Active estimation method and system for wideband VHF array channel delay error

Abstract

The present invention provides an active estimation method and system for a broadband VHF array channel delay error, belonging to the technical field of direction finding. The method comprises: obtaining the direction vectors of each frequency point of an auxiliary signal source relative to each array element in a broadband VHF array and performing normalization processing; determining the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point of the auxiliary signal source and performing normalization processing; calculating the channel delay error corresponding to each frequency point in an observation frequency band based on the eigenvector and the corresponding direction vector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization processing; and calculating the broadband VHF array channel delay error based on the channel delay error corresponding to each frequency point in the observation frequency band. The present invention can achieve efficient and accurate estimation of the broadband VHF array channel delay error, ensure broadband lightning VHF direction finding performance, and is suitable for correcting the broadband VHF array channel delay error.

Description

Technical Field

[0001] The invention belongs to the technical field of direction finding, and in particular relates to an active estimation method and system for broadband VHF array channel delay error. Background Art

[0002] Currently, broadband lightning VHF array direction-finding technology, with its advantages of high temporal resolution and high positioning accuracy, has attracted widespread attention from researchers in the fields of lightning location technology and lightning physics. With the refinement of lightning science research, in-depth studies of the ground lightning return stroke connection process, initial pre-breakdown process, forward breakdown development characteristics, bipolar narrow pulses, and some unconventional breakdown discharge processes have important scientific significance for revealing the mechanisms of lightning electrification and development. The inversion of these processes and the description of the detailed structure of the discharge channel rely on the development and application of broadband lightning VHF array direction-finding technology with high temporal and spatial resolution. In the more than 20 years since its introduction, broadband lightning VHF array direction-finding technology has undergone iterations and applications, including time of arrival (TOA) technology, interferometer technology, and current time reversal technology and multiple signal classification technology. The size of broadband lightning VHF arrays has also grown from two and three elements to four, seven, and even more elements, and their temporal and spatial resolutions have also been greatly improved.

[0003] As broadband lightning VHF arrays expand in size, the number of array elements increases, the array's physical aperture widens, and their spatial directivity and resolution capabilities improve. However, in practical applications, due to differences in observation system fabrication, installation, and site, as well as inconsistencies in acquisition channels, each array channel inevitably experiences a certain degree of delay error. The greater the number of array elements, the greater the likelihood of array channel delay error, and the correspondingly greater delay error fluctuations. The time difference between the actual array's direction vector and the received signal often exhibits a certain degree of deviation and perturbation due to array channel delay errors. This inevitably impacts the performance of broadband lightning VHF direction-finding technology, severely degrading it or even rendering it ineffective. Correcting broadband lightning VHF array channel delay errors is a pressing issue for the practical application of large-scale broadband VHF arrays. Furthermore, array error correction, particularly for broadband arrays, remains a hot and challenging research topic in the field of spatial spectrum estimation theory. Summary of the Invention

[0004] One of the objectives of the present invention is to provide an active estimation method for broadband VHF array channel delay error. The active estimation method can achieve efficient and accurate estimation of broadband VHF array channel delay error, ensure broadband lightning VHF direction finding performance, and is suitable for correcting broadband VHF array channel delay error.

[0005] A second object of the present invention is to provide an active estimation system for broadband VHF array channel delay error.

[0006] In order to achieve one of the above purposes, the present invention adopts the following technical solutions:

[0007] An active estimation method for broadband VHF array channel delay error, the active estimation method comprising the following steps:

[0008] Step S1, obtaining the direction vectors of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array and performing normalization processing;

[0009] Step S2: determining the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point of the auxiliary signal source and performing normalization processing;

[0010] Step S3: Calculate the channel delay error corresponding to each frequency point in the observation frequency band based on the eigenvector and the corresponding direction vector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization;

[0011] Step S4: Calculate the broadband VHF array channel delay error based on the channel delay error corresponding to each frequency point in the observation frequency band.

[0012] Furthermore, the specific implementation process of step S1 includes:

[0013] Step S11, obtaining the coordinates of each array element in the broadband VHF array and the azimuth and elevation angles of the auxiliary signal source relative to the broadband VHF array;

[0014] Step S12, calculating the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array;

[0015] Step S13: Select an array element from each array element in the broadband VHF array as a reference array element, and divide each directional element value in the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array by the directional element value corresponding to the frequency point of the reference array element.

[0016] Furthermore, the specific implementation process of step S2 includes:

[0017] Step S21, performing discrete Fourier transform on the auxiliary signal source radiation signal data received by each array element in the broadband VHF array to obtain frequency domain data of the broadband VHF array signal;

[0018] Step S22: calculating the covariance matrix of each frequency point corresponding to the frequency domain data of the broadband VHF array signal according to the frequency domain data of the broadband VHF array signal;

[0019] Step S23: performing singular value decomposition on the covariance matrix of each frequency point to obtain the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point;

[0020] Step S24: Divide each eigenvalue value in the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point by the eigenvalue value corresponding to the reference array element.

[0021] Furthermore, the specific implementation process of step S3 includes:

[0022] Step S31: Divide the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization by the direction vector of the corresponding array element after normalization to obtain the delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array;

[0023] Step S32: Calculate the natural logarithm of the delay error complex vector of each frequency point corresponding to each array element in the wideband VHF array and multiply it by a rotation factor to obtain the delay error rotation vector of each frequency point corresponding to each array element in the wideband VHF array;

[0024] Step S33, extracting the real part from the delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array and performing deconvolution processing;

[0025] Step S34: Divide the deconvolution result by the angular frequency of the corresponding frequency point.

[0026] Furthermore, the specific implementation process of step S4 includes:

[0027] Step S41: extracting all array channel delay errors within a threshold range from the channel delay errors corresponding to each frequency point in the observation frequency band;

[0028] Step S42: Calculate the average of all array channel delay errors within the threshold range; and use the average as the broadband VHF array channel delay error.

[0029] In order to achieve the second of the above objectives, the present invention adopts the following technical solutions:

[0030] An active estimation system for broadband VHF array channel delay error, the active estimation system comprising:

[0031] A first normalization processing module is used to obtain the direction vectors of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array and then perform normalization processing;

[0032] A second normalization processing module is used to determine the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point of the auxiliary signal source and perform normalization processing;

[0033] The first calculation module is used to calculate the channel delay error corresponding to each frequency point in the observation frequency band according to the eigenvector and the corresponding direction vector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization;

[0034] The second calculation module is used to calculate the wideband VHF array channel delay error according to the channel delay error corresponding to each frequency point in the observation frequency band.

[0035] Furthermore, the first normalization processing module includes:

[0036] A first acquisition submodule is configured to acquire the coordinates of each array element in a wideband VHF array and the azimuth and elevation angles of the auxiliary signal source relative to the wideband VHF array;

[0037] A first calculation submodule is used to calculate the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array;

[0038] A selection submodule selects an array element from each array element in the broadband VHF array as a reference array element, and divides each directional element value in the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array by the directional element value of the reference array element corresponding to the frequency point.

[0039] Furthermore, the second normalization processing module includes:

[0040] a discrete Fourier transform submodule, configured to perform discrete Fourier transform on the auxiliary signal source radiation signal data received by each array element in the broadband VHF array to obtain frequency domain data of the broadband VHF array signal;

[0041] A second calculation submodule is used to calculate the covariance matrix of each frequency point corresponding to the frequency domain data of the broadband VHF array signal according to the frequency domain data of the broadband VHF array signal;

[0042] A singular value decomposition submodule is used to perform singular value decomposition on the covariance matrix of each frequency point to obtain the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point;

[0043] The first division submodule is configured to divide each eigenvalue in the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point by the eigenvalue corresponding to the reference array element.

[0044] Furthermore, the first calculation module includes:

[0045] A second division submodule is configured to divide the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization by the direction vector of the corresponding array element after normalization to obtain a delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array;

[0046] A third calculation submodule is configured to calculate the natural logarithm of the delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array and multiply the natural logarithm of the complex vector by a rotation factor to obtain a delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array;

[0047] A first extraction submodule is configured to extract a real part from the delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array and then perform deconvolution processing;

[0048] The third phase division submodule is used to divide the deconvolution processing result by the angular frequency of the corresponding frequency point.

[0049] Furthermore, the second calculation module includes:

[0050] A second extraction submodule is configured to extract all array channel delay errors within a threshold range from the channel delay errors corresponding to each frequency point in the observation frequency band;

[0051] The fourth calculation submodule is configured to calculate the average of all array channel delay errors within the threshold range; and use the average as the broadband VHF array channel delay error.

[0052] In summary, the solution proposed in the present invention has the following technical effects:

[0053] The present invention sets an auxiliary signal source with a precisely known azimuth, obtains the direction vector of the auxiliary signal source relative to the broadband VHF array at each frequency point, and the covariance matrix of the array received signal at each frequency point, performs singular value decomposition on the covariance matrix of each frequency point, obtains the eigenvector corresponding to the maximum eigenvalue, and then combines the directional vectors of each frequency point to achieve efficient and accurate estimation of the broadband VHF array channel delay error. In short, the known azimuth of the auxiliary signal source is used to inversely calculate the unknown quantity of the broadband VHF array channel delay error, without the need to solve a complex nonlinear equation group, and has high efficiency. The invention is suitable for correcting the broadband VHF array channel delay error. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 1. A schematic flow chart of a method for actively estimating a wideband VHF array channel delay error according to an embodiment of the present invention;

[0056] Figure 2 This is a schematic diagram of the distribution of an "L"-shaped broadband lightning VHF array and auxiliary signal sources provided in an embodiment of the present invention;

[0057] Figure 3 Schematic diagram of channel delay errors corresponding to all frequency points within the observation frequency band obtained according to an embodiment of the present invention;

[0058] Figure 4 This is a schematic diagram of the broadband lightning VHF array channel delay error finally obtained in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0060] This embodiment provides an active estimation method for broadband VHF array channel delay error, referring to Figure 1 , the active estimation method comprises the following steps:

[0061] S1. Obtain the direction vectors of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array and perform normalization processing.

[0062] The array elements in the broadband VHF array are numbered and receive the radiation signal from the auxiliary signal source. The array used in this embodiment is an "L"-shaped broadband lightning VHF array consisting of 7 elements, with an element spacing of 9m. Figure 2 As shown, the array elements are numbered V1 to V7. The array element antennas of the broadband lightning VHF array of this embodiment are generally preferably broadband very high frequency antennas.

[0063] When setting up the auxiliary signal source, use a drone to mount a lightweight portable signal generator and fly it to the set height and hover. Figure 2 As shown, the position of the auxiliary signal source relative to the broadband lightning VHF array was measured using a high-precision theodolite measuring instrument. Figure 2 Where φ is the azimuth angle of the auxiliary signal source, and θ is the elevation angle of the auxiliary signal source. The numbers and coordinates of each array element, as well as the azimuth of the auxiliary signal source, are shown in Table 1.

[0064] Table 1 Coordinates of each element in the broadband VHF array and the azimuth and elevation angles of the auxiliary signal source

[0065]

[0066] In addition, this embodiment sets the broadband lightning VHF array channel delay error, and the setting parameters are shown in Table 2:

[0067] Table 2 Channel delay errors of each element in the broadband lightning VHF array

[0068] V1 V2 V3 V4 V5 V6 V7 Set delay error (ns) 0 -0.66 -2.67 0.17 -0.41 2.99 1.87

[0069] In summary, the specific implementation process of this step includes:

[0070] Step S11: Acquire the coordinates of each array element in the broadband VHF array and the azimuth and elevation angles of the auxiliary signal source relative to the broadband VHF array.

[0071] Step S12, calculating the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array;

[0072] Based on the orientation of the auxiliary signal source and the spatial coordinates of each element in the broadband VHF array, the direction vector corresponding to each frequency point of the auxiliary signal source (i.e., the direction vector of each frequency point of the auxiliary signal source relative to each element in the broadband VHF array) is calculated. In this embodiment, the direction vector of each frequency point of the auxiliary signal source relative to each element in the broadband VHF array is:

[0073]

[0074] in, is the direction vector corresponding to the direction vector of each array element in the broadband VHF array at the jth frequency point of the auxiliary signal source; j is the frequency of the jth frequency point of the auxiliary signal source, j=1,2,…,J, J is the number of frequency points; x m and y m are the abscissa and ordinate of the mth element in the wideband VHF array, respectively, m = 1, 2, …, M, where M is the number of elements in the wideband VHF array; and θ are the azimuth and elevation angles of the auxiliary signal source relative to the broadband VHF array, respectively; c is the speed of signal propagation. In this embodiment, the observation frequency f j The coverage range is 0~625MHz, J=256, θ=30°,M=7,c=3×10 8 m / s.

[0075] Step S13: Select an array element from each array element in the broadband VHF array as a reference array element, and divide each directional element value in the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array by the directional element value corresponding to the frequency point of the reference array element.

[0076] Select a reference array element and normalize the direction vectors of each frequency point relative to the array element. ref ,y ref ), ref = m, and normalize the direction vectors of each frequency point relative to the m-th array element and calculate according to the following formula:

[0077]

[0078] in, for Normalized direction vector; a(ref) is the direction vector from In this embodiment, ref=1.

[0079] S2. Determine the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point of the auxiliary signal source and perform normalization processing.

[0080] Perform discrete Fourier transform on the auxiliary signal source radiation signal data received by each element of the broadband VHF array to obtain the frequency domain data of the array signal, and calculate the covariance matrix of the array signal frequency domain data corresponding to each frequency point. The specific implementation process of this step includes:

[0081] Step S21, performing discrete Fourier transform on the auxiliary signal source radiation signal data received by each array element in the broadband VHF array to obtain frequency domain data of the broadband VHF array signal;

[0082] Step S22: calculating the covariance matrix of each frequency point corresponding to the frequency domain data of the broadband VHF array signal according to the frequency domain data of the broadband VHF array signal;

[0083] The covariance matrix of each frequency point corresponding to the frequency domain data of the broadband VHF array signal is calculated according to the following formula:

[0084]

[0085] Among them, R(f j ) is the covariance matrix of the jth frequency point corresponding to the frequency domain data of the broadband VHF array signal; X(f j )=[X1(f j );X2(f j );X3(f j );…;X M (f j )] is the frequency domain data of the broadband VHF array signal at the jth frequency point, and “H” represents the conjugate transpose;

[0086] Step S23: performing singular value decomposition on the covariance matrix of each frequency point to obtain the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point;

[0087] Step S24: Divide each eigenvalue value in the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point by the eigenvalue value corresponding to the reference array element.

[0088] Let the eigenvector corresponding to the maximum eigenvalue of the covariance matrix be U(f j )=[u1,u2,…,u m ,…,u M ] T ,u m represents U(f j ) in the mth component, “T” represents the transpose, according to the reference element number, in the eigenvector U(f j ) selects the characteristic component (i.e., the characteristic element value) corresponding to the reference element as the reference component, and calculates the characteristic vector U(f j ) can be normalized and calculated according to the following formula:

[0089]

[0090] Among them, Us(f j ) is the eigenvector corresponding to the maximum eigenvalue of the normalized covariance matrix; U(ref) is the eigenvector corresponding to the maximum eigenvalue of the covariance matrix U(f j ) is the refth characteristic element value. In this embodiment, ref=1.

[0091] S3. Calculate the channel delay error corresponding to each frequency point in the observation frequency band based on the eigenvector and the corresponding direction vector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization.

[0092] Divide the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization by the corresponding normalized direction vector to obtain the delay error complex vector of each frequency point corresponding to the broadband VHF array channel, calculate the natural logarithm of the delay error vector, and then multiply it by the rotation factor e(-iπ / 2) to obtain the delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array. Take the real part of the delay error rotation vector of each frequency point corresponding to the broadband VHF array channel, perform unwrapping processing, and then divide it by the angular frequency corresponding to each frequency point to obtain the channel delay error corresponding to all frequency points in the observation frequency band. The specific implementation process of this step includes:

[0093] Step S31: Divide the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization by the direction vector of the corresponding array element after normalization to obtain the delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array.

[0094] Step S32: Calculate the natural logarithm of the delay error complex vector of each frequency point corresponding to each array element in the wideband VHF array and multiply it by a rotation factor to obtain the delay error rotation vector of each frequency point corresponding to each array element in the wideband VHF array;

[0095] In this embodiment, the delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array is:

[0096]

[0097] Among them, Γ(f j ) is the delay error rotation vector of the jth frequency point corresponding to the broadband VHF array channel; a(ref) is the direction vector The reference element selected in .

[0098] Step S33, extracting the real part from the delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array and performing deconvolution processing;

[0099] Step S34: Divide the deconvolution result by the angular frequency of the corresponding frequency point.

[0100] In this embodiment, the channel delay error corresponding to each frequency point in the observation frequency band is:

[0101]

[0102] Among them, T(f j ) is the channel delay error at the jth frequency point in the observation frequency band; real[] is the value of Γ(f j ) real part operator; unwrap{} is the operator for real[Γ(f j)] is the operator for deconvolution; ω is the frequency f j The channel delay error of the broadband lightning VHF array in this embodiment is as follows: Figure 3 shown.

[0103] S4. Calculate the wideband VHF array channel delay error based on the channel delay error corresponding to each frequency point in the observation frequency band.

[0104] Eliminate the larger oscillation portion within the observation frequency band, and retain the flat portion of the change trend, which is the array channel delay error corresponding to each frequency point. Calculate the average of the delay error within the flat frequency band to obtain the final broadband VHF array channel delay error. The specific implementation process of this step includes:

[0105] Step S41: extracting all array channel delay errors within a threshold range from the channel delay errors corresponding to each frequency point in the observation frequency band;

[0106] Step S42: Calculate the average of all array channel delay errors within the threshold range; and use the average as the broadband VHF array channel delay error.

[0107] The broadband VHF array channel delay error in this embodiment is:

[0108]

[0109] Where τ is the broadband VHF array channel delay error; f k is the kth frequency corresponding to the flat frequency band (all array channel delay errors within the threshold range), k = 1, 2, ..., K, and K is the number of frequency points corresponding to the flat frequency band.

[0110] In this embodiment, the frequency range covered is 12MHz to 205MHz, and the number of frequency points K=80. Figure 4 As shown in Table 3, the final broadband lightning VHF array channel delay error is basically consistent with the delay error set above.

[0111] Table 3 Channel delay errors of each element in the broadband lightning VHF array obtained in this embodiment

[0112] V1 V2 V3 V4 V5 V6 V7 Estimated delay error (ns) 0 -0.6569 -2.6713 0.1672 -0.4148 2.9920 1.8779

[0113] This embodiment provides an auxiliary signal source with a precisely known azimuth, obtains the direction vector of the auxiliary signal source relative to the broadband VHF array at each frequency point, and the covariance matrix of the array received signal at each frequency point, performs singular value decomposition on the covariance matrix of each frequency point, obtains the eigenvector corresponding to the maximum eigenvalue, and then combines the directional vectors of each frequency point to achieve efficient and accurate estimation of the broadband VHF array channel delay error. In short, the known azimuth of the auxiliary signal source is used to inversely calculate the unknown quantity of the broadband VHF array channel delay error, without the need to solve a complex set of nonlinear equations. This embodiment is highly efficient and suitable for correcting the broadband VHF array channel delay error.

[0114] The above embodiment can be implemented by an active estimation system for broadband VHF array channel delay error given in the following embodiment:

[0115] An active estimation system for broadband VHF array channel delay error, the active estimation system comprising:

[0116] A first normalization processing module is used to obtain the direction vectors of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array and then perform normalization processing;

[0117] A second normalization processing module is used to determine the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point of the auxiliary signal source and perform normalization processing;

[0118] The first calculation module is used to calculate the channel delay error corresponding to each frequency point in the observation frequency band according to the eigenvector and the corresponding direction vector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization;

[0119] The second calculation module is used to calculate the wideband VHF array channel delay error according to the channel delay error corresponding to each frequency point in the observation frequency band.

[0120] Furthermore, the first normalization processing module includes:

[0121] A first acquisition submodule is configured to acquire the coordinates of each array element in a wideband VHF array and the azimuth and elevation angles of the auxiliary signal source relative to the wideband VHF array;

[0122] A first calculation submodule is used to calculate the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array;

[0123] A selection submodule selects an array element from each array element in the broadband VHF array as a reference array element, and divides each directional element value of the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array by the directional element value of the reference array element corresponding to the frequency point.

[0124] Furthermore, the second normalization processing module includes:

[0125] a discrete Fourier transform submodule, configured to perform discrete Fourier transform on the auxiliary signal source radiation signal data received by each array element in the broadband VHF array to obtain frequency domain data of the broadband VHF array signal;

[0126] A second calculation submodule is used to calculate the covariance matrix of each frequency point corresponding to the frequency domain data of the broadband VHF array signal according to the frequency domain data of the broadband VHF array signal;

[0127] A singular value decomposition submodule is used to perform singular value decomposition on the covariance matrix of each frequency point to obtain the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point;

[0128] The first division submodule is configured to divide each eigenvalue in the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point by the eigenvalue corresponding to the reference array element.

[0129] Furthermore, the first calculation module includes:

[0130] A second division submodule is configured to divide the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization by the direction vector of the corresponding array element after normalization to obtain a delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array;

[0131] A third calculation submodule is configured to calculate the natural logarithm of the delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array and multiply the natural logarithm of the complex vector by a rotation factor to obtain a delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array;

[0132] A first extraction submodule is configured to extract a real part from the delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array and then perform deconvolution processing;

[0133] The third phase division submodule is used to divide the deconvolution processing result by the angular frequency of the corresponding frequency point.

[0134] Furthermore, the second calculation module includes:

[0135] A second extraction submodule is configured to extract all array channel delay errors within a threshold range from the channel delay errors corresponding to each frequency point in the observation frequency band;

[0136] The fourth calculation submodule is configured to calculate the average of all array channel delay errors within the threshold range; and use the average as the broadband VHF array channel delay error.

[0137] The principles, formulas and parameter definitions involved in the above embodiments are all applicable and will not be described in detail here.

[0138] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of this application, several variations and improvements can be made, which all fall within the scope of protection of this application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. An active estimation method for broadband VHF array channel delay error, characterized in that: The active estimation method comprises the following steps: Step S1, obtaining the direction vectors of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array and performing normalization processing; Step S2: determining the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point of the auxiliary signal source and performing normalization processing; Step S3: Calculate the channel delay error corresponding to each frequency point in the observation frequency band based on the eigenvector and the corresponding direction vector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization; The specific implementation process of step S3 includes: Step S31: Divide the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization by the direction vector of the corresponding array element after normalization to obtain the delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array; Step S32: Calculate the natural logarithm of the delay error complex vector of each frequency point corresponding to each array element in the wideband VHF array and multiply it by a rotation factor to obtain the delay error rotation vector of each frequency point corresponding to each array element in the wideband VHF array; Step S33, extracting the real part from the delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array and performing deconvolution processing; Step S34: dividing the deconvolution result by the angular frequency of the corresponding frequency point; Step S4: Calculate the wideband VHF array channel delay error based on the channel delay error corresponding to each frequency point in the observation frequency band.

2. The active estimation method according to claim 1, characterized in that The specific implementation process of step S1 includes: Step S11, obtaining the coordinates of each array element in the broadband VHF array and the azimuth and elevation angles of the auxiliary signal source relative to the broadband VHF array; Step S12, calculating the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array; Step S13: Select an array element from each array element in the broadband VHF array as a reference array element, and divide each directional element value in the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array by the directional element value corresponding to the frequency point of the reference array element.

3. The active estimation method according to claim 2, characterized in that The specific implementation process of step S2 includes: Step S21, performing discrete Fourier transform on the auxiliary signal source radiation signal data received by each array element in the broadband VHF array to obtain frequency domain data of the broadband VHF array signal; Step S22: calculating the covariance matrix of each frequency point corresponding to the frequency domain data of the broadband VHF array signal according to the frequency domain data of the broadband VHF array signal; Step S23: performing singular value decomposition on the covariance matrix of each frequency point to obtain the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point; Step S24: Divide each eigenvalue value in the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point by the eigenvalue value corresponding to the reference array element.

4. The active estimation method according to claim 3, characterized in that The specific implementation process of step S4 includes: Step S41: extracting all array channel delay errors within a threshold range from the channel delay errors corresponding to each frequency point in the observation frequency band; Step S42: Calculate the average of all array channel delay errors within the threshold range; and use the average as the broadband VHF array channel delay error.

5. An active estimation system for broadband VHF array channel delay error, characterized in that: The active estimation system comprises: A first normalization processing module is used to obtain the direction vectors of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array and then perform normalization processing; A second normalization processing module is used to determine the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point of the auxiliary signal source and perform normalization processing; The first calculation module is used to calculate the channel delay error corresponding to each frequency point in the observation frequency band according to the eigenvector and the corresponding direction vector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization; The first calculation module includes: A second division submodule is configured to divide the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point after normalization by the direction vector of the corresponding array element after normalization to obtain a delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array; A third calculation submodule is configured to calculate the natural logarithm of the delay error complex vector of each frequency point corresponding to each array element in the broadband VHF array and multiply the natural logarithm of the complex vector by a rotation factor to obtain a delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array; A first extraction submodule is configured to extract a real part from the delay error rotation vector of each frequency point corresponding to each array element in the broadband VHF array and then perform deconvolution processing; The third phase division submodule is used to divide the deconvolution processing result by the angular frequency of the corresponding frequency point; The second calculation module is used to calculate the wideband VHF array channel delay error according to the channel delay error corresponding to each frequency point in the observation frequency band.

6. The active estimation system according to claim 5, characterized in that The first normalization processing module includes: A first acquisition submodule is configured to acquire the coordinates of each array element in a wideband VHF array and the azimuth and elevation angles of the auxiliary signal source relative to the wideband VHF array; A first calculation submodule is used to calculate the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array; A selection submodule selects an array element from each array element in the broadband VHF array as a reference array element, and divides each directional element value in the direction vector of each frequency point of the auxiliary signal source relative to each array element in the broadband VHF array by the directional element value of the reference array element corresponding to the frequency point.

7. The active estimation system according to claim 6, characterized in that The second normalization processing module includes: a discrete Fourier transform submodule, configured to perform discrete Fourier transform on the auxiliary signal source radiation signal data received by each array element in the broadband VHF array to obtain frequency domain data of the broadband VHF array signal; A second calculation submodule is used to calculate the covariance matrix of each frequency point corresponding to the frequency domain data of the broadband VHF array signal according to the frequency domain data of the broadband VHF array signal; A singular value decomposition submodule is used to perform singular value decomposition on the covariance matrix of each frequency point to obtain the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point; The first division submodule is configured to divide each eigenvalue in the eigenvector corresponding to the maximum eigenvalue of the covariance matrix of each frequency point by the eigenvalue corresponding to the reference array element.

8. The active estimation system according to claim 7, characterized in that The second calculation module includes: A second extraction submodule is configured to extract all array channel delay errors within a threshold range from the channel delay errors corresponding to each frequency point in the observation frequency band; The fourth calculation submodule is configured to calculate the average of all array channel delay errors within the threshold range; and use the average as the broadband VHF array channel delay error.

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