Array error correction method, correction device, correction system and storage medium

Abstract

The invention discloses an array error correction method, device and system and a computer readable storage medium. The array error correction method comprises the steps that an information source is arranged in a far-field area of a radar, and the radar is arranged on a rotary table; determining an angle search range of a signal direction of arrival, and generating a plurality of corresponding search points according to the search range; the rotary table is rotated to obtain array signals which are received by the radar at each search point and come from the information source; and determining the corrected steering vector of the corresponding search point according to each array signal. Thus, error correction is carried out based on the array signal actually received by each search point, the comprehensive influence of all errors suffered by the antenna array in the actual working environment can be captured, independent estimation of various errors is not needed, and the error correction efficiency is improved. The array element directional diagram error, the array element position error, the channel amplitude-phase error and the angle-dependent array element mutual coupling error are corrected at the same time, and the correction precision is high.

Description

Technical Field

[0001] The present application relates to the field of radar signal processing technology, and in particular to an array error correction method, a correction device, a correction system and a computer-readable storage medium. Background Art

[0002] With the continuous development of intelligent driving, the demand for environmental perception of automobiles is constantly increasing. Millimeter-wave radar has been widely used due to its high accuracy, low cost, concealed installation, and all-weather operation. The angle measurement performance of radar mainly depends on the antenna array layout and angle estimation algorithm. In order to obtain accurate direction of arrival (DOA) estimation, the array error needs to be corrected. At present, the correction accuracy of the error correction method is poor. Summary of the invention

[0003] The embodiments of the present application provide an array error correction method, a correction device, a correction system and a computer-readable storage medium to solve at least one of the above-mentioned technical problems.

[0004] The array error correction method of the embodiment of the present application includes:

[0005] Setting a signal source in a far field region of the radar, and setting the radar on a turntable;

[0006] Determine an angular search range of the signal arrival direction, and generate a plurality of corresponding search points according to the search range;

[0007] Rotating the turntable to obtain the array signal from the information source received by the radar at each search point;

[0008] A corrected steering vector of the corresponding search point is determined according to each array signal.

[0009] In some embodiments, determining the corrected steering vector of the corresponding search point according to each array signal includes:

[0010] Calculate the corresponding covariance matrix according to each of the array signals;

[0011] Perform eigenvalue decomposition according to each of the covariance matrices to obtain a corresponding signal eigenvector;

[0012] Each of the signal feature vectors is used as the corrected steering vector of the corresponding search point.

[0013] In certain embodiments, the array signal is:

[0014]

[0015] in, is the array signal of the kth search point, E k is the total error matrix of the k-th search point, is the total array steering vector of the kth search point, s k (t) is the baseband signal at the t-th snapshot, is the noise vector of the t-th snapshot.

[0016] In some embodiments, the step of calculating a corresponding covariance matrix according to each of the array signals comprises:

[0017] A corresponding covariance matrix is ​​calculated according to each of the array signals and the number of snapshots of each of the array signals.

[0018] In some embodiments, the covariance matrix is:

[0019]

[0020] in, is the covariance matrix, is the array signal of the kth search point, The conjugate transpose of , L is the number of snapshots.

[0021] In some embodiments, performing eigenvalue decomposition according to each of the covariance matrices to obtain a corresponding signal eigenvector includes:

[0022] Perform eigenvalue decomposition on each of the covariance matrices to obtain corresponding eigenvalues ​​and corresponding signal eigenvectors.

[0023] In some embodiments, the decomposition result of the covariance matrix is:

[0024]

[0025] in, is the covariance matrix, α 1,k ≥α 2,k ≥…≥α MN-1,k ≥α MN,k is the characteristic value, M is the number of transmitting antennas of the radar, N is the number of receiving antennas of the radar, is the signal eigenvector corresponding to the eigenvalue, The conjugate transpose of .

[0026] In some embodiments, the array error correction method further comprises:

[0027] A signal subspace and a noise subspace are determined according to the eigenvalue and the signal eigenvector.

[0028] In some embodiments, the signal subspace and the noise subspace are:

[0029]

[0030] in, is the signal subspace, Σ s,k =α 1,k , is the noise subspace, Σ n,k =diag{α 2,k ,α 3,k ,…,α MN,k}.

[0031] In some embodiments, the far field region has a range of:

[0032]

[0033] Wherein, F is the distance between the information source and the radar, D is the antenna aperture of the radar, and λ is the operating wavelength of the radar.

[0034] In certain embodiments, the array signals satisfy a normal distribution.

[0035] In some embodiments, the antenna array in the radar is a uniform array or a sparse array.

[0036] In some embodiments, the information source is configured to propagate the signal transmitted by the radar back to the radar at the same angle as the signal incident on the information source.

[0037] In some embodiments, the information source is a corner reflector or a transceiver antenna device.

[0038] In some implementations, the search range is greater than or equal to a visual field of the radar.

[0039] In some embodiments, the search point is a one-dimensional search point or a two-dimensional search point.

[0040] In certain embodiments, the radar is a MIMO radar or a non-MIMO radar.

[0041] The array error correction device of the embodiment of the present application includes:

[0042] A setting module, used to set a signal source in a far field area of ​​the radar and set the radar on a turntable;

[0043] A generation module, used to determine an angular search range of the signal arrival direction, and generate a plurality of corresponding search points according to the search range;

[0044] An acquisition module, used for rotating the turntable to acquire the array signal from the information source received by the radar at each search point;

[0045] A determination module is used to determine the corrected steering vector of the corresponding search point according to each array signal.

[0046] The array error correction system of the embodiment of the present application includes one or more processors and a memory, the memory stores a computer program, and when the computer program is executed by the processor, the array error correction method of any of the above embodiments is implemented.

[0047] The computer-readable storage medium of the embodiment of the present application stores a computer program thereon, and when the program is executed by a processor, the array error correction method of any of the above embodiments is implemented.

[0048] In the array error correction method, correction device, correction system and computer-readable storage medium of the embodiment of the present application, the radar is driven to rotate by rotating the turntable to obtain the array signal from the source received by the radar at each search point, and the corrected steering vector of the corresponding search point is determined according to each array signal, and error correction is performed on each search point within the search range. In this way, error correction is performed based on the array signal actually received at each search point, and the comprehensive influence of all errors to which the antenna array is subjected in the actual working environment can be captured, without any limitation on the array error type, and without the need to estimate multiple errors separately, so that the array element pattern error, array element position error, channel amplitude and phase error and angle-dependent array element mutual coupling error can be corrected simultaneously, and the correction accuracy is high.

[0049] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0051] Figure 1 is a flow chart of an array error correction method according to certain embodiments of the present application;

[0052] Figure 2 is a flow chart of an array error correction method according to certain embodiments of the present application;

[0053] Figure 3 is a flow chart of an array error correction method according to certain embodiments of the present application;

[0054] Figure 4 is a flow chart of an array error correction method according to certain embodiments of the present application;

[0055] Figure 5 is a flow chart of an array error correction method according to certain embodiments of the present application;

[0056] Figure 6 is a schematic diagram of a normalized spatial spectrum when array error correction is not performed in certain embodiments of the present application;

[0057] Figure 7 is a schematic diagram of a normalized spatial spectrum after array error correction in certain embodiments of the present application;

[0058] Figure 8 is a schematic diagram of a normalized spatial spectrum when array error correction is not performed in certain embodiments of the present application;

[0059] Fig. 9 is a schematic diagram of a normalized spatial spectrum after array error correction in certain embodiments of the present application;

[0060] Fig.10 is a schematic diagram of a module of an array error correction device according to some embodiments of the present application;

[0061] Fig.11 is a schematic diagram of a module of an array error correction system according to some embodiments of the present application;

[0062] Fig.12 It is a schematic diagram of the connection status between a computer-readable storage medium and a processor in certain embodiments of the present application. DETAILED DESCRIPTION

[0063] The following is a further description of the embodiments of the present application in conjunction with the accompanying drawings. The same or similar reference numerals in the accompanying drawings represent the same or similar elements or elements with the same or similar functions from beginning to end. In addition, the embodiments of the present application described below in conjunction with the accompanying drawings are exemplary and are only used to explain the embodiments of the present application, and cannot be understood as limiting the present application.

[0064] See also Figure 1 , the embodiment of the present application provides an array error correction method. The array error correction method includes:

[0065] 010: Set up a signal source in the far field area of ​​the radar and set the radar on a turntable;

[0066] 020: Determine the angle search range of the signal arrival direction, and generate corresponding multiple search points according to the search range;

[0067] 030: Rotate the turntable to obtain the array signal from the source received by the radar at each search point;

[0068] 040: Determine the corrected steering vector of the corresponding search point according to each array signal.

[0069] In the array error correction method of the embodiment of the present application, the radar is driven to rotate by rotating the turntable to obtain the array signal from the source received by the radar at each search point, and the corrected steering vector of the corresponding search point is determined according to each array signal, and error correction is performed on each search point within the search range. In this way, error correction is performed based on the array signal actually received at each search point, and the comprehensive impact of all errors to which the antenna array is subjected in the actual working environment can be captured. There is no restriction on the array error type, and there is no need to estimate multiple errors separately, so that the array element pattern error, array element position error, channel amplitude and phase error, and angle-dependent array element mutual coupling error can be corrected simultaneously, with high correction accuracy.

[0070] Specifically, a signal source is set in the far field area of ​​the radar, and the signal source remains stationary. The range of the far field area can be determined according to the antenna aperture and working wavelength of the radar. The radar is set on a turntable and can rotate with the turntable, and transmit and receive signals on the turntable. The angular search range of the signal wave arrival direction is determined, and multiple corresponding search points are generated according to the search range.

[0071] The turntable rotates within the search range, and the radar rotates with the turntable. The radar is located at multiple search points in turn, and transmits electromagnetic wave signals to the signal source at each search point. The signal source is used to receive the electromagnetic wave signal and transmit the electromagnetic wave signal back to the radar, so that the radar can receive the array signal from the signal source at each search point. The array signal received by the radar is obtained, and each array signal corresponds to a search point. According to each array signal, the corrected steering vector of the corresponding search point can be determined.

[0072] For multiple search points within the search range, a steering vector set can be obtained. The corrected steering vector set can be used for DOA estimation. DOA estimation refers to obtaining the distance information and azimuth information of the target object by processing the received echo signal (that is, the above-mentioned array signal).

[0073] It should be noted that the angle measurement performance of radar mainly depends on the antenna array layout and angle estimation algorithm. At present, the excellent performance of radar is obtained under ideal array conditions, but in practical applications, there are objectively many errors, such as array element pattern error, array element position error, channel amplitude and phase error, and array element mutual coupling error. These errors will cause the array manifold in signal DOA estimation to not match the ideal situation, resulting in a serious degradation of DOA estimation performance. In order to obtain accurate DOA estimation, the array error needs to be corrected.

[0074] In the related art, when performing error correction, the array manifold in DOA estimation is made to fit the actual situation by estimating the specific error, but only part of the error is considered and the correction accuracy is limited.

[0075] In the implementation mode of the present application, the array signal from the source received by the radar at each search point is obtained by rotating the turntable, and the corrected steering vector of the corresponding search point is determined according to each array signal, and error correction is performed on each search point within the search range. In this way, error correction is performed based on the array signal actually received at each search point, and the comprehensive impact of all errors to which the antenna array is subjected in the actual working environment can be captured, without any restrictions on the array error type, and without the need to estimate multiple errors separately, so that the array element pattern error, array element position error, channel amplitude and phase error, and angle-dependent array element mutual coupling error can be corrected simultaneously, with high correction accuracy.

[0076] In certain embodiments, the far field region ranges from:

[0077]

[0078] Among them, F is the distance between the signal source and the radar, D is the antenna aperture of the radar, and λ is the operating wavelength of the radar. In other words, the distance from the radar is greater than or equal to The area is the far field area.

[0079] Specifically, in the far field, since the signal source is far enough away from the radar, the wavefront of the electromagnetic wave emitted from the radar to the signal source can be approximated as a plane wave when it reaches the signal source. Similarly, when the electromagnetic wave is reflected from the signal source back to the radar, its wavefront can also be approximated as a plane wave when it reaches the radar antenna array. This plane wavefront characteristic can simplify the processing of radar signals, and a mathematical model based on plane waves can be used to analyze and interpret the received array signals.

[0080] See also Figure 2 In some embodiments, determining a corrected steering vector (i.e., 040) corresponding to each search point according to each array signal includes:

[0081] 041: Calculate the corresponding covariance matrix according to each array signal;

[0082] 042: Perform eigenvalue decomposition according to each covariance matrix to obtain the corresponding signal eigenvector;

[0083] 043: Use each signal feature vector as the corrected steering vector of the corresponding search point.

[0084] Specifically, after receiving the array signal from the source, the corresponding covariance matrix is ​​calculated for the array signal of each search point. Each covariance matrix is ​​subjected to eigenvalue decomposition to obtain the signal eigenvector corresponding to each array signal. Each signal eigenvector is used as the corrected steering vector of the corresponding search point, and then for multiple search points, a corrected steering vector set can be obtained for DOA estimation.

[0085] In certain embodiments, the array signal is:

[0086]

[0087] in, is the array signal of the kth search point, E k is the total error matrix of the k-th search point, is the total array steering vector of the kth search point, s k (t) is the baseband signal at the t-th snapshot, is the noise vector of the t-th snapshot.

[0088] Specifically, if the radar has M transmitting antennas and N receiving antennas, the array signal received at the kth search point is It can be expressed as:

[0089]

[0090] Among them, E T,k is the error matrix of the transmit array at the kth search point, E R,k The error matrix of the received array for the kth search point. is the steering vector of the k-th search point transmit array (normalized by the first element), Receive the steering vector of the array for the kth search point (normalized by the first element). is the total error matrix of the kth search point. is the total array steering vector of the kth search point. k (t) is the baseband signal at the t-th snapshot, is the noise vector of the t-th snapshot.

[0091] In some embodiments, the array signal satisfies a normal distribution. Normal distribution is an idealized description of signal distribution, which has uniformity and continuity. When the array signal satisfies a normal distribution, the accuracy of DOA estimation can be improved.

[0092] See also Figure 3 In some embodiments, the corresponding covariance matrix (ie, 041) is calculated according to each array signal, including:

[0093] 0411: Calculate the corresponding covariance matrix according to each array signal and the number of snapshots of each array signal.

[0094] Specifically, the array signal received by the radar includes the signal reflected by the source and the noise. Since the noise is uncorrelated or weakly correlated, and the signal reflected by the source may show strong spatial correlation, the covariance matrix can highlight this correlation difference, making it easier to distinguish between the signal and noise in subsequent processing.

[0095] In certain embodiments, the covariance matrix is:

[0096]

[0097] in, is the covariance matrix, is the array signal of the kth search point, The conjugate transpose of , L is the number of snapshots. The above covariance matrix represents the covariance matrix of the array signal at the k-th search point.

[0098] See also Figure 4 In some embodiments, eigenvalue decomposition is performed on each covariance matrix to obtain a corresponding signal eigenvector (ie, 042), including:

[0099] 0421: Perform eigenvalue decomposition on each covariance matrix to obtain the corresponding eigenvalue and the corresponding signal eigenvector.

[0100] Specifically, through eigenvalue decomposition, corresponding eigenvalues ​​and corresponding signal eigenvectors can be obtained, which is convenient for distinguishing signals from noise in subsequent processing.

[0101] In some embodiments, the result of performing eigenvalue decomposition on the covariance matrix is:

[0102]

[0103] in, is the covariance matrix, α 1,k ≥α 2,k ≥…≥α MN-1,k ≥α MN,k is the characteristic value, M is the number of radar transmitting antennas, N is the number of radar receiving antennas, is the signal eigenvector corresponding to the eigenvalue, for The conjugate transpose of .

[0104] See also Figure 5 In some embodiments, the array error correction method further comprises:

[0105] 044: Determine the signal subspace and noise subspace based on the eigenvalues ​​and signal eigenvectors.

[0106] Specifically, after obtaining the eigenvalues ​​and signal eigenvectors according to the covariance matrix, the signal subspace and the noise subspace can be further determined according to the eigenvalues ​​and the signal eigenvectors. In some embodiments, the signal subspace and the noise subspace are:

[0107]

[0108] in, is the signal subspace, Σ s,k =α 1,k . is the noise subspace, Σ n,k =diag{α 2,k ,α 3,k ,…,α MN,k}.

[0109] Since the steering vector contains errors falls in the signal subspace, so Among them, ξ k is a complex constant, and the signal eigenvector and the steering vector containing the error differ by only one complex constant. Therefore, when using the subspace method for DOA estimation, the signal eigenvector of the k-th search point in the signal subspace can be directly used as the steering vector of the k-th search point in DOA estimation.

[0110] For multiple search points within the search range, the set of guidance vectors can be obtained The corrected steering vector set Used in subspace algorithm for DOA estimation.

[0111] In the related art, the array manifold in DOA estimation is made to fit the actual situation by estimating the specific error, which requires a large amount of calculation. For methods that do not require estimating the specific error, the signal-to-noise ratio is high, and additional signal transceivers are required to achieve the signal-to-noise ratio requirement, which makes the system complex and costly.

[0112] However, the array error correction method of the embodiment of the present application does not need to calculate specific errors. When performing DOA estimation, the signal eigenvector of the k-th search point can be directly used as the steering vector of the k-th search point of DOA estimation. In this way, the amount of calculation is effectively reduced. In addition, when the subspace method is used for DOA estimation, when the covariance matrix is ​​subjected to eigenvalue decomposition, the signal subspace and the noise subspace are decomposed, which is equivalent to decomposing the noise from the signal, so that the signal-to-noise ratio requirement in the DOA estimation process is low, and no other devices need to be added.

[0113] In some embodiments, the antenna array in the radar is a uniform array or a sparse array.

[0114] Specifically, the spacing between array elements in a uniform array is equal, and the array elements are arranged in a regular matrix or linear array. A sparse array can use a fraction of the array elements of a full array to construct a high-directivity array with reduced gain. A sparse array can be constructed by removing a portion of the array elements from a uniform array according to a certain optimization method. The spacing between array elements in a sparse array is not necessarily equal.

[0115] In the related art, the error correction method has antenna array layout restrictions and can only correct the error of one antenna array. In the implementation of the present application, the antenna array in the radar can be a uniform array or a sparse array, without antenna array layout restrictions, and has a wide range of applications.

[0116] In some embodiments, the information source is used to propagate the signal transmitted by the radar back to the radar at the same angle as the signal incident on the information source. The information source is a corner reflector or a transceiver antenna device.

[0117] Specifically, the radar rotates with the turntable and transmits an electromagnetic wave signal to the signal source at each search point. The signal source is used to receive the electromagnetic wave signal and transmit the electromagnetic wave signal back to the radar, so that the radar receives the array signal. The signal source is a device with special reflection characteristics. If the electromagnetic wave signal is incident on the signal source at an angle of θ, the signal source can transmit the electromagnetic wave signal back to the radar at an angle of θ.

[0118] In some implementations, the search range is greater than or equal to the visual field of the radar.

[0119] Specifically, the radar's visual field refers to the angular range that the radar can detect. The search range is also the search range for DOA estimation. The search range is greater than or equal to the radar's field of view (FOV), so that the radar can detect target objects in all directions within the visual field. If the search range is smaller than the radar's visual field, it may result in blind spots, and the radar may not be able to detect the existence of all target objects, resulting in missed detections and affecting the detection performance of the radar system.

[0120] In some implementations, the search point is a one-dimensional search point or a two-dimensional search point.

[0121] Specifically, the search range may include only one dimension, for example, searching only in the horizontal direction. In this case, the search point is a one-dimensional search point. The search range may also include two dimensions, for example, searching in the horizontal direction and the vertical direction. In this case, the search point is a two-dimensional search point. In this way, the array error estimation method of the embodiment of the present application can be applied to one-dimensional DOA estimation and two-dimensional DOA estimation, and has a wide range of applications.

[0122] In certain embodiments, the radar is a MIMO radar or a non-MIMO radar.

[0123] Specifically, a multiple input multiple output (MIMO) radar refers to a radar including multiple transmitting antennas and multiple receiving antennas. A MIMO radar can send multiple signals at the same time and receive corresponding multiple reflected echoes at the same time. A non-MIMO radar refers to a radar including one transmitting antenna, and the receiving antenna can be one or more. In the implementation manner of the present application, the radar can be a MIMO radar or a non-MIMO radar, which has a wide range of applications.

[0124] The application of the array error correction method according to the embodiment of the present application in a non-MIMO radar is described in detail below.

[0125] A radar including one transmitting antenna and six receiving antennas is used. The signal source and the receiving array are in the same plane. The receiving array uses a minimum redundancy array, and the receiving array layout is 0.5λ*[01261013], where λ is the wavelength of the electromagnetic wave signal emitted by the radar in the air. The angle search range of DOA is [-90°, 90°], and the search is performed at intervals of 0.1°, so the total number of search points is K=1801.

[0126] The ideal array steering vector of the kth search point (i.e., the receiving array steering vector) is

[0127]

[0128] Among them, θ k is the direction of the kth search point.

[0129] Since the error matrix E k The impact on the steering vector is to change the amplitude and phase of each element in the steering vector. Therefore, random amplitude and phase errors are added to each element of the steering vector to represent the impact of array error on the steering vector. Assume that the receiving array amplitude error Δb i Obeying the uniform distribution of [0, 2], the phase error It obeys the uniform distribution of [-π / 2, π / 2], i = 1, 2, ..., 6. The error is only related to the search point and has nothing to do with the number of snapshots. The steering vector containing the error can be expressed as:

[0130]

[0131] Substitute the above steering vector containing the error into the following formula:

[0132]

[0133] The array signal received by the radar at the kth search point can be obtained.

[0134] Assuming that the signal-to-noise ratio (SNR) during calibration is 10 dB, the array signal satisfies the normal distribution, the noise is Gaussian white noise and is uncorrelated with the signal source, and the number of snapshots is L = 200, the covariance matrix of the array signal can be estimated using the following formula:

[0135]

[0136] Perform eigenvalue decomposition on the above covariance matrix to obtain the signal eigenvector of the k-th search point, specifically including:

[0137]

[0138] Among them, α 1,k ≥α 2,k ≥…≥α 5,k ≥α 6,k is the eigenvalue of the covariance matrix. are the eigenvectors corresponding to the eigenvalues ​​of the covariance matrix. is the signal subspace, Σ s,k =α 1,k . is the noise subspace, Σ n,k =diag{α 2,k ,α 3,k ,…,α 6,k}.

[0139] The signal eigenvector is used as the steering vector for DOA estimation, that is:

[0140]

[0141] By controlling the rotation of the turntable, the steering vector of each search point is corrected to obtain a steering vector set that can be used for DOA estimation.

[0142] The correction effect is tested below. Assume that there are three signal sources, which are located at θ1 = -25°, θ2 = 0° and θ3 = 35°, respectively, with a signal-to-noise ratio SNR = 25dB and a snapshot number L = 200. The received array signal is:

[0143]

[0144] The covariance matrix of the array received signal can be estimated using the following formula:

[0145]

[0146] Perform eigenvalue decomposition on the covariance matrix to obtain the noise subspace, which includes:

[0147]

[0148] Among them, α1≥α2≥…≥α5≥α6 are the eigenvalues ​​of the covariance matrix. are the eigenvectors corresponding to the eigenvalues ​​of the covariance matrix. is the signal subspace, Σ s =diag{α1,α2,α3}, is the noise subspace, Σ n =diag{α4,α5,α6}.

[0149] Any subspace DOA estimation algorithm can be used to perform spatial spectrum calculation and DOA estimation. Taking the MUSIC algorithm as an example, the calculation formula of the spatial spectrum without error correction is:

[0150]

[0151] The calculation formula of the spatial spectrum after error correction is:

[0152]

[0153] like Figure 6 As shown in Figure 1, this is the normalized spatial spectrum without error correction. There are multiple peaks with similar amplitudes in the spatial spectrum. The three highest peaks obviously deviate from the direction of the signal source. The DOA estimation results of the three signal sources are -45.3°, -41.9°, and 16.8°, respectively. Under such array errors, direct DOA estimation cannot obtain accurate results.

[0154] like Figure 7 As shown in the figure, it is the normalized spatial spectrum after error correction. There are three obvious spectrum peaks in the direction of the source, and the spectrum peak value is significantly higher than the spatial spectrum value in the non-source direction. The DOA estimation results of the three sources are -25°, 0° and 35°, respectively. It can be seen that after error correction is performed using the array error correction method of the implementation mode of the present application, accurate DOA estimation can be performed on the non-MIMO radar.

[0155] The application of the array error correction method according to the embodiment of the present application in MIMO radar is described in detail below.

[0156] A radar including 5 transmitting antennas and 6 receiving antennas is used. The signal source and the array are in the same plane. The transmitting array adopts a non-uniform sparse array with a layout of 0.5λ*[014294357]. The receiving array adopts a minimum redundancy array with a layout of 0.5λ*[01261013], where λ is the wavelength of the electromagnetic wave signal emitted by the radar in the air. The angle search range of DOA is [-90°, 90°], and the search is performed at intervals of 0.1°. The total number of search points is K=1801.

[0157] The ideal transmission array steering vector of the kth search point is:

[0158]

[0159] Among them, θ k is the direction of the kth search point.

[0160] Since the error matrix E k The impact on the steering vector is to change the amplitude and phase of each element in the steering vector. Therefore, we can add random amplitude and phase errors to each element of the steering vector to represent the impact of array error on the steering vector. Assume that the amplitude error Δb of the transceiver array is i Obeying the uniform distribution of [0, 1.5], the phase error Obeys the uniform distribution of [-π / 2, π / 2], i=1, 2, …, 11.

[0161]

[0162]

[0163] Substitute the above steering vector containing the error into the following formula:

[0164]

[0165] The array signal received by the radar at the kth search point can be obtained.

[0166] Assuming that the signal-to-noise ratio (SNR) during calibration is 10 dB, the array signal satisfies the normal distribution, the noise is Gaussian white noise and is uncorrelated with the signal source, and the number of snapshots is L = 200, the covariance matrix of the array received signal can be estimated using the following formula:

[0167]

[0168] Perform eigenvalue decomposition on the covariance matrix to obtain the signal eigenvector of the k-th search point, including:

[0169]

[0170] Among them, α 1,k ≥α 2,k ≥…≥α 29,k ≥α 30,k is the eigenvalue of the covariance matrix. are the eigenvectors corresponding to the eigenvalues ​​of the covariance matrix. is the signal subspace, Σ s,k =α 1,k . is the noise subspace, Σ n,k=diag{α 2,k ,α 3,k ,…,α 30,k}.

[0171] The signal eigenvector is used as the steering vector for DOA estimation, that is:

[0172]

[0173] By controlling the rotation of the turntable, the steering vector of each search point is corrected to obtain the steering vector set used for DOA estimation.

[0174] The correction effect is tested below. Assume that there are three signal sources, which are located at θ1 = -25°, θ2 = 0° and θ3 = 35°, respectively, with a signal-to-noise ratio SNR = 25dB and a snapshot number L = 200. The received array signal is:

[0175]

[0176] The covariance matrix of the array signal can be estimated using the following formula:

[0177]

[0178] Perform eigenvalue decomposition on the above covariance matrix to obtain the noise subspace, which specifically includes:

[0179]

[0180] Among them, α1≥α2≥…≥α5≥α 30 is the eigenvalue of the covariance matrix. are the eigenvectors corresponding to the eigenvalues ​​of the covariance matrix. is the signal subspace, Σ s =diag{α1,α2,α3}. is the noise subspace, Σ n =diag{α4,α5,…,α 30}.

[0181] Any subspace DOA estimation algorithm can be used to perform spatial spectrum calculation and DOA estimation. Taking the MUSIC algorithm as an example, the calculation formula of the spatial spectrum without error correction is:

[0182]

[0183] in

[0184] The calculation formula of the spatial spectrum after error correction is:

[0185]

[0186] like Figure 8 As shown in Figure 1, this is the normalized spatial spectrum without array error correction. The three highest peaks in the spatial spectrum obviously deviate from the direction of the signal source. The DOA estimation results of the three signal sources are -73.1°, -40.1°, and 20.9°, respectively. Under such array errors, direct DOA estimation cannot obtain accurate results.

[0187] like Fig. 9 As shown in the figure, it is the normalized spatial spectrum after array error correction. There are three obvious spectrum peaks in the direction of the information source, and the spectrum peak value is significantly higher than the spatial spectrum value in the non-information source direction. The DOA estimation results of the three information sources are -25°, 0° and 35° respectively. It can be seen that after correction by the array error correction method of the embodiment of the present application, the DOA estimation of the MIMO radar can be accurately performed.

[0188] See also Fig.10 , the embodiment of the present application also provides an array error correction device 100. The array error correction device 100 includes a setting module 10, a generation module 20, an acquisition module 30 and a determination module 40. The setting module 10 is used to set a signal source in the far field area of ​​the radar and set the radar on a turntable. The generation module 20 is used to determine the angular search range of the signal arrival direction and generate a corresponding plurality of search points according to the search range. The acquisition module 30 is used to rotate the turntable to obtain the array signal from the signal source received by the radar at each search point. The determination module 40 is used to determine the corrected steering vector of the corresponding search point according to each array signal.

[0189] In some embodiments, the determination module 40 is specifically used to calculate the corresponding covariance matrix according to each array signal; perform eigenvalue decomposition according to each covariance matrix to obtain the corresponding signal eigenvector; and use each signal eigenvector as the corrected steering vector of the corresponding search point.

[0190] In some implementations, the determination module 40 is specifically configured to calculate a corresponding covariance matrix according to each array signal and the number of snapshots of each array signal.

[0191] In some implementations, the determination module 40 is specifically configured to perform eigenvalue decomposition on each covariance matrix to obtain corresponding eigenvalues ​​and corresponding signal eigenvectors.

[0192] In some implementations, the determination module 40 is further configured to determine a signal subspace and a noise subspace according to the eigenvalues ​​and the signal eigenvectors.

[0193] It should be noted that the explanation of the array error correction method in the aforementioned embodiment is also applicable to the array error correction device 100 in the embodiment of the present application, and will not be elaborated here.

[0194] See also Fig.11 The embodiment of the present application further provides an array error correction system 200, the array error correction system 200 includes one or more processors 210 and a memory 220, the memory 220 stores a computer program, and when the computer program is executed by the processor 210, the array error correction method of any of the above embodiments is implemented.

[0195] For example, when the computer program is executed by the processor 210, the following array error correction method is implemented:

[0196] 010: Set up a signal source in the far field area of ​​the radar and set the radar on a turntable;

[0197] 020: Determine the angle search range of the signal arrival direction, and generate corresponding multiple search points according to the search range;

[0198] 030: Rotate the turntable to obtain the array signal from the source received by the radar at each search point;

[0199] 040: Determine the corrected steering vector of the corresponding search point according to each array signal.

[0200] For another example, when the computer program is executed by the processor 210, the following array error correction method is implemented:

[0201] 041: Calculate the corresponding covariance matrix according to each array signal;

[0202] 042: Perform eigenvalue decomposition according to each covariance matrix to obtain the corresponding signal eigenvector;

[0203] 043: Use each signal feature vector as the corrected steering vector of the corresponding search point.

[0204] It should be noted that the explanations of the array error correction method and the array error correction device 100 in the aforementioned embodiments are also applicable to the array error correction system 200 in the embodiments of the present application, and will not be further described here.

[0205] See also Fig.12 The computer-readable storage medium 300 of the embodiment of the present application stores a computer program 310 thereon, and when the program is executed by the processor 320, the array error correction method of any of the above-mentioned embodiments is implemented.

[0206] For example, when the computer program 310 is executed by the processor 320, the following array error correction method is implemented:

[0207] 010: Set up a signal source in the far field area of ​​the radar and set the radar on a turntable;

[0208] 020: Determine the angle search range of the signal arrival direction, and generate corresponding multiple search points according to the search range;

[0209] 030: Rotate the turntable to obtain the array signal from the source received by the radar at each search point;

[0210] 040: Determine the corrected steering vector of the corresponding search point according to each array signal.

[0211] For another example, when the computer program 310 is executed by the processor 320, the following array error correction method is implemented:

[0212] 041: Calculate the corresponding covariance matrix according to each array signal;

[0213] 042: Perform eigenvalue decomposition according to each covariance matrix to obtain the corresponding signal eigenvector;

[0214] 043: Use each signal feature vector as the corrected steering vector of the corresponding search point.

[0215] It should be noted that the explanations and descriptions of the array error correction method and the array error correction device 100 in the aforementioned embodiments are also applicable to the computer-readable storage medium 300 in the embodiments of the present application, and will not be further described here.

[0216] In summary, in the array error correction method, correction device 100, correction system 200 and computer-readable storage medium 300 of the embodiment of the present application, the radar is driven to rotate by rotating the turntable to obtain the array signal from the source received by the radar at each search point, and the corrected steering vector of the corresponding search point is determined according to each array signal, and error correction is performed on each search point within the search range. In this way, error correction is performed based on the array signal actually received at each search point, and the comprehensive influence of all errors to which the antenna array is subjected in the actual working environment can be captured, without any limitation on the array error type, and without the need to estimate multiple errors separately, so that the array pattern error, array element position error, channel amplitude and phase error and angle-dependent array element mutual coupling error can be corrected simultaneously, and the correction accuracy is high.

[0217] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0218] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0219] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable storage medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, a computer-readable storage medium can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable storage media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable storage medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0220] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0221] A person of ordinary skill in the art will appreciate that all or part of the steps carried by the method for implementing the above-mentioned embodiment can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment. In addition, each functional unit in each embodiment of the present application can be integrated into a processing module, or each unit can exist physically alone, or two or more units can be integrated into one module. The above-mentioned integrated module can be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. The above-mentioned storage medium can be a read-only memory, a disk or an optical disk, etc.

[0222] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. An array error correction method, characterized in that: include: Setting a signal source in a far field region of the radar, and setting the radar on a turntable; Determine an angular search range of the signal arrival direction, and generate a plurality of corresponding search points according to the search range; Rotating the turntable to obtain the array signal from the information source received by the radar at each search point; A corrected steering vector of the corresponding search point is determined according to each array signal.

2. The array error correction method according to claim 1, characterized in that: The step of determining the corrected steering vector of the corresponding search point according to each array signal comprises: Calculate the corresponding covariance matrix according to each of the array signals; Perform eigenvalue decomposition according to each of the covariance matrices to obtain a corresponding signal eigenvector; Each of the signal feature vectors is used as the corrected steering vector of the corresponding search point.

3. The array error correction method according to claim 1, characterized in that: The array signal is: in, is the array signal of the kth search point, E k is the total error matrix of the k-th search point, is the total array steering vector of the kth search point, s k (t) is the baseband signal at the t-th snapshot, is the noise vector of the t-th snapshot.

4. The array error correction method according to claim 2, characterized in that: The calculating the corresponding covariance matrix according to each of the array signals comprises: A corresponding covariance matrix is ​​calculated according to each of the array signals and the number of snapshots of each of the array signals.

5. The array error correction method according to claim 4, characterized in that: The covariance matrix is: in, is the covariance matrix, is the array signal of the kth search point, for The conjugate transpose of , L is the number of snapshots.

6. The array error correction method according to claim 2, characterized in that: The performing eigenvalue decomposition according to each of the covariance matrices to obtain a corresponding signal eigenvector includes: Perform eigenvalue decomposition on each of the covariance matrices to obtain corresponding eigenvalues ​​and corresponding signal eigenvectors.

7. The array error correction method according to claim 6, characterized in that: The decomposition result of the covariance matrix is: in, is the covariance matrix, α 1,k ≥α 2,k ≥…≥α MN-1,k ≥α MN,k is the characteristic value, M is the number of transmitting antennas of the radar, N is the number of receiving antennas of the radar, is the signal eigenvector corresponding to the eigenvalue, for The conjugate transpose of .

8. The array error correction method according to claim 6, characterized in that: The array error correction method further comprises: A signal subspace and a noise subspace are determined according to the eigenvalue and the signal eigenvector.

9. The array error correction method according to claim 8, characterized in that: The signal subspace and the noise subspace are: in, is the signal subspace, Σ s,k =α 1,k , is the noise subspace, Σ n,k =diag{α 2,k ,α 3,k ,…,α MN,k }.

10. The array error correction method according to claim 1, characterized in that: The range of the far field region is: Wherein, F is the distance between the information source and the radar, D is the antenna aperture of the radar, and λ is the operating wavelength of the radar.

11. The array error correction method according to claim 1, characterized in that: The array signal satisfies a normal distribution.

12. The array error correction method according to claim 1, characterized in that: The antenna array in the radar is a uniform array or a sparse array.

13. The array error correction method according to claim 1, characterized in that: The information source is used to propagate the signal transmitted by the radar back to the radar at the same angle as the angle at which the signal is incident to the information source.

14. The array error correction method according to claim 12, characterized in that: The information source is a corner reflector or a transceiver antenna device.

15. The array error correction method according to claim 1, characterized in that: The search range is greater than or equal to the visual angle of the radar.

16. The array error correction method according to claim 1, characterized in that: The search point is a one-dimensional search point or a two-dimensional search point.

17. The array error correction method according to claim 1, characterized in that: The radar is a MIMO radar or a non-MIMO radar.

18. An array error correction device, characterized in that: include: A setting module, used to set a signal source in a far field area of ​​the radar and set the radar on a turntable; A generation module, used to determine an angular search range of the signal arrival direction, and generate a plurality of corresponding search points according to the search range; An acquisition module, used for rotating the turntable to acquire the array signal from the information source received by the radar at each search point; A determination module is used to determine the corrected steering vector of the corresponding search point according to each array signal.

19. An array error correction system, characterized in that: The array error correction system includes one or more processors and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the array error correction method according to any one of claims 1 to 17 is implemented.

20. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the array error correction method described in any one of claims 1 to 17 is implemented.

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