments, the radar system and the terminal device can be separately set; specifically, the terminal device includes: a processor 10, a memory 11, and a bus 12. The processor 10 can be a CPU. The memory 11 is used to store one or more programs. When the one or more programs are executed by the processor 10, the target detection method of the above-mentioned embodiment is executed.

[0129] The processor 10 can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the target detection method can be completed by the hardware integrated logic circuit in the processor 10 or the instructions in the form of software. The above-mentioned processor 10 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0130] The memory 11 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory.

[0131] The bus 12 may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus. Figure 1 Although only one bidirectional arrow is used in the figure, it does not mean that there is only one bus 12 or only one type of bus 12 .

[0132] The memory 11 is used to store programs, such as programs corresponding to the target detection device. The target detection device includes at least one software function module that can be stored in the memory 11 in the form of software or firmware or fixed in the operating system (OS) of the terminal device. After receiving the execution instruction, the processor 10 executes the program to implement the target detection method.

[0133] Possibly, the terminal device provided in the embodiment of the present application further includes a communication interface 13. The communication interface 13 is connected to the processor 10 via a bus. The terminal device can communicate and interact with other devices via the communication interface 13. It should be understood that Figure 1 The structure shown is only a schematic diagram of a portion of the terminal device. The terminal device may also include Figure 1 More or fewer components as shown, or with Figure 1 Different configurations are shown. Figure 1 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0134] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or the flowchart, and the combination of boxes in the block diagram and / or the flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0135] In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0136] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0137] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0138] It will be apparent to those skilled in the art that the present application is not limited to the details of the exemplary embodiments described above, and that the present application can be implemented in other specific forms without departing from the spirit or essential features of the present application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present application. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A target detection method, characterized in that: Applied to a radar device, the radar device comprises a receiving antenna group and a transmitting antenna group, the receiving antenna group comprises at least two groups of receiving antennas, the transmitting antenna group comprises at least two groups of transmitting antennas, the at least two groups of receiving antennas are arranged horizontally with a fixed spacing, and the at least two groups of transmitting antennas are arranged sequentially with the fixed spacing in both the horizontal direction and the vertical direction, and the method comprises: Determine a target point based on the echo data received by the receiving antenna group; Constructing a corresponding two-dimensional angle spectrum according to the target point; Determine the coordinate value of the target point according to the two-dimensional angle spectrum, wherein the coordinate value includes the vertical coordinate of the target point in the vertical direction; Determine the vertical azimuth of the target point according to the vertical coordinate, the vertical array antenna spacing and the carrier wavelength; The step of determining the coordinate value of the target point according to the two-dimensional angle spectrum comprises: Performing modulo calculation on the two-dimensional angle spectrum; The two-dimensional angle spectrum after the modulo calculation is searched in the horizontal direction to obtain the vertical maximum value, and the dimension reduction process is performed according to the index of the vertical maximum value to obtain the horizontal angle spectrum; Determining an angle spectrum threshold value according to the mean value, the maximum value and the preset angle spectrum threshold parameter of the horizontal angle spectrum; Screening out a maximum value greater than a threshold value of the angle spectrum from the horizontal angle spectrum; The maximum value is subjected to quadratic curve interpolation processing to obtain the coordinate value of the target point.

2. The target detection method according to claim 1, characterized in that: The expression of the angle spectrum threshold is: A th =(A max -A ref )F th Among them, A th Characterize the angle spectrum threshold, A max Characterizes the maximum value of the horizontal angle spectrum, A ref Characterizes the mean of the horizontal angle spectrum, F th Characterize the angle spectrum threshold parameter.

3. The target detection method according to claim 1, characterized in that: The step of determining the target point based on the echo data received by the receiving antenna group includes: removing low frequency components in the echo data; Perform range Fourier transform and Doppler fast Fourier transform on the echo data after removing the low-frequency components to obtain the RD domain signal spectrum; Performing a modulus calculation on the RD domain signal spectrum to obtain a modulus value of the RD domain signal spectrum; Performing incoherent superposition on the modulus values ​​of the RD domain signal spectrum to obtain the RD domain signal spectrum amplitude; Obtaining a one-dimensional distance spectrum according to the RD domain signal spectrum amplitude; Points in the one-dimensional distance spectrum that are higher than a one-dimensional distance threshold are determined as the target points.

4. The target detection method according to claim 3, characterized in that: The step of constructing a corresponding two-dimensional angle spectrum according to the target point comprises: Arranging the amplitudes of the target points in the RD domain signal spectrum to obtain a corresponding virtual aperture array; Wherein, the virtual aperture array is an arrangement and combination of the receiving antenna group relative to different transmitting antennas; A Hanning window is added to the virtual aperture array in the horizontal direction, a horizontal Fourier transform is performed, and then a spectrum shift is performed; a Hanning window is added to the virtual aperture array in the vertical direction, a vertical Fourier transform is performed, and then a spectrum shift is performed, so as to obtain the two-dimensional angular spectrum.

5. The target detection method according to claim 1, characterized in that: The determining the vertical azimuth of the target point according to the vertical coordinate, the vertical array antenna spacing and the carrier wavelength includes: Determine the ratio of the vertical array antenna spacing to the carrier wavelength and the number of FFT points in the vertical direction; The vertical azimuth of the target point is determined according to the vertical coordinate, the ratio and the number of FFT points.

6. The target detection method according to claim 5, characterized in that: The expression of the vertical azimuth angle is: in, represents the vertical azimuth, in radians; represents the vertical coordinate; N2 represents the number of FFT points in the vertical direction; d int Characterizes the ratio of the vertical array antenna spacing to the carrier wavelength.

7. The target detection method according to claim 1, characterized in that: The coordinate value also includes the horizontal coordinate of the target point in the horizontal direction, and the method further includes: The horizontal azimuth of the target point is determined according to the horizontal coordinate, the horizontal array antenna spacing and the carrier wavelength.

8. The target detection method according to claim 7, characterized in that: The expression of the horizontal azimuth angle is: Wherein, θ represents the horizontal azimuth angle, in radians; θ index represents the horizontal coordinate; N1 represents the number of FFT points in the horizontal direction; d int Characterizes the ratio of the horizontal array antenna spacing to the carrier wavelength.

9. A target detection device, characterized in that: Applied to a radar device, the radar device comprises a receiving antenna group and a transmitting antenna group, the receiving antenna group comprises at least two groups of receiving antennas, the transmitting antenna group comprises at least two groups of transmitting antennas, the at least two groups of receiving antennas are arranged horizontally with a fixed spacing, and the at least two groups of transmitting antennas are arranged sequentially with the fixed spacing in both the horizontal direction and the vertical direction, and the device comprises: A preprocessing unit, configured to determine a target point based on the echo data received by the receiving antenna group; and construct a corresponding two-dimensional angle spectrum according to the target point; A calculation unit, configured to determine the coordinate value of the target point according to the two-dimensional angle spectrum, wherein the coordinate value includes the vertical coordinate of the target point in the vertical direction; and determine the vertical azimuth of the target point according to the vertical coordinate, the vertical array antenna spacing and the carrier wavelength; The method of determining the coordinate value of the target point based on the two-dimensional angle spectrum includes: performing modulus calculation on the two-dimensional angle spectrum; searching the two-dimensional angle spectrum after the modulus calculation along the horizontal direction to obtain a vertical maximum value, and performing dimensionality reduction processing based on the index of the vertical maximum value to obtain a horizontal angle spectrum; determining an angle spectrum threshold based on the mean, maximum value and preset angle spectrum threshold parameters of the horizontal angle spectrum; screening out a maximum value greater than the angle spectrum threshold from the horizontal angle spectrum; and performing quadratic curve interpolation processing on the maximum value to obtain the coordinate value of the target point.

10. A radar device, characterized in that: It comprises a receiving antenna group, a transmitting antenna group and a signal processing module; the receiving antenna group comprises at least two groups of receiving antennas, the transmitting antenna group comprises at least two groups of transmitting antennas, the at least two groups of receiving antennas are arranged horizontally with a fixed spacing, and the at least two groups of transmitting antennas are arranged in sequence with the fixed spacing in both the horizontal and vertical directions; the signal processing module is respectively connected to the receiving antenna group and the transmitting antenna group, and is used to determine the vertical azimuth of the target by the method described in any one of claims 1-8.

11. A movable platform, characterized in that: The radar device comprising the radar device according to claim 10.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

13. A terminal device, characterized in that: include: A processor and a memory, the memory being used to store one or more programs; When the one or more programs are executed by the processor, the method according to any one of claims 1 to 8 is implemented.

Images