MIMO frequency-modulated continuous-wave millimeter wave radar array reconfigurable array pattern sharing method

Abstract

A method for sharing reconfigurable array modes in a MIMO frequency-modulated millimeter-wave radar array is proposed. Based on the echo signal data matrices obtained after analog-to-digital conversion of different modes, range-dimensional Fast Fourier Transform (FFT) and velocity-dimensional FFT are performed on them respectively to obtain the range-Doppler spectrum of different transmit / receive antenna combinations. Different modes with the same gain in the MIMO radar system are combined. Among the combinations with the same gain, the mode corresponding to the largest virtual array aperture in the horizontal and elevation directions under that gain is selected. The angles of these two modes are resolved and matched separately, and then combined to achieve the maximum virtual array aperture resolution. Digital beamforming is used to match the angle information obtained under the maximum aperture virtual array in the horizontal and elevation dimensions. This invention can effectively increase the maximum array aperture in the original modes with the same gain by utilizing the complementary effect between different reconfigurable array modes while using virtual array reconfigurable technology or MIMO technology.

Description

Technical Field

[0001] This invention relates to a technology in the field of millimeter-wave radar, specifically to a method for sharing reconfigurable array modes of an L-shaped antenna array for a multiple-input multiple-output (MIMO) frequency-modulated continuous wave millimeter-wave radar. Background Technology

[0002] Existing MIMO millimeter-wave radar array reconfigurable technology primarily utilizes the phase information between channels, i.e., in time division multiplexing (TDM) mode, simultaneously activating multiple transmit elements or multiple receive elements, effectively increasing the diversity of virtual array configurations and forming a reconfigurable array. model, TX represents the number of array elements activated simultaneously, and n represents the number of array elements activated simultaneously in the RX direction. Reconfiguration can effectively improve the system's signal-to-noise ratio (SNR) and detection range. However, in certain modes, the reconfigurable L-shaped array cannot maintain half-wavelength spacing between array elements. Therefore, using the DOA super-resolution algorithm to solve for the target cannot accurately determine the two-dimensional spatial angle of the target, potentially leading to large errors in azimuth or elevation angle resolution. Consequently, accurate 4D spatial positioning of the target is impossible, and target point clouds cannot be formed. Summary of the Invention

[0003] This invention addresses the problems of existing MIMO technology, such as large or even incorrect angle information calculation errors for targets when the signal-to-noise ratio (SNR) is low due to environmental noise, the limited detection range of MIMO radar, which can only detect targets at short distances, and the inability to achieve accurate angle resolution in the elevation or azimuth dimension. It proposes a method for sharing reconfigurable array modes of MIMO frequency-modulated millimeter-wave radar arrays. While using virtual array reconfigurable technology or MIMO technology, it utilizes the complementary effect between different reconfigurable array modes to effectively increase the maximum array aperture in the original modes with the same gain.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to a method for sharing reconfigurable array modes in a MIMO frequency-modulated millimeter-wave radar array, comprising:

[0006] Step 1: During the initialization phase of the Time Division Multiplexing (TDM) MIMO radar, the number of transmit and receive antennas activated at different times is set according to requirements. This results in different virtual array arrangements at different times, enabling array reconstruction of the traditional MIMO radar and achieving the desired mode. , where m is the number of transmitting antennas that are turned on, and n is the number of receiving antennas that are turned on.

[0007] Step 2: Perform range-dimensional fast Fourier transform and velocity-dimensional fast Fourier transform on the echo signal data matrix obtained after analog-to-digital conversion based on different modes to obtain the range-Doppler spectrum of different transmit and receive antenna combinations.

[0008] Step 3: Combine different modes with the same gain in the MIMO radar system. In the combination with the same gain, select the mode corresponding to the virtual array aperture with the largest horizontal and vertical direction under that gain. Determine the angles of the two modes separately and match them. Combine them to achieve the maximum virtual array aperture angle resolution. Specifically, for the mode corresponding to the virtual array aperture with the largest horizontal and vertical direction, the range-Doppler spectrum is obtained by using the constant false alarm rate (CFAR) algorithm to obtain the target's range and velocity. The subspace method (TLS-ESPRIT) super-resolution angle estimation algorithm is used to solve for the angle information of different target points to obtain the maximum virtual array aperture angle resolution.

[0009] Step 4: Use digital beamforming to match the angle information obtained from solving the maximum aperture virtual array in the horizontal and pitch dimensions.

[0010] Technical effect

[0011] This invention improves SNR and maximum detection range by activating different numbers of transmitting and receiving antennas to form MIMO radar arrays with different modes. It also enhances reconfigurable MIMO radar array technology through mode sharing, expanding the maximum aperture of reconfigurable radar and improving the angular resolution of the array. Compared to existing technologies, this invention improves the SNR and detection range of MIMO architecture millimeter-wave radar systems through virtual array reconfiguration, while also addressing the issue that some reconfigurable modes can only detect azimuth or elevation angle information in a single dimension. Furthermore, by introducing mode sharing, it effectively increases the aperture of the largest array in a group of virtual reconfigurable arrays with the same gain, further increasing the maximum aperture compared to the single-mode array with the same gain. This improves spatial angle detection accuracy and allows for the acquisition of different spatial angle dimensions, achieving the effect of obtaining accurate 2D spatial angle information and increasing the aperture of the largest virtual array in a group of virtual reconfigurable arrays with the same gain. In the aforementioned 4T8R L-type array, the maximum aperture of the reconfigurable array group with a normalized gain of 6 is increased from... Upgraded to The maximum aperture of the reconfigurable array group with a normalized gain of 12 is from Upgraded to Similarly, the aperture of other gain groups can be increased. While improving the fact that some modes can only solve for single-dimensional angle information, increasing the aperture can effectively improve the angle estimation accuracy. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating the shared reconfigurable array modes of the L-shaped array of the present invention;

[0013] Figure 2 This is a flowchart of the present invention;

[0014] Figure 3 This is a block diagram of a MIMO FMCW radar system as an example.

[0015] Figure 4 Example Schematic diagram of an L-shaped radar antenna array;

[0016] Figure 5 Example Schematic diagram of an L-shaped radar antenna array MIMO virtual array;

[0017] Figure 6 Example Schematic diagram of a reconfigurable L-type radar antenna array;

[0018] Figure 7 This is a schematic diagram of the spatial wave model for an embodiment.

[0019] Figure 8 Example A schematic diagram of a reconfigurable array group mode sharing of an L-type radar antenna array with a normalized gain of 6.

[0020] Figure 9 This is a schematic diagram of shared data processing for a reconfigurable array group mode with a normalized gain of 6 in the embodiment.

[0021] Figure 10 This is a schematic diagram of a two-dimensional spatial angular coordinate system for an embodiment.

[0022] Figure 11 The image shows the SNR-RMSE results of the reconfigurable array group with normalized gain 6 for the embodiment.

[0023] Figure 12 The image shows the SNR-RMSE result of the reconfigurable array group with a normalized gain of 12 for the embodiment. Specific implementation methods

[0024] like Figure 3As shown, this embodiment illustrates a MIMO frequency-modulated millimeter-wave radar array reconfigurable array mode sharing system that implements the above-described method. It includes: a signal source 1 and a transmit branch consisting of a transmit power divider 2, a power amplifier 3, and a transmit antenna array TX connected thereto; and a receive branch consisting of a receive power divider 4, a low-noise amplifier 5, and a receive antenna array RX connected thereto. The output of the low-noise amplifier 5 is sequentially equipped with a low-pass filter 6, an analog-to-digital converter 7, and a signal processor 8. The signal source 1 generates a transmit signal, which is then multiplied by the transmit power divider 2 and transmitted through the power amplifier 3 to the ports of each transmit antenna TX. Simultaneously, the signal is scattered by a spatial target, generating an echo signal, which is received by the receive antenna array RX and mixed with the signal from the receive power divider 4. The down-converted signal passes through the low-noise amplifier 5 and the low-pass filter 6, is converted by the analog-to-digital converter 7, sampled, and then processed by the signal processor 8 for L-shaped reconfigurable virtual array mode sharing.

[0025] The signal processor 8 includes: a MIMO signal processing unit, an array reconfigurable unit, an array mode sharing unit, and a target space two-dimensional angle signal detection unit. The MIMO signal processing unit is connected to the radar ADC sampling data to process the most original radar signal. The array reconfigurable unit reconfigures the virtual array elements of the MIMO architecture to form virtual arrays with different modes. The array mode sharing unit forms mode sharing among different and complementary reconfigurable array modes in the same gain mode virtual reconfigurable array group. The target space two-dimensional angle information detection unit processes the received information and estimates the angle of arrival.

[0026] like Figure 4 As shown, the transmit antenna array TX and the receive antenna array RX constitute a 4T8R L-type MIMO antenna array, wherein: the transmit array is a three-element uniform linear array with half-wavelength spacing in the azimuth direction and a two-element uniform linear array with half-wavelength spacing in the elevation direction; the receive array is a four-element uniform linear array with 1.5 times the wavelength spacing in the azimuth direction and a five-element uniform linear array with one wavelength spacing in the elevation direction.

[0027] like Figure 5 As shown, the L-shaped MIMO antenna array uses the principle of virtual array equivalence to convert a MIMO antenna array with M transmitting antennas and N receiving antennas into a single transmitting antenna. A SIMO antenna array with multiple receiving antennas forms a MIMO radar virtual antenna array.

[0028] In this embodiment, the 4T8R L-shaped array can be equivalently formed into a 12-element half-wavelength uniform linear array with a maximum aperture in the azimuth direction and a 10-element half-wavelength uniform linear array in the elevation direction, i.e., the equivalent virtual array is The L-shaped array, the digital-to-analog converter 7 can acquire a total of 21 data points (one array element is shared in the azimuth and pitch directions). The DOA algorithm can be used to solve the pitch and azimuth angle information of the space target using the data received by the virtual array.

[0029] like Figure 2 The diagram illustrates a method for sharing reconfigurable array modes in a MIMO frequency-modulated millimeter-wave radar array, as described in this embodiment. The specific steps include:

[0030] Step 1: Acquire signals from the MIMO radar antenna array and generate a virtual array. Then, combine data from different transmit and receive channels to form a reconfigurable array. model, Let t be the number of array elements activated simultaneously by TX, and n be the number of array elements activated simultaneously by RX. Then the maximum sensing range of the system is... System signal-to-noise ratio When multiple transmit and receive antennas are activated, the overall array gain of the system... By changing the operating mode of the MIMO virtual array, the system's sensing range and signal-to-noise ratio (SNR) can be effectively improved. Modes with the same gain are defined as virtual reconfigurable array groups with the same gain mode, where: This refers to the radar's transmission power. The target's RCS (radio frequency response) cross-sectional area. The gain of the radar transmitting and receiving antennas. For radar operating wavelength, Boltzmann's constant, Where B is the operating temperature, B is the operating bandwidth, and L is the loss factor. Noise figure This refers to the distance between the target and the radar.

[0031] Step 2, the chirp signal transmitted by the FMCW radar is Furthermore, the speed of electromagnetic wave propagation in space is the speed of light, which is much greater than the target's speed. Therefore, it can be approximated that the target did not move more than the range resolution during signal transmission and reception. The signal carrier frequency is [value], and the signal period is [value]. bandwidth is The modulation slope , If the initial phase of the signal is given, then the intermediate frequency signal obtained after receiving the signal and down-converting it is: ,in: and Received and transmitted signals, Signal amplitude, The relative distance between the target and the radar. The so-called "slow time" The speed of light. This intermediate frequency signal is a single-frequency signal, with a frequency of... , The distance between the target and the radar, i.e. The peak value of the signal spectrum can then be obtained by performing a Fast Fourier Transform on the intermediate frequency signal, thus revealing the distance between the target and the radar. The phase difference between two adjacent chirps... That is, the target's velocity is obtained as: The target's velocity information can be obtained by performing a Fast Fourier Transform (FFT) on the phase information at the peak frequency of the range spectrum to obtain the phase change frequency. Multiple transmitted chirp signals are received, down-converted to intermediate frequency (IF) signals, and stored in a data matrix. The number of rows corresponds to the number of chirp signals, and the number of columns corresponds to the number of FFT points. By performing an FFT on each row, the peak frequency information can be obtained, allowing the calculation of the range between the target and the radar. Similarly, performing an FFT on the phase information at the peak frequency column yields the phase frequency, allowing the calculation of the target's velocity information. Based on the obtained multi-target range and velocity information, a multi-target range-doppler (RD) map can be generated.

[0032] Step 3: Introduce complementary characteristics between modes, i.e., a shared reconfigurable array mode method: Combine two modes with the same gain in the virtual reconfigurable array, one with the maximum horizontal array aperture and the other with the maximum elevation array aperture, solve for the angle information in two dimensions and perform matching. Specifically, for each mode, obtain the target's range and Doppler readings using CFAR, such as... Figure 7 As shown, the signal model is established. Since the angle information in both dimensions is solved using a one-dimensional linear array, when there are M antenna elements forming a one-dimensional linear array, the element spacing is... There are K narrowband signals in the space, respectively Let the spatial direction of these signals be... When the first unit is the reference unit, the received signal of each unit is: ,in This represents the additive noise of each antenna element. The above model can be represented using a matrix. ,in For array to receive signals, For the envelope of the signal, For additive noise (stationary Gaussian random process), Let be the manifold matrix of the signal, where As the phase difference vector, the TLS-ESPRIT algorithm is used to solve for the one-dimensional angle for the two virtual arrays with the largest aperture in each dimension. The received signals of the first M-1 elements of the linear array are selected as the X subarray, and the received signals of the last M-1 elements are selected as the Y subarray. Then the received data can be represented as: , ,in The difference matrix is ​​represented by the combination of the two submatrices as follows: Then use Z to obtain the covariance matrix. We perform eigenvalue decomposition on the covariance matrix and select the eigenvectors corresponding to the K largest eigenvalues ​​as the spatial signal subspace. Since the eigenvector signal subspace and the space spanned by the array manifold matrix are the same, we have... Therefore, there must exist a non-singular matrix T such that This is true, therefore, based on the configuration of Z and the array manifold matrix, we obtain... ,in This represents the signal subspace acquired by the X array. If the signal subspace acquired by the Y array is represented, then Considering the existence of errors in the actual data, that is , , Therefore, there is And it is necessary to make the correction matrix and vector As small as possible, that is: , sorted out It is possible to know yes The right singular vector corresponds to the minimum singular value. Therefore, by correctly calibrating the matrix and vectors, finding the correct right singular vector yields the desired result. That is, finding the matrix , making Minimum, while satisfying the constraints: As previously known, F is The right singular vector corresponding to the minimum singular value. Based on the singular value solving method, for... Perform eigenvalue decomposition to find the eigenvectors corresponding to the K smallest eigenvalues, thereby constructing a matrix F, which is then divided into upper and lower parts. The matrix distribution corresponds to and Thus, we obtain At the same time, combined It can be obtained ,in Since T is a non-singular matrix, then and They are similar matrices, sharing common eigenvalues, and because It is a diagonal matrix, which means we can say: yes The eigenvalue diagonal matrix. Therefore, for Eigenvalue decomposition can be used to obtain Then through The corresponding direction of arrival can be obtained, thus completing the one-dimensional angle solution.

[0033] Step 4: After step 3, use the digital beamforming (DBF) method to match the angle information of the two dimensions obtained by solving the maximum aperture virtual array in the horizontal and pitch dimensions.

[0034] The digital beamforming method described above specifically involves: when the spacing of the equally spaced linear arrays is... The signal is perpendicular to the array normal. When incident at an angle, the array's output signal... Where: X is the received signal mentioned above, For signal steering vector, .

[0035] like Figure 8 As shown, this is the... The L-type radar antenna array shares a virtual reconfigurable array mode with a normalized gain of 6. The normalized gain 6 array group includes... , , Three reconfigurable modes, all with MIMO radar system gain. Six times the mode size, for the three reconfigurable modes mentioned above, find the aperture array with the largest half-wavelength spacing. The mode features a four-element half-wavelength uniform linear array for elevation and a five-element half-wavelength uniform linear array for azimuth. With only a seven-element half-wavelength uniform linear array for azimuth, it is impossible to accurately solve for the elevation angle information of the target. The model has a seven-element half-wavelength uniform linear array for elevation, which cannot accurately solve for the azimuth angle information of the target. Only a limited number of elements can be reconstructed. This mode can accurately solve for two-dimensional angles, while the other two modes cannot. A complementary approach is used to introduce a shared definition for each mode, dynamically configuring the radar's operating mode. The azimuth direction of the mode is a seven-element half-wavelength uniform linear array and The elevation direction of the mode is composed of an L-shaped array of seven half-wavelength uniform linear arrays to solve for the two-dimensional spatial angle information. That is, the modes share virtual array elements, so that two reconfigurable modes with complementary dimensions can be combined. The L-shaped virtual antenna array allows for two-dimensional angle estimation compared to other arrays in this gain group. model The L-shaped virtual antenna array increases the maximum aperture and enables both modes to have the ability to resolve angles in two-dimensional space. The mode sharing method defined by this complementary principle can be applied between modes in any virtual reconfigurable array group with the same gain mode, which can form the maximum aperture in the group and compensate for the resolution dimension.

[0036] like Figure 9 As shown, this is the shared data processing procedure for the reconfigurable array group mode with a normalized gain of 6. By enabling the positions of multiple equivalent virtual array elements for both transmitting and receiving elements, the elevation and azimuth of the two modes are complementary. L-shaped half-wavelength uniformly spaced array In the first chirp cycle, TX1 and TX4 are simultaneously activated for signal transmission. RX1, RX5, and RX6 are simultaneously activated for data reception, forming channel 1; RX1, RX2, and RX7 are activated for data reception, forming channel 2; RX1, RX3, and RX7 are activated for data reception, forming channel 3; RX1, RX4, and RX7 are activated for data reception, forming channel 4; RX2, RX4, and RX7 are activated for data reception, forming channel 5; and RX3, RX4, and RX7 are activated for data reception, forming channel 6. In the second chirp cycle, TX3 and TX4 are simultaneously activated for signal transmission, and RX3, RX4, and RX7 are activated for data reception, forming channel 7. This forms a reconfigurable seven-element azimuth half-wavelength uniform virtual linear array. The seven transmitted data points are stored in a data matrix, with the number of rows corresponding to the number of channels and the number of columns corresponding to the number of FFT points. The same processing is applied to the two reconfigurable modes. Two data matrices are obtained by processing the data of each of the two reconfigurable modes separately. Then, a super-resolution algorithm is used to solve for and match the two-dimensional angle information of the target space to obtain the two-dimensional angle information of the target space. This achieves the desired normalized gain. The L-shaped array, compared to the reconfigurable mode, increases the detection dimension of some modes and increases the maximum array aperture in this gain group, thereby improving the angle detection accuracy.

[0037] like Figure 10 The image shows a schematic diagram of selecting a two-dimensional angle in a spatial coordinate system. and The two-dimensional spatial angle information of the target is used to solve the angle information of the target using the TLS-ESPRIT-based two-dimensional spatial angle solution method.

[0038] like Figure 11 As shown, the curve of RMSE for the two-dimensional spatial angle estimation of a reconfigurable array group with a normalized gain of 6 as a function of SNR is presented. Due to the single-mode... and Since it's impossible to solve the angles in both dimensions, the error is extremely large. Therefore, for both dimensions, the angles cannot be solved. Pattern and The simulation comparison used two arrays in the same mode, and the incoming wave spatial angle was set to... The radar bandwidth is 4GHz, the number of snapshots is 256, and the center frequency is 60GHz. Assuming... If the SNR is -10dB, then the SNR corresponding to the reconfigurable array group with a normalized gain of 6 is -2.2dB. Therefore, the simulation SNR is set from -2.2dB to 12.8dB, and 200,000 Monte Carlo simulations are performed at each SNR to calculate the estimated angle RMSE. From the figure, it can be seen that after adopting mode sharing, two modes in a virtual reconfigurable array group with the same gain can be complementaryly combined and used to solve for angle information in different dimensions. This solves the problem that some modes can only solve for single-dimensional angle information, and also allows for obtaining the maximum virtual array aperture of multi-mode combination in a virtual reconfigurable array group with the same gain, increasing the array aperture compared to single-mode operation.

[0039] like Figure 12 The figure shows the RMSE curve of the two-dimensional spatial angle estimation of a reconfigurable array group with normalized gain of 12 as a function of SNR. The virtual array formation and data processing flow of this gain mode virtual reconfigurable array group is the same as the process described above. Due to the single mode and Since it's impossible to solve the angles in both dimensions, the error is extremely large. Therefore, for both dimensions, the angles cannot be solved. Pattern and The simulation comparison used two arrays in the same mode, and the incoming wave spatial angle was set to... The radar bandwidth is 4GHz, the number of snapshots is 256, and the center frequency is 60GHz. Assuming... If the SNR is -10dB, then the SNR corresponding to the reconfigurable array group with a normalized gain of 12 is 0.8dB. Therefore, the simulated SNR is set from 0.8dB to 15.8dB, and 200,000 Monte Carlo simulations are performed at each SNR to calculate the RMSE of the estimated angle. The conclusion is the same as above.

[0040] Compared with existing technologies, this method utilizes the characteristic that different modes in a virtual reconfigurable array group with the same gain have the same gain but different virtual array apertures. It introduces complementary characteristics to combine arrays of different modes, forming the largest virtual array aperture in the virtual reconfigurable array group. Compared with MIMO reconfigurable methods, this method can improve the radar's sensing range and system SNR, and also address the problem that some modes cannot be solved in two dimensions. Furthermore, it increases the maximum virtual array aperture in a virtual reconfigurable array group with the same gain, for example, the maximum aperture of the reconfigurable array group with a normalized gain of 6 in the aforementioned 4T8R L-type array increases from... Upgraded to The maximum aperture of the reconfigurable array group with a normalized gain of 12 is from Upgraded to Similarly, other gain groups can also have their aperture increased to effectively improve the accuracy of angle estimation.

[0041] In summary, this invention, while fully utilizing the multi-channel data of the MIMO array for virtual array reconfigurability, introduces complementary characteristics. It leverages the fact that different modes in a virtual reconfigurable array group with the same gain mode have the same gain but different array apertures to share modes and combine them to form the largest aperture in the gain group. This increases the array aperture compared to single-mode operation and can also improve the problem that some reconfigurable modes cannot solve for two-dimensional angle information when working alone. This invention achieves a groundbreaking mode sharing mechanism for MIMO virtual reconfigurable arrays.

[0042] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A method for sharing reconfigurable array modes in a MIMO frequency-modulated millimeter-wave radar array, characterized in that, include: Step 1: During the initialization phase of the Time Division Multiplexing (TDM) MIMO radar, the number of transmit and receive antennas activated at different times is set according to requirements. This results in different virtual array arrangements at different times, enabling array reconstruction of the traditional MIMO radar and achieving the desired mode. , where m is the number of transmitting antennas that are turned on, and n is the number of receiving antennas that are turned on; Step 2: Perform range-dimensional fast Fourier transform and velocity-dimensional fast Fourier transform on the echo signal data matrix obtained after analog-to-digital conversion based on different modes to obtain the range-Doppler spectrum of different transceiver antenna combinations. Step 3: Combine different modes with the same gain in the MIMO radar system. In the combination with the same gain, select the mode corresponding to the largest virtual array aperture in the horizontal and elevation directions under that gain. Determine the angle of these two modes separately and match them. Combine them to achieve the maximum virtual array aperture angle determination. Step 4: Use digital beamforming to match the angle information obtained from solving the maximum aperture virtual array in the horizontal and pitch dimensions.

2. The method for sharing reconfigurable array modes of a MIMO frequency-modulated millimeter-wave radar array according to claim 1, characterized in that, Step 1 specifically includes: acquiring signals from the MIMO radar antenna array and generating a virtual array, then combining data from different transmit and receive channels to form a reconfigurable array, i.e. Mode, maximum sensing range of the system Signal-to-noise ratio When multiple transmit and receive antennas are activated, the overall array gain of the system... ,in: t is the number of array elements that TX can activate simultaneously, and n is the number of array elements that RX can activate simultaneously. This refers to the radar's transmission power. The target's RCS (radio frequency response) cross-sectional area. The gain of the radar transmitting and receiving antennas. For radar operating wavelength, Boltzmann's constant, Where B is the operating temperature, B is the operating bandwidth, and L is the loss factor. Noise figure This refers to the distance between the target and the radar.

3. The method for sharing reconfigurable array modes of a MIMO frequency-modulated millimeter-wave radar array according to claim 1, characterized in that, Step 2 specifically includes: the chirp signal emitted by the FMCW radar is... The received signal is down-converted to obtain the intermediate frequency signal. The distance between the target and the radar is obtained by performing a Fast Fourier Transform (FFT) on the intermediate frequency (IF) signal to obtain the peak value of the signal spectrum. The phase change frequency is then obtained by performing an FFT on the phase information at the peak frequency of the range spectrum, which in turn yields the target's velocity information. Multiple transmitted chirp signals are received, down-converted to obtain IF signals, and stored in a data matrix. The number of rows corresponds to the number of chirp signals, and the number of columns corresponds to the number of FFT points. Performing an FFT on each row yields the peak frequency information, allowing the calculation of the distance between the target and the radar. Performing an FFT on the phase information at the peak frequency column yields the phase frequency, which in turn yields the target's velocity information. Based on the obtained multi-target range and velocity information, a multi-target RD map is generated, where: The signal carrier frequency is [value], and the signal period is [value]. bandwidth is The modulation slope , The initial phase of the signal. and Received and transmitted signals, Signal amplitude, The relative distance between the target and the radar. Slow time The speed of light; this intermediate frequency signal is a single-frequency signal; frequency , The distance between the target and the radar, i.e. Phase difference between two adjacent chirps That is, the target's velocity is obtained as: .

4. The method for sharing reconfigurable array modes of a MIMO frequency-modulated millimeter-wave radar array according to claim 1, characterized in that, Step 3 specifically involves: obtaining the range-Doppler spectrum of the mode corresponding to the largest virtual array aperture in the horizontal and pitch directions using a constant false alarm rate algorithm to obtain the target's range and velocity; and then using a subspace super-resolution wave angle estimation algorithm to solve for the angle information of different target points to obtain the maximum virtual array aperture solution angle.

5. The method for sharing reconfigurable array modes of a MIMO frequency-modulated millimeter-wave radar array according to claim 1 or 4, characterized in that, For each mode, the target's range and Doppler readings are obtained using CFAR to establish the signal model. Since the angle information in both dimensions is calculated using a one-dimensional linear array, when there are M antenna elements forming a one-dimensional linear array with an element spacing of... There are K narrowband signals in the space, respectively Let the spatial direction of these signals be... When the first unit is the reference unit, the signal received by each unit is: For the two virtual arrays with the largest aperture in each dimension, the one-dimensional angle is solved using the TLS-ESPRIT algorithm. The first M-1 elements of the linear array are selected as the X subarray, and the last M-1 elements are selected as the Y subarray. Then the received data... , Merge the two subarrays into Then use Z to obtain the covariance matrix. The covariance matrix is ​​decomposed using eigenvalues, and the eigenvectors corresponding to the K largest eigenvalues ​​are selected as the spatial signal subspace, where: The additive noise of each antenna element can be represented by a matrix representation of the above model. , For array to receive signals, For the envelope of the signal, For additive noise in a stationary Gaussian random process, Let be the manifold matrix of the signal. The phase difference vector, It is the phase difference matrix; The eigenvector signal subspace and the space spanned by the array manifold matrix are the same, therefore we have Therefore, there must exist a non-singular matrix T such that This is true, therefore, based on the configuration of Z and the array manifold matrix, we obtain... ,in: The signal subspace acquired for the X array. For the signal subspace obtained by the Y array, then Considering the existence of errors in the actual data, that is , , Therefore, there is And it is necessary to make the correction matrix and vector As small as possible, that is: , sorted out By correctly calibrating the matrix and vectors, finding the correct right singular vector yields the desired result. That is, finding the matrix , making Minimum, while satisfying the constraints: Where: F is The right singular vector corresponding to the minimum singular value, according to the singular value solving method, is... Perform eigenvalue decomposition to find the eigenvectors corresponding to the K smallest eigenvalues, thereby constructing a matrix F, which is then divided into upper and lower parts. The matrix distribution corresponds to and Thus obtain At the same time, combined get , ,in: The eigenvalue diagonal matrix, for Eigenvalue decomposition yields And then Once the corresponding direction of arrival is determined, the one-dimensional angle solution is complete.

6. The method for sharing reconfigurable array modes of a MIMO frequency-modulated millimeter-wave radar array according to claim 1, characterized in that, Step 4 specifically includes: in step 3, using digital beamforming (DBF) to solve for the corresponding angle information under the maximum aperture virtual array in both the horizontal and pitch dimensions.

7. A system for implementing the method for sharing reconfigurable array modes of a MIMO frequency-modulated millimeter-wave radar array according to any one of claims 1-6, characterized in that, include: The signal source and the transmitting branch consisting of a transmitting power divider, a power amplifier, and a transmitting antenna array TX connected to it, and the receiving branch consisting of a receiving power divider, a low-noise amplifier, and a receiving antenna array RX connected in sequence, wherein: the output terminal of the low-noise amplifier is equipped with a low-pass filter, an analog-to-digital converter, and a signal processor in sequence. The signal source generates a transmitting signal, the transmitting power divider generates multiple transmitting signals and passes through the power amplifier to the ports of each transmitting antenna TX; at the same time, the signal is scattered by the spatial target to generate an echo signal, which is received by the receiving antenna array RX and mixed with the signal from the receiving power divider. The down-converted signal passes through the low-noise amplifier and the low-pass filter, is converted by the analog-to-digital converter and sampled, and is then shared by the signal processor in an L-type reconfigurable virtual array mode.

8. The system according to claim 7, characterized in that, The signal processor includes: a MIMO signal processing unit, an array reconfigurable unit, an array mode sharing unit, and a target space two-dimensional angle signal detection unit. The MIMO signal processing unit is connected to the radar ADC sampling data to process the most primitive radar signal. The array reconfigurable unit reconfigures the virtual array elements of the MIMO architecture to form virtual arrays with different modes. The array mode sharing unit forms mode sharing among different and complementary reconfigurable array modes in the same gain mode virtual reconfigurable array group. The target space two-dimensional angle information detection unit processes the received information and performs arrival angle estimation.

9. The system according to claim 7, characterized in that, The transmit antenna array TX and receive antenna array RX constitute a 4T8R L-type MIMO antenna array, wherein: the transmit array is a three-element uniform linear array with half-wavelength spacing in the azimuth direction and a two-element uniform linear array with half-wavelength spacing in the elevation direction; the receive array is a four-element uniform linear array with 1.5 times the wavelength spacing in the azimuth direction and a five-element uniform linear array with one wavelength spacing in the elevation direction. The L-shaped MIMO antenna array described above uses the principle of virtual array equivalence to convert a MIMO antenna array with M transmit antennas and N receive antennas into a single transmit antenna. A SIMO antenna array with multiple receiving antennas forms a MIMO radar virtual antenna array.

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