Target angle measurement method of sparse antenna array, vehicle-mounted millimeter wave radar and product

Abstract

The application provides a target angle measurement method of a sparse antenna array, a vehicle-mounted millimeter wave radar and a product. The sparse antenna array comprises n unit antenna groups arranged repeatedly, each unit antenna group comprises m unit antennas, the spacing between the unit antenna groups is not equal to the spacing between adjacent unit antennas in the unit antenna group. The method comprises the following steps: determining the unit antenna subarray corresponding to each unit antenna based on the unit antennas contained in each unit antenna group of the sparse antenna array; acquiring the signals received by each unit antenna subarray; processing the signals to obtain the first angle spectrum corresponding to each unit antenna subarray; performing non-coherent accumulation on the first angle spectrum of each unit antenna subarray to obtain the second angle spectrum; performing angle peak value detection on the second angle spectrum to obtain a potential angle set; and determining the real target angle from the potential angle set according to the angle spectrum data of the unit antenna subarray corresponding to each potential angle in the potential angle set.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle-mounted radar, in particular to a target angle measurement method of sparse antenna array, a vehicle-mounted millimeter wave radar and a computer program product. BACKGROUND

[0002] The millimeter wave radar can measure the distance, speed and angle of the target by transmitting and receiving electromagnetic waves. Compared with the camera and the laser radar, the millimeter wave radar has good environmental adaptability and weather adaptability, and can adapt to strong light, night, heavy rain, heavy fog and dust application scenarios, and has been widely used in vehicle-mounted ADAS (Advanced Driving Assistance System) auxiliary driving system and vehicle-mounted AD (Autonomous Driving) automatic driving system. Through the mutual fusion of the camera, the laser radar and the millimeter wave radar, the redundancy of intelligent decision-making can be improved, and the high reliability and high safety of the ADAS auxiliary driving or the AD automatic driving can be realized.

[0003] At present, the application of the millimeter wave radar in the vehicle-mounted is mainly limited by the angle resolution, which is also the main disadvantage of the millimeter wave radar compared with the camera and the laser radar. In order to improve the angle resolution of the millimeter wave radar, the direction-finding aperture of the millimeter wave radar needs to be increased. The vehicle-mounted millimeter wave radar generally adopts a uniform half-wavelength antenna array, and more transceiving channels are needed to realize a large direction-finding aperture, resulting in a sharp rise in hardware cost.

[0004] In order to solve the problem of high hardware cost caused by the realization of a large direction-finding aperture by the uniform half-wavelength array, a sparse array method can be adopted to realize a low-cost and high-angle resolution direction-finding scheme. However, the sparse array can cause high side lobes or false grating lobes. The non-uniform sparse array can cause high side lobes, and the uniform sparse array can cause false grating lobes.

[0005] In order to apply the sparse array method to the vehicle-mounted millimeter wave radar, realize a low-cost large direction-finding aperture, and improve the angle resolution of the vehicle-mounted millimeter wave radar, the problem of false targets caused by the high side lobes or grating lobes of the sparse array needs to be solved. SUMMARY

[0006] In order to solve the existing technical problems, the present application provides a target angle measurement method of sparse antenna array, a vehicle-mounted millimeter wave radar and a computer program product, which can effectively solve the problem of false targets.

[0007] In a first aspect, a target angle measurement method for a sparse antenna array is provided. The sparse antenna array includes n groups of unit antennas arranged repeatedly, each group of unit antennas including m unit antennas, the spacing between the groups of unit antennas being different from the spacing between adjacent unit antennas in each group of unit antennas. The method includes:

[0008] Based on the unit antennas included in each group of unit antennas in the sparse antenna array, a unit antenna subarray corresponding to each unit antenna is determined. Each unit antenna subarray is composed of unit antennas with the same serial number in each group of unit antennas.

[0009] Signals received by each unit antenna subarray are obtained, and the signals are processed to obtain a first angle spectrum corresponding to each unit antenna subarray. The first angle spectrum of each unit antenna subarray is then non-coherently accumulated to obtain a second angle spectrum.

[0010] The second angle spectrum is subjected to angle peak detection to obtain a set of potential angles.

[0011] Based on the angle spectrum data of the unit antenna subarrays corresponding to each potential angle in the set of potential angles, a real target angle is determined from the set of potential angles.

[0012] In a second aspect, a vehicle-mounted millimeter wave radar is provided. The vehicle-mounted millimeter wave radar includes a millimeter wave radar processor and a memory. The memory stores a computer program that can be executed by the millimeter wave radar processor.

[0013] The computer program is executed by the millimeter wave radar processor to implement the target angle measurement method for the sparse antenna array described in any embodiment of the present application.

[0014] The antenna array used for angle measurement is formed by a MIMO working mode or a non-MIMO working mode.

[0015] In a third aspect, a computer program product is provided. The computer program product includes a computer program that, when executed by a processor, implements the target angle measurement method for the sparse antenna array described in any embodiment of the present application.

[0016] The target angle measurement method of the sparse antenna array provided by the above embodiment utilizes the repeated arrangement of the n-unit antenna groups to form the sparse antenna array, splits the sparse antenna array into a plurality of unit antenna sub-arrays according to the unit antennas included in the unit antenna groups, respectively receives signals by the unit antenna sub-arrays, processes the signals to obtain a first angle spectrum corresponding to each unit antenna sub-array, non-coherent accumulates the first angle spectrum of each unit antenna sub-array to obtain a second angle spectrum, detects an angle peak value of the second angle spectrum to obtain a potential angle set, determines a real target angle from the potential angle set according to the angle spectrum data of the unit antenna sub-array corresponding to each potential angle in the potential angle set. In this way, the sparse antenna array is equivalent to a plurality of unit antenna sub-arrays as sparse uniform arrays, the first angle spectrum obtained by processing the signals received by each unit antenna sub-array can be used for subsequent screening of the real target angle, so that the sparse uniform array is used to effectively reduce the number of antenna channels and reduce the cost of the radar, and the angle spectrum data obtained by the unit antenna sub-array as a receiving unit can be used to realize high-resolution angle measurement and eliminate false targets of grating lobes.

[0017] The vehicle-mounted millimeter wave radar and the computer program product provided by the above embodiment belong to the same concept as the target angle measurement method of the corresponding sparse antenna array, so they have the same technical effects as the target angle measurement method of the corresponding sparse antenna array. Here, no further description is given. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 An application scenario diagram of the target angle measurement method of the sparse antenna array in an embodiment.

[0019] Figure 2 A structural schematic diagram of the vehicle-mounted millimeter wave radar in an embodiment.

[0020] Figure 3 A flowchart of the target angle measurement method of the sparse antenna array in an embodiment.

[0021] Figure 4 A schematic diagram of the sparse antenna array in an embodiment.

[0022] Figure 5 A schematic diagram of the sparse antenna array in an embodiment. Figure 4 A schematic diagram of the sparse antenna array in an embodiment.

[0023] Figure 6 A schematic diagram of the sparse antenna array in an embodiment. Figure 4 A schematic diagram of the sparse antenna array in an embodiment.

[0024] Figure 7 A schematic diagram of the angle spectrum in an embodiment.

[0025] Figure 8Fig. 1 is a schematic diagram of a known half-wavelength non-thinned uniform antenna array.

[0026] Figure 9 Fig. 2 is a schematic diagram of the principle of a target angle measurement method for a sparse antenna array in an optional embodiment.

[0027] Figure 10 Fig. 3 is a flowchart of a target angle measurement method for a sparse antenna array in an optional embodiment.

[0028] Figure 11 Fig. 4 is a flowchart of the working process of a vehicle-mounted millimeter wave radar in an embodiment.

[0029] Figure 12 Fig. 5 is a schematic diagram of a sparse antenna array in an optional embodiment.

[0030] Figure 13 Fig. 6 is a schematic diagram of a transmitting array and a receiving array forming a sparse antenna array in a non-MIMO working mode.

[0031] Figure 14 Fig. 7 is a schematic diagram of a transmitting array and a receiving array forming a sparse antenna array in a MIMO working mode.

[0032] Figure 15 Fig. 8 is a schematic diagram of a sparse antenna array decomposed into a plurality of unit antenna sub-arrays. Figure 12

[0033] Fig. 9 is a schematic diagram of a sparse antenna array equivalent to a phase interferometer between sub-arrays. Figure 16 Figure 12 Fig. 10 is a schematic diagram of an angle spectrum corresponding to a target incoming direction of 10°.

[0034] Figure 17 Fig. 11 is a schematic diagram of the structure of a vehicle-mounted millimeter wave radar provided in an embodiment.

[0035] DETAILED DESCRIPTION Figure 18 The technical solutions of the present application will be further described in detail below in combination with the accompanying drawings and specific embodiments.

[0036] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in combination with the accompanying drawings. The described embodiments should not be regarded as limiting the present application, and all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0037] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in combination with the accompanying drawings. The described embodiments should not be regarded as limiting the present application, and all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0038] ​In the following description, the expression "some embodiments" refers to a subset of all possible embodiments, and it is to be understood that "some embodiments" can be the same subset or different subsets as each other, and can be combined with each other as long as there is no conflict.

[0039] In the following description, the terms "first", "second", "third" are merely used to distinguish similar objects, and do not represent a specific order of the objects. Understandably, "first", "second", "third" can be interchanged in a specific order or sequence as long as it is allowed, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein.

[0040] Referring to Figure 1 The optional application scenario diagram of the target angle measurement method of the sparse antenna array provided by an embodiment of the application applied to the vehicle-mounted millimeter wave radar is shown in FIG. 1. The vehicle-mounted millimeter wave radar 200 is usually installed on both sides of the front of the vehicle 100. The common installation positions are not limited to the front position shown in the figure, and also include front corners, rear positions, rear corners and the like, which are used for detecting and sensing surrounding environment targets (target 1, target 2, target 3). Figure 1

[0041] Referring to Figure 2 The structural schematic diagram of the vehicle-mounted millimeter wave radar is shown in FIG. 2. The vehicle-mounted millimeter wave radar mainly consists of four functional parts:

[0042] 1) Antenna array, consisting of a transmitting array and a receiving array. The vehicle-mounted millimeter wave radar generally adopts a MIMO (Multiple-Input Multiple-Output) working mode, and the antenna array required for direction finding is realized through the MIMO working mode between the unit antennas of the transmitting array. The sparse antenna array provided by the embodiments of the application refers to the final direction finding antenna array. The sparse antenna array can be formed through a MIMO working mode, or can be formed through a non-MIMO working mode. The specific method of forming the sparse antenna array does not affect the use of the target angle measurement method of the sparse antenna array provided by the embodiments of the application, and the specific form of the unit antenna also does not affect the use of the target angle measurement method of the sparse antenna array provided by the embodiments of the application.

[0043] ​2) MRTR (Millimeter-wave Radar Transceiver), millimeter-wave radar transceiver module or chip, mainly composed of a transmitting component, a receiving component, and a linear frequency modulation local oscillator component. The MRTR generates and transmits millimeter-wave radar working waveform signals, and receives and discretely samples target reflected waveform signals, and sends the sampled reflected waveform signals to the MRP (Millimeter-wave Radar Processor).

[0044] 3) MRP (Millimeter-wave Radar Processor), millimeter-wave radar processor, receiving reflected waveform signals from the MRTR and performing digital processing to obtain distance, speed, and angle information of environmental targets, and implementing clustering, identification, and track tracking of targets, and outputting point cloud level detection results or target level detection results. From the main function, the MRP is mainly composed of a ranging module, a speed measurement module, an angle measurement module, and a target clustering, identification, and tracking module, and the above modules can be realized by embedded software, FPGA (Field Programmable Gate Array), or ASIC (Application Specific Integrated Circuit). The target angle measurement method of the sparse antenna array provided in the embodiments of the present application is mainly completed in the MRP angle measurement module. The implementation form, composition method, or module division method of the MRP does not affect the use of the target angle measurement method of the sparse antenna array provided in the embodiments of the present application.

[0045] 4) Readable and writable memory, used for storing millimeter-wave radar working data, including pre-stored working parameter data and process data, such as the structure size parameters of the sparse antenna array provided in the embodiments of the present application, and the threshold parameters required by the sparse antenna array angle measurement method provided in the embodiments of the present application.

[0046] It should be noted that the composition form or composition method of the above vehicle-mounted millimeter-wave radar functional parts does not affect the use of the target angle measurement method of the sparse antenna array provided in the embodiments of the present application; in terms of application scenarios, the target angle measurement method of the sparse antenna array provided in the embodiments of the present application can be applied to all applications using electromagnetic waves for target direction finding, and is not limited to vehicle-mounted millimeter-wave radar applications.

[0047] Please refer to Figure 3 A target angle measurement method of a sparse antenna array provided in the embodiments of the present application includes the following steps:

[0048] S101, based on the unit antennas contained in each unit antenna group in the sparse antenna array, determine the unit antenna subarray corresponding to each unit antenna; wherein, each unit antenna subarray is composed of unit antennas with the same sequence number in each unit antenna group.

[0049] A sparse antenna array is an array where the distance between adjacent antenna elements is greater than half the wavelength of the transmitted waveform signal. A sparse uniform array is an array where the distance between adjacent antenna elements is equal and this distance is greater than half the wavelength of the transmitted waveform signal. A half-wavelength non-sparse uniform array is an array where the distance between adjacent antenna elements is equal and this distance is equal to half the wavelength of the transmitted waveform signal.

[0050] In this embodiment, the sparse antenna array includes n repeated antenna groups, each antenna group containing m antenna elements. The spacing between antenna groups is not equal to the spacing between adjacent antenna elements within an antenna group.

[0051] Please see Figure 4 This is a schematic diagram of a sparse antenna array consisting of n repeated antenna groups, where each antenna group contains m antenna elements. For example, if m equals 3, the antenna elements within each antenna group consist of... Figure 4 The diagram shows three antenna units represented by triangles, circles, and rectangles. For clarity, they are referred to as antenna unit T, antenna unit C, and antenna unit S, respectively. Within each antenna unit group, the spacing between the antenna units includes the spacing d1 between antenna unit T and antenna unit C, and the spacing d2 between antenna unit T and antenna unit S. The spacing d3 between antenna unit groups refers to the distance between the last antenna unit of the preceding antenna unit group and the first antenna unit of the following antenna unit group, such as the spacing between antenna unit S of the preceding antenna unit group and antenna unit T of the following antenna unit group. It should be noted that the number of antenna elements within each antenna group can be adjusted adaptively according to specific needs, increasing or decreasing the number of antenna elements within each antenna group. The number of antenna groups in a sparse antenna array can also be adjusted according to specific needs, increasing or decreasing the number of antenna groups. The more antenna elements within each antenna group and / or the more antenna groups there are, the longer the direction finding baseline of the phase interferometer formed by the subarrays of the antenna groups will be, which is beneficial to improving the angle unambiguity accuracy and angle measurement accuracy, and improving the robustness of the angle measurement results to noise, but the cost will be higher.

[0052] Please see Figure 5 Based on the number of antenna elements within each antenna group, a sparse antenna array can be divided into multiple antenna subarrays. Each antenna subarray is a sparse and uniform subarray. Each antenna subarray consists of antenna elements with the same index within each antenna group, still using the [missing information - likely a specific format or structure].Figure 4 In each unit antenna group, for example, each unit antenna includes a first unit antenna T, a second unit antenna C, and a third unit antenna S, the first unit antennas T of the same serial number in each unit antenna group form a first unit antenna subarray, the second unit antennas C of the same serial number in each unit antenna group form a second unit antenna subarray, and the third unit antennas S of the same serial number in each unit antenna group form a third unit antenna subarray. In each unit antenna subarray, the distance between adjacent unit antennas is the distance between two unit antennas of the same serial number in adjacent unit antenna groups, which is denoted by d0. Therefore, d0 is at least greater than the maximum distance d2 between unit antennas in the same unit antenna group. In a specific example, d0 is greater than 1.5 times the wavelength (denoted by λ) of the transmitted waveform signal of the vehicle-mounted millimeter wave radar, that is, d0 > 1.5λ.

[0053] In S103, signals received by each unit antenna subarray are obtained, and the signals are processed to obtain a first angle spectrum corresponding to each unit antenna subarray. Then, non-coherent accumulation is performed on the first angle spectrum of each unit antenna subarray to obtain a second angle spectrum.

[0054] The sparse antenna array is equivalent to being disassembled into multiple unit antenna subarrays, and the unit antenna subarrays are used as receiving units of echo signal data. The phase interference formed by the multiple unit antenna subarrays is used to obtain signals respectively received by each unit antenna subarray. The signals corresponding to each unit antenna subarray are processed to obtain an angle spectrum corresponding to each unit antenna subarray. Then, non-coherent accumulation is performed on the angle spectrum corresponding to each unit antenna subarray to obtain an angle spectrum for angle peak detection. In order to facilitate description and differentiation, in the embodiments of the present application, the angle spectrum corresponding to each unit antenna subarray obtained by processing the signals corresponding to each unit antenna subarray is referred to as a first angle spectrum, and the angle spectrum obtained by performing non-coherent accumulation on the angle spectrum corresponding to each unit antenna subarray is referred to as a second angle spectrum. The non-coherent accumulation refers to an accumulation method of directly superimposing amplitudes or powers without using the phase relationship of the signals.

[0055] In S105, angle peak detection is performed on the second angle spectrum to obtain a potential angle set.

[0056] The angle peak detection performed on the second angle spectrum after non-coherent accumulation can obtain a peak detection result containing all real angles and false angles. The real angles and the false angles obtained by angle peak detection are combined to form a potential angle set. Both the real angles and the false angles can be referred to as potential angles.

[0057] In S107, a real target angle is determined from the potential angle set according to the angle spectrum data of the unit antenna subarray corresponding to each potential angle in the potential angle set.

[0058] The angle spectrum data of the unit antenna subarray corresponding to each potential angle is angle spectrum data obtained by processing signals received by the unit antenna subarray as a receiving unit corresponding to each potential angle. After all potential angles are obtained through angle peak value detection, the angle spectrum data obtained by processing signals received by each unit antenna subarray can be used for subsequent screening of real target angles.

[0059] The target angle measurement method of the sparse antenna array provided in the above embodiments uses n unit antenna groups to repeatedly arrange to form a sparse antenna array, converts the sparse antenna array into a plurality of unit antenna subarrays as a sparse uniform array, decomposes the plurality of unit antenna groups of the sparse antenna array into a plurality of unit antenna subarrays, processes angle spectrum data obtained by processing signals received by the plurality of unit antenna subarrays as receiving units, and uses the angle spectrum data to screen real target angles after all potential angles are obtained through angle peak value detection. Therefore, the sparse uniform array can be used to effectively reduce the number of antenna channels, reduce the cost of the radar, and the angle spectrum data obtained by using the unit antenna subarray as a receiving unit can be used to achieve high-resolution angle measurement and eliminate false targets of grating lobes.

[0060] In some embodiments, step S107 comprises:

[0061] According to the angle spectrum data of the unit antenna subarray corresponding to each potential angle in the set of potential angles, the inter-subarray phase interferometer formed by each unit antenna group uses a phase interferometer angle measurement algorithm to perform angle measurement and deambiguity, and determines a real target angle from the set of potential angles.

[0062] The relative spatial positions between the plurality of unit antenna subarrays obtained by decomposing each unit antenna group of the sparse antenna array can be equivalent to an inter-subarray phase interferometer, as shown in the following table. Figure 6 As shown in the table, the relative spatial positions between the subarray T, the subarray C, and the subarray S corresponding to the first unit antenna T, the second unit antenna C, and the third unit antenna S can be equivalent to an inter-subarray phase interferometer TCS.

[0063] The phase interferometer angle measurement algorithm is a technique for measuring the direction of arrival of a radio signal by using the phase information of the radio signal arriving at a direction-finding antenna. This algorithm is not affected by signal strength attenuation and has higher direction-finding accuracy than the amplitude method. The phase interferometer angle measurement algorithm is usually based on the direction-finding principle of a one-dimensional interferometer. When a target signal radiates to an antenna array, there is a certain time difference between the signals received by the elements on the same baseline due to the distance between the elements of the antenna array. This time difference can be converted into a phase difference under certain conditions, that is, the phase interferometer direction-finding algorithm can use the phase difference between the signals received by the elements on the same baseline to complete the direction-finding of the target.

[0064] Angle measurement and ambiguity resolution refers to the process of recovering the true angle value from ambiguous angle measurement results in the angle measurement process. The angle measurement ambiguity resolution algorithm can be selected from various known algorithms, such as increasing the baseline length, using long and short baselines, high and low frequencies, and frequency modulation, which can effectively improve the accuracy of angle measurement and reduce ambiguity. The present application does not limit this. Based on the angle spectrum data of the unit antenna subarray corresponding to each potential angle in the potential angle set, the subarray phase interferometer equivalent to the multiple unit antenna subarrays uses the phase interferometer angle measurement algorithm for angle measurement ambiguity resolution, deletes the false angle, and obtains the true angle of arrival direction to determine the true target angle.

[0065] In this way, the target angle measurement method of the sparse antenna array provided by the above embodiment uses the first angle spectrum obtained by processing the signals received by the multiple unit antenna subarrays as receiving units, and uses the second angle spectrum obtained by non-coherent accumulation for angle peak detection. After determining all potential angles, the subarray phase interferometer composed of multiple unit antenna subarrays can be used to determine the true target angle from all potential angles.

[0066] In some embodiments, the unit antennas include a first unit antenna T, a second unit antenna C, and a third unit antenna S, and the unit antenna subarrays include a first unit antenna subarray composed of the first unit antenna T, a second unit antenna subarray composed of the second unit antenna C, and a third unit antenna subarray composed of the third unit antenna S. Step S107 includes:

[0067] According to the angle spectrum data A T of the first unit antenna subarray, the angle spectrum data A C of the second unit antenna subarray, and the angle spectrum data A S of the third unit antenna subarray corresponding to each potential angle in the potential angle set, respectively.

[0068] The subarray phase interferometer composed of each unit antenna group uses the phase interferometer angle measurement algorithm for angle measurement ambiguity resolution. According to whether the angle spectrum data A T , A C , and A S corresponding to each potential angle satisfy the phase interference relationship, the true target angle is determined from the potential angle set.

[0069] Optionally, the phase interference relationship is shown in the following formula 1 and formula 2:

[0070]

[0071] Wherein, f represents the frequency of the transmitted and received waveform signal, λ represents the wavelength of the transmitted waveform signal, d1 is the distance between the first unit antenna T and the second unit antenna C in the unit antenna group, and d2 is the distance between the second unit antenna T and the third unit antenna S in the unit antenna group.

[0072] In the equivalent inter-subarray phase interferometer TCS based on the relative spatial positions among the subarray T, the subarray C and the subarray S, the phase interference of the subarray T, the subarray C and the subarray S satisfies the theoretical relationship shown in the formula 1 and the formula 2. Wherein, A T represents the signal received by the subarray T or the complex angle spectrum of the subarray T, A C represents the signal received by the subarray C or the complex angle spectrum of the subarray C, A S represents the signal received by the subarray S or the complex angle spectrum of the subarray S.

[0073] In the above embodiment, the second angle spectrum is obtained by processing the signals of the multiple unit antenna subarrays to obtain the corresponding first angle spectrum, and then performing non-coherent accumulation based on the first angle spectrum, the potential angle is obtained by angle peak detection for the second angle spectrum, and whether the angle spectrum data of each unit antenna subarray corresponding to each potential angle in the potential angle set satisfies the phase interference relationship is used to determine the real target angle from the potential angle set.

[0074] In some embodiments, in the inter-subarray phase interferometer, d1 and d2 respectively satisfy the following relationships, as shown in the formula 3 and the formula 4:

[0075]

[0076] Wherein, 0 < θ max ≤ 90°.

[0077] The inter-subarray phase interferometer formed by the multiple unit antenna subarrays after the decomposition of each unit antenna group, wherein the size represents the relative spatial position between different unit antenna subarrays, d1 and d2 need to satisfy the direction finding resolution ambiguity requirement of the phase interferometer in the direction finding angle coverage range, and the maximum coverage range of the direction of arrival angle θ is θ max The constraint relationship of d1 and d2 is shown in the formula 3 and the formula 4.

[0078] In an optional specific example, d1 is 0.5λ, and d2 is λ. In this way, the combination of the multiple unit antenna subarrays after the decomposition of each unit antenna group can be equivalent to the inter-subarray phase interferometer of the half-wavelength non-sparse uniform array.

[0079] In an optional specific example, the distance between adjacent unit antennas in each unit antenna subarray is d0, and d0 is 4λ. The size of d0 is related to the number of unit antennas in each unit antenna group, the distance between adjacent unit antennas in each unit antenna group, and the distance between adjacent unit antenna groups. Taking the inter-subarray phase interferometer TCS composed of subarrays T, C and S as an example, the inter-subarray phase interferometer TCS is a 3-unit phase interferometer or a 2-baseline phase interferometer. It should be noted that the sparse antenna array in the embodiments of the present application is not limited to a 3-unit phase interferometer or a 2-baseline phase interferometer. The number of unit antennas in the phase interferometer can be increased or decreased. The more the number of unit antennas, the longer the direction-finding baseline of the inter-subarray phase interferometer, which can effectively improve the angle unambiguousness precision and the angle measurement precision, and improve the robustness of the angle measurement result to noise, but the cost is higher. The less the number of unit antennas, the lower the cost, but the direction-finding baseline of the inter-subarray phase interferometer is shorter, and the robustness of the angle measurement result to noise is reduced.

[0080] In some embodiments, step S103 comprises:

[0081] performing one-dimensional range FFT processing on the discrete digital signal obtained after the received target reflected waveform signal is processed by the discrete digital signal sampling, to obtain a one-dimensional range FFT result;

[0082] performing two-dimensional velocity FFT processing on the one-dimensional range FFT result, to obtain a two-dimensional velocity FFT result;

[0083] performing constant false alarm detection on the two-dimensional velocity FFT result, to obtain a detection point data;

[0084] performing angle dimension FFT processing on the detection point data using each unit antenna subarray, to obtain a first angle spectrum corresponding to each unit antenna subarray, and performing non-coherent accumulation on the first angle spectrum, to obtain a second angle spectrum.

[0085] The signals received by each unit antenna subarray are mainly information required for angle measurement, which is generally relative amplitude information and relative phase information between internal antenna channels of the subarray T, the subarray C and the subarray S, and then angle measurement operation is performed through FFT (Fast Fourier Transform) or DBF (Digital Beam Forming), in the embodiment, the angle measurement operation mainly includes one-dimensional distance FFT processing, two-dimensional velocity FFT processing and constant false alarm detection, so as to obtain the angle spectrum (i.e., the first angle spectrum) corresponding to the subarray T, the subarray C and the subarray S respectively; and non-coherent accumulation is performed on the angle spectrum corresponding to the subarray T, the subarray C and the subarray S respectively, so as to improve the sensitivity of angle peak detection, and the angle spectrum (i.e., the second angle spectrum) used for angle peak detection is obtained.

[0086] In some embodiments, step S107 comprises:

[0087] selecting any potential angle in the potential angle set to obtain the angle dimension FFT result of the unit antenna subarray corresponding to the potential angle;

[0088] performing direction finding on the inter-subarray phase interferometer according to the size parameter of the inter-subarray phase interferometer formed by the unit antenna groups and the angle dimension FFT result;

[0089] calculating the angle deviation between the potential angle and the direction finding angle of the inter-subarray phase interferometer;

[0090] judging whether the angle deviation is less than a set threshold value;

[0091] if the angle deviation is less than the set threshold value, taking the current direction finding result of the inter-subarray phase interferometer as a qualified direction finding result;

[0092] performing angle measurement and ambiguity resolution on all potential angles, and determining the real target angle from the potential angle set.

[0093] wherein, based on the uniform sparse subarray corresponding to the unit antenna subarray, there are grating lobes, the real target angle is θ, but there are false angles θ f1 , θ f2 , θ f3 , θ f4 After peak detection on the second angle spectrum, all detection points will include the real angle θ and the false angles θ f1 , θ f2 , θ f3 , θ f4 Only the peak detection result cannot distinguish the real angle θ and the false angles θ f1 , θ f2 , θf3 θ f4 For ease of description, we will use both the true angle θ and the pseudo angle θ. f1 θ f2 θ f3 θ f4 The potential angle obtained from angle peak detection is used to represent the angle, but the true angle and false angle cannot be clearly distinguished before angle measurement and deblurring. The true angle θ and all false angles θ obtained from angle peak detection are then considered. f1 θ f2 θ f3 θ f4 A potential angle set is formed by combining the data, and based on the index of the potential angle set in the second angle spectrum, the angular dimension FFT data of subarrays T, C, and S corresponding to each potential angle in the potential angle set are obtained respectively. Based on the angular dimension FFT data of subarrays T, C, and S corresponding to each potential angle, angle measurement and deambiguity are performed using an inter-subarray phase interferometer (TCS). False angles θ are removed based on whether the angular deviation between each potential angle and the direction-finding angle of the inter-subarray phase interferometer is less than a set threshold. f1 θ f2 θ f3 θ f4 This allows us to obtain the true direction and angle of the incoming wave, θ.

[0094] like Figure 7 As shown, in the angle spectrum used for peak angle detection, the direction of arrival of the target wave comes only from the azimuth of the main lobe. The directions indicated by grating lobes-1,-2,-3, and-4 are false targets. The position and number of false targets in the grating lobes are related to the direction of arrival of the target wave, the spacing and number of unit antennas of the T, C, and S subarrays, and the wavelength λ of the transmitted waveform signal of the vehicle-mounted millimeter-wave radar. By using an inter-subarray phase interferometer and an angle measurement algorithm for angle measurement de-ambiguity, the high-resolution direction-finding results of the T, C, and S subarrays can be de-ambigued by removing false targets in the directions indicated by grating lobes-1,-2,-3, and-4, thus obtaining the direction-finding result of the main lobe azimuth, which determines the true target angle.

[0095] To gain a more comprehensive understanding of the target angle measurement method for sparse antenna arrays provided in the embodiments of this application, please refer to [the relevant documentation / reference]. Figures 8 to 17 ,by Figure 2 The structure of the vehicle-mounted millimeter-wave radar shown, and Figure 4 Taking the sparse antenna array shown as an example, the main workflow of vehicle-mounted millimeter-wave radar and the target angle measurement method of sparse antenna array are explained.

[0096] The sparse antenna array can be formed by a MIMO working mode, can be formed by a non-MIMO working mode, can be an all-physical antenna array, or can be a part of a physical antenna array, and a specific method for forming the sparse antenna array does not affect the use of the target angle measurement method of the sparse antenna array provided in the embodiments of the present application.

[0097] In the case that the wavelength λ of the transmitted waveform signal remains the same, the array angle measurement resolution depends on the size of the array aperture. The larger the array aperture, the smaller the angle measurement resolution, and the stronger the resolution capability of the vehicle-mounted millimeter wave radar on multiple targets. In the example, the aperture size of the sparse uniform subarray for high-resolution direction finding is D0=(n-1)*d0.

[0098] Please refer to Figure 8 , the known half-wavelength non-sparse uniform array, to achieve the same direction finding aperture of the T, C, and S subarrays, the number of antennas needs to be m=D0 / (0.5λ)+1=(n-1)*d0 / (0.5λ)+1. Since d0>0.5λ, m>n, the number of antenna channels of the half-wavelength non-sparse uniform array is much larger than that of the sparse uniform array, and the sparse uniform array can effectively reduce the number of antenna channels and thus reduce the cost of the radar.

[0099] Specifically, the following examples illustrate the advantages of the sparse uniform array provided in the embodiments of the present application over the known half-wavelength non-sparse uniform array as shown in Figure 8 .

[0100] For the half-wavelength non-sparse uniform array as shown in Figure 8 , the relationship between the angle resolution Δθ (unit rad) and the number of unit antennas m is shown in the following formula 5:

[0101]

[0102] Taking the vehicle-mounted millimeter wave radar to achieve an angle resolution of 1° (corresponding to 0.0175 rad) as an example, the number of antennas of the half-wavelength non-sparse uniform array is calculated based on formula 5, and it can be known that m=114.

[0103]

[0104] And as an example of the sparse uniform array based on the repeated arrangement of n unit antenna groups proposed in the embodiments of the present application, the size of the sparse uniform array in the phase interferometer between the subarrays can be designed as shown in the following formulas 6-8:

[0105] d0=4λ; (formula 6)

[0106] d1=0.5λ; (formula 7)

[0107] d² = λ; (Formula 8)

[0108] A uniform sparse array corresponds to the example of d0 = 4λ. To achieve an angular resolution of 1° (corresponding to 0.0175 rad), the number of element antenna groups is n = 14, as shown in Equation 9. Figures 12-14 As shown.

[0109]

[0110] Figure 12 The example of a uniform sparse array shown has 14*3=42 antennas, which is only... Figure 8 The number of antennas in the half-wavelength non-sparse uniform array example shown is 42 / 114 = 37%. The uniform sparse array significantly reduces the number of antennas and channels of the vehicle-mounted millimeter-wave radar. Figure 12 The sparse uniform array example shown can be a physical array formed by non-MIMO or a virtual array formed by MIMO; it can be the entire array or a partial subarray of the entire array.

[0111] If it is a non-MIMO operating mode, typically the transmitter array adopts a full phased array synthesis operating mode. Figure 12 The sparse uniform array shown represents either the entire receiving array or a portion of it. For example, in non-MIMO operating mode, the transmitting and receiving arrays of a sparse uniform array vehicle-mounted millimeter-wave radar could be as follows: Figure 13 As shown, the topology of the transmitting array does not affect the direction finding function of the receiving array.

[0112] If it is in MIMO working mode Figure 12 The sparse, uniform array shown represents either the entire MIMO virtual receiver array or a portion of it. For example, in MIMO operating mode... Figure 12 The transmitting and receiving arrays of the sparse uniform array vehicle-mounted millimeter-wave radar shown can be as follows: Figure 14 As shown.

[0113] The target angle measurement method for sparse antenna arrays of vehicle-mounted millimeter-wave radar provided in this application embodiment mainly consists of... Figure 2 The MRP millimeter-wave radar processor shown executes, as Figure 9 and Figure 10 As shown, it includes the following steps:

[0114] S11 obtains the information required for angle measurement through subarrays T, C, and S; the information required for angle measurement mainly includes the relative amplitude and relative phase information between the antenna channels inside subarrays T, C, and S.

[0115] S12, obtain the angle spectrum of the subarray T, the subarray C and the subarray S by FFT (Fast Fourier Transform) angle measurement operation or DBF (Digital Beam Forming) angle measurement operation.

[0116] S13, perform non-coherent accumulation on the angle spectrum of the subarray T, the subarray C and the subarray S to obtain the angle spectrum for angle peak value detection.

[0117] S14, perform angle peak value detection on the angle spectrum after non-coherent accumulation.

[0118] S15, combine the angles obtained by angle peak value detection to form a potential angle set, and obtain the angle FFT data of the subarray T, the subarray C and the subarray S corresponding to each potential angle in the potential angle set according to the index of the potential angle set in the angle spectrum for angle peak value detection.

[0119] S16, use the angle FFT data of the subarray T, the subarray C and the subarray S corresponding to each potential angle to perform angle deambiguity by using the inter-subarray phase interferometer TCS to determine the real target angle.

[0120] Since the uniform sparse array has grating lobes, all the detection points after peak value detection on the angle spectrum after non-coherent accumulation will include real angle and false angle information, and only the angle peak value detection result cannot distinguish the real angle and the false angle. The potential angle set formed based on the real angle and the false angle is used to perform angle deambiguity by using the inter-subarray phase interferometer TCS to eliminate the false angle and obtain the real direction of arrival angle.

[0121] The typical working process of the vehicle-mounted millimeter wave radar using the sparse antenna array and the angle measurement method proposed in the embodiments of the present application is as shown in Figure 11 , which includes the following steps:

[0122] S211, power on and initialize the vehicle-mounted millimeter wave radar.

[0123] S212, the vehicle-mounted millimeter wave radar receives a start working instruction.

[0124] S221, the MRTR chip receives the waveform signal reflected by the target.

[0125] S222, the MRTR chip performs discrete ADC sampling on the received waveform signal reflected by the target.

[0126] S230, the MRP chip performs one-dimensional distance FFT processing on the discrete ADC signal from the MRTR chip.

[0127] S231, the MRP chip performs two-dimensional velocity FFT processing on the one-dimensional distance FFT processing result.

[0128] S232, the MRP chip performs CFAR constant false alarm detection on the two-dimensional velocity FFT processing result.

[0129] S233, the MRP chip performs angle dimension FFT processing on the constant false alarm detection false alarm points using the subarray T, the subarray C and the subarray S respectively.

[0130] S234, the MRP chip performs non-coherent accumulation on the angle dimension FFT results of the subarray T, the subarray C and the subarray S.

[0131] S235, the MRP chip performs angle peak detection on the angle FFT results after non-coherent accumulation.

[0132] S236, according to the size parameters of the sparse antenna array, the MRP chip performs main lobe and grating lobe pairing on the angle peak detection result. It should be noted that the main lobe and grating lobe pairing refers to an optional detection principle of angle peak detection, that is, by screening the detected radiation intensity, the peak value with the maximum radiation intensity and the intensity substantially matched with it is found as the main lobe and grating lobe pairing result, and all potential angles are sequentially determined to form a potential angle set.

[0133] S237, the MRP chip selects any angle in the main lobe and grating lobe pairing result. That is, any potential angle in the potential angle set is selected.

[0134] S238, the MRP chip uses the selected angle to index the angle dimension FFT results of the subarray T, the subarray C and the subarray S.

[0135] S239, according to the size parameters between the subarray T, the subarray C and the subarray S and the angle dimension FFT results, the MRP chip performs phase interferometer direction finding between the subarray T, the subarray C and the subarray S.

[0136] S240, the angle deviation between each angle in the current main lobe and grating lobe pairing and the phase interferometer direction finding angle is calculated.

[0137] S241, it is judged whether the angle deviation is less than a set threshold value; if yes, it is determined that the direction finding angle is valid, and the phase interferometer direction finding angle is taken as the final direction finding result, otherwise, the direction finding fails.

[0138] S242, the phase interferometer ambiguity resolution of all main lobe and grating lobe pairing results is completed in a loop.

[0139] S243, the direction finding processing of all CFAR constant false alarm false alarm points is completed in a loop.

[0140] The S244 MRP chip performs target clustering, identification, and tracking, and performs target-level data processing.

[0141] The S245 MRP chip outputs point cloud-level detection results or target-level detection results.

[0142] S246, loops through scene target detection, outputs detection results, until the condition for stopping operation is met.

[0143] Among them, according to Figure 12 The sparse antenna array shown, with subarrays T, C, and S forming an inter-subarray phase interferometer TCS, is as follows: Figure 15 As shown.

[0144] Assumption Figure 12 If the direction of incoming wave from the target, as shown by the sparse antenna array, is θ = 10°, then for... Figure 16 The angle spectra of subarrays T, C, and S after noncoherent accumulation are shown below. Figure 17 As shown.

[0145] For example Figure 17 By performing angular peak detection on the angular spectrum shown, we can obtain... Figure 17 The true angle of 10° corresponding to the main lobe peak shown in the figure, and the false angles of -55.8°, -35.2°, -19.1°, -4.4°, 25.1°, and 42.3° corresponding to the six grating lobe peaks respectively, together constitute the potential angle set.

[0146] according to Figure 17 The indices of each potential angle in the potential angle set are shown, and the angle spectrum data of each potential angle in the sparse uniform subarray examples T, C, and S are obtained respectively. For each sparse uniform subarray example T, C, and S in the same sparse uniform array, the angle spectrum of the potential angle set is the same.

[0147] Figure 12 The sparse antenna array shown receives a signal with a target arrival direction of θ = 10°. The angle spectrum of the potential angle set in the sparse uniform subarray examples T, C, and S satisfies the theoretical relationship shown in Equations 10 and 11 below:

[0148]

[0149] Examples of uniform subarrays T, C, and S are as follows: Figure 15 As shown, A T Let A represent the angle spectrum in the potential angle set matrix T. C Let A represent the angle spectrum of the latent angle set in subarray C. S Let f represent the angle spectrum of the potential angle set in the subarray S, and let f represent the frequency of the transmitted and received waveform signals.

[0150] The spectral relationships of the latent angle sets in the sparse uniform subarray examples T, C, S satisfy the following: Figure 16 The example TCS (Transient Phase Interferometer) is shown. Based on the angle spectra of the latent angle set in the sparse uniform subarray examples T, C, and S (as shown in Equations 1 and 2 above), the angle spectra of the sparse uniform subarray examples T, C, and S can be represented by A. T A C A S (indication) and Figure 16 The example TCS (Transient Phase Interferometer) shown can be used to select a known phase interferometer angle measurement algorithm to obtain the unique incoming wave direction θ = 10°, and eliminate such... Figure 17 The purpose of this study is to achieve high-resolution angle measurement of sparse antenna arrays and eliminate false targets in their grating lobes, as shown in the diagram.

[0151] The vehicle-mounted millimeter-wave radar with the sparse antenna array and its angle measurement method proposed in the above embodiments has at least the following characteristics:

[0152] First, to meet the direction finding requirements of vehicle-mounted millimeter-wave radar for low cost and high angular resolution, a sparse antenna array is divided into multiple subarrays of a sparse uniform array. The angle spectrum corresponding to each subarray is obtained by processing the received signals of each subarray. An angle spectrum for angle peak detection is obtained based on the angle spectrum corresponding to each subarray, and a potential angle set containing real and false angles is obtained. Then, the angle measurement and deambiguation method of inter-subarray phase interferometer is used to achieve low-resolution angle measurement and eliminate grating lobe false angles.

[0153] Second, it supports angle de-ambiguity algorithms for inter-subarray phase interferometers composed of two or more subarrays. The more subarrays there are, the longer the direction finding baseline of the inter-subarray phase interferometer is, which can effectively improve the angle de-ambiguity accuracy and angle measurement accuracy, and improve the robustness of the angle measurement results to noise.

[0154] Third, high-resolution angle measurement of vehicle-mounted millimeter-wave radar can be achieved based on sparse and uniform array. The antenna spacing of the array aperture unit can be much greater than half a wavelength, which can effectively reduce the number of transceiver channels and antennas of vehicle-mounted millimeter-wave radar with high angle measurement resolution, thereby effectively reducing the cost of vehicle-mounted millimeter-wave radar with high angle measurement resolution.

[0155] In another aspect, please refer to the embodiments of this application. Figure 2 and Figure 18 Furthermore, a vehicle-mounted millimeter-wave radar is provided, including a millimeter-wave radar processor 201 and a memory 202. The memory 202 stores a computer program that can be executed by the millimeter-wave radar processor 201; when the computer program is executed by the millimeter-wave radar processor 201, it implements the target angle measurement method of the sparse antenna array described in any embodiment of this application.

[0156] Optionally, the vehicle-mounted millimeter wave radar further comprises an antenna array and a millimeter wave radar transceiver module; the antenna array comprises a transmitting antenna array and a receiving antenna array; and the millimeter wave radar transceiver module comprises a transmitting component, a receiving component and a linear frequency modulation local oscillator source component.

[0157] Optionally, the antenna array used for angle measurement can be formed by a MIMO working mode, a non-MIMO working mode or other methods; and the antenna array used for angle measurement is a sparse antenna array formed by repeating arrangement of n unit antenna groups. Here, the antenna array used for angle measurement can be a physical array or a virtual array, and can be all arrays or part of sub-arrays in the antenna array. The foregoing embodiments have mentioned this, and thus will not be described here again.

[0158] In another aspect, the embodiment of the present application further provides a computer program product comprising a computer program, which, when executed by a processor, implements the target angle measurement method of the sparse antenna array according to any of the embodiments of the present application.

[0159] In another aspect, the embodiment of the present application further provides a computer readable storage medium, which stores a computer program. The computer program, when executed by a processor, implements each process of the target angle measurement method of the sparse antenna array according to the above embodiment and achieves the same technical effects. To avoid repetition, details will not be described here again. The computer readable storage medium can be, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0160] It should be noted that, in this document, the terms "comprising", "containing" or any other variant thereof are intended to cover non-exclusive inclusion, so that processes, methods, articles or apparatuses that include a series of elements not only include those elements, but also include other elements not explicitly listed, or further include elements inherent to such processes, methods, articles or apparatuses. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of another identical element in the process, method, article or apparatus comprising the element.

[0161] Those skilled in the art can clearly understand the above-mentioned embodiment method can be realized by means of software and the necessary general hardware platform, of course, can also be through hardware, but in many cases the former is a better implementation. Based on such understanding, the technical solutions of the present application essentially or say the part of the prior art contribution can be embodied in the form of software products, the computer software product is stored in a storage medium (such as ROM / RAM, magnetic disc, optical disc), including a number of instructions to make a terminal (may be a mobile phone, computer, server, or network equipment, etc.) executes the method described in various embodiments of the present application.

[0162] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this, any skilled in the art within the scope of the technology disclosed in the present application, can easily think of changes or replacement, should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A target angle measurement method for a sparse antenna array, wherein the sparse antenna array comprises n repeated antenna groups, each antenna group comprising m antenna elements, and the spacing between the antenna groups is not equal to the spacing between adjacent antenna elements within the antenna group, characterized in that... The method includes: Based on the element antennas contained in each element antenna group in the sparse antenna array, the element antenna subarray corresponding to each element antenna is determined; wherein, each element antenna subarray is composed of element antennas with the same sequence number in each element antenna group; The signals received by each of the unit antenna subarrays are acquired, the signals are processed to obtain the first angular spectrum corresponding to each of the unit antenna subarrays, and then the first angular spectrum of each of the unit antenna subarrays is non-coherently accumulated to obtain the second angular spectrum. Angular peak detection is performed on the second angular spectrum to obtain the potential angle set; Based on the angle spectrum data of the unit antenna subarrays corresponding to each potential angle in the potential angle set, the angle measurement and deambiguity are determined by using the phase interferometer angle measurement algorithm of the phase interferometer formed by each unit antenna group to determine the true target angle from the potential angle set. The unit antenna includes a first unit antenna T, a second unit antenna C, and a third unit antenna S. The distance between the first unit antenna T and the second unit antenna C in the unit antenna group, and the distance between the second unit antenna T and the third unit antenna S in the unit antenna group, all satisfy the direction-finding deambiguity requirements of the phase interferometer within the direction-finding angle coverage range.

2. The target angle measurement method for a sparse antenna array according to claim 1, characterized in that, The unit antenna subarray includes a first unit antenna subarray composed of the first unit antenna T, a second unit antenna subarray composed of the second unit antenna C, and a third unit antenna subarray composed of the third unit antenna S; the step of determining the true target angle from the potential angle set by using the angle spectrum data of the unit antenna subarrays corresponding to each potential angle in the potential angle set, and performing angle measurement and deambiguation using a phase interferometer angle measurement algorithm through an inter-subarray phase interferometer composed of each unit antenna group, includes: Based on the angle spectrum data A of the first unit antenna subarray corresponding to each potential angle in the potential angle set. T Angular spectrum data A of the second unit antenna subarray C and the angular spectrum data A of the third unit antenna subarray S ; An angle measurement and deambiguity resolution are performed using an inter-array phase interferometer composed of each of the aforementioned unit antenna groups, and based on the angle spectrum data A corresponding to the potential angles. T A C A S Whether the phase interference relationship is satisfied, so as to determine the true target angle from the potential angle set.

3. The target angle measurement method for a sparse antenna array according to claim 2, characterized in that, The phase interference relationship is as follows: ； ； Where θ is the direction angle of incoming wave, f represents the frequency of the transmitted and received waveform signals, λ represents the wavelength of the transmitted waveform signal, d1 is the distance between the first unit antenna T and the second unit antenna C in the unit antenna group, and d2 is the distance between the second unit antenna T and the third unit antenna S in the unit antenna group.

4. The target angle measurement method for a sparse antenna array according to claim 3, characterized in that, The following relationships are satisfied by d1 and d2 respectively: ； ； Where, 0 < θ max ≤90°, θ max θ represents the maximum coverage area.

5. The target angle measurement method for a sparse antenna array according to claim 3, characterized in that, d1 is 0.5λ, and d2 is λ.

6. The target angle measurement method for a sparse antenna array according to claim 3, characterized in that, Within the unit antenna subarray, the distance between adjacent unit antennas is d0, where d0 is 4λ.

7. The target angle measurement method for a sparse antenna array according to claim 1, characterized in that, The process of acquiring the signals received by each of the unit antenna subarrays, processing the signals to obtain the first angular spectrum corresponding to each of the unit antenna subarrays, and then performing non-coherent accumulation of the first angular spectrum of each of the unit antenna subarrays to obtain the second angular spectrum includes: The discrete digital signal obtained by discrete digital signal sampling processing of the received target reflection waveform signal is subjected to one-dimensional distance FFT processing to obtain the one-dimensional distance FFT result. The one-dimensional distance FFT result is processed by a two-dimensional velocity FFT to obtain a two-dimensional velocity FFT result; The two-dimensional velocity FFT results are subjected to constant false alarm detection to obtain over-detection point data; The over-detection point data is processed by angular dimension FFT using each of the unit antenna subarrays to obtain the first angular spectrum corresponding to each of the unit antenna subarrays. The first angular spectrum is then non-coherently accumulated to obtain the second angular spectrum.

8. The target angle measurement method for a sparse antenna array according to claim 7, characterized in that, The step of determining the true target angle from the potential angle set by using the angle spectrum data of the unit antenna subarrays corresponding to each potential angle in the potential angle set, and performing angle measurement and deambiguation using a phase interferometer algorithm on the inter-subarray phase interferometer composed of each unit antenna group, includes: Select any potential angle from the potential angle set and obtain the corresponding angle-dimensional FFT result of the unit antenna subarray; Based on the size parameters of the inter-subarray phase interferometer formed by each unit antenna group and the angular dimension FFT results, the direction of the inter-subarray phase interferometer is determined. Calculate the angular deviation between the potential angle and the direction-finding angle of the inter-subarray phase interferometer; Determine whether the angle deviation is less than a set threshold; If the angle deviation is less than the set threshold, the current direction finding result of the inter-subarray phase interferometer is taken as a qualified direction finding result. The angle measurement and deblurring of all potential angles are performed iteratively, and the true target angle is determined from the set of potential angles.

9. A vehicle-mounted millimeter-wave radar, characterized in that, It includes a millimeter-wave radar processor and a memory, wherein the memory stores a computer program that can be executed by the millimeter-wave radar processor; When the computer program is executed by the millimeter-wave radar processor, it implements the target angle measurement method for a sparse antenna array as described in any one of claims 1 to 8. The antenna array used for angle measurement is formed through either MIMO or non-MIMO operating modes.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the target angle measurement method for a sparse antenna array as described in any one of claims 1 to 8.

Images