Frequency-guided array signal space-frequency information fusion processing method and device

Abstract

The application discloses a kind of frequency guidance-based array signal space-frequency information fusion processing method and device, applied to field programmable gate array (FPGA), by obtaining the multiple array signals for carrying out target detection received by target radar array;Any one of the multiple array signals is subjected to frequency detection, and at least one target frequency value is obtained;At least one target frequency value is subjected to frequency conversion filtering according to the multiple array signals, and at least one target array signal corresponding to at least one target frequency value is obtained;At least one target array signal is subjected to angle of arrival estimation, and at least one angle of arrival is obtained;According to at least one target frequency value and at least one angle of arrival, the corresponding relationship of target frequency value and angle of arrival is determined.The application utilizes single-channel signal to carry out frequency measurement, and then carries out filtering processing to multiple array signals and carries out angle of arrival estimation, and subsequent frequency retrieval is not necessary, and the FPGA resource utilization is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radar signal processing, and particularly relates to a frequency-guided array signal space-frequency information fusion processing method and device. BACKGROUND

[0002] With the increasing improvement of the science and technology level, the low-altitude economy has become a main driving force for economic development, and higher requirements for the target identification capability of wireless communication and radar systems are put forward for application scenarios such as urban unmanned logistics, low-altitude traffic management and civil radar monitoring. The low-altitude electromagnetic environment has the characteristics of high target density, strong dynamics and complex spatial distribution. The traditional airspace target identification method still has problems such as low real-time performance and low FPGA hardware resource utilization. SUMMARY

[0003] In order to solve the above problems existing in the prior art, the application provides a frequency-guided array signal space-frequency information fusion processing method and device.

[0004] The technical problem to be solved by the application is solved by the following technical scheme:

[0005] In a first aspect, the application provides a frequency-guided array signal space-frequency information fusion processing method, applied to a field programmable gate array (FPGA), and the method comprises the following steps:

[0006] Obtaining a plurality of array signals received by a target radar array for target detection;

[0007] Frequency detecting any one of the plurality of array signals to obtain at least one target frequency value;

[0008] Frequency filtering the plurality of array signals according to the at least one target frequency value to obtain at least one target array signal corresponding to the at least one target frequency value;

[0009] Performing angle of arrival estimation on the at least one target array signal to obtain at least one angle of arrival;

[0010] According to the at least one target frequency value and the at least one angle of arrival, determining the corresponding relationship between the target frequency value and the angle of arrival.

[0011] In a second aspect, the application provides a frequency-guided array signal space-frequency information fusion processing device, applied to an FPGA, and the device comprises:

[0012] An acquisition module, configured to acquire a plurality of array signals received by a target radar array for target detection;

[0013] The frequency detection module is configured to perform frequency detection on any one of the multiple array signals to obtain at least one target frequency value.

[0014] The frequency conversion filtering module is configured to perform frequency conversion filtering on the multiple array signals according to the at least one target frequency value to obtain at least one target array signal corresponding to the at least one target frequency value.

[0015] The angle of arrival estimation module is configured to perform angle of arrival estimation on the at least one target array signal to obtain an angle of arrival corresponding to the at least one target array signal.

[0016] The fusion module is configured to determine a corresponding relationship between the target frequency value and the angle of arrival according to the at least one target frequency value and the angle of arrival corresponding to the at least one target array signal.

[0017] The application provides a frequency-guided array signal space-frequency information fusion processing method and device, which is applied to a field programmable gate array (FPGA) and comprises the following steps: obtaining multiple array signals received by a target radar array for target detection; performing frequency detection on any one of the multiple array signals to obtain at least one target frequency value; performing frequency conversion filtering on the multiple array signals according to the at least one target frequency value to obtain at least one target array signal corresponding to the at least one target frequency value; performing angle of arrival estimation on the at least one target array signal to obtain at least one angle of arrival; and determining a corresponding relationship between the target frequency value and the angle of arrival according to the at least one target frequency value and the at least one angle of arrival. The application performs filtering processing on the multiple array signals after frequency detection on single-channel signals, and then performs angle of arrival estimation, so that frequency retrieval is not required subsequently, and the FPGA resource utilization rate is improved.

[0018] The application will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a flowchart of a frequency-guided array signal space-frequency information fusion processing method provided by an embodiment of the application;

[0020] Figure 2 is a process diagram of a frequency-guided array signal space-frequency information fusion processing method provided by an embodiment of the application;

[0021] Figures 3A to 3C is a simulation result diagram of a frequency-guided array signal space-frequency information fusion processing method provided by an embodiment of the application;

[0022] Figure 4 is a structural diagram of a frequency-guided array signal space-frequency information fusion processing device provided by an embodiment of the application. DETAILED DESCRIPTION

[0023] The application will be described in further detail below with reference to specific embodiments, but the embodiments of the application are not limited thereto.

[0024] The embodiment of the application provides a frequency guidance-based array signal space-frequency information fusion processing method, which is applied to an FPGA (Field Programmable Gate Array). Figure 1 And Figure 2 The method comprises the following steps:

[0025] S10, obtaining a plurality of array signals received by a target radar array and used for target detection.

[0026] Optionally, the target radar array can be a uniform linear array.

[0027] Exemplarily, the number of the plurality of array signals is determined by the number of array elements of the target radar array, for example, if the number of array elements is 8, 8 array signals (which can also be referred to as channels) are obtained. After the 8 array signals are obtained, the array signals can also be preprocessed, such as channel amplitude and phase calibration.

[0028] S20, performing frequency detection on any one of the plurality of array signals to obtain at least one target frequency value.

[0029] Optionally, the step S20 can specifically comprise:

[0030] After windowing processing is performed on any one of the plurality of array signals, fast Fourier transform is performed to obtain spectrum data; a plurality of rounds of maximum preservation processing are performed on the spectrum data to obtain maximum preservation spectrum; and at least one target frequency value is determined from the maximum preservation spectrum.

[0031] Exemplarily, a Hamming window is first added to any one of the plurality of array signals, and then fast Fourier transform is performed to obtain spectrum data; a plurality of rounds of maximum preservation processing are performed on the spectrum data to obtain maximum preservation spectrum; and peak value searching is performed based on the maximum preservation spectrum, so as to ensure that all signals during scanning are detected, and at least one target frequency value corresponding to a detected target is screened out. The number of target frequency values is determined by the number of targets.

[0032] S30, performing frequency conversion filtering on the plurality of array signals according to the at least one target frequency value to obtain at least one target array signal corresponding to the at least one target frequency value.

[0033] Optionally, the step S30 can specifically comprise:

[0034] S301, respectively taking each target frequency value as a center frequency of a digital down conversion (DDC) module of the FPGA, performing frequency conversion processing on the multi-path array signal to obtain a multi-path array signal after frequency conversion.

[0035] Each of the multi-path array signals after frequency conversion contains a baseband signal.

[0036] Optionally, the frequency conversion processing formula of the DDC module can be expressed as:

[0037]

[0038] , wherein, represents the multi-path array signal, represents the i-th target frequency value, represents the multi-path array signal after frequency conversion, represents a time sequence, represents an imaginary unit.

[0039] S302, performing low-pass filtering on the multi-path array signal after frequency conversion to obtain at least one target array signal corresponding to at least one target frequency value.

[0040] The target array signal is the baseband signal in each of the multi-path array signals after frequency conversion.

[0041] For example, respectively taking each target frequency value as a center frequency of a DDC module of the FPGA, performing frequency conversion processing on the multi-path array signal to obtain a multi-path array signal after frequency conversion. For example, assuming that the target frequency values of each of the array signals are , , , and performing DDC frequency conversion with the target frequency value as the center frequency, the frequencies of the three frequencies after frequency conversion in each of the array signals can be obtained as , , . The frequency of 0 is the baseband signal.

[0042] Then, performing low-pass filtering on the multi-path array signal after frequency conversion, retaining the baseband signal and removing other frequency signals, i.e., obtaining the target array signal corresponding to each target frequency value in the multi-path array signal after frequency conversion, which is used for subsequent DOA estimation. The parameters of the filtering processing are: the center frequency is 0, the stop band is 2 MHz, and the pass band is 1 MHz.

[0043] S40, performing DOA estimation on the at least one target array signal to obtain at least one DOA.

[0044] Optionally, the step S40 can specifically include:​​

[0045] S401, if the number of target array signals is less than or equal to two, performing direction of arrival estimation on each target array signal respectively to obtain a direction of arrival corresponding to each target array signal.

[0046] Exemplarily, when the number of target array signals is one or two, the target array signals can be respectively input into two multiple signal classification (MUSIC) modules for direction of arrival calculation, and a direction of arrival corresponding to each target array signal is output respectively.

[0047] S402, if the number of target array signals is greater than two, fusing the target array signals according to a preset rule to obtain a plurality of fused array signals; each fused array signal contains two target array signals, and at least two fused array signals contain a same target array signal; performing direction of arrival estimation on the plurality of fused array signals to obtain a direction of arrival corresponding to each fused array signal.

[0048] Optionally, in step S402, the plurality of target array signals are fused according to the preset rule to obtain the plurality of fused array signals, and specifically can include:

[0049] According to a preset fusion order, performing frequency spectrum shift on part of the plurality of target array signals, and fusing all adjacent two target array signals to obtain the plurality of fused array signals.

[0050] Among them, the two target array signals contained in the fused array signal are different in frequency, and the number of fused array signals is one less than the number of target array signals.

[0051] Exemplarily, if the number of target array signals is greater than two, for example, three, the target array signals are arranged according to a preset fusion order as target array signal 1 (corresponding to target frequency value f1), target array signal 2 (corresponding to target frequency value f2), and target array signal 3 (corresponding to target frequency value f3) respectively. .The preset fusion order can be flexibly set by those skilled in the art according to actual conditions, for example, according to the size order of the target frequency value, and the present embodiment does not limit this.

[0052] ​​In the process of fusing all adjacent two target array signals according to the preset fusion order, the two fused target array signals need to have different frequencies so as to facilitate subsequent MUSIC algorithm calculation, and therefore, before fusion, spectrum shifting needs to be performed on part of the target array signals in the plurality of target array signals. For example, taking the size order of the target frequency values as the preset fusion order, the signal of the intermediate frequency value (for example, target array signal 2) can be spectrum shifted, and then target array signal 1 and target array signal 2 are fused to obtain a fused array signal, and target array signal 2 and target array signal 3 are fused to obtain a fused array signal.

[0053] Here, the spectrum shifting frequency can be 5MHz.

[0054] Optionally, the implementation process of the MUSIC algorithm of the embodiment is as follows:

[0055] 1) Covariance matrix estimation of the target array signal:

[0056] Suppose that K target array signals are obtained , and the covariance matrix is calculated is expressed as:

[0057]

[0058] wherein, is the noise power estimation value, denotes the conjugate transpose, is the unit matrix, , denotes the th target array signal.

[0059] 2) Subspace decomposition: the eigenvalue decomposition IP pair generated by Visit HLS tool is subjected to eigenvalue decomposition to obtain:

[0060] ;

[0061] wherein, denotes the eigenvector of , and denotes the eigenvalue sequence of .

[0062] The eigenvalues are arranged in descending order as: , and the corresponding eigenvectors are , , . Since the number of target frequency values (i.e., the number of targets) has been determined in step S20, based on the eigenvalues​ the number of sorted target frequency values partitioning a signal subspace and a noise subspace, wherein the signal subspace is composed of eigenvectors corresponding to the first the noise subspace is composed of eigenvectors corresponding to the last ; wherein is the number of array elements.

[0063] Here, the number of targets has been determined by step S20 in the embodiment, and in the prior art, the number of targets needs to be estimated using the minimum description length (MDL) criterion, which is relatively complex to implement on an FPGA and requires a large amount of resources. It can be seen that the embodiment greatly reduces the consumption of FPGA resources.

[0064] 3) Spatial spectrum construction: use FPGA to construct the MUSIC spatial spectrum function , which is represented as:

[0065]

[0066] wherein, is the steering vector of the target radar array at the angle , and represents the vector length.

[0067] 4) Spectrum peak search and DOA extraction: scan within the preset signal incident angle range according to a preset step size, detect the local maximum value of the spatial spectrum, and select the angle corresponding to the first highest spectrum peak as the incoming wave direction estimation value of the target array signal, i.e., the DOA corresponding to each target array signal.

[0068] Since the MUSIC algorithm has high computational complexity and long computation time, in the embodiment, all adjacent two target array signals are fused to obtain multiple fused array signals, and the DOA of the multiple fused array signals is estimated, so that the data amount of the MUSIC algorithm operation can be reduced, the operation speed can be improved, and the real-time performance can be improved.

[0069] S50, determining the correspondence between the target frequency value and the DOA according to at least one target frequency value and at least one DOA.

[0070] Optionally, step S50 can specifically include:

[0071] ​​If multiple fusion array signal corresponding wave direction angle is obtained. Wherein, each fusion array signal corresponding to the wave direction angle of the two target array signals contained, and the wave direction angle corresponding to the same target array signal is equal.

[0072] According to the preset fusion order, the target frequency value corresponding to the two target array signals contained in all fusion array signals and the wave direction angle corresponding to all fusion array signals, the correspondence between the target frequency value and the wave direction angle is determined.

[0073] Exemplarily, in the order of the preset fusion order, the target array signal 1 (corresponding to the target frequency value ), the target array signal 2 (corresponding to the target frequency value ) and the target array signal 3 (corresponding to the target frequency value ) are arranged, the target array signal 1 and the target array signal 2 are fused to obtain the fusion array signal 1, the target array signal 2 and the target array signal 3 are fused to obtain the fusion array signal 2, and the fusion array signal 1 and the fusion array signal 2 are input into the DOA estimation module 1 and the DOA estimation module 2 respectively for calculation, and the wave direction angle 1 of the target array signal 1 and the wave direction angle 2 of the target array signal 2 contained in the fusion array signal 1, and the wave direction angle 2 of the target array signal 2 and the wave direction angle 3 of the target array signal 3 contained in the fusion array signal 2 are output, then two same wave direction angle 2 corresponding to the target array signal 2 can be determined, and then based on the target frequency value of the target array signal 2, the correspondence between the wave direction angle 2 of the target array signal 2 and the target frequency value can be determined; further, according to the target array signal contained in the fusion array signal 1 and the fusion array signal 2, the correspondence between the wave direction angle 1 of the target array signal 1 and the target frequency value , and the correspondence between the wave direction angle 3 of the target array signal 3 and the target frequency value can be determined respectively.

[0074] The array signal space-frequency information fusion processing method based on frequency guidance provided by the embodiment has the following advantages compared with the prior art: (1) single cycle data processing clock period <1ms, compared with the traditional space-frequency fusion method, the real-time performance is greatly improved. (2) after frequency measurement using single channel signal, the multiple array signals are filtered and processed for wave direction angle estimation, and subsequent frequency retrieval is not required, the resource utilization rate is higher than that of the traditional method. The method of the embodiment can effectively improve the real-time performance and accuracy of target detection in a multi-target environment.

[0075] The array signal space-frequency information fusion processing method based on frequency guidance provided by the embodiment has the following advantages compared with the prior art: (1) single cycle data processing clock period <1ms, compared with the traditional space-frequency fusion method, the real-time performance is greatly improved. (2) after frequency measurement using single channel signal, the multiple array signals are filtered and processed for wave direction angle estimation, and subsequent frequency retrieval is not required, the resource utilization rate is higher than that of the traditional method. The method of the embodiment can effectively improve the real-time performance and accuracy of target detection in a multi-target environment.

[0076] The simulation linear array radar array used in the embodiment has 8 array elements, a carrier frequency of 300MHz, an array element spacing of half the signal wavelength, and 1000 points.

[0077] Figure 3A The MUSIC direction of arrival estimation result before frequency conversion filtering in the simulation shows that the three measured directions of arrival are-10°, 30° and 35°.

[0078] Figure 3B The result of fusing the low-pass filtering result after converting 46MHz to the baseband and the low-pass filtering result after converting 20MHz to the baseband and then performing the MUSIC direction of arrival estimation shows that the measured angles are-10° and 30°.

[0079] Figure 3C The result of fusing the low-pass filtering result after converting 37MHz to the baseband and the low-pass filtering result after converting 20MHz to the baseband and then performing the MUSIC direction of arrival estimation shows that the measured angles are 35° and 30°.

[0080] The above two direction of arrival estimation results can determine that the 30° direction of arrival corresponds to 46MHz, the-10° direction of arrival corresponds to 20MHz, and the 35° direction of arrival corresponds to 37MHz.

[0081] Corresponding to the array signal space-frequency information fusion processing method based on frequency guidance, the embodiment of the application further provides an array signal space-frequency information fusion processing device based on frequency guidance. Figure 4 As shown in the figure, the device can include:

[0082] The acquisition module 401 is configured to acquire a plurality of array signals received by a target radar array for target detection.

[0083] The frequency detection module 402 is configured to perform frequency detection on any one of the plurality of array signals to obtain at least one target frequency value.

[0084] The frequency conversion filtering module 403 is configured to perform frequency conversion filtering on the plurality of array signals according to the at least one target frequency value to obtain at least one target array signal corresponding to the at least one target frequency value.

[0085] The direction of arrival estimation module 404 is configured to perform direction of arrival estimation on the at least one target array signal to obtain a direction of arrival corresponding to the at least one target array signal.

[0086] The fusion module 405 is configured to determine the correspondence between the target frequency value and the direction of arrival according to the at least one target frequency value and the direction of arrival corresponding to the at least one target array signal.

[0087] The specific content of the device can be seen from the steps of the frequency-guided array signal space-frequency information fusion processing method provided in the first aspect, and will not be repeated here.

[0088] The frequency-guided array signal space-frequency information fusion processing device provided in the present application has the following advantages compared with the prior art: (1) the single-cycle data processing clock period is <1ms, and the real-time performance is greatly improved compared with the traditional space-frequency fusion method; (2) the frequency is measured using a single-channel signal, and then the multi-channel array signal is filtered and processed for direction of arrival estimation, and subsequent frequency retrieval is not required, and the resource utilization rate is higher than that of the traditional method. The device of the embodiment can effectively improve the real-time performance and accuracy of target detection in a multi-target environment.

[0089] It should be noted that, for the device, since it is basically similar to the method embodiment, the description is relatively simple, and the related parts can be seen from the part of the method embodiment.

[0090] It should be noted that the terms "first", "second", and the like are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application.

[0091] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present application.

[0092] Although the present application has been described in connection with certain embodiments, persons skilled in the art will understand and appreciate that many modifications can be made to the described embodiments and these modifications can be made without departing from the scope of the application in its broader aspects. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality, and the

[0093] The above description is further detailed in connection with specific preferred embodiments of the application, and it is not to be construed that the specific implementation of the application is limited to these descriptions. For those skilled in the art, without departing from the concept of the application, a number of simple deductions or substitutions can be made, and all of these should be considered as falling within the scope of protection of the application.

Claims

1. A frequency direction-based array signal space-frequency information fusion processing method, characterized in that, The method applied to a field programmable gate array (FPGA) comprises the following steps: acquiring a plurality of array signals received by a target radar array for target detection; performing frequency detection on any one of the plurality of array signals to obtain at least one target frequency value; performing frequency conversion filtering on the plurality of array signals according to the at least one target frequency value to obtain at least one target array signal corresponding to the at least one target frequency value; if the number of target array signals is less than or equal to two, performing angle of arrival estimation on each target array signal to obtain an angle of arrival corresponding to each target array signal; if the number of target array signals is greater than two, fusing a plurality of target array signals according to a preset rule to obtain a plurality of fused array signals; each fused array signal contains two target array signals, and at least two fused array signals contain the same target array signal; performing angle of arrival estimation on the plurality of fused array signals to obtain an angle of arrival corresponding to each fused array signal; if the angles of arrival of the two target array signals corresponding to each fused array signal are equal, determining a corresponding relationship between a target frequency value and an angle of arrival according to a preset fusion order, the target frequency values of the two target array signals contained in all fused array signals, and the angles of arrival corresponding to all fused array signals.

2. The method of claim 1, wherein, The fusing of the plurality of target array signals according to the preset rule to obtain the plurality of fused array signals comprises the following steps: performing frequency spectrum shift on part of the plurality of target array signals according to a preset fusion order, and fusing all adjacent two target array signals to obtain a plurality of fused array signals; the two target array signals contained in each fused array signal have different frequencies, and the difference between the number of fused array signals and the number of target array signals is one.

3. The method of claim 1, wherein, The frequency detection on any one of the plurality of array signals to obtain at least one target frequency value comprises the following steps: performing windowing processing on any one of the plurality of array signals, and then performing fast Fourier transform to obtain frequency spectrum data; performing multiple rounds of maximum retention processing on the frequency spectrum data to obtain maximum retention frequency spectrum; determining at least one target frequency value from the maximum retention frequency spectrum.

4. The method of claim 1, wherein, The frequency conversion filtering on the plurality of array signals according to the at least one target frequency value to obtain at least one target array signal corresponding to the at least one target frequency value comprises the following steps: taking each target frequency value as a center frequency of a digital down conversion (DDC) module of the FPGA to perform frequency conversion processing on the plurality of array signals to obtain a plurality of frequency-converted array signals; each frequency-converted array signal contains a baseband signal; performing low-pass filtering on the plurality of frequency-converted array signals to obtain at least one target array signal corresponding to the at least one target frequency value, wherein the target array signal is the baseband signal in each frequency-converted array signal.

5. The method of claim 4, wherein, The frequency conversion processing formula of the DDC module is represented as ； wherein, represents a multi-channel array signal, represents a first target frequency value, represents a multi-channel array signal after frequency conversion, represents a time series, represents an imaginary unit.

6. The method of claim 1, wherein, The target radar array is a uniform linear array.

7. A frequency direction based array signal space-frequency information fusion processing device, characterized in that, The device is applied to a field programmable gate array (FPGA) and comprises: an acquisition module configured to acquire a plurality of array signals received by a target radar array for target detection; a frequency detection module configured to perform frequency detection on any one of the plurality of array signals to obtain at least one target frequency value; a frequency conversion filtering module configured to perform frequency conversion filtering on the plurality of array signals according to the at least one target frequency value to obtain at least one target array signal corresponding to the at least one target frequency value; a direction of arrival estimation module configured to, if the number of target array signals is less than or equal to two, perform direction of arrival estimation on each target array signal to obtain a direction of arrival corresponding to each target array signal; if the number of target array signals is greater than two, fuse a plurality of target array signals according to a preset rule to obtain a plurality of fused array signals, wherein each fused array signal contains two target array signals, and at least two fused array signals contain a same target array signal; and perform direction of arrival estimation on the plurality of fused array signals to obtain a direction of arrival corresponding to the plurality of fused array signals; a fusion module configured to, if the directions of arrival corresponding to the plurality of fused array signals are obtained, wherein the directions of arrival of the two target array signals contained in each fused array signal are equal, and the directions of arrival corresponding to a same target array signal are equal; determine a correspondence between a target frequency value and a direction of arrival according to a preset fusion order, target frequency values corresponding to the two target array signals contained in all fused array signals, and the directions of arrival corresponding to all fused array signals.

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